[mythtv] [PATCH] -- picking wrong AC-3 audio stream to play

Brad Templeton brad+mydev at templetons.com
Thu Feb 17 18:03:01 UTC 2005


On Thu, Feb 17, 2005 at 08:00:03AM -0500, Doug Larrick wrote:
> Brad Templeton wrote:
> >
> >    "Picking the wrong audio stream from multi-stream AC3 causing no 
> >    sound?"
> >
> >
> >This patch makes the code do what the comments say it does, in that
> >the comments say it scans through the streams and picks the first adequate
> >audio stream.  The code has a countdown loop which breaks out at the first
> >match, which thus will be the highest numbered stream.
> 
> I submitted roughly the same patch a month or so ago (indeed, I have it
> in my local tree), which was not accepted because apparently the
> existing code does the "right" thing for most DVDs.

I was not aware that that the recording player played DVDs at all.

However, right now the code doesn't do what the comments say -- though
actually my patch doesn't quite bring it in line either.   Looking more
deeply at the code, all it does is grab the first AC3 track, the channel
count test is not applied.    So a slightly more complex rewrite is
needed to do what the comments say.

It might also make sense to take the stream with the highest bitrate.
if there is a tie for having the most tracks.    Right now (pre-patch)
the code does none of those things, it just picks the last stream.

Which, at least for PBS recordings here, is wrong, and makes them
silent, which is not what we want.
> 
>  I suppose the recorder could make an entry in the database indicating
> which audio stream to prefer, but that doesn't help (a) older recordings
> or (b) dvds.

Again, am I missing something?  When does the player play DVDs?  Or is
this something planned for the future, switching from mplayer for that
function?


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