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This feature allows to play the recording file even if the recording was interrupted due to some error. The media data in such MP4 file will be available to play according to MP4 atoms.
Recording file rotation by MP4 header filling
Since build 5.2.2012 a recording MP4 file will automatically be rotated when a space is reserved for MP4 header in file and MOOV atom in MP4 header becomes filled. For example, if a 1920x1080 stream is publishing with bitrate 3 Mbps and 30 fps, and the stream is recording with the following settings
| Code Block | ||
|---|---|---|
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mp4_container_moov_first_reserve_space=true mp4_container_moov_reserved_space_size=2048 |
then one recording part will should be near 22 minutes length and long (near 510 Mb in size).
Updating MP4 header without space reservation
It is necessary to reserve a huge space for MP4 file header for a long streams recording. For example, moire than 5 M should be reserved to record a 1080p stream for one hour, and a much space will be left empty for a shorter recordings. To resolve this, since build 5.2.2020 MP4 hedaer actualization flow was changed. With the following parameter
| Code Block | ||
|---|---|---|
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mp4_container_write_header_on_fly=true |
and other settings left by default, the MP4 header will be written to a separate file. Thus, the recording consist of two files:
| Code Block | ||||
|---|---|---|---|---|
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-rw-r--r-- 1 flashphoner flashphoner 45293 Jul 15 09:58 test-f6a0c740-4255-11ef-af8d-e781f7a0d3ed.mp4.header
-rw-r--r-- 1 flashphoner flashphoner 924777 Jul 15 09:58 test-f6a0c740-4255-11ef-af8d-e781f7a0d3ed.mp4.tmp |
A header data are writtent to .header file and a mediadata are written to .tmp file. The files are concatenated when recording is finished
| Code Block | ||||
|---|---|---|---|---|
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-rw-r--r-- 1 flashphoner flashphoner 1930149 Jul 15 09:58 test-f6a0c740-4255-11ef-af8d-e781f7a0d3ed.mp4 |
If the recording was occasionally stopped by some failure, the header file and the data file remain on disk. In this case the files should be concatenated manually to play the data recorded
| Code Block | ||||
|---|---|---|---|---|
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cat test-f6a0c740-4255-11ef-af8d-e781f7a0d3ed.mp4.header test-f6a0c740-4255-11ef-af8d-e781f7a0d3ed.mp4.tmp > test-f6a0c740-4255-11ef-af8d-e781f7a0d3ed.mp4 |
Client side
If stream recording is enabled on the server, whether the stream is recorded or not is determined by the value of record parameter passed into the createStream function in the script of the publisher client:
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