JP2004260374A - Decoding reproducing method, decoding reproducing device and multimedia information receiving device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide decoding reproducing method/device for judging whether PTS (Presentation Time Stamp) which is added to an encoded frame and shows the time the frame is reproduced is correct by less calculation and to provide a multimedia information receiving device. <P>SOLUTION: When CI (Configuration Information) which is added to the encoded frame and shows a form of encoding is correctly received (step 41e), and when STC (System Time Clock) being a reference synchronizing signal of the decoding/reproducing device is reset (step 41g), received PTS is judged to be correct. <P>COPYRIGHT: (C)2004,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a decoding / reproducing method for inputting and reproducing encoded information, a decoding / reproducing apparatus, and a multimedia information receiving apparatus, and more particularly, to a process for correcting an error in a reproduction time.
[0002]
[Prior art]
In a multimedia information processing system that encodes and transmits a multimedia program composed of a moving image and an audio according to the MPEG system and decodes and reproduces the moving image and the audio, the moving image and the audio are encoded in units called frames. Is added to the playback time (Presentation Time Stamp, hereinafter referred to as PTS) and transmitted to the decoding / playback apparatus. A frame for a moving image is a temporally continuous still image, and a frame for a sound is a sound divided at regular time intervals.
[0003]
Then, in order to play back the encoded moving image and audio in synchronization with each other, the encoded frame is decoded, and the decoded frame and the PTS added to the encoded frame are both stored in the memory. To memorize. Then, when the time indicated by the reference synchronization signal (System Time Clock, hereinafter referred to as STC) of the decoding and reproducing apparatus coincides with the time of the PTS, the frame stored in the memory is reproduced.
[0004]
Here, the STC is always calibrated so as to indicate the time indicated by a program clock reference value (Program Clock Reference, hereinafter referred to as PCR) added to the encoded multimedia program.
[0005]
By the way, for example, in a system for transmitting and reproducing coded multimedia information in real time using a mobile communication terminal device, errors may occur in the PTS during the transmission of coded information. In such a case, it is not unusual for the error to be input to the decoding / reproducing apparatus without being corrected by the transmission apparatus.
[0006]
The reason is that, in a system that transmits and reproduces coded multimedia information in real time using a mobile communication terminal device, the transmission bit rate is low. Since a redundant bit cannot be added, and a UDP (User Datagram Protocol) protocol that does not perform retransmission is used, a retransmission function of a TCP (Transmission Control Protocol) protocol used in the Internet may be used. It is not possible.
[0007]
Here, the encoded moving image has a larger amount of information than the encoded audio, so that an error in the PTS is more likely to be mixed in the encoded moving image information than in the encoded audio information.
[0008]
Therefore, in a moving picture decoding / reproducing method for a system for transmitting and reproducing coded multimedia information in real time using a mobile communication terminal device, even if an error is included in the PTS, the moving picture is reproduced by audio. It is necessary to correct the error in order to reproduce in synchronization with. As a method of the correction, a process of adding time information different from the PTS to the encoded image frame and performing detection and correction of the PTS error using the time information is performed (for example, Patent Document 1). reference.).
[0009]
[Patent Document 1]
JP-A-2002-135777 (page 2-3, FIG. 2)
[0010]
[Problems to be solved by the invention]
However, in the above-described conventional method, when an error is included in the PTS added to a plurality of consecutive encoded frames, the error is included in the PTS added to the subsequent encoded frames. There is a problem that a large amount of calculation is required to determine whether or not the calculation is performed.
[0011]
The present invention has been made in order to solve the above problems, and provides a decoding / reproducing method, a decoding / reproducing apparatus, and a multimedia information receiving apparatus capable of determining that an error is not included in a PTS with a small amount of calculation. With the goal.
[0012]
[Means for Solving the Problems]
In order to achieve the above object, a decoding / reproducing method according to the present invention comprises the steps of: receiving information in which coded information is added with information representing a time at which the information is reproduced and the encoding method; Decoding the encoded information according to the information representing the method of the above, when the error of the reproduction time is detected, the time is corrected, and at the corrected reproduction time, the decoded information is used as a reproduction signal. A decoding and reproducing method for outputting, before the correction, determining whether or not information indicating the encoding method is correct, and determining that the information indicating the encoding method is correct, The reproduced information is output as a reproduction signal at the reproduction time.
[0013]
Also, the decoding and reproducing method of the present invention receives information in which encoded information is added with information indicating a time at which the information is reproduced and the encoding method, and according to the information indicating the encoding method. A decoding / reproducing method for decoding the encoded information, correcting the time when an error in the reproduction time is detected, and outputting the decoded information as a reproduction signal at the corrected reproduction time. Therefore, before the correction, and when it is determined that the information representing the encoding method is not correct, determine whether the reproduction time of the encoded information is correct, When it is determined that the reproduction time of the encoded information is correct, the decoded information is output as a reproduction signal at the reproduction time.
[0014]
According to the present invention, when encoding method information can be correctly input, and when a time reset instruction is input to a means for measuring the reproduction time of decoded information, reproduction is performed with a small amount of calculation. The time can be determined to be error-free.
[0015]
BEST MODE FOR CARRYING OUT THE INVENTION
An embodiment of a decoding and reproducing method according to the present invention will be described below with reference to the drawings. FIG. 1 is a block diagram showing a configuration of a mobile communication terminal device to which a decoding and reproducing method according to an embodiment of the present invention is applied.
[0016]
The mobile communication terminal device includes a control device 1 for controlling the entire device, an antenna 2a, a communication device 2b, a transmission / reception device 3, an input device 4 for inputting an operation instruction from a user, a moving image and a voice. An encoding / decoding device 5 for encoding, decoding, and reproducing a multimedia program composed of: a camera 6a, a display device 6b, a microphone 6c, and a speaker 6d.
[0017]
The communication device 2b outputs the high-frequency signal received by the antenna 2a to the transmission / reception device 3, and transmits the high-frequency signal output from the transmission / reception device 3 from the antenna 2a.
[0018]
Next, the operation of the transmitting / receiving device 3 will be described. The transmitting / receiving device 3 amplifies, frequency-converts and demodulates a high-frequency signal from the communication device 2b, sends an encoded multimedia program signal obtained thereby to the encoding / decoding device 5, and transmits a control signal to the control device. Send to 1. The transmission / reception device 3 further modulates, frequency-converts, and amplifies the encoded multimedia program signal output from the encoding / decoding device 5 and the control signal output from the control device 1 to obtain a high-frequency signal. And sends it to the communication device 2b.
[0019]
FIG. 2 is a block diagram illustrating a configuration of the encoding / decoding device 5. The encoding / decoding device 5 includes a demultiplexing unit 11, a moving image encoding unit 12, a moving image decoding unit 13, an image buffer 14, an image reproduction control unit 15, a time management unit 21, a STC unit. 22, an audio encoding unit 23, an audio decoding unit 24, an audio buffer 25, and an audio reproduction control unit 26.
[0020]
The operation of the mobile communication terminal according to the embodiment of the present invention configured as described above will be described.
[0021]
First, the operation of the demultiplexer 11 will be described. The demultiplexing unit 11 multiplexes the encoded image frame signal output from the moving image encoding unit 12 and the encoded audio frame signal output from the audio encoding unit 23, and The transmitted multimedia program signal is transmitted to the transmission / reception device 3.
[0022]
That is, the demultiplexing unit 11 creates a PES (Packetized Elementary Stream) packet by combining a plurality of encoded image frame signals output from the moving image encoding unit 12 with respect to the moving image input from the camera 6a. I do.
[0023]
The time at which each image frame called B_TS is reproduced is added to the frame header information in all the encoded image frame signals output from the moving image encoding unit 12, and a part of the encoding is performed. The obtained image frame signal includes information called CI (Configuration Information) (information indicating a coding format of the moving image), such as an encoding profile, an image size, and a necessary size of the image buffer 14. Are added to the PES packet. B_TS is a time that is uniquely defined for a moving image and has no relation to audio.
[0024]
The demultiplexing unit 11 further creates a PES packet by adding a PTS, which is a time at which the image frame signal is reproduced, to the encoded image frame signal at the head of the PES packet. Note that PTS may be added to other encoded image frame signals.
[0025]
FIG. 3A illustrates a situation in which the first encoded image frame signal 31a to the m-th encoded image frame signal 31b constitute one PES packet (image).
[0026]
Here, B_TS is added to the frame header information in all the encoded image frame signals. That is, B_TS (31c) is added to the first encoded image frame signal 31a, and B_TS (31d) is similarly added to the m-th encoded image frame signal 31b. ing.
[0027]
Further, CI (31e) and PTS (31f) are further added to the first encoded image frame signal 31a.
[0028]
The demultiplexing unit 11 further creates a PES packet by combining a plurality of encoded audio frame signals output from the audio encoding unit 23 with respect to the audio input from the microphone 6c. Also, a PTS, which is the time at which the audio frame is reproduced, is added to the head encoded audio frame signal of the PES packet. Note that PTS may be added to other encoded audio frame signals.
[0029]
FIG. 3B shows a situation in which the first encoded audio frame signal 32a to the n-th encoded audio frame signal 32b constitute one PES packet (audio). Here, PTS (32c) is added to the first encoded audio frame signal 32a.
[0030]
Subsequently, the demultiplexing unit 11 divides the PES packet of the image and the PES packet of the audio into fixed-length TS (Transport Stream) packets for each packet, and adds a PCR for each TS packet to add a PCR to the transmission / reception device 3. Send to FIG. 3C shows a situation in which one PES packet is divided into a first TS packet 33a to a p-th TS packet 33b, and a PCR is added for each TS packet. That is, PCR (33c) is added to the first TS packet 33a, and PCR (33d) is added to the p-th TS packet 33b.
[0031]
The demultiplexing unit 11 separates the encoded multimedia program signal output from the transmission / reception device 3 into an encoded image frame signal, an encoded audio frame signal, and a PCR. Then, the encoded image frame signal is sent to the moving image decoding unit 13, the encoded audio frame signal is sent to the audio decoding unit 24, and the PCR is sent to the time management unit 21.
[0032]
That is, the multimedia program signal output from the transmission / reception device 3 is composed of a plurality of TS packets having the structure of FIG. 3C, and receives a signal to which PCRs 33c,... Among them, the PCRs 33c,..., 33d are separated and sent to the time management unit 21.
[0033]
The demultiplexing unit 11 separates the TS packet and integrates the TS packet into a PES packet. If the PES packet is a packet composed of the encoded image frame signal shown in FIG. The encoded image frame signal including the PTS, CI, and B_TS is sent to the moving image decoding unit 13.
[0034]
If the PES packet is a packet composed of the encoded audio frame signal shown in FIG. 3B, the PTS included in the PES packet and the encoded audio frame signal are sent to the audio decoding unit 24.
[0035]
Next, the operation of the video encoding unit 12 will be described. The moving image encoding unit 12 first creates an image frame signal, that is, a temporally continuous still image, from the moving image signal output from the camera 6a.
[0036]
Subsequently, for each obtained image frame signal, it is subjected to discrete cosine transform, and the obtained discrete cosine transform coefficient is quantized and encoded. Subsequently, a time B_TS for reproducing the frame header information in the obtained encoded image frame signal is added to the frame header information, and a CI is added to a part of the encoded image frame signal to perform multiplexing. It is sent to the separation unit 11.
[0037]
Next, the operation of the video decoding unit 13 will be described. FIG. 4 shows a flowchart of the operation of the video decoding unit 13. The video decoding unit 13 starts operation (step 41a), and receives the encoded image frame signal output from the demultiplexing unit 11. At that time, the PTS, CI, and B_TS added to the encoded image frame signal are also received at the same time (step 41b).
[0038]
Subsequently, the received encoded image frame signal is decoded according to the encoding method indicated by the CI. That is, a coded image frame signal is decoded, the decoded signal is inverse-quantized, and then inverse discrete cosine transform is performed to obtain a decoded image frame signal, that is, a still image is obtained. The data is stored in the buffer 14 (step 41c).
[0039]
Subsequently, the moving image decoding unit 13 adds the time PTS to be reproduced to the obtained decoded image frame signal. Therefore, first, it is checked whether or not PTS is added to the received encoded image frame signal (step 41d). If added, it is checked whether an error is mixed in the added PTS.
[0040]
That is, first, if CI is added to the received encoded image frame signal, it is added to the previously received encoded image frame signal, and is stored in the video decoding unit 13. It is checked whether the CI is the same as the CI (step 41e). If they are the same, the CI is correct, so it is determined that there is no error in the PTS added to the received encoded image frame signal. This is because the CI and the PTS are transmitted as the same or adjacent TS packets, so that when one is transmitted correctly, the other can be regarded as transmitted correctly.
[0041]
Subsequently, the PTS and the image frame signal decoded in step 41c are stored in the image buffer 14 (step 41f).
[0042]
If it is determined in step 41e that the correct CI has not been added, the video decoding unit 13 checks whether or not an STC reset signal has been received from the time management unit 21 (step 41g). When the STC reset signal is received, it is determined that there is no error in the PTS, and the PTS and the image frame signal decoded in step 41c are stored in the image buffer 14 (step 41f).
[0043]
This is because, when the STC reset signal is received from the time management unit 21, it means that a certain program has ended and the first encoded image frame of another program has been sent from the demultiplexing unit 11. Since the continuity of the PTS added to the received encoded image frame signal with the past PTS is lost and error detection based on the continuity described later becomes impossible, the added PTS is regarded as correct. Is appropriate.
[0044]
If the STC reset signal has not been received in step 41g, the video decoding unit 13 determines whether the PTS added to the received encoded image frame signal and the previously received encoded image frame signal have been received. Is compared with the error-free PTS stored in the video decoding unit 13 and the presence or absence of an error in the PTS added to the received encoded image frame signal is verified (step 41h). ).
[0045]
For example, two criteria are used as the verification criteria in step 41h. As a first criterion, if it is agreed that the image frame signals will be sent in the order of reproduction, the PTS added to the received encoded image frame signal is compared with the past error-free PTS. Is smaller, the added PTS is determined to be erroneous.
[0046]
Further, as a second criterion, a difference between a PTS added to a received encoded image frame signal and a past error-free PTS, a B_TS added to a received encoded image frame signal, and a moving image The image decoding unit 13 compares the difference with the B_TS added to the encoded image frame signal to which the error-free PTS is added and stores the difference between the two differences by a predetermined number. If so, the PTS determines that there is an error.
[0047]
If none of these criteria is met in step 41h, the video decoding unit 13 determines that the PTS has no error, and compares the PTS with the image frame signal decoded in step 41c. Is stored in the image buffer 14 (step 41f). At this time, the PTS and the B_TS are stored in the video decoding unit 13 as an error-free PTS and a B_TS added to the encoded image frame signal to which the PTS has been added.
[0048]
On the other hand, when it is determined in step 41d that the PTS is not added to the received encoded image frame signal, and in step 41h, an error is found in the PTS added to the received encoded image frame signal. If it is determined that there is, the video decoding unit 13 estimates the PTS corresponding to the received encoded image frame signal, and stores the PTS and the image frame signal decoded in step 41 c in the image buffer 14. (Step 41i).
[0049]
Here, the estimated value of the PTS for the received encoded image frame signal is added to the B_TS added to the image frame signal and the encoded image frame signal to which the error-free PTS is added. It is obtained by calculating the difference from the obtained B_TS and adding the difference to the past error-free PTS.
[0050]
After storing the PTS of the image frame signal in the image buffer 14 in Step 41f or Step 41i, the video decoding unit 13 returns to Step 41b (Step 41j) and performs processing of the next image frame.
[0051]
Next, the operation of the image reproduction control unit 15 will be described. The image reproduction control unit 15 reads the time indicated by the STC unit 22 and searches whether a PTS at the same time as the read time is stored in the image buffer 14. If it is stored, the decoded image frame signal stored in the image buffer 14 together with the PTS, that is, a still image is read out and displayed on the display device 6b.
[0052]
Next, the operation of the time management unit 21 will be described. The time management unit 21 receives the PCR output from the demultiplexing unit 11 and calibrates the STC unit 22 so that the time indicated by the PCR is indicated by the STC unit 22. When the time management unit 21 detects an STC reset, the time management unit 21 sends a signal indicating the STC reset to the video decoding unit 13 and the audio decoding unit 24.
[0053]
Here, the detection of the STC reset in the time management unit 21 is based on the fact that the time indicated by the PCR changes stepwise before and after a certain point in time with a difference of a predetermined value or more. Alternatively, the PCR may include an identifier indicating whether the program has been changed, and the identifier may indicate that the program has been changed.
[0054]
Next, the operation of the audio encoding unit 23 will be described. First, the audio encoding unit 23 creates an audio frame signal from the audio signal output from the microphone 6c, that is, an audio signal divided at predetermined time intervals.
[0055]
Subsequently, the audio encoding unit 23 performs time-frequency conversion on each of the obtained audio frame signals by an AAC (Advanced Audio Coding) method. Subsequently, the obtained Modified Discrete Cosine Transform (MDCT) coefficient is quantized and coded. The addition of the PTS is as described above. Subsequently, the obtained encoded audio frame signal is sent to the demultiplexing unit 11.
[0056]
Next, the operation of the audio decoding unit 24 will be described. The audio decoding unit 24 first receives the encoded audio frame signal output from the demultiplexing unit 11. At this time, the PTS added thereto is also received at the same time. Subsequently, the received encoded audio frame signal is decoded, and the decoded signal is inverse-quantized and subjected to inverse time-frequency conversion, whereby the decoded audio frame signal, that is, the audio signal having a fixed time width is obtained. And the signal is stored in the audio buffer 25.
[0057]
Subsequently, the audio decoding unit 24 adds a playback time PTS to the decoded audio frame signal, similarly to the moving image. If the PTS is added to the received encoded audio frame signal, the PTS and the decoded audio frame signal are stored in the audio buffer 25.
[0058]
If the PTS is not added to the audio frame signal, a PTS is obtained by adding a predetermined estimated value to the PTS added to the past encoded audio frame signal. That is, the number of frames k (k = m-1) between the currently encoded voice frame (frame m) from the past encoded voice frame (frame 1) is calculated. The estimated value is calculated by adding the number (k × t) obtained by multiplying the time width t of the sound included in one sound frame. The PTS thus obtained and the decoded audio frame signal are stored in the audio buffer 25.
[0059]
Next, the operation of the audio reproduction control unit 26 will be described. The audio reproduction control unit 26 reads the time indicated by the STC unit 22 and searches whether the PTS at the same time as the read time is stored in the audio buffer 25. If it is stored, a decoded audio frame signal stored in the audio buffer 25 together with the PTS, that is, an audio signal having a fixed time width is sent to the speaker 6d to generate sound.
[0060]
In the present embodiment, the error detection of the PTS added to the encoded voice frame is not performed, but may be performed. Although the moving image is one moving image, the moving image may be defined as a group of moving images of a plurality of arbitrary shapes. In such a case, the present invention can be applied to decoding and reproduction performed for each of the moving images having the arbitrary shapes.
[0061]
Further, the encoding of the image frame is based on the discrete cosine transform method, but the present invention is not limited to this, and the encoding of the audio frame is based on the AAC method. However, the present invention is not limited to this. The present invention is not limited to the above configuration, and various modifications are possible.
[0062]
Further, the above description has been made by taking an example in which the present invention is applied to a mobile communication terminal device. However, the present invention can naturally be applied to a receiving device of a broadcasting system.
[0063]
【The invention's effect】
As described above, according to the present invention, when a CI (Configuration Information), which is added to an encoded frame and indicates the encoding format, is correctly received, it is a reference synchronization signal of the decoding / reproducing apparatus. When the STC (System Time Clock) is reset, the time to reproduce the received frame and the PTS (Presentation Time Stamp) are judged to be correct, so that the PTS received with a small amount of calculation is judged to be correct. Can be.
[Brief description of the drawings]
FIG. 1 is a block diagram showing a mobile communication terminal device according to an embodiment of the present invention.
FIG. 2 is a block diagram showing an encoding / decoding device according to the embodiment of the present invention.
FIG. 3 is a diagram showing a data structure of an encoded multimedia program according to the embodiment of the present invention.
FIG. 4 is a flowchart showing the operation of the video decoding unit according to the embodiment of the present invention.
[Explanation of symbols]
5 Encoding / decoding device 11 Demultiplexing unit 13 Video decoding unit 15 Image reproduction control unit 21 Time management unit 22 STC unit 24 Audio decoding unit 26 Audio reproduction control unit

Claims (14)

Received information added to the encoded information, the information representing the time and the encoding method to reproduce the information,
Decoding the encoded information according to the information representing the encoding method,
A decoding and reproducing method for correcting the time when an error of the reproducing time is detected, and outputting the decoded information as a reproduction signal at the corrected reproducing time,
Before the correction, determine whether the information indicating the encoding method is correct,
A decoding / reproducing method, wherein, when it is determined that the information indicating the encoding method is correct, the decoded information is output as a reproduction signal at the time of the reproduction. Received information added to the encoded information, the information representing the time and the encoding method to reproduce the information,
Decoding the encoded information according to the information representing the encoding method,
A decoding and reproducing method for correcting the time when an error of the reproducing time is detected, and outputting the decoded information as a reproduction signal at the corrected reproducing time,
Before the correction, and when it is determined that the information representing the encoding method is not correct, determine whether the time to reproduce the encoded information is correct,
A decoding / reproducing method, wherein, when it is determined that the reproduction time of the encoded information is correct, the decoded information is output as a reproduction signal at the reproduction time. When the information indicating the encoding method is the same as the information received in the past,
2. The decoding and reproducing method according to claim 1, wherein it is determined that the information indicating the encoding method is correct. Receiving information to which the encoded information is added with the time and time reference information for reproducing the information,
Decoding the encoded information,
A decoding and reproducing method for correcting the time when an error of the reproducing time is detected, and outputting the decoded information as a reproduction signal at the corrected reproducing time,
Before the correction, determine whether there is continuity in the encoded information from the time reference information,
When it is determined that there is no continuity, the decoded information is output as a reproduced signal at the time of the reproduction, and the decoded information is reproduced. Receiving information to which the encoded information is added with the time and time reference information for reproducing the information,
Decoding the encoded information,
A decoding and reproducing method for correcting the time when an error of the reproducing time is detected, and outputting the decoded information as a reproduction signal at the corrected reproducing time,
Before the correction, and when it is determined from the time reference information that the encoded information has continuity, it is determined whether the time to reproduce the encoded information is correct Judge,
A decoding / reproducing method, wherein, when it is determined that the reproduction time of the encoded information is correct, the decoded information is output as a reproduction signal at the reproduction time. 5. The decoding / reproducing method according to claim 4, wherein when the time indicated by the time reference information changes in a stepwise manner equal to or more than a predetermined value, it is determined that the encoded information does not have the continuity. . Means for receiving information in which information representing the time at which the information is reproduced and the encoding method are added to the encoded information,
Means for decoding the encoded information according to the information representing the encoding method, and correcting the time when an error in the reproduction time is detected, and decoding the decoded time at the corrected reproduction time. Means for outputting information as a reproduction signal,
Before the correction, the information indicating the encoding method is compared with the information received in the past, and when it is determined that the information indicating the encoding method is correct, the decoded information is reproduced. A decoding and reproducing device provided with means for outputting a reproduced signal at a time when the decoding and reproducing are performed. Means for receiving information in which information representing the time at which the information is reproduced and the encoding method are added to the encoded information,
Means for decoding the encoded information according to the information representing the encoding method, and correcting the time when an error in the reproduction time is detected, and decoding the decoded time at the corrected reproduction time. Means for outputting information as a reproduction signal,
Before the correction, and when it is determined that the information representing the encoding method is not correct, the reproduction time of the encoded information and the reproduced past encoded information Comparing the reproduction time with the reproduction time, and when it is determined that the reproduction time of the encoded information is correct, means for outputting the decoded information as a reproduction signal at the reproduction time is provided. A decoding / playback apparatus characterized by the above-mentioned. Means for receiving information in which encoded information is added with a time at which the information is reproduced and time reference information,
Means for decoding the encoded information;
Means for correcting the time when an error in the time to reproduce is detected, and means for outputting the decoded information as a reproduction signal at the corrected time to reproduce,
Before the correction, it is determined whether or not the encoded information has continuity from the time reference information, and when it is determined that there is no continuity, the time at which the decoded information is reproduced is determined. A decoding and reproducing apparatus characterized by further comprising means for outputting the reproduced signal as a reproduced signal. Means for receiving information in which encoded information is added with a time at which the information is reproduced and time reference information,
Means for decoding the encoded information;
Means for correcting the time when an error in the time to reproduce is detected, and means for outputting the decoded information as a reproduction signal at the corrected time to reproduce,
Before the correction, and when it is determined from the time reference information that the encoded information has continuity, the reproduction time of the encoded information and the past reproduced time By comparing the encoded information with the reproduction time, if it is determined that the encoded information is reproduced, the decoded information is output as a reproduced signal at the reproduced time. A decoding and reproducing apparatus characterized by comprising means. Output means;
Means for receiving information in which a plurality of types of encoded information are added to at least one type of encoded information, and information representing a time at which the information is reproduced and the encoding method are added;
Means for decoding the encoded information according to the information representing the encoding method, and correcting the time when an error in the reproduction time is detected, and decoding the decoded time at the corrected reproduction time. Means for sending information to the output means for reproduction and output, and before the correction, comparing the information indicating the coding method with the information received in the past, the information indicating the coding method is Means for transmitting the decrypted information to the output means at the time of reproduction to reproduce and output the decoded information when it is determined to be correct. Before the correction, and when it is determined that the information indicating the encoding method is not correct, the reproduction time of the encoded information and the reproduced past encoded information Comparing the reproduction time with the reproduction time, and when it is determined that the reproduction time of the encoded information is correct, sending the decoded information to the output means at the reproduction time to reproduce and output the information; The multimedia information receiving apparatus according to claim 11, further comprising: Output means;
Means for receiving a plurality of types of encoded information, wherein at least one type of encoded information is added with a time for reproducing the information and time reference reference information;
Means for decoding the encoded information;
Means for correcting the time when an error in the time of reproduction is detected, sending the decoded information to the output means at the corrected time of reproduction and outputting the reproduced information, and before the correction, It is determined from the time reference information whether or not the encoded information has continuity, and if it is determined that there is no continuity, the decoded information is sent to the output unit at the time of the reproduction. And a means for reproducing and outputting. Before the correction, and when it is determined from the time reference information that the encoded information has continuity, the reproduction time of the encoded information and the past reproduced time By comparing the time at which the encoded information is reproduced with the time at which the encoded information is reproduced, if it is determined that the time at which the encoded information is reproduced is correct, the decoded information is sent to the output means at the time at which the reproduced information is reproduced. 14. The multimedia information receiving apparatus according to claim 13, further comprising means for reproducing and outputting the multimedia information.

Images