[FFmpeg-user] Fifo muxer with ISMV output results in corrupted video

[Louis Geuten]

Hello,

It seems that using the argument "-flags +global_header" with the bitstream
filter "dump_extra" fixes the issue.
Why this isn't needed when directly muxing with ISMV instead of fifo is
beyond me.


On Tue, 23 Jun 2020 at 12:03, Louis Geuten <louis.geuten at freecaster.com>
wrote:

> Hello,
>
> I'm using ffmpeg to transcode vod or live content using h264 through the
> ISMV protocol.
> I have had a few issues with networking recently, and decided to try to
> use the fifo muxer to decouple the output I/O from the encoding.
>
> However it seems that the video packets produced by the muxer are not
> valid. The audio seems fine.
> Saving the file on disk allow me to probe it, and it fails with the
> following error:
>
> [extract_extradata @ 0x48c9900] No start code is found.
> bonjour/Stream(v-0-1280): Invalid data found when processing input
>
> I have attached the output logs for both commands.
>
> The *fifo* command, which produces corrupt video files
> *(Job-7-Run-36.err)*
> /usr/local/bin/ffmpeg -nostdin -loglevel trace -probesize 20M
> -analyzeduration 10M -y -re -stream_loop -1 -i kuro_demo.mp4 -map 0:0 -vf
> "scale=1280:720" -pix_fmt yuv420p -preset veryfast -tune zerolatency
> -x264opts no-sliced-threads:nal-hrd=cbr:scenecut=0:qpmax=45:keyint=25
> -minrate 2600K -maxrate 2600K -bufsize 5200K -b:v:0 2600K -flags +cgop -g
> 25 -keyint_min 25 -r 25.000000 -c:v:0 libx264 -an -bsf:v dump_extra -f fifo
> -fifo_format ismv -queue_size 200 -drop_pkts_on_overflow 1
> -attempt_recovery 1 -recovery_wait_time 1 -restart_with_keyframe 1
> -format_opts
> frag_duration=1920000:movflags=isml+frag_keyframe:write_prft=wallclock:fflags=+genpts
> bonjour/Stream(v-0-1280) -map 0:1 -c:a:0 aac -b:a:0 96K -ac 2
> -metadata:s:a:0 language=und -bsf:v dump_extra -f fifo -fifo_format ismv
> -queue_size 200 -drop_pkts_on_overflow 1 -attempt_recovery 1
> -recovery_wait_time 1 -restart_with_keyframe 1 -format_opts
> fflags=+genpts:frag_duration=1920000:movflags=isml+frag_keyframe:write_prft=wallclock
> bonjour/Stream(a-0-und)
>
> The same command without using the fifo muxer: (*Job-7-Run-37.err*)
> /usr/local/bin/ffmpeg -nostdin -loglevel trace -probesize 20M
> -analyzeduration 10M -y -re -stream_loop -1 -i kuro_demo.mp4 -map 0:0 -vf
> "scale=1280:720" -pix_fmt yuv420p -preset veryfast -tune zerolatency
> -x264opts no-sliced-threads:nal-hrd=cbr:scenecut=0:qpmax=45:keyint=25
> -minrate 2600K -maxrate 2600K -bufsize 5200K -b:v:0 2600K -flags +cgop -g
> 25 -keyint_min 25 -r 25.000000 -c:v:0 libx264 -an -f ismv -movflags
> isml+frag_keyframe -write_prft wallclock -fflags +genpts -frag_duration
> 1920000 bonjour/Stream(v-0-1280) -map 0:1 -c:a:0 aac -b:a:0 96K -ac 2
> -metadata:s:a:0 language=und -f ismv -fflags +genpts -frag_duration 1920000
> -movflags isml+frag_keyframe -write_prft wallclock bonjour/Stream(a-0-und)
>
> I am using the latest git HEAD commit
> (44ce333f03e5daf7883147938f74018cec287aec) built from source.
>
> Is there some option I am missing to make the output ISMV file correct ?
> Or is this a bug in the fifo muxer ?
>
> Thanks for the help.
>


-- 

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