Is there any way to use FFMPEG expressions in bitstream filters options?

Question

FFMPEG allows to set User Data Unregistered in SEI block with h264_metadata bitstream filter:

ffmpeg -i input/test.mp4 \
       -bsf:v             \
       "h264_metadata=sei_user_data=c5bfd5ee-b030-11ec-b909-0242ac120002+waagh" \
       -f h264              \
          test.h264

I know it is possible to use FFMPEG expression evaluation mechanism in filter bodies, is it possible to do that in bitstream filter bodies? More specifically, I would like to encode a current Unix timestamp into SEI block to calculate actual latency during playback.

None of my attempts to use expressions in bitstream filter bodies worked.

Answer 1

The implementation is per-option rather than per-filter or per component type. For sei_user_data in h264_metadata, it's not implemented.