VSE: MKV file has varying frames depending on if added as proxied or non-proxied strip #47141

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David Salvo · 2016-01-08T06:37:30+01:00

David Salvo commented

2016-01-08 06:37:30 +01:00

I've come across so many hard-to-isolate timing issues with sound/video in the VSE, so I'm trying really hard to isolate them now where possible... Lots of differing lengths between sound/movie streams (with FPS correctly set), and it's hard to know if the problem lies with blender or the AV libraries. I've had problems with the original MTS files, seem to have had more luck converting to MKV, but they seem to have problems as well on and off...

I've attached an MKV file which opens with 2 blank video frames at the end (they will either appear as frozen frames, or black frames) even though it shows the no. of frames as matching the audio (119/119).
However if I create a proxy for it, then open it again, it opens with 117 video frames (which seems to be the correct one).

Open blender VSE
Set framerate to 25 FPS
Open attached file 00085.mkv (will open as 119/119)
Create proxy for file
Open 00085.mkv again, video component will open as 117 frames.

Not sure if there's an easy way to diagnose where the fault lies for this?
I'll try to isolate an error with the original MTS files too if possible.

Am running nightly build 7e6d096, Mint 17.3, NVIDIA G92 [GeForce 9800 GT].

File is below:
00085.mkv

I've come across so many hard-to-isolate timing issues with sound/video in the VSE, so I'm trying really hard to isolate them now where possible... Lots of differing lengths between sound/movie streams (with FPS correctly set), and it's hard to know if the problem lies with blender or the AV libraries. I've had problems with the original MTS files, seem to have had more luck converting to MKV, but they seem to have problems as well on and off... I've attached an MKV file which opens with 2 blank video frames at the end (they will either appear as frozen frames, or black frames) even though it shows the no. of frames as matching the audio (119/119). However if I create a proxy for it, then open it again, it opens with 117 video frames (which seems to be the correct one). 1. Open blender VSE 2. Set framerate to 25 FPS 3. Open attached file 00085.mkv (will open as 119/119) 4. Create proxy for file 5. Open 00085.mkv again, video component will open as 117 frames. Not sure if there's an easy way to diagnose where the fault lies for this? I'll try to isolate an error with the original MTS files too if possible. Am running nightly build 7e6d096, Mint 17.3, NVIDIA G92 [GeForce 9800 GT]. File is below: [00085.mkv](https://archive.blender.org/developer/F271989/00085.mkv)

David Salvo commented

2016-01-08 06:37:30 +01:00

Changed status to: 'Open'

David Salvo commented

2016-01-08 06:37:30 +01:00

Added subscriber: @slinkeepie

Sergey Sharybin commented

2016-01-08 08:45:14 +01:00

Added subscriber: @Sergey

Sergey Sharybin commented

2016-01-08 08:45:14 +01:00

Changed status from 'Open' to: 'Archived'

Sergey Sharybin closed this issue

2016-01-08 08:45:14 +01:00

Sergey Sharybin self-assigned this 2016-01-08 08:45:14 +01:00

Sergey Sharybin commented

2016-01-08 08:45:14 +01:00

This is somewhat broken video, it's easy to see when using "Record Run no Gaps" timecode. This timecode basically tries to decode every frame and if frame fails to be decoded for some reason it's being ignored. Same exact behavior happens with generating proxies -- if some frame fails to be decoded it's being dropped. In your video there are two frames which can not be decoded, which causes video strip to shrink.

What you can do is try transcoding the video in an external application like mencoder or ffmpeg and use transcoded result in Blender.

Thanks for the report, but it's not really a Blender bug.

This is somewhat broken video, it's easy to see when using "Record Run no Gaps" timecode. This timecode basically tries to decode every frame and if frame fails to be decoded for some reason it's being ignored. Same exact behavior happens with generating proxies -- if some frame fails to be decoded it's being dropped. In your video there are two frames which can not be decoded, which causes video strip to shrink. What you can do is try transcoding the video in an external application like mencoder or ffmpeg and use transcoded result in Blender. Thanks for the report, but it's not really a Blender bug.

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VSE: MKV file has varying frames depending on if added as proxied or non-proxied strip #47141