CN113571100A

CN113571100A - MP4 generation method, device, equipment and storage medium

Info

Publication number: CN113571100A
Application number: CN202110815158.4A
Authority: CN
Inventors: 杜春华; 李盛
Original assignee: Afirstsoft Co Ltd
Current assignee: Shenzhen Ruan Niu Technology Group Co ltd
Priority date: 2021-07-19
Filing date: 2021-07-19
Publication date: 2021-10-29
Anticipated expiration: 2041-07-19
Also published as: CN113571100B

Abstract

The invention relates to the field of video generation, and discloses a method, a device, equipment and a storage medium for generating MP 4. The method comprises the following steps: creating an MP4 file frame, and writing mdat data in the MP4 file frame; analyzing the input audio-video data stream to generate a media data stream and media metadata information; generating a moov offset value according to the mdat data and the media data stream; writing the moov offset value into the media metadata information to generate moov data; generating new mdat data in the MP4 file frame according to the mdat data and the media data stream; writing media data streams in sequence at the positions where mdat data exist in the MP4 file frame; judging whether the audio-video data stream is finished or not; if not, continuing to analyze the input audio and video data stream to generate a media data stream and media metadata information; if the data is finished, generating MP4 data based on all data in the MP4 file frame.

Description

MP4 generation method, device, equipment and storage medium

Technical Field

The present invention relates to the field of video generation, and in particular, to a method, an apparatus, a device, and a storage medium for generating MP 4.

Background

The existing network video device generally adopts a power supply circuit to supply power when recording videos, and has no standby battery. When the power supply is powered off due to the fact that a power supply circuit is loosened or damaged and a power supply main switch is turned off due to external reasons, sudden power failure or blocking is easy to occur when videos are recorded, and therefore the video files are recorded and made mistakes, and therefore the video recording files are incomplete and cannot be played normally. In addition to power failure, plugging or loosening of the removable storage, and dead halt caused by software and hardware faults and the like.

Meanwhile, the conventional mp4 file is usually generated by creating an mp4 file, and during the writing process of the mp4 file, since the sizes of the index part (moov) for storing media stream information and the part (mdat) for storing media stream data increase with the increase of the media stream data, the moov of the conventional mp4 library is buffered in a memory when the mp4 file is written. Only writing part of the media stream data mdat into the hard disk, and writing the head of the file into the hard disk after all data are written. That is, while mdat continues to be written, power is off, and moov is not written into the file, so mdat media stream data cannot be read from moov. In the prior art, the mp4 file has an abnormal occurrence in the recording process, such as power failure or process crash, which results in the recorded file being invalid.

Disclosure of Invention

The invention mainly aims to solve the technical problem that the recorded files are invalid due to abnormal occurrences such as power failure or process crash of mp4 files in the recording process.

The first aspect of the present invention provides a method for generating MP4, including the steps of:

creating an MP4 file frame, and writing mdat data in the MP4 file frame;

analyzing the input audio-video data stream to generate a media data stream and media metadata information;

generating a moov offset value according to the mdat data and the media data stream;

writing the moov offset value into the media metadata information to generate moov data;

generating new mdat data in the MP4 file frame according to the mdat data and the media data stream;

writing media data streams in sequence at the positions where mdat data exist in the MP4 file frame;

judging whether the audio-video data stream is finished or not;

if not, continuing to analyze the input audio and video data stream to generate a media data stream and media metadata information;

if the data is finished, combining and generating MP4 data based on all data in the MP4 file frame.

Optionally, in a first implementation manner of the first aspect of the present invention, the analyzing the input audio and video data stream and generating the media data stream and the media metadata information includes:

and analyzing and processing the input audio and video data according to a preset MP4 multiplexing algorithm to generate a media data stream and media metadata information.

Optionally, in a second implementation manner of the first aspect of the present invention, the format of the audio/video data stream includes: flv format.

Optionally, in a third implementation manner of the first aspect of the present invention, the generating a moov offset value according to the mdat data and the media data stream includes:

calculating a first stored value of said media data stream, analyzing a second stored value of said mdat data;

adding the first stored value to the second stored value to obtain a moov offset value.

Optionally, in a fourth implementation manner of the first aspect of the present invention, the writing the moov offset value into the media metadata information, and generating moov data includes:

obtaining the offset position of the moov according to the moov offset value;

and writing the moov offset value into the media metadata information according to the offset position to generate moov data.

Optionally, in a fifth implementation manner of the first aspect of the present invention, the creating an MP4 file framework includes:

calling a preset initial MP4 file frame, writing ftyp in the initial MP4 file frame, and generating an MP4 file frame.

Optionally, in a sixth implementation manner of the first aspect of the present invention, the ftyp includes: header x 088.

The second aspect of the present invention provides an apparatus for generating an MP4, wherein the apparatus for generating an MP4 comprises:

the creating module is used for creating an MP4 file frame, and writing mdat data in the MP4 file frame;

the analysis module is used for analyzing the input audio and video data stream and generating a media data stream and media metadata information;

a first generating module, configured to generate a moov offset value according to the mdat data and the media data stream;

the second generation module is used for writing the moov offset value into the media metadata information to generate moov data;

a third generating module, configured to generate new mdat data in the MP4 file frame according to the mdat data and the media data stream;

a sequential writing module, configured to write a media data stream in sequence at a position where mdat data exists in the MP4 file frame;

the judging module is used for judging whether the audio and video data stream is finished or not;

the loop module is used for continuously analyzing the input audio and video data stream if the audio and video data stream is not finished, and generating a media data stream and media metadata information;

and the combination generation module is used for combining and generating MP4 data based on all the data in the MP4 file frame if the data is finished.

The third aspect of the present invention provides an MP4 generating apparatus, including: a memory having instructions stored therein and at least one processor, the memory and the at least one processor interconnected by a line; the at least one processor invokes the instructions in the memory to cause the generation device of the MP4 to perform the generation method of MP4 described above.

A fourth aspect of the present invention provides a computer-readable storage medium having stored therein instructions, which, when run on a computer, cause the computer to execute the above-described generation method of MP 4.

In the embodiment of the invention, the media stream information moov is written in by pre-calculating the position of the moov, and then the media data stream is written to update the mdat, so that the moov header is prevented from power failure or process crash caused by abnormality, the mp4 file which is being recorded can still be played, the reliability of generating the mp4 file is improved, and the storage space of the file is not required to be increased.

Drawings

FIG. 1 is a schematic diagram of an embodiment of a method for generating MP4 according to an embodiment of the present invention;

FIG. 2 is a diagram illustrating the data structure of MP4 according to an embodiment of the present invention;

FIG. 3 is a diagram of an embodiment of a device for generating MP4 according to the embodiment of the present invention;

fig. 4 is a schematic diagram of an embodiment of a generation device of the MP4 in the embodiment of the present invention.

Detailed Description

The embodiment of the invention provides a method, a device, equipment and a storage medium for generating MP 4.

The terms "first," "second," "third," "fourth," and the like in the description and in the claims, as well as in the drawings, if any, are used for distinguishing between similar elements and not necessarily for describing a particular sequential or chronological order. It will be appreciated that the data so used may be interchanged under appropriate circumstances such that the embodiments described herein may be practiced otherwise than as specifically illustrated or described herein. Furthermore, the terms "comprises," "comprising," or "having," and any variations thereof, are intended to cover non-exclusive inclusions, such that a process, method, system, article, or apparatus that comprises a list of steps or elements is not necessarily limited to those steps or elements expressly listed, but may include other steps or elements not expressly listed or inherent to such process, method, article, or apparatus.

For convenience of understanding, a specific flow of the embodiment of the present invention is described below, and referring to fig. 1, an embodiment of the method for generating MP4 in the embodiment of the present invention includes:

101. creating an MP4 file frame, and writing mdat data in the MP4 file frame;

102. analyzing the input audio-video data stream to generate a media data stream and media metadata information;

in the 101-102 embodiment, as shown in fig. 2, it is shown that the MP4 file frame has format data such as ftyp, mdat, moov, and the like, and mdat data is written first.

In step 101, the following steps may be performed:

1011. calling a preset initial MP4 file frame, writing ftyp in the initial MP4 file frame, and generating an MP4 file frame.

In this embodiment, the ftyp includes: the header 088 is used as data of a header file, the MP4 file includes ftyp as a header file, an mdat format file and a moov format file, the mdat format file and the moov format file are continuously modified in a later processing step, and the ftyp is used as a header file in an initial MP4 file frame to obtain an MP4 file frame.

In step 102, the following steps may be performed:

1021. and analyzing and processing the input audio and video data according to a preset MP4 multiplexing algorithm to generate a media data stream and media metadata information.

In this embodiment, the multiplexing algorithm is implemented by using a programming manner to implement the function of the multiplexer, and decomposes the input audio data into a media stream data stream and media metadata information, where the media stream data stream is mainly entity data of audio and video, the media metadata information is mainly data describing the entity data, and the format of the audio and video data stream includes: flv format.

103. Generating a moov offset value according to the mdat data and the media data stream;

in this embodiment, the mdat data is mainly entity data for describing audio and video, and the moov offset value is obtained according to a deviation between the mdat data and the media data stream.

Preferably, the following steps may be performed in step 103:

1031. calculating a first stored value of said media data stream, analyzing a second stored value of said mdat data;

1032. adding the first stored value to the second stored value to obtain a moov offset value.

Steps 1031 and 1032 mainly illustrate how the moov offset value is obtained, and the moov offset value is generated by adding the storage value size of the media data stream and the storage value size of the mdat data.

104. Writing the moov offset value into the media metadata information to generate moov data;

in this embodiment, the moov offset value is mainly content describing the offset position, and moov data is written in the MP4 file frame by adjusting the description content of the media metadata information based on the offset value.

Preferably, the step 104 may perform the following steps:

1041. obtaining the offset position of the moov according to the moov offset value;

1042. and writing the moov offset value into the media metadata information according to the offset position to generate moov data.

In steps 1041 and 1042, media stream information is written according to the offset position of moov, a new moov is generated, mainly to record the mdat size, the mdat size is updated, and then media data is written at the previously recorded mdat size position. moov will be written first, moov will be written to the process, and previous moov will be overwritten by the new media data stream.

105. Generating new mdat data in the MP4 file frame according to the mdat data and the media data stream;

106. writing media data streams in sequence at the positions where mdat data exist in the MP4 file frame;

in

steps

105 and 106, media stream data is written as new mdat data based on the original mdat data, and the length of the new mdat data is calculated to generate an mdat data frame. In the process, the media data stream is further written in the new mdat data frame at the position of the original mdat data, and finally a new whole segment of mdat data is generated.

107. Judging whether the audio-video data stream is finished or not;

108. if not, continuing to analyze the input audio and video data stream to generate a media data stream and media metadata information;

109. if the data is finished, combining and generating MP4 data based on all data in the MP4 file frame.

In step 107-109, it is the main loop analysis that whether the generation of the MP4 data is completed, and if not, step 108 means returning to step 102 for further loop processing. If it is done, the MP4 file frame is used to generate MP4 data according to the written data.

With reference to fig. 3, the method for generating MP4 in the embodiment of the present invention is described above, and a device for generating MP4 in the embodiment of the present invention is described below, where an embodiment of the device for generating MP4 in the embodiment of the present invention includes:

a creating module 301, configured to create an MP4 file frame, and write mdat data in the MP4 file frame;

an analysis module 302, configured to analyze an input audio/video data stream, and generate a media data stream and media metadata information;

a first generating module 303, configured to generate a moov offset value according to the mdat data and the media data stream;

a second generating module 304, configured to write the moov offset value into the media metadata information, and generate moov data;

a third generating module 305, configured to generate new mdat data in the MP4 file frame according to the mdat data and the media data stream;

a sequential writing module 306, configured to write a media data stream in sequence at a position where mdat data exists in the MP4 file frame;

a judging module 307, configured to judge whether the audio/video data stream has ended;

a loop module 308, configured to continue analyzing the input audio and video data stream if the input audio and video data stream is not ended, and generating a media data stream and media metadata information;

and a combination generating module 309, configured to, if the MP4 data is completed, generate MP4 data in combination based on all the data in the MP4 file frame.

Wherein the analysis module 302 is specifically configured to:

The first generating module 303 is specifically configured to:

The second generating module 304 is specifically configured to:

obtaining the offset position of the moov according to the moov offset value;

Wherein the creating module 301 is specifically configured to:

Fig. 3 describes the generation apparatus of the MP4 in the embodiment of the present invention in detail from the perspective of the modular functional entity, and the generation apparatus of the MP4 in the embodiment of the present invention in detail from the perspective of hardware processing.

Fig. 4 is a schematic structural diagram of a generating device of an MP4 according to an embodiment of the present invention, where the generating device 400 of the MP4 may have a relatively large difference due to different configurations or performances, and may include one or more processors (CPUs) 410 (e.g., one or more processors) and a memory 420, and one or more storage media 430 (e.g., one or more mass storage devices) for storing applications 433 or data 432. Memory 420 and storage medium 430 may be, among other things, transient or persistent storage. The program stored on storage medium 430 may include one or more modules (not shown), each of which may include a series of instruction operations in generating device 400 for MP 4. Further, processor 410 may be configured to communicate with storage medium 430 to execute a series of instruction operations in storage medium 430 on generating device 400 of MP 4.

The MP 4-based generating device 400 may also include one or more power supplies 440, one or more wired or wireless network interfaces 450, one or more input-output interfaces 460, and/or one or more operating systems 431, such as Windows Server, Mac OS X, Unix, Linux, FreeBSD, and the like. Those skilled in the art will appreciate that the generation device architecture of MP4 shown in fig. 4 does not constitute a limitation of the generation device based on MP4, and may include more or fewer components than shown, or some components in combination, or a different arrangement of components.

The present invention also provides a computer readable storage medium, which may be a non-volatile computer readable storage medium, and which may also be a volatile computer readable storage medium, having stored therein instructions, which, when run on a computer, cause the computer to perform the steps of the MP4 generation method.

It is clear to those skilled in the art that, for convenience and brevity of description, the specific working processes of the above-described systems, apparatuses, and units may refer to the corresponding processes in the foregoing method embodiments, and are not described herein again.

The integrated unit, if implemented in the form of a software functional unit and sold or used as a stand-alone product, may be stored in a computer readable storage medium. Based on such understanding, the technical solution of the present invention may be embodied in the form of a software product, which is stored in a storage medium and includes instructions for causing a computer device (which may be a personal computer, a server, or a network device) to execute all or part of the steps of the method according to the embodiments of the present invention. And the aforementioned storage medium includes: various media capable of storing program codes, such as a usb disk, a removable hard disk, a read-only memory (ROM), a Random Access Memory (RAM), a magnetic disk, or an optical disk.

The above-mentioned embodiments are only used for illustrating the technical solutions of the present invention, and not for limiting the same; although the present invention has been described in detail with reference to the foregoing embodiments, it will be understood by those of ordinary skill in the art that: the technical solutions described in the foregoing embodiments may still be modified, or some technical features may be equivalently replaced; and such modifications or substitutions do not depart from the spirit and scope of the corresponding technical solutions of the embodiments of the present invention.

Claims

1. A method for generating MP4, comprising the steps of:

creating an MP4 file frame, and writing mdat data in the MP4 file frame;

judging whether the audio-video data stream is finished or not;

2. The method for generating an MP4 of claim 1, wherein the analyzing an input audio-visual data stream to generate a media data stream and media metadata information comprises:

3. The method for generating MP4, according to claim 2, wherein the format of said audio-visual data stream includes: flv format.

4. The method for generating MP4 of claim 1, wherein the generating a moov offset value according to the mdat data and the media data stream comprises:

5. The method for generating the MP4 of claim 1, wherein the writing the moov offset value in the media metadata information generates moov data including:

obtaining the offset position of the moov according to the moov offset value;

6. The MP4 generation method of claim 1, wherein the creating of the MP4 file frame comprises:

7. The MP4 generation method of claim 6, wherein ftyp comprises: header x 088.

8. An apparatus for generating an MP4, wherein the apparatus for generating an MP4 comprises:

9. A generating device of an MP4, wherein the generating device of an MP4 comprises: a memory having instructions stored therein and at least one processor, the memory and the at least one processor interconnected by a line;

the at least one processor invokes the instructions in the memory to cause the generation device of the MP4 to perform the generation method of the MP4 of any of claims 1-7.

10. A computer-readable storage medium, on which a computer program is stored, which, when being executed by a processor, implements the method of generating an MP4 according to any one of claims 1-7.