Sega FILM demuxer doesn't pass through any packets for stream copy

[Misty De Meo]

Summary of the bug:

FFmpeg produces an empty file when trying to copy a stream using -c:v copy from a .CPK file using the segafilm demuxer. FFmpeg does successfully demux the stream when decoding video or audio; it only fails when copying the streams verbatim.

With debug enabled, I can see that each packet is producing a "cur_dts is invalid" message.

How to reproduce:

% ffmpeg -i input.cpk -c:v copy output.mov
ffmpeg version git master
built on March 18, 2018

The verbose logs for the input and output streams show no packets being muxed:

Input file #0 (/Users/vlcice/Games/Lunar files/Lunar Silver Star Story translation/FMVs/Cinepak/AN000.CPK):
  Input stream #0:0 (video): 2515 packets read (16913460 bytes);
  Input stream #0:1 (audio): 431 packets read (9518248 bytes);
  Total: 2946 packets (26431708 bytes) demuxed
Output file #0 (/tmp/copy.mov):
  Output stream #0:0 (video): 0 packets muxed (0 bytes);
  Total: 0 packets (0 bytes) muxed

[Carl Eugen Hoyos]

To make this a valid ticket please provide the command line you tested together with the complete, uncut console output.

[Misty De Meo]

Verbose log from attempting to copy stream

[Misty De Meo]

Test pattern Sega FILM file

[Misty De Meo]

Sure thing. I've attached the complete, uncut console output from a verbose log along with a test pattern file that reproduces the bug. The command line I tested was:

ffmpeg -i test.cpk -c:v copy -v debug copy.mov

[Gyan]

Despite the first frame being a keyframe, the packet isn't marked as such. If this is a typical valid file, then it's a bug in the demuxer code which marks keyframe status.

You can use ffmpeg -i test.cpk -c copy -copyinkf out.mov to stop ffmpeg from seeking a keyframe to start copying from. This should yield the entire stream in the output.

[Gyan]

Patch sent. ​https://patchwork.ffmpeg.org/patch/8068/

[Misty De Meo]

Thanks! I see after that there's a second bug which means invalid timestamp/duration data is set; I'll submit a patch for that as well.

[Gyan]

Fixed in cfe1a9d311de6c36641cf295004cdbc77d7b600c