[mythtv-users] Problems with audio in DVB transcodes

[Kenneth Aafløy]

Kent Williams wrote:
> I can't seem to get the audio in my DVB transcodes to work properly.
> I've tried many different settings for the MPEG2 profile under
> transcoders but each gives the same results. For the 'MP3' codec I've
> tried sampling rates of 32kHz, 44.1kHz, and 48kHz. One interesting
> point is that when changing the codec to 'uncompressed' (only tried
> this with a sample rate of 48kHz) I still get the same problem. This
> suggests to me that the problem is in the decoding?
> 
> I've created a short 30 second clip that can probably explain things
> better: http://scuznet.dyndns.org:8888/files/6005_20040121060000_20040

I have essentially no clue as where this problem might come from,
however, I can confirm that DVB transcoding works as a charm (from my
point of view), as I've used it' on a show for a couple of months now.

> The following is what is shown on mythbackend:
> Input #0, mpeg, from
> '/mnt/massstore/recordings/6005_20040121060000_20040121063000.nuv':
>  Stream #0.0: Video: mpeg2video, 720x576, 25.00 fps
>  Stream #0.1: Audio: mp2, 48000 Hz, stereo, 256 kb/s
> 2004-01-25 14:58:53 Fast-Forwarding from 0 to 5989
> 2004-01-25 14:59:23 Fast-Forwarding from 6739 to 53331
> [mpeg2video @ 0x84290c8]invalid mb type in P Frame at 35 2
> [mpeg2video @ 0x84290c8]concealing errors
> [mpeg2video @ 0x84290c8]Warning MVs not available
> 2004-01-25 14:59:25 Transcoding
> /mnt/massstore/recordings/6005_20040121060000_20040121063000.nuv done
>
> Any help would be very much appreciated!

What I want to point out, is that you probably have an on egde signal
issue (ie, your antenna is off a bit), or there has been some very
bad wether when you recorded this show. The invalid mb (macroblock)
won't come from a providers encoded mpeg2.

What follows is that the transcoder might be confused about the
errors in the stream, and misinterpret it's information.

Could you confirm this error with a recording that does not
excibit this kind of errors in it?

Kenneth