[mythtv] MPEG2-MPEG2 transcoding: Illegal video stream

Thomas Börkel thomas at boerkel.de
Fri Mar 3 17:48:19 UTC 2006


HI!

Geoffrey Hausheer wrote:
> On 3/3/06, Thomas Börkel wrote:
>> About that --ostream dvd option: IMHO, this should be the default. I
> will need to select what he wants to do, so this will remain an
> option.

Fine with me.

>>> those look fine.  you need to use --starttime and --chanid instead of
>>> --infile if you want to pull the cutlist from the database.
>> I tried. Still it ignored my cutlist in 0.19.
> I can't explain that to you, it works fine here on 0.19, and has since
> I released it.  If it works from within mythbackend, it will work from
> the command line too.

I will test again soon.

>> A friend missed the show and I want to give it to him. So I just burn it
> This is a case I'd like to be able to support entirely within
> mythtranscode at some point.  But again, you are thinking about cases
> where you encode the stream yourself.  I want to be able to support
> this for DVB/firewire cases too, which makes the problem significantly
> more challenging.

I don't understand, why DVB is more challenging, but I believe you. :-)

>> 2.
> This will be harder to achieve entirely within mythtranscode, but it
> may be doable.  the problem is that mp2 and ac3 use different packet
> sizes, so it requires a lot of care to handle properly.  It would also
> involve building PES headers for the audio stream, something I don't
> do today.  Just for the record, I am not interested in any method that
> splits the streams into elementary streams then muxes them together
> after processing, it does not work in the general case.  Any solution
> to any problem listed has to be able to work within the frame-by-frame
> processing that is done by mythtranscode.

OK.

>> 3.
>> I want to archive the show, but it is too big. So, I cut it with
> The audio has the same issue as above, but (depending on how it works)
> there is no reason that we couldn't apply something like tcrequant to
> the individual frames.  Ths is probably significantly easier than the
> audio conversion.

Great.

>> So, since ffmpeg and transcode are already present on Myth boxes,
>> mythtranscode could use them.
> Transcode isn't present on my myth box (or wasn't until I put it there
> to test your case).  ffmpeg isn't normally there either though myth
> includes the libav code, so we can perform the same operations ffmpeg
> does with some work.

Sorry, so I was wrong there.

>> For my use-cases, it would be perfect, if mythtranscode could convert
>> the audio and optionally requant the video. And, as I said above, the
>> result should always be DVD compliant.
> Again, these could all be options, but there is no 'should always' about it.

OK.

>> Next step would be some DVD mastering code like VDR has, but this is not
>> as good as TMPGEnc DVD Author for example, so it is not that necessary
>> for me.
> Again, it has been discussed, just need someone to do the work.
> 
> Basically, there is a whole lot of work needed to implement the above
> in mythtranscode, and I don't have sufficient motivation to do it all
> (I use mythtranscode primarily to clean up broken streams, and remove
> commercials, and have never burned anything I record to DVD).  So I'll
> be happy to accept patches, but don't expect massive new features to
> just appear out of the blue.

Allright. Maybe the DVD authoring stuff does not even belong to 
mythtranscode, but should be an extra program/module. I haven't looked 
at MythBurn yet.

Please let me know, how I can test your fix (see other mail from today).

Thanks!

Thomas



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