[mythtvnz] Transcoding help?...

[Tony Sauri]

On Mon, 10 Aug 2009 23:36, Ross and Jemima Knudsen wrote:
> Hi Tony,
>
> Thanks for your response.  I didn't think that mythtranscode worked at
> all.  Everything I read seemed to indicate it can't handle h264 content.

I have found this write-up that has been helping me understand h264 in ffmpeg

     http://rob.opendot.cl/index.php/useful-stuff/ffmpeg-x264-encoding-guide/

h264 encoding is slow though I get about 3 fps on my 3GHz 1GB Ram P4!

> I can definitely relate to the audio sync issues.  Its hard to tell but
> I think the sync gets worse the longer it plays.  

Yes I noticed that too.

I have found that if you use mythtranscode the sound sems to stay in sync
 very nicely ... the downside being that there are fewer knobs to "twiddle"
 and you get a nuv file that might have to be processed again to get to a
 more standard container format.  Also as I pointed out it seems to be
 "flakey" at the moment with approx 5% of my transcodes failing .

> I tried a number of
> different options based on what you suggested for a "lossless"
> transcode.  I got the following output:
>
> http://openwrt.pastebay.org/pastebay.php?dl=39551
>
> What I think is interesting is that video output is not quite identical
> to the input even though its supposed to be copying the stream.  Also
> I'm assuming that the reference frame errors, unref short failure and
> missing picture errors are ok and not causing my problems...

I get the same sorts of errors  sometimes many sometimes few ... I just
presumed that they were transmission errors on the broadcast stream (there is
no error correction like in a TCP/IP stream).
They seem to do no harm although I do sometimes see some artifacts that only
last a frame or two.