Issue when concatenating mkvs using ffmpeg: How to

问题:

I've attempted to concatenate 2 mkv videos with ffmpeg, using the following commands:

ffmpeg -i file-01.mkv -f mpegts -c copy -bsf:v h264_mp4toannexb file-01.mpeg.ts
ffmpeg -i file-02.mkv -f mpegts -c copy -bsf:v h264_mp4toannexb file-02.mpeg.ts
ffmpeg -isync -i "concat:file-01.mpeg.ts|file-02.mpeg.ts" -f matroska
-c copy output.mkv

However, I receive the following error:

[matroska @ 0x7fc72a000600] Timestamps are unset in a packet for stream 0. This is deprecated and will stop working in the future. Fix your code to set the timestamps properly [matroska @ 0x7fc72a000600] Can't write packet with unknown timestamp av_interleaved_write_frame(): Invalid argument

How do I go about setting the timestamps?

回答1:

Not necessarily a solution, per se, but mkvmerge worked for me in the end. Was much simpler, too:

mkvmerge -o "merged.mkv" "file1.mkv" +"file2.mkv"

回答2:

Ok, try these steps:

ffmpeg -i file-01.mkv -c copy -map v 01.mp4
ffmpeg -i file-02.mkv -c copy -map v 02.mp4
ffmpeg -i 01.mp4 -i file-01.mkv -map 0:v -map 1:a -c copy -bsf:v h264_mp4toannexb file-01.mpeg.ts
ffmpeg -i 02.mp4 -i file-02.mkv -map 0:v -map 1:a -c copy -bsf:v h264_mp4toannexb file-02.mpeg.ts
ffmpeg -i "concat:file-01.mpeg.ts|file-02.mpeg.ts" -f matroska
-c copy output.mkv

Some H.264 streams have packets with no PTS values. FFmpeg has haphazard support for muxing these streams.