Copy and merge video streams - lossless operation

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dakiri
Posts: 3
Joined: Mon Dec 03, 2012 5:32 pm

Copy and merge video streams - lossless operation

Post by dakiri »

Feature request:
Copy and merge video tracks (titles, chapters) without reencoding them. This would be the analog of the pass though option for audio. It would by default operate on the VOB files composing a title.

Benefits of this feature:
- Other external encoders could be applied by the user for formats which HandBrake does not yet support.
- No decrease in fidelity without reencode, but allows repackaging from multiple files into a single file.
- Flexibility to reencode audio but not reencode video.
Smithcraft
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Joined: Thu Jan 22, 2009 8:04 pm

Re: Copy and merge video streams - lossless operation

Post by Smithcraft »

I believe that every time muxing has been requested it has been rejected. If you check some of the threads you will see that one of the reasons is to prevent feature bloat. Another reason is that Handbrake needs to sometimes alter the audio, even when it's passthrough, to handle issues in the video stream.

SC
dakiri
Posts: 3
Joined: Mon Dec 03, 2012 5:32 pm

Re: Copy and merge video streams - lossless operation

Post by dakiri »

Searching, focusing on the Feature Requests forum, I find no past request that I can identify as being exactly this feature.

I found some relating to switching between MKV & MP4 and
I found an analogous request for subtitles, but there was no reply to it.
viewtopic.php?t=23633

Copying the video could restrict the output format to what is convenient to program so that it is easy to implement. I guess that would be VOB and maybe MP4. This would avoid an AV synchronization issue that might occur switching between MKV & MP$.

Even being restricted to a certain output format, it would still be quite useful.
jamiemlaw
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Re: Copy and merge video streams - lossless operation

Post by jamiemlaw »

As far as I'm aware:

There are cases during encoding where audio and video can become out of sync. To get back in sync, HandBrake removes or duplicates video frames, because it's a lot less noticeable than repeating a slice of audio or inserting a chunk of silence. With video passthrough, if the audio and video get out of sync, HandBrake is screwed, because it can't manipulate the video in order to fix it.

You can create MKV files and losslessly join MKV files together with MKVMerge. You can losslessly convert MKVs to MP4s with MP4Box or Subler. You can losslessly convert VOB files to MKV with MakeMKV. You can join DVD titles using DVD2One. Using a combinations of these programs in conjunction with HandBrake, you should be able to do what you're looking for.
Smithcraft
Veteran User
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Joined: Thu Jan 22, 2009 8:04 pm

Re: Copy and merge video streams - lossless operation

Post by Smithcraft »

I just searched for 'rejected'

Video passthru
video passthrough
Video Passthru?

So, those are just the ones that were rejected. I think there are a couple where the title wasn't changed.

SC
dakiri
Posts: 3
Joined: Mon Dec 03, 2012 5:32 pm

Re: Copy and merge video streams - lossless operation

Post by dakiri »

Thanks for the replies.
Would there be a timing issue if a VOB is being generated as output format?
Reading those other threads, I see that the premise that HandBrake may alter timing of video frames is fundamental to HandBrake's operation.
I only have GNU/Linux here; otherwise, DVD2One might provide what I seek. Thanks for the suggestion, though.
TedJ
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Joined: Wed Feb 20, 2008 11:25 pm

Re: Copy and merge video streams - lossless operation

Post by TedJ »

So you want to rip and merge MPEG2 video from DVD sources without transcoding?
  1. Rip the titles you need from DVD using MakeMKV.
  2. Merge the extracted titles using MKVToolNix.
  3. ???
  4. Profit!
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