JP5391899B2 - Digital signal multiplexing method and digital signal multiplexing apparatus - Google Patents

Description

  The present invention relates to a digital signal multiplexing method and a digital signal multiplexing apparatus for multiplexing a plurality of encoding-type digital signals and transmitting them through a fixed-band transmission line.

  In recent years, switching from analog signals to digital signals, such as television broadcast radio waves, has been rapidly progressing. In such broadcast radio wave transmission facilities, a plurality of digital signals such as audio (voice) signals and video (video) signals are encoded (compressed) and multiplexed while being synchronized, and the usable bandwidth is fixed. Transmit through a transmission line (fixed band transmission line).

  In this way, when encoding and multiplexing a plurality of digital signals, as shown in FIG. 9, an integrated control unit 12 that comprehensively controls the plurality of encoding units 10a, 10b, and 10c is provided, and integrated control is performed. The unit 12 monitors the encoding complexity and the information amount that change every moment in each of the encoding units 10a, 10b, and 10c. Then, the integrated control unit 12 assigns resources (information amount permitting output, etc.) according to the complexity and information amount of the digital signals input to the respective encoding units 10a, 10b, and 10c, and the total amount is a transmission path. Are allocated to the individual encoding units 10a, 10b, and 10c within a range not exceeding the bandwidth (statistical multiplexing method).

  Further, when the multiplexing control unit corresponding to the integrated control unit reads the encoded data from the buffer of each encoding unit (channel), the setting of the encoding unit is set according to the data amount of the encoded data of each encoding unit. A technique for distributing a surplus bandwidth with respect to a rate to reading of encoding from a buffer of another encoding unit is disclosed (for example, Patent Document 1).

JP 11-252555 A

  By using the technique of Patent Document 1 described above and other statistical multiplexing methods, it is possible to level the quality deterioration of the data accompanying encoding between the encoding units (channels), and the transmission efficiency of the encoded data Can be improved.

  However, when digital signals that cannot be simply compared in complexity and quality, such as the audio signal and video signal described above, are multiplexed, control for allocating the resource allocation amount for each encoding unit is complicated. Thus, the processing load of the integrated control unit increases.

  Further, for example, as represented by MPEG (Moving Picture Experts Group) -2, which is a video signal encoding method, the input order of digital signals input to the encoding unit and the output after encoding. When the output order is different, the control for distributing resources to a digital signal (video signal) of such an encoding system and a digital signal (audio signal) of another encoding system becomes more complicated. The integrated control unit must perform the above-described resource allocation after performing such a complicated calculation, and the processing load on the integrated control unit is significantly increased.

  Therefore, the bandwidth allowed for the fixed-band transmission path is fixedly distributed in advance according to the processing capability of each encoding unit, and each encoding unit is encoded only within the distributed band. It is possible. In such a configuration, there is an advantage that the processing load of the integrated control unit can be reduced because each encoding unit operates independently, but the actual encoded data amount in each encoding unit is less than the upper limit encoded data amount In addition, a surplus area that is not used at all occurs, resulting in a decrease in transmission efficiency.

  In view of such a problem, the present invention relies on the integrated control unit even when a plurality of types of digital signals are encoded and transmitted by simply adding a simple configuration to each independent encoding unit. It is an object of the present invention to provide a digital signal multiplexing method and a digital signal multiplexing apparatus capable of appropriately allocating resources and improving transmission efficiency and improving the overall quality of encoded data.

In order to solve the above problems, a digital signal multiplexing method according to the present invention includes a digital signal multiplexing apparatus in which a first encoding unit, a second encoding unit, and a multiplexing unit are connected to each other. A digital signal multiplexing method using and multiplexing a digital signal, wherein the first encoding unit encodes the first digital signal and assigns a first allocated encoded data amount allocated to the first encoding unit; Generating surplus information indicating a surplus data amount corresponding to a difference from an actual encoded data amount in the first encoding unit and a first encoding timing which is time information indicating a time when the surplus data amount occurs; The surplus information is transmitted to the second encoding unit, and the second encoding unit is an extension corresponding to the sum of the surplus data amount and the second allocated encoded data amount allocated to the second encoding unit. If the second digital signal is encoded using the data amount as the additional allocation information amount, and a part or all of the surplus data amount cannot be consumed by encoding the second digital signal, the unconsumed data that is the amount of data that cannot be consumed Generating unconsumed information indicating the amount and the first encoding timing, transmitting the unconsumed information to the first encoding unit, transmitting the encoded second digital signal to the multiplexing unit, The encoding unit adds dummy data corresponding to the unconsumed data amount of the unconsumed information received from the second encoding unit to the first digital signal encoded at the first encoding timing indicated by the unconsumed information. Then, the first digital signal to which the dummy data is added is transmitted to the multiplexing unit, and the multiplexing unit transmits the first digital signal transmitted by the first encoding unit and the second encoding unit. A second digital signal by multiplexing the, the first digital signal and second digital signal obtained by multiplexing, and transmits to the outside through the fixed band transmission path.

  In the digital signal multiplexing method of the present invention, resources are allocated by each individual encoding unit as a subject. That is, the first encoding unit is the main body, and the amount of surplus data in its own encoding is given to the second encoding unit, and the second encoding unit encodes the value obtained by adding the excess data as an upper limit. Carry out Further, the second encoding unit rearranges the unconsumed data amount that could not be consumed by itself in the first encoding unit. In such a digital signal multiplexing method, the complicated control process of resource reallocation by the integrated control unit is not involved, the transmission efficiency is improved with a simple configuration of only transmission between individual encoding units, and the encoded data is The overall quality can be improved.

In order to solve the above problems, another digital signal multiplexing method of the present invention is a digital signal multiplexing method in which a first encoding unit, a second encoding unit, and a multiplexing unit are connected to each other. A digital signal multiplexing method for multiplexing digital signals using an apparatus, wherein a first encoding unit encodes a first digital signal and is assigned to a first encoding unit. Surplus information indicating a surplus data amount corresponding to the difference between the amount and the actual encoded data amount in the first encoding unit, and first encoding timing which is time information indicating a time when the surplus data amount occurs. Generating and transmitting surplus information to the second encoding unit, which corresponds to the sum of the surplus data amount and the second allocated encoded data amount allocated to the second encoding unit. If the second digital signal is encoded using the extension data amount as the additional allocation information amount, and a part or all of the surplus data amount cannot be consumed by encoding the second digital signal, the unconsumed data that is the amount of data that cannot be consumed Generating unconsumed information indicating the amount and the first encoding timing, transmitting the unconsumed information to the multiplexing unit, transmitting the encoded second digital signal to the multiplexing unit, The dummy data corresponding to the unconsumed data amount of the unconsumed information received from the second encoding unit is generated at a timing corresponding to the first encoding timing indicated by the unconsumed information, and the dummy data and the first encoding are generated. The first digital signal transmitted by the unit and the second digital signal transmitted by the second encoding unit are multiplexed and multiplexed dummy data, the first digital signal, and The second digital signal, and transmits to the outside through the fixed band transmission path.

  In the digital signal multiplexing method of the present invention, the first encoding unit is the main body, and the surplus data amount in its own encoding is given to the second encoding unit, and the second encoding unit is the surplus data portion. Encoding is performed using the value obtained by adding as the upper limit. Also, the second encoding unit in the present invention transmits the unconsumed data amount that cannot be consumed by itself to the multiplexing unit, and the multiplexing unit generates dummy data corresponding to the unconsumed data amount as the surplus data area. To do. In such a digital signal multiplexing method, as in the above-described invention, transmission is performed with a simple configuration of only transmission between individual encoding units and multiplexing units without complicated control processing of resource reallocation by the integrated control unit. Efficiency can be improved and the overall quality of the encoded data can be improved.

In order to solve the above problems, a digital signal multiplexing apparatus according to the present invention is a digital signal multiplexing apparatus in which a first encoding unit, a second encoding unit, and a multiplexing unit are connected to each other. The first encoding unit includes a first encoding unit that encodes the first digital signal with the first allocation encoded data amount as an upper limit, and a first allocation encoded data amount and the first encoding unit. Generating surplus information indicating a surplus data amount corresponding to a difference from the actual encoded data amount, and first encoding timing that is time information indicating a time when the surplus data amount occurs, and generating a second encoding unit When the surplus data amount received by the second encoding unit and the encoding in the second encoding unit cannot consume part or all of the surplus data amount, the unconsumed data amount that cannot be consumed The dummy data corresponding to the unconsumed data amount of the unconsumed information indicating the data amount and the first encoding timing is added to the first digital signal encoded at the first encoding timing indicated by the unconsumed information And a signal generator that transmits to the multiplexing unit, and the second encoding unit is allocated to the second encoding unit and the excess data amount indicated in the excess information received from the first encoding unit. A second encoding unit that encodes the second digital signal and transmits it to the multiplexing unit, and generates unconsumed information, with the extended data amount corresponding to the sum of the second allocation encoded data amount as the additional allocation information amount And a non-consumption generation unit that transmits to the first encoding unit, and the multiplexing unit includes a first digital signal transmitted by the first encoding unit and a second digital signal transmitted by the second encoding unit. With digital signals A multiplexing processing unit for duplicating the first digital signal and second digital signals multiplexed, characterized in that it comprises a multiplexing transmission unit for transmitting to the outside through the fixed band transmission path.

In order to solve the above problems, another digital signal multiplexing apparatus according to the present invention is a digital signal multiplexing in which a first encoding unit, a second encoding unit, and a multiplexing unit are connected to each other. The first encoding unit includes a first encoding unit that encodes the first digital signal with the first allocation encoded data amount as an upper limit, and the first allocation encoded data amount and the first encoding. Generating surplus information indicating a surplus data amount corresponding to a difference from an actual encoded data amount in a section and a first encoding timing which is time information indicating a time when the surplus data amount occurs, and generating a second code A surplus generation unit that transmits to the encoding unit, and the second encoding unit includes a surplus data amount indicated in the surplus information received from the first encoding unit and a second allocation allocated to the second encoding unit. Encoded data amount and The extended data amount corresponding to the sum is used as the additional allocation information amount, the second digital signal is encoded and transmitted to the multiplexing unit, and the surplus data amount is reduced by the encoding of the second encoding unit. A non-consumption generation unit that generates non-consumption information indicating the amount of unconsumed data that is the amount of data that cannot be consumed and the first encoding timing, and transmits the non-consumption information to the multiplexing unit. The multiplexing unit includes a signal generation unit that generates dummy data corresponding to the amount of unconsumed data of the unconsumed information received from the second encoding unit, the dummy data, and the first data transmitted by the first encoding unit. A multiplexing processing unit that multiplexes the digital signal and the second digital signal transmitted by the second encoding unit in correspondence with the first encoding timing indicated by the unconsumed information, and the multiplexed dummy data; Data, the first digital signal and second digital signal, characterized in that it comprises a multiplexing transmission unit for transmitting to the outside through the fixed band transmission path.

  The components corresponding to the technical idea of the above-described digital signal multiplexing method and the description thereof can be applied to the digital signal multiplexing apparatus.

  One or both of the first encoding unit and the second encoding unit are present in plural, and the total amount of surplus data amount of one or more first encoding units is equal to one or more second encoding units. , May be distributed according to predetermined conditions. Further, the predetermined condition may be any of equal distribution, proportional distribution based on the second allocated encoded data amount, and proportional distribution based on the capacity of the buffer of the second encoding unit.

  Even when there are a plurality of first encoding units and second encoding units, the digital signal multiplexing apparatus of the present invention can perform resource calculation by simply distributing the total amount of surplus data according to a predetermined condition. Appropriate reassignment can be performed reliably.

  The encoding of the first digital signal is performed based on an audio lossless encoding method, and the encoding of the second digital signal is an MPEG-2, MPEG-4 / AVC, or Motion-JPEG code. It may be executed based on the conversion method.

  According to the digital signal multiplexing device of the present invention, the surplus data amount that accompanies fluctuations in the data amount after encoding, which is caused by using the audio lossless encoding method, is preferably consumed by other encoding units. Can do. In addition, when the second digital signal is a video signal and MPEG-2, MPEG-4 / AVC, or Motion-JPEG, in which quality degradation due to encoding is inevitable, is used as an encoding method. The surplus data amount generated in the encoding method can be suitably used for improving the image quality after encoding.

  In the present invention, even when a plurality of types of digital signals are encoded and multiplexed and transmitted simply by adding a simple configuration to each independent encoding unit, resources are appropriately allocated without depending on the integrated control unit, It is possible to increase the transmission efficiency and improve the overall quality of the encoded data.

It is the block diagram which showed the rough connection relation of the digital signal multiplexing system. It is a functional block diagram which shows the electric constitution of the digital signal multiplexing apparatus concerning 1st Embodiment. It is explanatory drawing which shows transition of the buffer storage amount of the virtual buffer in a video encoding unit. It is a flowchart which shows the flow of a process of the audio lossless encoding unit concerning 1st Embodiment. It is a flowchart which shows the flow of a process of the video encoding unit concerning 1st Embodiment. It is a sequence diagram which shows the flow of the whole process of the digital signal multiplexing apparatus concerning 1st Embodiment. It is a functional block diagram which shows the electric constitution of the digital signal multiplexing apparatus concerning 2nd Embodiment. It is a sequence diagram which shows the flow of the whole process of the digital signal multiplexing apparatus concerning 2nd Embodiment. It is the functional block diagram which showed the electrical structure of the conventional digital signal multiplexing apparatus.

  Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. The dimensions, materials, and other specific numerical values shown in the embodiment are merely examples for facilitating understanding of the invention, and do not limit the present invention unless otherwise specified. In the present specification and drawings, elements having substantially the same function and configuration are denoted by the same reference numerals, and redundant description is omitted, and elements not directly related to the present invention are not illustrated. To do.

(First embodiment: digital signal multiplexing system 100)
FIG. 1 is a block diagram showing a schematic connection relationship of the digital signal multiplexing system 100. As shown in FIG. 1, the digital signal multiplexing system 100 includes a digital signal multiplexing device 110, a broadcast antenna 120, a reception antenna 130, and a digital tuner built-in television 140.

  For example, when the program production staff records a program using the imaging device 114 and the microphone 116 in the studio of the television station 112, the recorded video (video signal) and sound (audio signal) are stored in an ADC (Analog Digital Converter) (not shown). It is converted into a digital signal and transmitted to the digital signal multiplexer 110 as a digital video signal and a digital audio signal.

  The digital signal multiplexer 110 multiplexes the digital video signal and the digital audio signal and broadcasts them through the broadcast antenna 120. The television 140 with a built-in digital tuner receives the broadcast digital signal via the receiving antenna 130, reconstructs video and audio from the received digital signal, and synchronizes the video and audio. Play audio.

  In such a digital signal multiplexing system 100, among the transmission paths from the digital signal multiplexing apparatus 110 to the digital tuner built-in television 140, the path from the broadcast antenna 120 to the receiving antenna 130 is particularly a usable frequency band of radio waves. Is strictly limited for each broadcasting station. Therefore, the data amount (transmission rate) per unit time that can be transmitted by the digital signal multiplexer 110 is a fixed value (fixed band transmission path).

  In such a fixed-band transmission line, when digital signals that cannot be simply compared in encoding complexity and quality, such as audio signals and video signals, are multiplexed, control for allocating the resource allocation amount for each encoding unit Becomes complicated, and the processing load of the integrated control unit increases.

  Therefore, it is conceivable that the bandwidth allowed for the fixed-band transmission path is allocated in advance according to the processing capability of each encoding unit, and each encoding unit is encoded only within the allocated band. When the actual encoded data amount in each encoding unit is less than the allocated encoded data amount, a surplus area that is not used at all is generated, resulting in a decrease in transmission efficiency.

  In the following embodiments, in the above-described multiplexing of digital television broadcast digital signals, resources are appropriately allocated without relying on an integrated control unit to increase transmission efficiency, and to improve the overall quality of encoded data. A digital signal multiplexing apparatus 110 and a digital signal multiplexing method that can be improved will be described.

(Digital signal multiplexer 110)
FIG. 2 is a functional block diagram showing an electrical configuration of the digital signal multiplexing apparatus 110 according to the first embodiment. The digital signal multiplexing apparatus 110 includes an audio lossless encoding unit 200 as a first encoding unit, a video encoding unit 202 as a second encoding unit, and a multiplexing unit 204. In the following embodiment, an example is given in which the digital signal multiplexing device 110 is used for digital television broadcasting. However, the present invention is not limited to this, and for example, video of a monitoring camera and audio of a microphone are multiplexed and transmitted / received. It can also be used for security systems.

  The audio lossless encoding unit 200 performs a lossless encoding process on the digital audio signal transmitted from the microphone 116 with the first allocated encoded data amount as an upper limit. Here, lossless encoding is an arithmetic lossless encoding in which data before encoding and data that has undergone encoding and decoding are completely equal, and compression is performed within a reversible range. .

  In the present embodiment, the first allocated encoded data amount is the upper limit value of the encoded data amount (data amount after encoding) allocated per block formed by a plurality of audio samples serving as encoding units. In general, it is obtained by multiplying the encoded data rate per second by the ratio of the block (number of samples per block / sampling frequency).

  In the lossless encoding process performed by the audio lossless encoding unit 200, the data amount after encoding may be substantially equal to the data amount before encoding when the compression rate is low. Therefore, when a fixed first allocation encoded data amount is set in the audio lossless encoding unit 200, it is necessary to specify an encoded data rate substantially equal to the pre-encoding data amount that is the worst value in order to guarantee lossless compression. is there.

  The video encoding unit 202 encodes the digital video signal transmitted from the imaging device 114 after adding the second allocation encoded data amount and updating the encoding upper limit information amount. Here, the second allocated encoded data amount is the encoded data amount allocated per block (one picture) in the same manner as the first allocated encoded data amount, and is generally encoded per second. It is derived by dividing the video picture rate (number of pictures per second) by the data rate. The encoding upper limit information amount will be described in detail later.

  In the present embodiment, the encoding method of the video encoding unit 202 uses the MPEG2-Video (MPEG-2) method, which is a video encoding method widely used in digital television broadcasting. However, the present invention is not limited to this, and various video encoding schemes such as AVC “MPEG-4 Part 10: Advanced-Video-Coding” (MPEG-4 / AVC), Motion-JPEG, and the like may be used.

  In the MPEG2-Video system or the like, the quantization value is adjusted on the premise of a fixed rate. Therefore, in a state where the surplus data processing of the present embodiment described later is not applied, the video encoding unit 202 to the multiplexing unit 204 are used. The average value of the transmission rates transmitted to the video encoding unit 202 is substantially equal to the encoded transmission rate assigned to the video encoding unit 202.

  In the encoding in the video encoding unit 202, the remaining encoded data amount is ensured by using a buffer, even if the allocated second allocated encoded data amount is not consumed and encoded. The amount of encoded data reserved according to the complexity of the digital video signal transmitted from the imaging device 114 can be used adaptively.

  However, the total buffer capacity is strictly limited by the encoding method together with the total buffer capacity on the decoding side, for example, the total buffer capacity of the video decoding unit built in the television 140 with built-in digital tuner. The control of the encoded data amount of the encoding unit 202 is limited to a range that does not exceed the total buffer capacity.

  In the present embodiment, the total buffer capacity of the video encoding unit 202 is the total buffer capacity held by the virtual buffer verifier used for code amount control in the processing amount control unit 256 (to be described later) of the video encoding unit 202. Is the same. A virtual buffer verifier is a conceptual buffer that is installed to ensure consistency in coding rate and buffer capacity for encoding in the video encoding unit 202 and decoding in the video decoding unit. is there.

  The multiplexing unit 204 multiplexes the digitally encoded signals (digital audio signal and digital video signal) received from the audio lossless encoding unit 200 and the video encoding unit 202 and transmits them through the broadcast antenna 120.

  In order not to exceed the transmission rate (fixed transmission rate A) of the fixed band transmission path for transmitting the multiplexed digital signal, the first upper limit transmission rate B (audio side) and the second upper limit transmission rate C (video side) ) Is set so as to satisfy the relational expression of A ≧ B + C.

  In addition, since the actual encoded data amount in the audio lossless encoding unit 200 described above is equal to or less than the first allocated encoded data amount, the first allocated encoded data amount and the actual encoded data in the first encoding unit. An unused area is generated in the fixed-band transmission line by an amount of surplus data corresponding to the difference from the amount. If such an unused area is left as it is, indefinite data will be mixed and this will cause a problem in decoding, or cause data loss. For example, data is assigned to the unused area.

  In this embodiment, instead of adding dummy data and transmitting it, another encoding unit (video encoding unit 202) adds and transmits significant data for the data area corresponding to the unused area. In this way, the unused area of the fixed band transmission path is effectively used. Hereinafter, specific configurations of the audio lossless encoding unit 200, the video encoding unit 202, and the multiplexing unit 204 that have such effects with a simple configuration will be described.

(Audio lossless encoding unit 200)
The audio lossless encoding unit 200 includes an audio frame memory 210, a prediction unit 212, a differential encoding unit 214, an audio entropy encoding unit 216, an audio ES (Elementary Stream) multiplexing unit 218, and an audio ES buffer 220. And a surplus generation unit 222. In the audio lossless encoding unit 200, the components related to the encoding of the digital audio signal function as a first encoding unit, and the audio ES multiplexing unit 218 functions as a signal generation unit.

  The audio frame memory 210 temporarily holds the digital audio signal transmitted from the microphone 116 in units of frames. The prediction unit 212 derives a prediction coefficient from the digital audio signal held in the audio frame memory 210 based on the continuity of the digital audio signal, that is, the property that the future value has a causal relationship with the past value, Predict future digital audio signals.

  The differential encoding unit 214 derives and encodes a residual signal that is a difference between the prediction signal of the prediction unit 212 and the actual digital audio signal.

  The audio entropy encoding unit 216 performs entropy encoding processing on the residual signal encoded by the differential encoding unit 214 to generate an entropy encoded signal. The entropy encoding process is an encoding process in which compression is performed by assigning a shorter code to frequently occurring data.

  The audio ES multiplexing unit 218 multiplexes the entropy encoded signal generated by the audio entropy encoding unit 216 and auxiliary information such as a prediction coefficient of the prediction unit 212 and transmits the multiplexed information to the multiplexing unit 204 described later as an audio ES signal. .

  The audio ES buffer 220 temporarily holds the audio ES signal generated by the audio ES multiplexing unit 218.

  The audio ES multiplexing unit 218 described above encodes the dummy data received from the video encoding unit 202 and corresponding to the amount of unconsumed data of unconsumed information described later at the first encoding timing indicated by the unconsumed information. To the audio ES signal.

  Therefore, when the surplus generation unit 222 described later transmits surplus information, the audio ES multiplexing unit 218 receives unconsumed information for the surplus information or times out after a predetermined time has passed without receiving the unconsumed information. Until then, the digital audio signal (audio ES) encoded at the first encoding timing is not transmitted to the multiplexing unit 204 but held in the audio ES buffer 220.

  The surplus generation unit 222 includes a surplus data amount corresponding to the difference between the first allocated encoded data amount allocated to the audio lossless encoding unit 200 and the actual encoded data amount, and the first code that has been encoded. The surplus information indicating the encoding timing is generated and transmitted to the video encoding unit 202.

  In the present embodiment, the first encoding timing is the timing at which the audio lossless encoding unit 200 has performed encoding, and is also the timing at which the surplus data amount has occurred. Further, the surplus data amount indicates the amount of data that is not consumed in the process of lossless encoding among the first assigned encoded data amount allocated to the audio lossless encoding unit 200.

(Video encoding unit 202)
The video encoding unit 202 includes a video frame memory 230, a DCT (Discrete Cosine Transform) 232, a quantization unit 234, an inverse quantization unit 236, an IDCT 238, an adder 240, a prediction memory 242, and motion detection. Unit 244, motion compensation unit 246, subtractor 248, video entropy encoding unit 250, video ES multiplexing unit 252, video ES buffer 254, processing amount control unit 256, and non-consumption generation unit 258 , Including. In the video encoding unit 202, a component related to encoding of the digital video signal functions as a second encoding unit.

  The video frame memory 230 temporarily holds the digital video signal transmitted from the imaging device 114 for each frame.

  The DCT 232 converts the digital video signal for each frame held in the video frame memory 230 into a frequency domain signal (discrete cosine transform). At this time, if the target frame is an I (original image) picture, the DCT 232 uses the image data of the target frame as it is. If the target frame is a P (forward prediction) picture or a B (bidirectional prediction) picture, the DCT 232 The difference value between the image and the reference image is converted into a frequency domain signal.

  Thereafter, the DCT 232 performs a zigzag scan process on each frame of the converted digital video signal to rearrange the low frequency components (DC components) in ascending order of frequencies, and collects high frequency components that have little influence on image quality even if omitted.

  The quantization unit 234 performs the surplus data amount indicated in the surplus information received from the audio lossless encoding unit 200 on the image of each frame of the digital video signal subjected to the zigzag scan process, and the video encoding unit 202. Quantization processing is performed in accordance with the code amount control of the processing amount control unit 256 described later, with the extended data amount corresponding to the sum of the second allocated encoded data amount allocated to the additional allocation information amount. In this embodiment, the quantization process is a compression process such as dividing by a predetermined coefficient and rounding to an integer value to remove a high-resolution component that is difficult to identify with human eyes. The additional allocation information amount will be described in detail later.

  The inverse quantization unit 236 multiplies the image of each frame after quantization by a predetermined coefficient used for division (inverse quantization). The IDCT 238 performs inverse discrete cosine transform on the dequantized image of each frame. The processing of the inverse quantization unit 236 and IDCT 238 is a simple decoding process called local decoding.

  The adder 240 transmits the I picture as it is to the prediction memory 242 out of the locally decoded frames. In addition, for the P picture and the B picture, among the predicted images generated by the motion compensation unit 246, which will be described later, the corresponding reference image is added to decode the original image and transmitted to the prediction memory 242.

  The prediction memory 242 temporarily holds the image of each frame transmitted from the adder 240. The motion detection unit 244 derives a motion vector (direction component and distance) between images of each frame transmitted from the video frame memory 230 and transmits the motion vector to the motion compensation unit 246. The motion compensation unit 246 creates a prediction image using the reference image and the motion vector in the prediction memory 242 and transmits the prediction image to the adder 240 and the subtracter 248.

  The subtractor 248 derives a difference between the original image in the video frame memory 230 and the predicted image transmitted from the motion compensation unit 246. The difference is compressed through the DCT 232 and the quantization unit 234 and transmitted through the multiplexing unit 204, as in the digital video signal described above.

  By using the configuration including the motion detection unit 244 and the motion compensation unit 246, the correlation between the images of each frame that moves back and forth in time is used to extract a moving object (part) and pay attention to the object before and after the image. A high compression ratio is realized by obtaining a motion vector from the difference between the two and encoding the difference between the predicted image generated using the motion vector and the original image.

  The video entropy encoding unit 250 performs entropy encoding processing on auxiliary information such as the difference between the image of each frame quantized by the quantization unit 234 and the original image and the predicted image.

  In this embodiment, the video entropy encoding unit 250 performs entropy encoding processing on auxiliary information such as the difference between the image of each frame quantized by the quantization unit 234 and the original image and the predicted image. And transmit to the video ES multiplexing unit 252.

  The video ES multiplexing unit 252 multiplexes the entropy encoded signal and various auxiliary information such as motion vectors to generate a video ES and transmits it to the video ES buffer 254 described later.

  The video ES buffer 254 temporarily holds the video ES transmitted from the video ES multiplexing unit 252.

  The processing amount control unit 256 needs to hold an additional allocation information amount that is an amount of encoded data allocated to the second encoding unit 202 for each frame, for example, when encoding images with different complexity levels. As a result, the amount of encoded data is controlled for each image in consideration of the attributes of I, P, and B so that the accumulated amount of the virtual buffer after encoding is kept substantially constant. Further, as described above, since the virtual buffer total capacity is strictly limited by the encoding method, the processing amount control unit 256 performs encoding so as not to exceed the upper limit capacity or less than the lower limit capacity. Control the amount of data.

  In the present embodiment, as described above in the description of the quantization unit 234, the processing amount control unit 256 outputs the surplus data amount indicated in the surplus information received from the audio lossless encoding unit 200 and the video encoding unit 202. The extension data amount corresponding to the sum of the allocated second allocation encoded data amount is set as the additional allocation information amount, and the code amount of the component functioning as the second encoding unit is controlled.

  When the video entropy encoding unit 250 cannot partially or completely consume the surplus data amount, the unconsumption generation unit 258 and the unconsumed data amount that cannot be consumed and the first encoding timing (excess data) The unconsumed information indicating the timing at which the amount is generated is generated and transmitted to the audio lossless encoding unit 200.

  FIG. 3 is an explanatory diagram showing the transition of the buffer accumulation amount of the virtual buffer in the video encoding unit 202. In particular, FIG. 3A shows the transition of the data capacity (buffer storage amount) stored in the virtual buffer of the video encoding unit 202 of this embodiment, and FIG. 3B shows this embodiment as a comparative example. The transition of the storage amount of the virtual buffer of the video encoding unit to which the surplus data processing is not applied is shown.

  In FIG. 3, the horizontal axis represents time, and the vertical axis represents buffer accumulation. As shown by a broken line in FIG. 3B, the buffer accumulation amount gradually increases with a constant increase amount with time, and when the encoded signal is generated at a timing corresponding to the moving image frame rate indicated by the alternate long and short dash line. It shows how the amount of data consumed decreases.

  Since the video encoding unit 202 of the present embodiment can increase the amount of encoded data by the amount of surplus data, the buffer storage amount is compared with that in FIG. 3B as shown in FIG. Compared to the example, it is increased by the solid arrow.

  Further, as indicated by a dotted arrow in FIG. 3A, since the amount exceeding the total capacity of the virtual buffer cannot be consumed, the amount of unconsumed data is obtained. Thus, the unconsumed data amount indicates the amount of data that cannot be consumed by the video encoding unit 202 out of the surplus data amount.

  The non-consumption generation unit 258 includes the unconsumed data amount in the non-consumption information and transmits it to the audio lossless encoding unit 200. The audio ES multiplexing unit 218 described above in the description of the audio lossless encoding unit 200 uses the non-consumption data. Dummy data corresponding to the data amount is inserted as stuffing data.

  In this embodiment, since the MPEG2-Video system is adopted, rearrangement of the I picture, P picture, and B picture occurs with respect to the digital video signal as described above. In addition, the digital video signal is processed based on a frame rate of 50 Hz or 60 Hz, but the digital audio signal does not always match this frame rate. Furthermore, even if the frame rates are the same, the encoding timings do not always match. For this reason, the time axes of the digital audio signal and the digital video signal processed in the same time zone do not necessarily match.

  As described above, even when processing is performed under a condition in which the time axes do not match, the audio lossless encoding unit 200 includes the first encoding timing in the surplus information, thereby consuming the surplus data amount. If the timing of the digital video signal (frame) to be performed is limited to a predetermined time range (for example, ± 60 msec) from the first encoding timing, it is possible to avoid an extreme difference between the generation of excessive data and the timing of consumption.

  Further, the processing amount control unit 256 accumulates the surplus data amount according to the difficulty level for each frame of the encoding of the digital video signal transmitted from the imaging device 114 and the accumulation amount of the virtual buffer. It may be consumed separately according to the timing. With this configuration, it is possible to level the quality degradation of data accompanying encoding between frames. In this case, the surplus data amount that cannot be consumed even when divided into a plurality of times becomes the unconsumed data amount.

  In addition, as described above, when the video encoding unit 202 does not consume the surplus data amount and transmits it to the audio lossless encoding unit 200 as the unconsumed data amount, the non-consumption generation unit 258 sets the first encoding timing. Include in unconsumed information. With this configuration, the audio lossless encoding unit 200 can reliably identify the digital audio signal at the timing when the surplus data amount occurs and add dummy data with reference to the first encoding timing. It is possible to avoid a situation where the position to be added is shifted and the transmission rate of the fixed band transmission path allocated to the television station 112 is exceeded.

  In the present embodiment, the first encoding timing and the second encoding timing indicated in the surplus information and the unconsumed information are provided by the audio lossless encoding unit 200 and the video encoding unit 202, respectively, which are not shown. It is indicated by a time stamp acquired at the timing of encoding from the same time generation unit, and at least a temporal position to which dummy data is added is specified. Further, the present invention is not limited to this case, and may be indicated by using a frame number or the like that is sequentially attached to the audio ES.

(Multiplexing unit 204)
The multiplexing unit 204 includes a multiplexing processing unit 270 and a multiplexing transmission unit 272. In addition, although the description is omitted for easy understanding, the multiplexing processing unit 270 includes a data broadcast encoded signal, transmission signal identification information, transmission error protection information, etc. in addition to the digital audio signal and the digital video signal. Also handle.

  The multiplexing processing unit 270 multiplexes the digital audio signal transmitted from the audio lossless encoding unit 200 and the digital video signal transmitted from the video encoding unit 202.

  The multiplexing transmission unit 272 transmits the multiplexed digital audio signal and digital video signal to the outside (broadcast antenna 120) through a fixed band transmission path.

  As described above, the digital signal multiplexing apparatus 110 according to the present embodiment adds the stuffing data to the position of the digital audio signal at the first encoding timing when the surplus data amount is generated, that is, the encoding is performed. Even in the multiplexing of a digital audio signal and a digital video signal that do not take frame synchronization, the same time management control mechanism as in the prior art can be applied as it is.

  In addition, the process of increasing the encoded data amount based on the surplus data amount is completed by adding dummy data corresponding to the unconsumed data amount by the audio lossless encoding unit 200. Even without adding a function, it is possible to maintain the transmission rate of the fixed-band transmission line and perform the multiplexing process.

  The processing amount control unit 256 of the present embodiment extends a conventional function of adjusting the amount of encoded data consumed by encoding according to the difficulty level of encoding, and adds a function that takes into account the amount of surplus data. With this configuration, while satisfying the above-described relational expression of the transmission rate of the fixed-band transmission path, the surplus data amount can be allocated to the necessary timing and necessary image encoding within the prescribed range of the total buffer capacity. Thus, it is possible to effectively use the unused area of the fixed band transmission path.

  The amount of unconsumed data described above is smaller than the amount of surplus data by the amount consumed by the video encoding unit 202. Therefore, even if dummy data corresponding to the amount of unconsumed data is added to the digital audio signal in the audio lossless encoding unit 200, the first upper limit transmission rate is not exceeded, and transmission after transmission through the fixed band transmission path The rate limit is not exceeded. Rather, dummy data having a data amount that takes into account the amount consumed by the video encoding unit 202 can be reliably added so as to match the transmission rate of the fixed-band transmission path.

  In the digital signal multiplexing apparatus 110 described above, the case where the digital audio signal and the digital video signal are multiplexed one by one has been described. However, multi-stream multiplexing is permitted in digital television broadcasting, and there are a plurality of first encoding units corresponding to the audio lossless encoding unit 200, such as one broadcast station broadcasting three programs simultaneously. Or there may be a plurality of second encoding units corresponding to the video encoding unit 202. Therefore, hereinafter, a digital signal multiplexing apparatus in which a plurality of first encoding units and second encoding units are arranged will be described.

  In the digital signal multiplexing apparatus, when one or both of the first encoding unit (audio lossless encoding unit 200) and the second encoding unit (video encoding unit 202) are present in plural, The total amount of surplus data of one or more first encoding units is distributed to the two encoding units according to a predetermined condition. Here, the predetermined condition is, for example, one of equal distribution, proportional distribution based on the second allocated encoded data amount, and proportional distribution based on the buffer capacity of the second encoding unit.

  Even in such a case, according to the digital signal multiplexing apparatus of the present embodiment, resources can be appropriately allocated without relying on the integrated control unit by simple calculation such as distributing the total amount of surplus data according to a predetermined condition. Allocation and transmission efficiency can be increased, and the overall quality of the encoded data can be improved.

  According to the digital signal multiplexing apparatus 110 described above, the video encoding unit 202 can suitably consume the surplus data amount that accompanies the fluctuation of the encoded data amount that is caused by using the audio lossless encoding method. . In addition, when the second digital signal is a video signal and MPEG-2, MPEG-4 / AVC, or Motion-JPEG, in which quality degradation due to encoding is inevitable, is used as an encoding method. The surplus data amount generated in the encoding method can be suitably used for improving the image quality after encoding. In the present embodiment, the multiplexing system is a standardized MPEG2 system. By using the MPEG2 system, the digital signal multiplexer 110 can be used for general purposes.

  Also, according to the digital signal multiplexing apparatus 110 of the present embodiment, each coding unit performs the resource allocation mainly. In other words, the audio lossless encoding unit 200 is mainly responsible for giving the video encoding unit 202 a surplus data amount in its own encoding, and the video encoding unit 202 uses the value obtained by adding the surplus data as an upper limit. Perform the encoding. In addition, the video encoding unit 202 rearranges the amount of unconsumed data that cannot be consumed by the video encoding unit 202 in the audio lossless encoding unit 200.

  With such a configuration, the existing control function provided in the processing amount control unit 256 of the video encoding unit 202 is effectively used without complicated control processing of resource reallocation by the integrated control unit, and individual encoding units With a simple configuration of only transmission in between, transmission efficiency can be improved and overall quality of encoded data can be improved.

  Further, in the digital signal multiplexing apparatus 110 according to the present embodiment, the surplus data amount generated in the audio lossless encoding unit 200 is directly received by the processing amount control unit 256 without using a buffer and consumed by the video entropy encoding unit 250. I am letting. Therefore, even when a video is encoded in the video encoding unit 202 immediately after the surplus data amount is generated in the audio lossless encoding unit 200, the processing amount control unit 256 immediately sets the surplus data amount. It can be consumed by the video entropy encoding unit 250 and can be encoded using the surplus data amount effectively.

  Next, a digital signal multiplexing method using the above-described digital signal multiplexing apparatus 110 will be described using a flowchart. The processing of the digital signal multiplexing method is repeatedly executed while the digital signal is transmitted to the digital signal multiplexing apparatus 110.

(Digital signal multiplexing method)
FIG. 4 is a flowchart showing a process flow of the audio lossless encoding unit 200 according to the first embodiment.

  The audio lossless encoding process is performed on the digital audio signal (S300), and surplus data that is the difference between the first allocation encoded data amount of the audio lossless encoding unit 200 and the actual encoded data amount of the audio lossless encoding unit 200 is obtained. It is determined whether the amount is 0 (zero) (S302). If the surplus data amount is 0 (YES in S302), an audio ES is generated and held (accumulated) in the audio ES buffer 220 (S304).

  If the surplus data amount is not 0 (NO in S302), surplus information indicating the surplus data amount and the first encoding timing at which encoding is performed is generated (S306) and transmitted to the video encoding unit 202 (S308). . Then, a video ES is generated from the encoded digital audio signal, and is stored in the audio ES buffer 220 in such a manner that it can be specified that it has been encoded at the first timing (S310).

  The audio lossless encoding unit 200 determines whether there is unconsumed information transmitted from the video encoding unit 202 (S312). If there is no unconsumed information (NO in S312), it is determined whether or not a predetermined time has elapsed from the first encoding timing (S314). If the predetermined time has not elapsed (NO in S314), the process returns to the non-consumed information presence / absence determination step (S312). If the predetermined time has elapsed (YES in S314), the already generated audio ES signal is output at a predetermined timing.

  If there is unconsumed information (YES in S312), the audio ES (encoded audio digital signal) corresponding to the first encoding timing of the unconsumed information is specified (S316), and the amount of unconsumed data in the audio ES Is assigned dummy data (S318).

  After the audio ES generation step (S304), after the dummy data provision step (S318), or when the predetermined time has elapsed in the predetermined time elapse determination step (S314) (YES in S314), the audio ES is multiplexed by the multiplexing unit 204. (S320).

  Next, the process flow of the video encoding unit 202 executed in parallel with the process of the audio lossless encoding unit 200 will be described.

  FIG. 5 is a flowchart showing a process flow of the video encoding unit 202 according to the first embodiment.

  The video encoding unit 202 determines whether there is surplus information transmitted from the audio lossless encoding unit 200 (S330). If there is surplus information (YES in S330), it is determined based on the buffer storage amount of the virtual buffer of the video encoding unit 202 whether or not the surplus data amount included in the surplus information can be consumed (S332). ).

  When a part or all of the surplus data amount included in the surplus information can be consumed (YES in S332), an extended data amount corresponding to the sum of the surplus data amount and the second allocated encoded data amount of the video encoding unit 202 is calculated. The digital video signal is encoded using the additional allocation information amount (S334).

  Then, the video encoding unit 202 determines whether or not the surplus data amount is consumed (without surplus) (S346). When the entire amount is not consumed, that is, when a part or all of the surplus data amount cannot be consumed in the encoding of the digital video signal (NO in S346), the unconsumed data amount that cannot be consumed and the first code Unconsumed information indicating the conversion timing is generated and transmitted to the audio lossless encoding unit 200 (S348).

  When there is no surplus information in the surplus information presence / absence determination step (NO in S330), or when the surplus data amount included in the surplus information cannot be consumed (NO in S332), the second allocated encoded data amount is used as the additional information amount. The digital video signal is encoded (S350).

  Then, when the entire amount is consumed in the surplus data amount consumption determination step (S346) (YES in S346), after the unconsumed information generation step (S348), or the encoding step with the second allocated encoded data amount (S350) ), The video encoding unit 202 transmits the encoded digital video signal to the multiplexing unit 204 (S352).

  The processes of the audio lossless encoding unit 200 and the video encoding unit 202 described with reference to FIGS. 4 and 5 are connected in the transmission of surplus information and unconsumed information. Such transmission and the subsequent audio lossless encoding unit Transmission / reception with 200, the video encoding unit 202, and the multiplexing unit 204 will be described with reference to FIG.

  FIG. 6 is a sequence diagram showing an overall processing flow of the digital signal multiplexing apparatus 110 according to the first embodiment.

  The audio lossless encoding unit 200 performs lossless encoding processing on the digital audio signal (S370), generates surplus information (S372), and transmits the surplus information to the video encoding unit 202 (S374).

  The video encoding unit 202 encodes the digital video signal as an additional allocation information amount in consideration of the extended data amount based on the surplus information (S376). Then, the video encoding unit 202 generates unconsumed information (S378), and transmits the unconsumed information to the audio lossless encoding unit 200 (S380).

  The audio lossless encoding unit 200 adds dummy data to the encoded digital audio signal (audio ES) based on the unconsumed information (S382), and transmits the audio ES to which the dummy data is added to the multiplexing unit 204. (S384).

  The video encoding unit 202 transmits the encoded digital video signal (video ES) to the multiplexing unit 204 (S386).

  The multiplexing unit 204 multiplexes the audio ES and video ES transmitted from the audio lossless encoding unit 200 and the video encoding unit 202 (S388), and transmits them to the outside (S390).

  As described above, by using the digital signal multiplexing method according to the present embodiment, a simple configuration of only transmission between individual coding units is possible without complicated control processing of resource reallocation by the integrated control unit. Therefore, it is possible to improve transmission efficiency and improve the overall quality of encoded data.

(Second Embodiment: Digital Signal Multiplexer 410)
In the first embodiment, the digital signal multiplexing apparatus 110 that returns the unconsumed data amount corresponding to the surplus data amount that could not be consumed by the video encoding unit 202 to the audio lossless encoding unit 200 has been described. In the second embodiment, a digital signal multiplexing apparatus will be described in which an unprocessed data amount is not returned to the audio lossless encoding unit 200, and the multiplexing unit 204 performs a process for compensating the unprocessed data amount. Note that components substantially the same as those of the digital signal multiplexing apparatus 110 described above are denoted by the same reference numerals and description thereof is omitted.

  FIG. 7 is a functional block diagram showing an electrical configuration of the digital signal multiplexing apparatus 410 according to the second embodiment. The digital signal multiplexing apparatus 410 includes an audio lossless encoding unit 200 as a first encoding unit, a video encoding unit 402 as a second encoding unit, and a multiplexing unit 404.

  Similarly to the first embodiment, the video encoding unit 402 encodes (compresses) the digital video signal transmitted from the imaging device 114 using the second allocation encoded data amount as the additional allocation information amount. Here, it is assumed that the video encoding unit 402 performs a fixed rate encoding process using the second assigned transmission rate as a target rate.

  In addition, the video encoding unit 402 includes a video frame memory 230, a DCT 232, a quantization unit 234, an inverse quantization unit 236, an IDCT 238, an adder 240, a prediction memory 242, a motion detection unit 244, A motion compensation unit 246, a subtractor 248, a video entropy encoding unit 250, a video ES multiplexing unit 252, a video ES buffer 254, a processing amount control unit 256, and an unconsumption generation unit 458 are included. Composed.

  The unconsumed generation unit 458 generates unconsumed information indicating the amount of unconsumed data corresponding to the amount of information that cannot be consumed in video encoding, and the first encoding timing.

  Then, the non-consumption generation unit 458 transmits the non-consumption information to the multiplexing unit 404 instead of the audio lossless encoding unit 200 unlike the first embodiment.

  The multiplexing unit 404 multiplexes the digital signals (digital audio signal and digital video signal) received from the audio lossless encoding unit 200 and the video encoding unit 402 and transmits them to the broadcast antenna 120, as in the first embodiment. .

  The multiplexing unit 404 includes a multiplexing processing unit 270, a signal generation unit 470, and a multiplexing transmission unit 472.

  The signal generation unit 470 generates dummy data corresponding to the unconsumed data amount of the unconsumed information received from the video encoding unit 402.

  The multiplexing processing unit 472 generates the dummy data generated by the signal generation unit 470, the digital audio signal transmitted by the audio lossless encoding unit 200, and the digital video signal transmitted by the video encoding unit 202, in particular dummy data. Are multiplexed in correspondence with the first encoding timing indicated by the unconsumed information. Such dummy data is handled as an adaptation field in MPEG-2 TS (Transport Stream).

  According to the digital signal multiplexing apparatus 410 of the present embodiment, each encoding unit is responsible for resource allocation. In addition, the video encoding unit 402 notifies the multiplexing unit of the amount of unconsumed data that cannot be consumed by itself, and the multiplexing unit generates dummy data corresponding to the amount of unconsumed data as a surplus data area. With this configuration, as in the first embodiment, the transmission efficiency is reduced with a simple configuration of only transmission between individual encoding units and multiplexing units without complicated control processing of resource reallocation by the integrated control unit. And the overall quality of the encoded data can be improved.

  Next, a digital signal multiplexing method using the above-described digital signal multiplexing apparatus 410 will be described using a flowchart.

(Digital signal multiplexing method)
FIG. 8 is a sequence diagram showing the overall processing flow of the digital signal multiplexing apparatus 410 according to the second embodiment. The processing from the audio digital signal encoding step (S370) to the unconsumed information generation step (S378) is substantially the same as the processing described with reference to FIG.

  The video encoding unit 402 transmits the generated unconsumed information to the multiplexing unit 404 (S580). The audio lossless encoding unit 200 transmits the audio ES to the multiplexing unit 204 (S384). The video encoding unit 402 transmits the encoded video signal (video ES) to the multiplexing unit 404 (S386).

  The multiplexing unit 404 generates dummy data corresponding to the unconsumed data amount of the unconsumed information received from the video encoding unit 402 (S582).

  Then, the multiplexing unit 404 multiplexes the dummy data, the digital audio signal, and the digital video signal transmitted by the video encoding unit 402 in correspondence with the first encoding timing indicated by the unconsumed information (S388). ) And transmitted to the outside (S390).

  As described above, according to the digital signal multiplexing method of the present embodiment, it is not necessary to perform complex control processing of resource reallocation by the integrated control unit, and only transmission between individual encoding units and multiplexing units is simplified. With a simple configuration, it is possible to improve transmission efficiency and improve the overall quality of encoded data.

  As mentioned above, although preferred embodiment of this invention was described referring an accompanying drawing, it cannot be overemphasized that this invention is not limited to this embodiment. It will be apparent to those skilled in the art that various changes and modifications can be made within the scope of the claims, and these are naturally within the technical scope of the present invention. Understood.

  Note that each step in the digital signal multiplexing method of the present specification does not necessarily have to be processed in time series in the order described in the flowcharts and sequence diagrams, and may include processing in parallel or by a subroutine.

  INDUSTRIAL APPLICABILITY The present invention can be used in a digital signal multiplexing method and a digital signal multiplexing apparatus that multiplex a plurality of encoding type digital signals and transmit them through a fixed band transmission line.

110, 410 ... digital signal multiplexer 200 ... audio lossless encoding unit (first encoding unit)
202, 402: Video encoding unit (second encoding unit)
204, 404 ... multiplexing unit 218 ... audio ES multiplexing unit (signal generation unit)
222 ... surplus generation units 258, 458 ... non-consumption generation unit 270 ... multiplexing processing unit 272 ... multiplexed transmission unit 470 ... signal generation unit

Claims (7)

A digital signal multiplexing method for multiplexing a digital signal using a digital signal multiplexer in which a first encoding unit, a second encoding unit, and a multiplexing unit are connected to each other,
The first encoding unit includes:
Encoding the first digital signal;
The surplus data amount corresponding to the difference between the first allocated encoded data amount allocated to the first encoding unit and the actual encoded data amount in the first encoding unit, and the time when the surplus data amount occurs And generating surplus information indicating first encoding timing that is time information indicating
Sending the surplus information to the second encoding unit;
The second encoding unit is
An extended data amount corresponding to the sum of the surplus data amount and the second assigned encoded data amount assigned to the second encoding unit is used as an additional assigned information amount, and a second digital signal is encoded,
When a part or all of the surplus data amount cannot be consumed by encoding the second digital signal, unconsumed information indicating the unconsumed data amount that is the amount of data that cannot be consumed and the first encoding timing is provided. Generate
Sending the unconsumed information to the first encoding unit;
Transmitting the encoded second digital signal to the multiplexing unit;
The first encoding unit includes:
Giving dummy data corresponding to the unconsumed data amount of the unconsumed information received from the second encoding unit to the first digital signal encoded at the first encoding timing indicated by the unconsumed information And
Transmitting the first digital signal to which the dummy data is added to the multiplexing unit;
The multiplexing unit is:
Multiplexing the first digital signal transmitted by the first encoding unit and the second digital signal transmitted by the second encoding unit;
A digital signal multiplexing method, wherein the multiplexed first digital signal and second digital signal are transmitted to the outside through a fixed band transmission path. A digital signal multiplexing method for multiplexing a digital signal using a digital signal multiplexer in which a first encoding unit, a second encoding unit, and a multiplexing unit are connected to each other,
The first encoding unit includes:
Encoding the first digital signal;
The surplus data amount corresponding to the difference between the first allocated encoded data amount allocated to the first encoding unit and the actual encoded data amount in the first encoding unit, and the time when the surplus data amount occurs And generating surplus information indicating first encoding timing that is time information indicating
Sending the surplus information to the second encoding unit;
The second encoding unit is
An extended data amount corresponding to the sum of the surplus data amount and the second assigned encoded data amount assigned to the second encoding unit is used as an additional assigned information amount, and a second digital signal is encoded,
When a part or all of the surplus data amount cannot be consumed by encoding the second digital signal, unconsumed information indicating the unconsumed data amount that is the amount of data that cannot be consumed and the first encoding timing is provided. Generate
Sending the unconsumed information to the multiplexing unit;
Transmitting the encoded second digital signal to the multiplexing unit;
The multiplexing unit is:
Generating dummy data corresponding to the unconsumed data amount of the unconsumed information received from the second encoding unit at a timing corresponding to the first encoding timing indicated by the unconsumed information;
Multiplexing the dummy data, the first digital signal transmitted by the first encoding unit, and the second digital signal transmitted by the second encoding unit;
A digital signal multiplexing method, wherein the multiplexed dummy data, the first digital signal, and the second digital signal are transmitted to the outside through a fixed band transmission path. A digital signal multiplexer in which a first encoding unit, a second encoding unit, and a multiplexing unit are connected to each other,
The first encoding unit includes:
A first encoding unit that encodes the first digital signal with the first allocated encoded data amount as an upper limit;
A first code that is time information indicating a surplus data amount corresponding to a difference between the first allocation encoded data amount and an actual encoded data amount in the first encoding unit, and a time when the surplus data amount occurs. A surplus generation unit that generates surplus information indicating the timing of transmission and transmits the surplus information to the second encoding unit;
An amount of unconsumed data received from the second encoding unit, which is the amount of data that cannot be consumed when the surplus data amount cannot be consumed in part or in whole by encoding in the second encoding unit; The dummy data corresponding to the unconsumed data amount of the unconsumed information indicating one encoding timing is added to the first digital signal encoded at the first encoding timing indicated by the nonconsumed information. A signal generator for transmitting to the multiplexing unit;
With
The second encoding unit is
Additional allocation information is added to the extended data amount corresponding to the sum of the surplus data amount indicated in the surplus information received from the first encoding unit and the second allocation encoded data amount allocated to the second encoding unit. A second encoder for encoding a second digital signal and transmitting it to the multiplexing unit;
An unconsumed generation unit that generates the unconsumed information and transmits the unconsumed information to the first encoding unit;
With
The multiplexing unit is:
A multiplexing processing unit that multiplexes the first digital signal transmitted by the first encoding unit and the second digital signal transmitted by the second encoding unit;
A multiplexed transmitter for transmitting the multiplexed first digital signal and the second digital signal to the outside through a fixed-band transmission path;
A digital signal multiplexing apparatus comprising: A digital signal multiplexer in which a first encoding unit, a second encoding unit, and a multiplexing unit are connected to each other,
The first encoding unit includes:
A first encoding unit that encodes the first digital signal with the first allocated encoded data amount as an upper limit;
A first code that is time information indicating a surplus data amount corresponding to a difference between the first allocation encoded data amount and an actual encoded data amount in the first encoding unit, and a time when the surplus data amount occurs. A surplus generation unit that generates surplus information indicating the timing of transmission and transmits the surplus information to the second encoding unit;
With
The second encoding unit is
Additional allocation information is added to the extended data amount corresponding to the sum of the surplus data amount indicated in the surplus information received from the first encoding unit and the second allocation encoded data amount allocated to the second encoding unit. A second encoder for encoding a second digital signal and transmitting it to the multiplexing unit;
If the surplus data amount cannot be consumed partly or entirely by the encoding of the second encoding unit, unconsumed information indicating the amount of unconsumed data that cannot be consumed and the first encoding timing An unconsumed generation unit that generates and transmits to the multiplexing unit;
With
The multiplexing unit is:
A signal generator that generates dummy data corresponding to an unconsumed data amount of the unconsumed information received from the second encoding unit;
The first code indicated by the unconsumed information includes the dummy data, the first digital signal transmitted by the first encoding unit, and the second digital signal transmitted by the second encoding unit. A multiplexing processing unit that multiplexes in accordance with the timing,
A multiplexed transmitter for transmitting the multiplexed dummy data, the first digital signal, and the second digital signal to the outside through a fixed-band transmission path;
A digital signal multiplexing apparatus comprising: There are a plurality of either one or both of the first encoding unit and the second encoding unit,
The total amount of surplus data amount of one or a plurality of the first encoding units is distributed to one or a plurality of the second encoding units according to a predetermined condition. Digital signal multiplexer.   The predetermined condition is any one of equal distribution, proportional distribution based on the second allocated encoded data amount, and proportional distribution based on a buffer capacity of the second encoding unit. Item 6. The digital signal multiplexing device according to Item 5. The encoding of the first digital signal is performed based on an audio lossless encoding scheme,
7. The encoding of the second digital signal is performed based on any one of MPEG-2, MPEG-4 / AVC, and Motion-JPEG encoding methods. 2. A digital signal multiplexing device according to item 1.

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