Not able to pipe gstreamer output into ffmpeg

Question

has anybody gotten gstreamer to successfully pipe it's video output into ffmpeg?

I've tried playing with /dev/stdout and I keep getting errors:

gst-launch -e v4l2src device=/dev/video0 ! 'video/x-raw-yuv,width=1920,height=1080,framerate=5/1' ! nv_omx_h264enc quality-level=2 ! mp4mux ! filesink location=/dev/stdout \ | ffmpeg -y -i - -codec copy -f flv test.flv

... [aac @ 0xebc4c0] Could not find codec parameters for stream 0 (Audio: aac (Main), 7.1, fltp, 1351 kb/s): unspecified sample rate Consider increasing the value for the 'analyzeduration' and 'probesize' options pipe:: could not find codec parameters Input #0, aac, from 'pipe:': Duration: N/A, bitrate: 1351 kb/s Stream #0:0: Audio: aac (Main), 7.1, fltp, 1351 kb/s [flv @ 0xec9280] sample rate not set Output #0, flv, to 'test.flv': Stream #0:0: Audio: aac, 7.1, 1351 kb/s Stream mapping: Stream #0:0 -> #0:0 (copy) Could not write header for output file #0 (incorrect codec parameters ?): Invalid argument ubuntu@tegra-ubuntu:~$

Running the commands separately (replacing /dev/stdout with a file) works fine.

If you got it to work and can share how you did it, that would be great.

Thanks.

is there an audio stream in there? full command line and uncut console output please? — rogerdpack

Roy D'atze Roy D'atze · Accepted Answer · 2020-10-09T18:30:46

You can not use MP4 as a streaming format, as it cannot be parsed linear, e.g. without random access. Therefore it works with files, but not via a pipe.

Replacing the container format with a format that can be streamed should do the trick:

gst-launch -e v4l2src device=/dev/video0 \
! 'video/x-raw-yuv,width=1920,height=1080,framerate=5/1' \
! nv_omx_h264enc quality-level=2 ! matroskamux \
! filesink location=/dev/stdout \
 | ffmpeg -y -i - -codec copy -f flv test.flv

Not able to pipe gstreamer output into ffmpeg

1 Answers