VC1 skip forward issue

Hi. I’ve noticed that when skipping forward VC1 encoded films incrementally using direction right, the video behaves properly up to 5 presses (10mins in my case). When pressing right six times (20mins ahead) video loses sound then freezes. This is happening with all my vc1 files on both a vero 4K and 4K+ and across different hard drives. Not a big deal, but hopefully useful for you to know. Thanks.

In my experience VC1 is patchy on the Vero. On the 3.14 kernel I have some interlaced 1080/59.94 material that has intermittent picture corruption on the Vero but not on the Pi, and for the moment interlaced VC1 is very broken on 4.9, but hopefully both these can be fixed at some point.

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What container are you using (.MP4, .MKV, etc…)? Can you post MediaInfo for one of the files?

Hi. I’m using MKV containers, created using Makemkv. I know how to upload logs but I’m unsure how to post mediainfo details. Thanks.

Hi,

You can create the mediainfo-output of the affected media file on the OSMC device:

  1. login via SSH, user osmc, password osmc
  2. if not already installed: sudo apt-get update && sudo apt-get install mediainfo
  3. cdto the directory containing the video/audio material in question
  4. since mediainfoonly needs to read the header information of the file data, copy the first 4 Mbytes of the media file to a new file:
    dd if="<media file>" of=purgeme.bin bs=1024 count=4096
  5. upload the decoded media information using
    mediainfo purgeme.bin|paste-log
  6. publish the returned URL here in this topic
  7. remove the created media file snippet
    rm purgeme.bin

Thanks

https://paste.osmc.tv/exiyetegiv

Thanks!

Hi,

Please could you post some logs, showing the issue as well?

Thanks Tom.

Hopefully I’ve done this correctly. Tested the file by increasing the number of forward skips incrementally until 7 skips (jump 20 minutes forward) freezes playback. Thanks.

https://paste.osmc.tv/ibonuluzox

Hi @Tee77

  • Does this occur for any part of the film in your testing (makes it easier for me to repro)?
  • Is Dirty Harry the affected title? If so – is this just a straight VC-1 HD-DVD/BD rip?

I want to take a look at the issue firsthand and improve VC-1 overall

Thanks

Sam

I’ve tested this and can confirm the problem. I did find one interesting thing… If I play a movie where it’s about 25 minutes in and stop it. I can start it again at the 25M point. But it I start from the beginning and go to a chapter 24M in, I get the same problem.

EDIT: And another interesting thing. I found I can skip back 20M with no problem. It’s only forward that’s the issue.

Thanks for looking in to this Sam. As far as I can tell this happens for any part of the film- skipping 20mins ahead from either the beginning or middle of the film results in the same issue. Yes, Dirty Harry is the title- it‘s a straight Blu-ray rip using Makemkv. If it helps, other affected blurays (ripped the same way) exhibiting identical behaviour are Back To The Future, Caddyshack, The Goonies, Lord of the Rings (Theatrical version), Pan’s Labyrinth. Thanks.

Interesting. Just tested this and can confirm skipping back 20mins works fine. Also just found that skipping forward chapters on vc1 files will eventually lead to a sad face.

I have this same issue on my VC-1 Blu-ray remuxes. I have attached a test file below.

Steps to reproduce the bug
Start the video and skip straight to chapter “Wrong Man” or “Well-Dressed Guitar”.

What happens
Audio freezes while video might work for some seconds before freezing too. Time shows as minus 6 hours.

Test file (sorry for the large file, can’t really be smaller as issues begin when skipping about 20 minutes)