[mythtv-users] nuvexport/transcode + dvb + a/v sync problem

Nick knowledgejunkie at gmail.com
Thu May 19 09:09:40 UTC 2005


On 5/19/05, Philip Nelson <phatfil at optusnet.com.au> wrote:
> On Thu, 19 May 2005 17:46, Nick wrote:
> > Basically I suggested running a Java app called ProjectX,
> > which will fix up your DVB file before you attempt to transcode it
> 
> I just grabbed the latest version of ProjectX - however I don't seem to be
> able to get it to do much with my file - it doesn't seem to recognise the
> mpeg4 video stream.
> From the Info tab:
> 
> Video:  no video found at a short scan
> Audio:  MPEG-1, Layer3, 48000Hz, stereo, 128kbps, noCRC
> 
> So I think this isn't really going to help me since I don't have the original
> mpeg2 dvb stream?

Philip,

As I wrote in the previous message, this is to be run on the original
DVB TS/PS or hardware captured MPEG2 file *before* it is transcoded.
If you do not have the original file, I can't see the a/v sync issue
being overcome unless you do some further editing in something like
VirtualDub to cut the file in half (saving to a lossless intermediate
file), adjust the sync issue by adding a delay (+ or -) to the audio
stream, and then joining the two files back together (still not a
guaranteed solution though).

I'd also *never* recommend exporting a DVB file to mp4 (of which DivX,
XVid etc all are) and then re-exporting to mp4 again. You will lose a
lot of quality in the process. The ideal process would be to take the
DVB file, "fix" it if there are errors in the streams (there usually
are in my UK recorded DVB files), make the cuts (using lossless GOP
editing), and then export it to the final XVid file. This should
ensure the highest quality output, and is likely to be much quicker
also, as the intermediate mp4 is not used.

HTH,
Nick


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