CN101399949A - Method for recording audio and video interlaced format file - Google Patents

Abstract

The invention discloses a method for recording audio and video interlaced format files, wherein the audio and video interlaced format files comprise file headers and content blocks, and the method comprises the following steps: respectively writing preset values of a plurality of recording information into corresponding fields in a file header and a content block, wherein the recording information is the video and audio length of an audio and video interlaced format file; when receiving the multimedia data, writing the multimedia data into a content block, and recording an audio and video interlaced format file; and when the audio and video interlaced format file is recorded, correcting the file header and the field corresponding to the recording information in the content block according to the actual value of the recording information. By applying the invention, when the recording process encounters abnormal interruption, the audio and video interlaced format file can be ensured to be normally accessed because the audio and video interlaced format file has a complete and legal structure.

Description

A method for recording audio and video interleaved format files

technical field

The invention relates to a file recording method, in particular to a method for recording audio and video interleaved format files.

Background technique

With the development of multimedia technology, the monitoring system has been able to track the image through real-time recording, for example: applied to the security monitoring system. The content recorded by such a monitoring system is of high importance, and the continuity of the recorded content is extremely high.

Audio and video interleaved format file (AVI file, audio and video interleaved file) is one of the most commonly used file formats for real-time video recording. Cutting audio and video into multiple data chunks, and interleaving (interleave) the file format of audio and video data chunks, in the present invention, the data chunks of interleaved transmission are generally referred to as multimedia data (multiplexed media data). Moreover, the audio and video interleaved format file adopts the storage method of the data interactive file format, that is, adopts a file format (meta-format) in which data blocks are stored in tagged chunks.

Generally speaking, a complete audio and video interleaved format file must have a file header (header) conforming to the specification of the AVI standard for playing by a multimedia player. Therefore, if an abnormal interruption occurs during the recording process, such as a power outage, the recorded file format is likely to be unable to reproduce the recorded file before the power outage because there is no file header legally describing the structure. Video data.

FIG. 1 is a schematic flow chart of recording audio and video interleaved format files in the prior art. Please refer to FIG. 1 , generally speaking, the initial information of the audio and video interleaved format file is set at the beginning of the recording (step S101 ), such as the sampling frequency of the recorded voice. While recording, write video and audio data one by one (step S102), and determine whether the recording is over (step S103). If the recording is not finished, continue to write video and audio data (step S102). If the recording is finished, the index contained in the audio-visual data is organized, and the file header is written according to the complete audio-visual data (step S104).

However, the above-mentioned recording method is to write the file header according to the complete audio-visual data after the recording is completed, that is to say, it is impossible to know the correct file header that should be written at last during the recording process. As a result, if the power is interrupted or fails during the recording process, the recorded audio and video interleaved format files will not be able to reproduce the audio and video data recorded before the interruption because there is no legal and complete file header.

Therefore, in the prior art, the purpose of reproducing the video and audio data recorded before the interruption is realized by updating the file header from time to time.

Fig. 2 is another schematic flowchart of recording audio and video interleaved format files in the prior art. Please refer to FIG. 2 . The difference from FIG. 1 is that in FIG. 2 , after each video data is written (step S202 ), the file header is updated according to the recorded video data (step S203 ). After the recording is finished (step S204), the file header is corrected according to the complete video and audio data (step S205).

The above method can realize replaying the audio-visual data recorded before the interruption, but the working efficiency of the recording system is greatly reduced due to the frequent change of the file header along with the recording content.

Contents of the invention

The invention provides a method for recording audio and video interleaved format files, which is used to ensure that the recording system can normally access the audio and video interleaved format files recorded before the interruption when encountering abnormal interruption during the recording process.

The present invention provides a method for recording audio and video interleaved format files, wherein the audio and video interleaved format files include file headers and content blocks. The method writes a plurality of preset values of the recording information into the file header and the field corresponding to the recording information in the content block respectively, and the recording information is the audio-video length of the audio-video interleaved format file. When the multimedia data is received, the multimedia data is written into the content block, and the audio and video interleaved format files are recorded.

The present invention also provides a method for recording audio and video interleaved format files, wherein the audio and video interleaved format files include file headers and content blocks. The method writes a plurality of preset values of the recording information into the file header and the field corresponding to the recording information in the content block respectively, and the recording information is the audio-video length of the audio-video interleaved format file. When the multimedia data is received, the multimedia data is written into the content block, and the audio and video interleaved format files are recorded. Every preset time, a threshold value is used to update the corresponding fields of the recording information in the file header and the content block, wherein the threshold value is greater than or equal to the conversion of each recording information until the time required for the next update value.

The above-mentioned method for recording audio and video interleaved format files includes performing initialization processing for setting initial information of the audio and video interleaved format files.

In the above-mentioned method for recording an audio-video interleaved format file, the audio-video interleaved format file further includes an index block, and the block types of multiple sub-blocks contained in the content block and the offsets for playing each sub-block are written into the index block.

It can be seen from the above technical solution that, in a method for recording an audio-video interleaved format file according to the present invention, when recording, pre-write the preset value of the recording information about the audio-video interleaved format file. Therefore, even if an abnormal interruption is encountered during the recording process, the interleaved audio and video files recorded before the interruption can be accessed because the recorded audio and video interleaved format files conform to the standard structure.

Description of drawings

FIG. 1 is a schematic flow chart of recording audio and video interleaved format files in the prior art.

Fig. 2 is another schematic flowchart of recording audio and video interleaved format files in the prior art.

FIG. 3 is a schematic structural diagram of an audio and video interleaved format file according to the present invention.

FIG. 4 is a schematic flowchart of recording audio and video interleaved format files according to Embodiment 1 of the present invention.

Fig. 5 is a schematic flowchart of recording audio and video interleaved format files according to another embodiment of the present invention.

Explanation of symbols in the attached drawings

301: Data Interchange File Format Block

301a: file header

301b: Content Block

301c: Index Block

302a, 302b: sub-blocks

Detailed ways

In order to make the object, technical solution and advantages of the present invention clearer, the present invention will be further described in detail below with reference to the accompanying drawings and examples.

Embodiments of the present invention provide a method for accessing video and audio data recorded before the interruption on the recording medium when an abnormal interruption occurs during the recording process.

FIG. 3 is a schematic structural diagram of an audio and video interleaved format file according to the present invention. Please refer to FIG. 3 , each audio and video interleaved format file is constructed by a data exchange file format block (RIFF chunk), and the data exchange file format block can include multiple sub-chunks (sub-chunk). Wherein, the sub-chunk of the data exchange file format can be a directory block (LIST chunk) or a regular sub-chunk (regular sub-chunk). For example, the directory block is a file header 301a, a content block 301b, and the regular sub-chunk is an index block 301c. The structure of the directory block is the same as that of the data exchange file format block, which can contain directory sub-blocks or regular sub-blocks, but regular sub-blocks cannot contain any sub-blocks.

A complete data exchange file format block 301 includes a file header 301a, a content block 301b and an optional index block 301c. The file header 301a is used to record the recording information of the audio-video interleaved format file, for example: the size (RIFF size) of the data exchange file format block, the frame number (avih#frames) of the audio-visual data, the length (video length) of the video data (ie The number of frames of video data), the length of audio data (audio length) (that is, the number of samples of audio data) and other related fields related to the length of audio and video data. The content block 301b is used to record the size (movi size) of the video and audio data it contains and the video and audio data recorded.

Since video and audio data is divided into multiple data blocks, for example: each video data block is a frame, and these data blocks are respectively recorded in the sub-blocks 302a and 302b included in the content block 301b, in this embodiment, The description is convenient, and two sub-blocks are used for illustration. In practical applications, a content block may also include multiple sub-blocks. The index block 301c is used to record the offset (offset) of playing these data blocks and the content size (size) of the data blocks, so as to quickly find the desired data when replaying (playback), fast-forwarding or reversing audio-visual data. The chunk of data to play. In addition, the index block 301c can also be used to record the block type of the data block, for example: whether the block type of the video data block is an I (intra) frame.

FIG. 4 is a schematic flowchart of recording audio and video interleaved format files according to Embodiment 1 of the present invention. Please refer to FIG. 3 and FIG. 4 , at the beginning of recording, an initialization process (step S401 ) is performed to set the initial information of the audio and video interleaved format file, such as audio sampling frequency or video compression format. Next, write the preset value of the recording information into the field corresponding to the recording information in the file header 301a and the content block 301b (step S402), wherein the recording information is related to the video and video length of the audio and video interleaved format file, for example: the number of frames of video data , the size of video and audio data, or the number of audio data samples, etc. It is common knowledge in the art to write the recording information into the field related to the video length of the audio-video interleaved format file, so it will not be repeated here.

In this embodiment, the preset value of the recording information written in the file header 301a can be a preset value of multiple recorded information, and the preset value can be the size of a RIFF block (equivalent to the size of video and audio data) , the number of video data frames, and the number of audio data samples, and the preset value of the recording information written in the content block 301b may be the size of the video and audio data. Since in the actual recording system, the standardized audio and video interleaved format file fields have certain restrictions on these recording information, so in this embodiment, the preferred preset value of the recording information is the recording specified by the standard The maximum value of the information is more preferably consistent with the maximum value of the recorded information that the recording system can record, or is greater than or equal to the actual value of the recorded information recorded by the recording system.

For example, the video frame rate regulated by the National Television Standards Committee (hereinafter referred to as NTSC) is about 30 frames/second (frames/second). If the audio-visual data in NTSC format is to be recorded, and the video-audio length that can be recorded by the recording system is, for example, 3 hours, then in the field of the video data length (video length) and the video-audio file frame number (avih#frames) in the file header 301a, write The maximum number of video data frames that can be recorded into the recording system, that is, 3 hours x 60 minutes/hour x 60 seconds/minute x 30 frames/second = 324,000 frames. The maximum number of audio data samples allowed to be recorded by the recording system will also be filled in the field of audio data length. In the same way, correspondingly write the maximum value that the recording system can record in other fields. According to the technical means commonly used by those skilled in the art, if you want to record video and audio data in the European national television standard (phase alternating line, PAL) format, you can make corresponding settings according to the maximum frame rate of the standard specification.

Next, write the multimedia data into the content block 301b, record the audio and video interleaved format file (step S403), and determine whether the recording is completed (step S404). If the recording is not completed, continue to write the multimedia data into the content block 301b (step S403). If the recording is completed, the field corresponding to the recording information in the file header 301a and the content block 301b is corrected according to the actual value of the recording information (step S405). Generally speaking, when the multimedia data is written into the content block 301b, the block types of the sub-blocks (for example: 302a, 302b) contained in the content block 301b, and the offsets of playing each sub-block will also be recorded in the index in block 301c. After the recording is completed, the information recorded in the index block 301c is organized.

From the flow diagram in Figure 4, it can be seen that even if an abnormal interruption is encountered during the recording process, although the recording information of the final recording cannot be predicted, the audio and video interleaved format files recorded before the interruption have standard and complete structure, which can be accessed normally. Therefore, compared with the method in the prior art that writes the file header according to the actual recording information after the recording ends (as shown in Figure 1), the embodiment of the present invention can reproduce the file header before the interruption when encountering an abnormal interruption during the recording process. The recorded video and audio data. Moreover, this embodiment has higher work efficiency compared with the method of updating the file header frequently in the prior art (as shown in FIG. 2 ).

Fig. 5 is a schematic flowchart of recording audio and video interleaved format files according to another embodiment of the present invention. In this embodiment, by setting a preset time T1, the recording information recorded in the file header 301a and the content block 301b is periodically updated. Referring to FIG. 3 and FIG. 5 , an initialization process is performed at the beginning of recording for setting initial information of audio and video interleaved format files (step S501 ). Next, write the preset value of the recording information converted by the preset time T1 into the field corresponding to the recording information in the file header 301a and the content block 301b (step S502), and write multimedia data in the content block 301b to record audio Video interlaced format file (step S503). The default value of the recording information written for the first time is the value of recording information converted from recording at least T1 time.

Next, it is judged whether the recording is finished (step S504). If the recording is completed, the field corresponding to the recording information in the file header 301a and the content block 301b can be modified according to the actual value of the recording information (step S505). If the recording is not completed, it is judged whether the recording time reaches the above-mentioned preset time T1 (step S506). If the preset time T1 has not been reached, continue to write multimedia data (step S503). When the recording time reaches the preset time T1, the first update is performed, and a threshold value is used to update the field corresponding to the recording information in the file header 301a and the content block 301b (step S502), wherein the threshold value is greater than Or equal to the value of the recording information scaled up to the time required for the next update.

For example, assuming that the recording information is the number of video frames, and the system is set to be updated every 30 minutes, then when initializing the recording, the default value of the number of video frames written for the first time is at least 30 minutes ( That is, greater than or equal to the value of the number of video frames converted from the actual recording time before updating). When the recording passes for a period of time, such as 18 minutes, and encounters an abnormal interruption, the recording system can still play the recording before the abnormal interruption because the file header of the audio and video interleaved format file records the number of video frames at least 30 minutes long video data.

If 30 minutes of normal recording have elapsed, the system will perform the first update. At this time, the number of video frames converted by at least 60 minutes (that is, the total time elapsed until the next update) is written into its corresponding field (that is, the field of video data length in the file header 301a), so that it can be ensured that when an abnormal interruption is encountered during the recording process, the video and audio data recorded before the 60th minute can still be played.

As can be seen from the above, in this embodiment, when updating for the Nth time, the written threshold value is at least the value of the recording information converted from T1×(1+N) time, where N is zero or positive integer. Therefore, by periodically updating the recording information, when an abnormal interruption occurs during the recording process, it can still ensure that the system can play the video and audio data recorded before the interruption.

In practice, this embodiment is not limited to the order of writing the preset value of the recording information (step S502 ) and writing the multimedia data (step S503 ). The preset value of the recording information written (step S502) is the value of the recording information converted into the preset time T1, and as shown in Figure 4, the recording information conforming to the standard of the audio and video interlaced format file can be adopted. The maximum value, or greater than or equal to the actual value of the recording information that can be recorded by the recording system, or the maximum value of the recording information that can be recorded by the recording system is used as the preset value of the recorded recording information.

To sum up, in this embodiment, when recording, the preset value of the recording information is written in the fields corresponding to the recording information in the file header 301a and the content block 301b, and multimedia data is written to record audio and video interleaved format files. Therefore, even if an abnormal interruption is encountered during the recording process, although the correct recording information after the recording is completed cannot be obtained, the audio and video interleaved format files recorded before the interruption can be accessed normally due to their standard and complete structure .

In the recording process of this embodiment, the time period is greater than or equal to the time required for the next update (for example, T1×(1+N), where T1 is the preset update time, and N is the number of updates). The value of the converted recording information (that is, the threshold value) is used to update the field corresponding to the recording information in the file header and the content block, so as to ensure that the recording information before the abnormal interruption can be played.

In the above embodiment, after the recording is completed, the fields corresponding to the recording information in the file header 301a and the content block 301b can be modified selectively according to the actual value of the recording information.

Although the present invention has been disclosed above with preferred embodiments, it is not intended to limit the present invention. Any person skilled in the art can make some changes and modifications without departing from the spirit and scope of the present invention. Therefore The scope of rights claimed in the present invention should be based on the description of the application scope of the invention, rather than being limited to the above-mentioned embodiments.

Claims (17)

1. A method for recording an audio-video interleaved format file, wherein the audio-video interleaved format file comprises a file header and a content block, it is characterized in that the method comprises: Writing a plurality of preset values of recording information into the file header and the field corresponding to the recording information in the content block respectively, the recording information being the audio-video length of the audio-video interleaved format file; and A multimedia data is written into the content block, and the audio and video interleaved format file is recorded. 2. The method of claim 1, further comprising: After recording the audio and video interleaved format file, modify the corresponding fields in the file header and the content block respectively according to the actual value of the recording information. 3. The method according to claim 1, wherein the preset value of the recording information is the maximum value of the recording information regulated by the audio-video interleaved format file standard. 4. The method according to claim 1, wherein the preset value of the recording information is greater than or equal to an actual value of the recording information that can be recorded by a recording system. 5. The method according to claim 1, wherein the preset value of the recording information is the maximum value of the recording information that can be recorded by a recording system. 6. The method of claim 1, further comprising: Executing an initialization process for setting a plurality of initial information of the audio and video interleaved format file. 7. The method of claim 1, wherein the audio-video interleaved format file further comprises an index block, the method further comprising: Write the block types of the multiple sub-blocks included in the content block and the offsets for playing each of the sub-blocks into the index block. 8. The method according to claim 1, wherein the recording information comprises one of the following or any combination thereof of the audio and video interleaved format file: a video data frame number, an audio data sample number, a The total number of frames, the format block size of a data interaction file, and the content block size. 9. A method for recording an audio-video interleaved format file, wherein the audio-video interleaved format file comprises a file header and a content block, it is characterized in that the method comprises: Writing preset values of a plurality of recording information into the file header and the field corresponding to the recording information in the content block respectively, the recording information is the audio-video length of the audio-video interleaved format file; writing a multimedia data into the content block, recording the audio video interleaved format file; and Every preset time, update the corresponding fields in the file header and the content block with a threshold value, the threshold value is greater than or equal to the conversion of the recording information up to the time required for the next update value. 10. The method of claim 9, further comprising: After recording the audio and video interleaved format file, modify the corresponding fields in the file header and the content block respectively according to the actual value of the recording information. 11. The method according to claim 9, wherein the preset value of the recording information is the maximum value of the recording information regulated by the audio-video interleaved format file standard. 12. The method according to claim 9, wherein the preset value of the recording information is greater than or equal to an actual value of the recording information recorded by a recording system. 13. The method according to claim 9, wherein the preset value of the recording information is the maximum value of the recording information that can be recorded by a recording system. 14. The method according to claim 9, wherein the preset value of the recording information is the value of the recording information converted according to the preset time. 15. The method of claim 9, further comprising: Executing an initialization process for setting a plurality of initial information of an audio and video interleaved format file. 16. The method of claim 9, wherein the audio-video interleaved format file further comprises an index block, the method further comprising: Write the block types of the multiple sub-blocks included in the content block and the offsets for playing each of the sub-blocks into the index block. 17. The method according to claim 9, wherein the recording information includes one of the following or any combination of the audio and video interleaved format files: a video data frame number, an audio data sample number, a The total number of frames, the format block size of a data interaction file, and the content block size.

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