After extraction video AVC/H264 stream from DASH mp4-segment SEI messages are put prior SPS/PPSges

[Shevach]

Summary of the bug:
mp4-dash segment containing AVC/H264 video is not self-decoded since SPS/PPS are present in mp4 init-file (within stsd-box).
To make a mp4-dash segment decodable i concatenate the init-file with the segment and then apply ffmpeg to extract the elementary video stream, e.g.

ffmpeg -i test.mp4 -vcodec copy -vbsf h264_mp4toannexb -f h264 test.h264

i receive AVC/H.264 stream with the start SEI messages (e.g. timing SEI) transmitted prior to SPS/PPS.

To reproduce this issue i attach test.mp4 (which is a concatenation of init.mp4 and a mp4 dash segment.

[Shevach]

In shaka-packager there is an option 'init_segment' to generate the 'init' mp4 file containing SPS/PPS applicable to all segments.

i provide an example how to generate mp4 dash segments with the init-file (test_init.mp4):

/packager-linux 'in=test.ts , stream=video, init_segment=test_init.mp4, segment_template=test_$Number$.mp4' --profile vod --mpd_output test.mpd --dump_stream_info --min_buffer_time=0.1 --segment_duration=0.5 --strip_parameter_set_nalus=false

As a results test_1.mp4, test_2.mp4, ... segments are generated and in addition test_init.mp4 file is also produced.

[Balling]

Is this still a problem? BTW, there is this. ​https://patchwork.ffmpeg.org/project/ffmpeg/patch/abe4571410fa4ef3947119d5064dea3e@mx.toyon.corp/