Video Freezing on Merged MKV - Not sure if authoring or playback issue

[SuperSaiyanMusashi]

Files: https://www.mediafire.com/file/9usu4oqqel3z7uq/112_-Mini_Arc_Part%25282%2529.mkv/file https://www.mediafire.com/file/54l3zf8rhxzkmf8/112_-Mini_Arc_Part%25283%2529.mkv/file

Describe the bug I merged 2 small MKVs but when I played the resulting combined video on VLC or WMP the video stops at the split point while the sound keeps going. However If I back up or skip to a point after where it stopped, it shows the correct video. When the merged file is brought into Lossless Cut, it plays fine, albeit without the sound.

To Reproduce Merge the 2 files above, play resulting MKV in Windows Media Player or VLC.

Expected behavior I would expect the merged file to play the videos back to back smoothly.

Desktop (please complete the following information): Windows 10

Additional context Since skipping / rewinding seems to get the correct picture to show, I know the data for it must be present in the file, and I suspect this might be a playback problem as opposed to an authoring issue with Lossless Cut, so I'm open to recommendations for other players too. The stem files in the link are blu-ray grade and use TrueHD Audio, which I'd like to keep if possible.

[JasonShearer]

I was having this issue while merging several videos last night.

[slrslr]

I have tried OP's files and after merging using LC 3.36.0 on Linux (OP having Windows), i see the same problem as OP describe. "ffplay -loglevel verbose file" shows: [truehd @ 0x7faa0002cc00] Lossless check failed - expected 43, calculated 2c. nothing more interesting. When played using "VLC -vv file", then it shown some warnings I have tried to merge also using: ffmpeg -i "concat:112 - Mini Arc Part (2).mkv|112 - Mini Arc Part (3).mkv" -c copy out.mkv ffplay out.mkv and the result is same as LosslessCut. So merging is not the issue maybe.. but cutting or the fragments or not using fragments made by losslessCut?

[SpencerMeow]

So haven't they fixed it yet???

[mifi]

I noticed that these videos have a lot of tracks (streams). Could be worth trying to disable all tracks except video and see if it has the same issue. If it does not, then selectively re-enable tracks until it stops working. Lossless merging is really complex and is handled by ffmpeg, so not much losslesscut can do about any such issues.

[SuperSaiyanMusashi]

Ah hello!

My current version of the "whole video" has only the video and a single audio track; Along the way I noticed I could shed some dead time by parsing out the video track and the main audio track then recombining them. It still gets the choke-ups at the same spots though, forcing me to keep multiple video files and play them sequentially.

[mifi]

Do OP's video parts come from losslesscut ? If so I can only suggest first exporting a file with only a few tracks (e.g. audio and video). then open that new file and try to cut+merge that.

[SuperSaiyanMusashi]

Ey. Yes all the pieces came from Losslesscut except for the original rips of the movies which came from MakeMKV. I tried removing all the tracks except for the video and a single audio track but I still got the hold up when playing the merged video.

[mifi]

I can only suggest trying:

• try the different avoid_negative_ts values in the export dialog
• Try both Cut modes keyframe/normal
• to cut the pieces from the command line with a newer version of ffmpeg and see if that helps. (go to the help sheet and find the commands there and use them on the command line)

[SuperSaiyanMusashi]

I will see what these do next time I work on vids.

[ValZapod]

[truehd @ 0x7faa0002cc00] Lossless check failed - expected 43, calculated 2c.

Will be IMHO fixed in https://patchwork.ffmpeg.org/project/ffmpeg/patch/[email protected]/

Flushing when seeking and thus those lossless warnings is fixed in https://github.com/FFmpeg/FFmpeg/commit/5673a4842556b79a92a1ede6e9696506fd4161ad

[SuperSaiyanMusashi]

[truehd @ 0x7faa0002cc00] Lossless check failed - expected 43, calculated 2c.

Will be IMHO fixed in https://patchwork.ffmpeg.org/project/ffmpeg/patch/[email protected]/

Flushing when seeking and thus those lossless warnings is fixed in FFmpeg/FFmpeg@5673a48

This patch might fix the issue I'm having? How do I use it?

[ValZapod]

This patch might fix the issue I'm having?

Sorry, I was wrong: it did not fix the issue here. The bug is in concat.