JP2009296501A - Multiplexing control apparatus and multiplexing control method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To reduce attribute data from being missed at a receiving side by surely multiplexing attribute data of encoded data. <P>SOLUTION: An attribute data multiplexing time setting section 215 performs setting in such a way as to generate an attribute data multiplexing time at least once for each multiplexing term of each frame on the basis of a system time during a predetermined period after a starting time point of a multiplexing term of each frame and a period excluding before and after the multiplexing term of each frame other than a predetermined period before an ending time point of the multiplexing term. A multiplexing section 216 multiplexes attribute data at one of a plurality of multiplexing times set by the attribute data multiplexing time setting section 215. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a multiplexing control device and a multiplexing control method for multiplexing encoded data such as video and audio and attribute data of the encoded data.

When multiplexing encoded data such as video and audio and its attribute data, the attribute data is important data for reproduction of the encoded data. There is a multiplexing control device (see, for example, Patent Document 1).
JP 2001-144711 A

  However, since the above-described multiplexing control device merely discloses multiplexing attribute data preferentially over encoded data, attribute data cannot be reliably encoded, or attribute data can be received on the receiving side. There was a problem that there was a risk of spilling.

  Therefore, an object of the present invention is to provide a multiplexing control device and a multiplexing control method that can reliably multiplex attribute data of encoded data and reduce the loss of attribute data on the receiving side.

In order to achieve the above object, a multiplexing control apparatus of the present invention is a multiplexing control apparatus that multiplexes encoded data comprising a plurality of frames and attribute data of the encoded data, wherein the encoded data An encoded data filling amount calculation unit for obtaining a sufficient amount of the encoded data virtual buffer based on the encoding rate of the encoded data, and an attribute data code for setting a magnification of the encoding rate of the attribute data with respect to the frame rate of the encoded data An encoding rate magnification setting unit, an attribute data full amount calculation unit for calculating a full amount of the attribute data virtual buffer based on the encoding rate magnification of the attribute data, a multiplexing time of the encoded data, and the attribute Excluding a predetermined period after the start time of each frame of the encoded data and a predetermined period before the end time based on the data encoding rate magnification An attribute data multiplexing time setting unit that sets a multiplexing time of the attribute data so that the attribute data is multiplexed in a period before and after each frame of the encoded data; and a multiplexing time of the encoded data And the attribute data multiplexing time, the encoded data virtual buffer filling amount, and the attribute data virtual buffer filling amount, in the exclusion period before and after each frame of the encoded data. A multiplexing control unit that controls multiplexing of the encoded data and the attribute data so that the data is multiplexed;
Here, the attribute data encoding rate magnification setting unit sets N (N is a natural number of 2 or more) times as a magnification of the encoding rate of the attribute data with respect to the encoding rate of the encoded data, and the attribute data The multiplexing time setting unit sets the exclusion period before and after each frame of the encoded data to (N−1) / (2N) of each frame of the encoded data so that the attribute data is multiplexed. You may make it set the multiplexing time of attribute data.
The multiplexing control method according to the present invention is a multiplexing control method for multiplexing encoded data composed of a plurality of frames and attribute data of the encoded data, wherein the encoding rate of the encoded data is adjusted. Based on the encoding data virtual buffer, a step of setting a ratio of the encoding rate of the attribute data to the encoding rate of the encoded data, and a ratio of the encoding rate of the attribute data. Based on the step of calculating the sufficiency of the attribute data virtual buffer, the multiplexing time of the encoded data, and the magnification of the encoding rate of the attribute data, the multiplexing of each frame of the encoded data The attribute data is multiplexed in the exclusion period before and after each frame of the encoded data excluding a predetermined period after the start time of the period and a predetermined period before the end time. A step of setting a multiplexing time of the attribute data, a multiplexing time of the encoded data, a multiplexing time of the attribute data, a sufficient amount of the encoded data virtual buffer, and the attribute Controlling the multiplexing of the encoded data and the attribute data so that the attribute data is multiplexed in the exclusion period before and after each frame of the encoded data based on the data virtual buffer fullness And having.

  In the present invention, the ratio of the encoding rate of the attribute data with respect to the encoding rate of the encoded data is set, and based on the ratio, the sufficient amount of the attribute data virtual buffer is calculated, and the multiplexed time of the encoded data and Based on the magnification of the encoding rate of the attribute data, set the multiplexing time of the attribute data, the multiplexing time of the encoding data, the multiplexing time of the attribute data, the sufficient amount of the encoded data virtual buffer, Since the multiplexing of the encoded data and the attribute data is controlled so that the attribute data is multiplexed in the exclusion period before and after each frame of the encoded data based on the fullness of the attribute data virtual buffer, the encoded data Attribute data can be reliably multiplexed, and the loss of attribute data on the receiving side can be reduced.

Embodiment 1. FIG.

  Hereinafter, as a first embodiment of the present invention, a description will be given of a multiplexing apparatus that multiplexes video encoded data and attribute data describing the encoding attribute of the video encoded data as an example. In the first embodiment, the video attribute data multiplexing time is based on the time information of the video encoding decoding time (DTS = Decoding Time Stamp) and presentation time (PTS = Presentation Time Stamp) included in the video encoded data. How to manage

  FIG. 1 is a block diagram showing an overall configuration diagram of a multiplexing apparatus according to Embodiment 1 of the present invention.

  In FIG. 1, the multiplexing apparatus includes an encoding control unit 101, a header generation unit 102, a video encoding unit 103, a video attribute data generation unit 104, an audio encoding unit 105, an audio attribute data generation unit 106, and a PSI data generation unit. 107, header data buffer 108, video encoded data buffer 109, video attribute data buffer 110, audio encoded data buffer 111, audio attribute data buffer 112, PSI data buffer 113, and multiplexing corresponding to the multiplexing control device of the present invention A control device 114, a multiplexing unit 115, and a stream buffer 116 are included.

  Next, the operation of the multiplexing apparatus shown in FIG. 1 will be described.

  The multiplexing control device 114 performs overall control of the multiplexing device in order to generate a transport stream (TS) that conforms to the MPEG system standard and similar system standards. The recording rate of this apparatus is set in consideration of conditions such as voice quality, remaining recording time, recording mode, and encoding rate. Next, all of the encoded stream such as video and audio encoded data, video data and audio data attribute data, and PSI (Program Specific Information) that configure the multiplexed stream based on the recording rate of this apparatus The recording rate of the data type is determined.

  The encoding control unit 101 controls the video encoding unit 103 and the audio encoding unit 105, controls the attribute data generation units 104 and 106 that describe the attributes of the encoded video and audio data, and the PSI data generation unit 107. Take control.

  The video encoding unit 103 is controlled so that video elementary encoding is performed for each video frame (29.97 Hz). Also, the generated video encoded data is sequentially written in the video encoded data buffer 109 in the ring buffer format. A video image in YUV format before being encoded is input to the video encoding unit 103 and compressed by an MPEG encoding method (MPEG2, H.264, etc.).

  Similarly, the audio encoding unit 105 performs audio elementary encoding for each audio frame, and the output audio encoded data is written into the audio encoded data buffer 112. PCM digital data obtained by A / D-converting microphone sound or line input sound is input to the sound encoding unit 105, and the sound is compressed by the MPEG encoding method (MP2, MP3).

  In this device, video attribute data describing display information such as video encoding coding type, PTS / DTS time information, frame rate, and image size is multiplexed with the video encoded data, thereby enabling random access during stream playback. Video attributes can be displayed for reasons such as enabling efficient editing operations because it is easier to search for change points of attributes when video streams are combined and streams with different attributes are combined and edited. Video attribute data is multiplexed into a transport stream (TS). The video attribute data generation unit 104 collects such attribute data relating to video encoding from the video encoding unit 103 or the encoding control unit 101, constructs the attribute data into packet data, and stores the packet data in the video attribute data buffer 110. .

  The audio attribute data includes information such as time information such as PTS, sampling period, and encoding bit rate. The voice attribute data generation unit 106 collects these pieces of information and writes them in the voice attribute data buffer 112.

  The PSI data generation unit 107 generates a PAT (Program Associatin Table), a PMT (Program MAP Table), and a PCR (Program Clock Reference) packet that are time information essential to the transport stream (TS), and stores them in the PSI data buffer 113. Write.

  When generating the 188-byte TS packet (TS) by dividing the video or audio encoded data that is the source data for multiplexing, the header generator 102 generates a TS header to be added to the head of the TS packet. Write to the header data buffer 108.

  The multiplexing unit 115 multiplexes video and audio encoded data and attribute data instructed to be multiplexed from the multiplexing control unit 114, which will be described later, by DMA transfer or the like. Control for adding a TS header is performed. In addition, the multiplexing unit 115 generates a TS packet by adding a TS header to the head of the packetized encoded data and attribute data, and sequentially writes the TS packet in the stream buffer 116.

  Then, the TS packet data accumulated in the stream buffer 116 is recorded on a recording medium as a file via a media I / F (not shown) or a file system manager (not shown), or a communication I / F. (Not shown) is transmitted or transmitted outside the apparatus as a multiplexed bit stream.

  FIG. 2 is a block diagram showing a detailed configuration of the multiplexing control device 114 of the first embodiment shown in FIG.

  2, the multiplexing control device 114 includes an encoded data rate calculation unit 201, an attribute data multiplexing rate magnification setting unit 202, an encoded data virtual buffer increase amount calculation unit 203, an attribute data virtual buffer increase amount calculation unit 204, System time generation unit 205, encoded data sufficiency calculating unit 206, attribute data sufficiency calculating unit 207, encoded data reading unit 208, multiplexing control unit 209, encoded data multiplexing time calculating unit 210, time and attribute information A storage unit 211, an attribute data multiplexing time calculation unit 212, and a VBV buffer model management unit 213 are included.

  The encoded data rate calculation unit 201 determines the recording rate of the TS stream, which is the recording rate of the apparatus, from the recording mode designated by the user or application, for example, the high image quality recording mode, the long time recording mode, etc. Are used to determine the encoding rate of all data to be multiplexed, such as video encoded data, audio encoded data, PSI data, video attribute data, audio attribute data, and PCR clock data.

  The encoded data virtual buffer increase amount calculation unit 203, based on the encoding rate of the video encoded data set by the encoded data rate calculation unit 201, the elapsed time of the system clock corresponding to 1 TS packet interval. The amount of increase in the virtual buffer of the encoded data accumulated in the virtual buffer (not shown) is calculated every time.

  The encoded data filling amount calculation unit 206 manages the buffer occupancy amount of the virtual buffer, and the filling amount in the virtual buffer increases by the increase amount calculated by the virtual buffer increase amount calculation unit 203 every system clock period corresponding to 1TP packet. However, when the sufficient amount reaches the size of the video virtual buffer, multiplexing of the video encoded data is executed and control is performed to reduce the virtual buffer occupancy by the size of the virtual buffer. is there.

  FIG. 3 is a diagram illustrating a transition of the buffer occupation amount of the virtual buffer.

  In the first embodiment, video encoded data is not stored in an actual memory and the memory occupation amount is not calculated, but as shown in FIG. A feature of multiplexing by the virtual buffer method is a method of repeatedly calculating that the amount of occupied packet is calculated and multiplexing the video encoded data corresponding to one packet when the virtual buffer is full.

  The attribute data multiplexing rate magnification setting unit 202 encodes the attribute data so as to generate the multiplexing time of the video attribute data at a rate higher than the frame rate of the encoded data with reference to the frame rate of the video encoded data. A magnification of a conversion rate (hereinafter, attribute encoding rate) is set.

  The attribute data virtual buffer increase amount calculation unit 204 calculates the increase amount of the attribute data virtual buffer every system clock period corresponding to one TP packet.

  The attribute data full amount calculation unit 207 manages increase / decrease in the buffer accumulation amount of the attribute data virtual buffer.

  The system time generation unit 205 manages increase or initialization of the system clock. In the MPEG system, a system time called PCR (Program Clock Reference) is defined, and the system clock increases with an accuracy of 27 MHz. PTS (Presentation Time Stamp) and DTS (Decoding Time Stamp), which are time information of encoded data of video and audio, are times obtained by converting the system clock to 90 kHz accuracy. Multiplexing time is also managed based on this system clock.

  For the sake of simplicity, FIG. 2 showing the detailed configuration of the multiplexing control device 114 shows only the configuration necessary for multiplexing management of video encoded data and video attribute data. Requires a virtual buffer increase amount calculation unit for voice encoded data, voice attribute data, PSI data, and PCR clock data, and a virtual buffer fullness calculation unit. Since the processing content of these arithmetic units is the same as that of the video encoded data, description thereof is omitted.

  The multiplexing control unit 209 collects the calculation results of the virtual buffer fullness calculation units 206 and 207 for both the video encoded data and the attribute data that operate independently of each other, and stores the data that the virtual buffer is full. This is detected and a multiplexing instruction is sent to the multiplexing unit 115 so as to multiplex the encoded data and the attribute data.

  The encoded data reading unit 208 reads encoded data of video and audio, acquires time information of PTS and DTS, and stores it in the time and attribute information storage unit 211.

  The encoded data multiplexing time calculation unit 210 obtains the multiplexing time of the video encoded data by, for example, the following equation (1).

Multiplex time of video encoded data (90KHz clock unit)
= DTS (PTS)-(VBV buffer occupancy / encoding rate) × 90000
... Formula (1)

Here, the VBV buffer (Video Buffering Verifier) is encoded video data defined by the MPEG2 standard.
The VBV buffer increases with a constant increase when the video recording rate is determined, but is modeled so that the data amount of one picture decreases from the VBV buffer each time video decoding is performed. For this reason, the multiplexing control device 114 also manages the occupation amount of the VBV buffer by modeling it. The VBV buffer model management unit 213 performs this. Note that the multiplexing time is determined using DTS time for Intra-Picture and Predictive-Picture, and PTS time for Bi-directional-Picture. A packet that does not have a DTS time, such as Bi-directional-Picture, is processed assuming that PTS = DTS. The above equation (1) is expressed in units of time counted by the 90 kHz clock of the system clock.

  The multiplexing control unit 209 compares the multiplexing time of the encoded data calculated by the above equation (1) with the current system time when the data to be multiplexed is set based on the full capacity of the virtual buffer. If the multiplexing time has reached the current time, the multiplexing of the data to be multiplexed is determined.

Here, two cases are assumed for the time of multiplexing the attribute data as shown in FIG. In FIG. 4 and FIG. 5, video encoded data and video attribute data are described as an example as encoded data and attribute data thereof.
In the first embodiment, the number of pictures constituting a GOP (Group Of Picture) is 15, the Intra-Picture interval is 15, and the Intra-Picture or Predictive-Pictute interval is 3. However, the present invention is not limited to this. Although an example in which only attribute data indicating attributes of Intra-Picture and Predictive-Picture is multiplexed will be described, the present invention is not limited to this.

  FIG. 4 shows a case where the attribute data multiplexing time is “video encoded data <video attribute data”, that is, the video attribute data multiplexing time is later than the video encoded data multiplexing time. It is explanatory drawing.

  In this case, the encoded data reading unit 208 reads the time information of PTS and DTS from the video encoded data stored in the video encoded data buffer 109, for example, attribute data at a time that is, for example, three frames earlier from the DTS time information. Therefore, if the multiplexing time of the attribute data is sufficiently later than the multiplexing time of the video encoded data, the encoded data reading unit 208 uses the DTS time information and If the attribute information such as the video coding coding type and the frame rate is accumulated in the time and attribute information storage unit 211, the time and attribute information storage unit 211 already stores the time each time the attribute data is multiplexed. Using the accumulated attribute data, the multiplexing time of the attribute data to be generated next can be calculated. . In the first embodiment, the time at which attribute data is multiplexed is described as (DTS-3 frame of video encoded data), but the present invention is not limited to this.

  The encoded data multiplexing time calculation unit 210 is called each time the encoded data is multiplexed, and the encoded data reading unit 208 obtains the DTS time of the video encoded data to be multiplexed next to obtain an expression. According to (1), the multiplexing time of the encoded data is calculated, and the multiplexing time of the encoded data is set in the multiplexing control unit 209.

  The attribute data multiplexing time calculation unit 212 uses the DTS time of the video encoded data referred to by the attribute data to be multiplexed next to determine the multiplexing time of the attribute data by the following equation (2), The time is set in the control unit 209.

Multiplex time of attribute data = (DTS-3 frame) +1/4 frame time (2)

  FIG. 5 illustrates the case where the attribute data multiplexing time is “video encoded data> video attribute data”, that is, the video attribute data multiplexing time is earlier than the video encoded data multiplexing time. FIG.

  In this case, since the video encoded data indicating the attribute data attribute has not been multiplexed at the attribute data multiplexing time, the time according to the method shown in FIG. 4 (in the case of video encoded data <attribute data) is reached. As a result, the PTS time information corresponding to the attribute information storage unit 211 is not stored. Therefore, the attribute data multiplexing time calculation unit 212 cannot multiplex attribute data at the expected time because the corresponding PTS information is not found even if the time information storage unit 211 is searched.

  Therefore, in preparation for such a case, the video encoded data buffer 109 controls to always store 4 frames or more in the video encoded data.

  In this case, the multiplexing unit 115 starts multiplexing after 4 frames of video encoded data are stored in the video encoded data buffer 109 at the start of recording. Since the multiplexing process is simpler than the video encoding process, the multiplexing process is completed in a short time. Therefore, even if the multiplexing of one frame of video is completed, the remaining accumulated video is not multiplexed, but waits until the video encoding is completed, and the video encoded data buffer 109 always has four frames of video code. Control is performed so as to maintain a state in which digitized data is accumulated. The stream multiplexed by the multiplexing unit 115 is transferred to the stream buffer 116.

  Here, the frame that is multiplexed first by the multiplexing unit 115 after starting recording is an Intra-Picture video frame having the minimum DTS of the encoded stream. Since this frame is a frame having a DTS, multiplexing of attribute data is also necessary. Therefore, at the same time, the multiplexing setting of the multiplexing of the video attribute is executed at the same time as the multiplexing setting of the first Intra-Picture. The attribute data multiplexing setting means setting the attribute data packet in the video attribute data buffer 110, calculating the attribute data multiplexing time, and setting the multiplexing time in the multiplexing control unit 209.

  FIG. 6 shows an example in which the generation times of the multiplexing times are plotted when the attribute data is multiplexed according to the conventional multiplexing control method.

  As shown in FIG. 6, conventionally, when attribute data is multiplexed at a rate of once every three frames, the frame position to be multiplexed has not been specified.

  On the other hand, in this embodiment, when the buffer accumulation amount of the multiplexed data by the virtual buffer is obtained by calculation, the encoding rate is not a perfect rate in calculation in order to always generate the multiplexing time twice in one video frame. , Use a slightly higher rate. By doing so, the opportunity of multiplexing is given at least twice per frame, but because the rate is slightly higher, the multiplexing time moves from the later time of one frame period to the earlier time for each multiplexing Will occur.

  In the present embodiment, the attribute data multiplexing time calculation unit 212 gives a multiplexing opportunity twice to one frame, and the time from the start time of the multiplexing period of the video frame to ¼ of the frame period. If the multiplexing time is invalid and control is performed so that a period after 1/4 of the frame period is determined to be valid, the attribute data multiplexing time occurs at least once in 1/4 to 3/4 of one frame period. I am doing so.

  If it is determined that the attribute data is to be multiplexed in the period from minus 3 frames to minus 2 frames from the DTS time described in the video encoded data, the conventional method is set to the first time of the video frame at a fixed period. Since a situation in which multiplexing occurs at the latest time of a video frame from a situation in which multiplexing occurs at a close time occurs, there are periodic cases where there is no margin from the specified time range. When the attribute data of the converted TS stream is received or played back, the time management of the data becomes severe, so that data is lost or the processing speed needs to be increased in order to eliminate the loss.

  On the other hand, in the case of this embodiment, as shown in FIG. 7, the encoded data virtual buffer increase amount calculation unit 203 calculates the increase amount of the encoded data virtual buffer based on the encoding rate of the encoded data. The encoded data sufficient amount calculation unit 206 calculates the full amount of the encoded data virtual buffer based on the increase amount, while the attribute data encoding rate magnification setting unit 202 determines the attribute data for the frame rate of the encoded data. The attribute data virtual buffer increase amount calculation unit 204 obtains the increase amount of the attribute data virtual buffer based on the magnification (in the case of FIG. 7, 2 times) and sets the attribute data sufficient amount. The computing unit 207 computes the sufficient amount of the attribute data virtual buffer based on the increase amount, and the multiplexing control unit 209 calculates the encoded data temporary data based on the system time. When the buffer fullness and the attribute data virtual buffer fullness reach the maximum value of each virtual buffer, the encoded data multiplexing time from the encoded data multiplexing time calculation unit 210 and the attribute data multiplexing time Based on the multiplexing time of the attribute data from the calculation unit 212, the multiplexing of the encoded data and the attribute data is controlled so that the attribute data is multiplexed in the exclusion period before and after each frame of the encoded data. Since at least one multiplexing time occurs in one-fourth to three-fourths of one frame period, it is a good result that the conventional problem does not occur.

  Next, a multiplexing processing procedure according to the first embodiment will be described with reference to a flowchart.

  FIG. 8 is a flowchart showing a multiplexing processing procedure according to the first embodiment.

  First, since the encoded data rate calculation unit 201 performs initialization for each functional block before starting multiplexing, a TS rate that is a recording rate of a transport stream (TS) from a specified recording mode is set. Then, the encoding rate of each encoded data is calculated (S801). For example, in the case of encoded data such as video code data having a different generated code amount for each picture, the maximum rate of each encoded data is calculated so that multiplexing is appropriately performed even if the maximum code amount occurs, Calculation is performed so that the sum of the maximum coding rates of the coded data does not exceed the TS rate.

Next, the encoded data virtual buffer increase amount calculation unit 203 and the attribute data multiplexing rate magnification setting unit 202 calculate the virtual buffer increase amount from the frame rate of the encoded data (S802). In other words, the virtual buffer is a virtual buffer for deciding whether or not to send a TS packet. The buffer is increased by a certain amount at the TS packet transmission interval, and the TS packet is decided to be sent when the buffer is full. To do. The virtual buffer increase amount is determined in proportion to the encoded data rate.
The buffer increase amount of the virtual buffer is calculated by the following equation (3).
Increase amount of virtual buffer = maximum value of virtual buffer × transmission cycle of TS packet / packet transmission cycle of encoded data (3)
For example, when the encoded data is multiplexed at a rate of once per 10 TS packets, the buffer increase amount is set to 1/10 of the maximum value of the virtual buffer.

  Next, the multiplexing unit 115 shown in FIG. 1 performs multiplexing start setting such as initialization of addresses of the respective areas of the header buffer 108, the video encoded data buffer 109, and the audio encoded data buffer 111 (S803). In addition, initialization of the address of the stream buffer 116 that outputs the multiplexed stream and initialization of the PSI data buffer 113, the video attribute data buffer 110, and the audio attribute data buffer 112 that multiplex the same data every time or all of the packets are performed. To do.

  Next, the encoded data reading unit 208 of the multiplexing control device 114 shown in FIG. 2 confirms whether the encoded video data to be multiplexed is set as a multiplexing target (step S804). Here, the state set as the multiplexing target means that the data to be multiplexed is stored in the video encoded data buffer 109, and the encoded data multiplexing time calculation unit 210 also calculates the multiplexing time. In other words, it is set in the multiplexing control unit 209. The encoded data reading unit 208 switches the multiplexing target for each picture. In the case of voice, the multiplexing target is switched and set for each voice frame.

  Only when the encoded data reading unit 208 determines that the video encoded data is not set to be multiplexed (“not set” in step S804), the encoded data reading unit 208 performs region setting for reading the video encoded data ( S805).

  Next, the encoded data multiplexing time calculation unit 210 multiplexes the video encoded data from the DTS (Decoding Time Stamp) time described in the video encoded data to be multiplexed read by the encoded data reading unit 208. Time (hereinafter referred to as video multiplexing time) is calculated (S806). Here, the encoded data multiplexing time calculation unit 210 first calculates the video multiplexing time from the data occupancy amount of the video encoded data buffer according to the VBV buffer model calculated by the VBV buffer model management unit 213. It calculates using shown (1).

  Video multiplexing time = Video DTS-Video VBV buffer occupancy / Video encoding rate (3)

  According to Equation (3), the larger the VBV buffer occupancy, the smaller the value of the video multiplexing time, so that multiplexing starts at an earlier time.

  On the other hand, the time and attribute information storage unit 211 stores the picture type, frame rate, DTS / PTS time information, and the like of the video encoded data from the video encoded data read by the encoded data reading unit 208 (S807). However, in this embodiment, since the multiplexing of video attribute data is limited to Intra-Pciture and Predictive-Picture, the time and attribute information storage unit 211 does not include the DTS time and attributes of Intra-Pciture and Predictive-Picture. Remember only the data.

  At this time, it is determined whether or not the attribute data multiplexing time is set (S808). If it is not set ("No setting" in S808), the attribute data multiplexing time calculation unit 212 determines the time and attribute information. Based on the picture type of the video encoded data stored in the storage unit 211 and the DTS / PTS information, the multiplexing time of the attribute data is determined and set in the multiplexing control unit 209 by the equation (2) described above. (S809).

  Multiplexing time of attribute data = DTS time-3 frames + 1/4 frames (Expression 4)

  According to Equation (4), the multiplexing time is calculated so that the attribute data is multiplexed at the center of the frame.

  Next, the encoded data sufficiency calculation unit 206 and the attribute data sufficiency calculation unit 207 update the virtual buffer occupancy by adding the virtual buffer increase calculated in S802 (S810).

  The multiplexing control unit 209 checks the data occupation amount of all virtual buffers, determines whether there is a virtual buffer whose virtual buffer amount exceeds 100%, and determines data to be multiplexed (S811). Here, the multiplexing control unit 209 determines to give a multiplexing opportunity of the encoded data when there is one encoded data whose virtual buffer amount exceeds 100%.

  When a plurality of encoded data exceeds 100% of each virtual buffer at the same time, the multiplexing control unit 209 determines, for example, according to the priority of the plurality of encoded data exceeding 100% of the virtual buffer. A multiplexing opportunity is given to one piece of optimum encoded data. Here, with regard to the priority of encoded data, for example, a PSI or PCR packet that needs to accurately control the multiplexing time interval has the highest priority. Next, since the attribute data packet has a high restriction on time, the priority is set high. On the other hand, the video packet with the most multiplexed time has the lowest priority.

  The multiplexing control unit 209 determines that there is multiplexed data if there is a virtual buffer whose virtual buffer data occupancy exceeds 100% (S811 “exceeds occupancy”), and so on. Multiplexing is executed as described above (S812 to S816).

  First, in the multiplexing element exceeding the occupied amount of the virtual buffer, the set multiplexing time is compared based on the system time from the system time generation unit 205. If the set multiplexing time is smaller than the system time, it is determined that the multiplexing time has arrived, and it is determined that multiplexing is to be performed (“time has been reached” in S812).

In accordance with the multiplexing instruction from the multiplexing control unit 209, the multiplexing unit 115 converts the encoded data or attribute data to be multiplexed into the video encoded data buffer 109, the attribute data buffer 110, the audio encoded data buffer 111, the audio attribute. The data is read from the data buffer 112, converted into TS packets, multiplexed by one TS packet, and the multiplexed TS packet is output to the stream buffer 116. For this reason, since the multiplexed data address also increases, the address of the TS packet output to the stream buffer 116 also increases by the amount of data of 1 TS (S813).
Since multiplexing has been performed, the virtual buffer size value is subtracted from the virtual buffer occupation amount to reset the virtual buffer occupation amount to zero (S814).
Subsequently, the multiplexing control unit 209 first determines whether the multiplexed data is attribute data or encoded data (S815).

When the multiplexed data is attribute data (S815 “is attribute data”), the multiplexing control unit 209 invalidates the multiplexing time set by the attribute data multiplexing time calculation unit 215. This is because attribute data is completed in one TS packet and is not subsequently multiplexed, so the multiplexing time is invalidated once. Further, the multiplexing time of attribute data to be multiplexed next is set again by the same procedure as described in S809 (S816).
The attribute data multiplexing time calculation unit 212 checks the PTS / DTS time of the encoded data stored at this time, and determines that the video packet to be multiplexed next is not stored yet. The multiplexing time cannot be calculated, so the multiplexing time may remain invalidated.

  On the other hand, if it is determined that the time has not been reached in S812, it is determined whether the element is attribute data (S917). If it is attribute data, the virtual buffer is cleared to zero by subtracting the same value as the size of the virtual buffer from the virtual buffer (S818).

  Then, the system time generation unit 205 updates the system time by one TS packet (S819).

  Then, the multiplexing control unit 114 determines whether or not to end the multiplexing (S820). When the multiplexing is continued (S820 “does not end”), the process returns to the process of S804, and the multiplexing is ended. In this case (S820 “end”), the end of multiplexing is set (S821). That is, the multiplexing control unit 114 invalidates all multiplexing times and stops video encoding and multiplexing.

  Therefore, according to the first embodiment, the encoded data virtual buffer increase amount calculation unit 203 obtains the increase amount of the encoded data virtual buffer based on the encoding rate of the encoded data, and the encoded data sufficient amount calculation unit. 206 calculates the fullness of the encoded data virtual buffer based on the increase amount, while the attribute data encoding rate magnification setting unit 202 sets the ratio of the encoding rate of the attribute data to the frame rate of the encoded data. The attribute data virtual buffer increase amount calculation unit 204 calculates the increase amount of the attribute data virtual buffer based on the magnification, and the attribute data full amount calculation unit 207 calculates the satisfaction amount of the attribute data virtual buffer based on the increase amount. The multiplexing control unit 209 calculates the fullness of the encoded data virtual buffer and the attribute data virtual buffer based on the system time. When the fullness reaches the maximum value of each virtual buffer, the multiplexed time of the encoded data from the encoded data multiplexing time calculation unit 210 and the multiplexing time of the attribute data from the attribute data multiplexing time calculation unit 212 Based on the above, the multiplexing of the encoded data and the attribute data is controlled so that the attribute data is multiplexed in the exclusion period before and after each frame of the encoded data.

  For this reason, according to the multiplexing control apparatus of the first embodiment, when the attribute data describing the encoding attribute of the encoded data of video or audio is multiplexed, the multiplexing time of the attribute data is set for each frame period. Since multiplexing is performed so as to be located at the center, multiplexing can be performed with a sufficient margin with respect to the start time or end time of the multiplexing period of each frame. As a result, it is possible to provide a stable multiplexing device that does not cause a loss of attribute data or an error in association between encoded data and attribute data on the receiving side that receives and reproduces the multiplexed transport stream (TS). it can.

  In the first embodiment, the video attribute data multiplexing opportunity has been described as an example of N = 2 times the video encoded frame. When N = 2, encoding of attribute data can be validated during a period from 1/4 to 3/4 of the video frame. The invalidation period in the first half and the invalidation period in the second half are ¼. This is shown in FIG.

  When the multiplexing opportunity of video attribute data is set to N = 3 times the video encoding frame, encoding of attribute data can be made effective in a period of 1/3 to 2/3 as shown in FIG. 9 (2). .

  The invalidation period in the first half and the invalidation period in the second half are 1/3.

  Furthermore, if the video attribute data multiplexing opportunity is set to N = 4 times the video encoding frame, the encoding of the attribute data may be enabled during the period of 3/8 to 6/8 as shown in FIG. 9 (3). it can. The invalidation period in the first half and the invalidation period in the second half are 3/8.

  In summary, when the magnification N of the encoding rate of the attribute data (N is a natural number of 2 or more) with respect to the frame rate of the encoded data, the effective period is 1 / N at the center of the frame. The period of the first half of the invalid period or the second half of the frame can be generalized as (N-1) / (2N).

  The present invention digitally multiplexes video and audio data encoded using high-efficiency encoding such as MPEG to generate a transport stream (TS) and store it in a file or transmit it via a network. The present invention can be applied to a multiplexing device and a multiplexing control method such as a recorder device and a digital video camera.

It is a figure which shows the multiplexing control apparatus which concerns on this invention, and the example of whole structure of a multiplexing apparatus. 3 is a block diagram illustrating a detailed configuration example of a multiplexing control device 114 according to the first embodiment. FIG. It is a figure which shows the buffer occupation amount of the virtual buffer of Embodiment 1. It is a figure which shows the example of the multiplexing time of attribute data in the case of video encoding data <video attribute data. It is a figure which shows the example of the multiplexing time of attribute data in the case of video attribute data <video encoding data. It is a figure which shows the example of the multiplexing time of the conventional attribute data. It is a figure which shows the example of the multiplexing time of the attribute data of Embodiment 1. 4 is a flowchart illustrating a multiplexing control procedure according to the first embodiment. It is a figure which shows the effective / ineffective period of the encoding rate N times of Embodiment 1. FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 100 Multiplexer 101 Encoding apparatus 102 Header generation part 103 Video encoding part 104 Video attribute data generation part 105 Audio | voice encoding part 106 Audio | voice attribute data generation part 107 PSI data generation part 108 Header data buffer 109 Video encoding data buffer 110 Video attribute data buffer 111 Audio encoded data buffer 112 Audio attribute data buffer 113 PSI data buffer 114 Multiplexing controller 115 Multiplexing unit 116 Stream buffer 201 Coding rate calculation unit 202 Attribute data multiplexing rate magnification setting unit 203 Encoded data Virtual buffer increase amount calculation unit 204, attribute data virtual buffer increase amount calculation unit 205 system time generation unit 206 encoded data full amount calculation unit 207 attribute data full amount calculation unit 208 No. data reading unit 209, the multiplexing control unit 210 encoded data multiplexing time calculating unit 211 time and attribute information storage unit 212 the attribute data multiplexing time calculating unit 213 VBV buffer model management unit

Claims (3)

A multiplexing control device that multiplexes encoded data composed of a plurality of frames and attribute data of the encoded data,
An encoded data sufficient amount calculation unit for determining a sufficient amount of the encoded data virtual buffer based on an encoding rate of the encoded data;
An attribute data encoding rate magnification setting unit for setting a magnification of the encoding rate of the attribute data with respect to a frame rate of the encoded data;
An attribute data sufficiency calculator that calculates the sufficiency of the attribute data virtual buffer based on the magnification of the encoding rate of the attribute data;
The encoding excluding a predetermined period after the start time of each frame of the encoded data and a predetermined period before the end time based on a multiplexing time of the encoded data and a rate of encoding of the attribute data An attribute data multiplexing time setting unit that sets a multiplexing time of the attribute data so that the attribute data is multiplexed in a period before and after each frame of data;
Each frame of the encoded data based on the multiplexed time of the encoded data, the multiplexed time of the attribute data, the fullness of the encoded data virtual buffer, and the fullness of the attribute data virtual buffer A multiplexing control unit that controls multiplexing of the encoded data and the attribute data so that the attribute data is multiplexed in the period before and after
A multiplexing control device. The multiplexing control device according to claim 1,
The attribute data encoding rate magnification setting unit
Set N (N is a natural number of 2 or more) times as a magnification of the encoding rate of the attribute data with respect to the frame rate of the encoded data;
The attribute data multiplexing time setting unit
The exclusion period before and after each frame of the encoded data is set to (N−1) / (2N) of each frame of the encoded data, and the multiplexing time of the attribute data is set so that the attribute data is multiplexed. Multiplexing control device to be set. A multiplexing control method for multiplexing encoded data composed of a plurality of frames and attribute data of the encoded data,
Obtaining a fullness of the encoded data virtual buffer based on the encoding rate of the encoded data;
Setting a magnification of the encoding rate of the attribute data with respect to the frame rate of the encoding data;
Calculating a sufficient amount of the attribute data virtual buffer based on a magnification of the encoding rate of the attribute data;
The encoding excluding a predetermined period after the start time of each frame of the encoded data and a predetermined period before the end time based on the multiplexing time of the encoded data and the encoding rate magnification of the attribute data Setting a multiplexing time of the attribute data so that the attribute data is multiplexed in the exclusion period before and after each frame of data;
Each frame of the encoded data based on the multiplexed time of the encoded data, the multiplexed time of the attribute data, the fullness of the encoded data virtual buffer, and the fullness of the attribute data virtual buffer Controlling the multiplexing of the encoded data and the attribute data so that the attribute data is multiplexed during the period before and after
A multiplexing control method comprising:

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