[mythtv-users] Is anyone else having problems with lossless MPEG-2 TS transcoding?

[Neil Milne]

2008/5/12 Scott Alfter <mythtv at salfter.dyndns.org>:
> Lately, I've had problems using MythTV's built-in lossless transcoding with
>  programs that were recorded as MPEG-2 transport streams.  I first ran into this
>  with Carrier (recorded in 1080i from an A180)...there seemingly was no audio,
>  but I think the video was OK.  I think the local PBS station puts out multiple
>  audio streams, and the transcoder picked the wrong one.

Yeah, this issue crops up in the UK too due to the mono audio
broadcast on some channels for hard-of-hearing. There's a one-line
patch you can apply to mpeg2fix.cpp to get it to ignore mono channels,
which is usually good enough in the UK as there is typically only a
single stereo audio channel broadcast.
 Here's the diff against revision 17294:
@@ -753,7 +753,7 @@
                 break;

             case CODEC_TYPE_AUDIO:
-                if (inputFC->streams[i]->codec->channels == 0)
+                if (inputFC->streams[i]->codec->channels < 2)
                 {
                     VERBOSE(MPF_GENERAL, QString(
                             "Skipping invalid audio stream: %1").arg(i));

I've not seen any video corruption, but I don't normally
auto-transcode, just do edits to stuff I'm going to keep for a while,
so perhaps it could happen and I haven't seen it yet.


Cheers,
Neil

-- 
Neil Milne