[MPlayer-users] How programmatically determine the correct one of two english soundtracks for an encode

[Reimar Döffinger]

On 6 Jul 2012, at 21:39, Graham Lawrence <gl00637 at gmail.com> wrote:
> I have a certain dvd image for which
>    mplayer dvd://1 -dvd-device VIDEO_TS -identify -frames 0
> gives me the following info
>    ID_DVD_TITLE_1_CHAPTERS=16
>    ID_DVD_TITLE_1_LENGTH=5915.467
>    ID_DVD_CURRENT_TITLE=1
>    There are 1 angles in this DVD title.
>    audio stream: 0 format: ac3 (mono) language: en aid: 128.
> 
>    ID_AUDIO_ID=128
>    ID_AID_128_LANG=en
>    audio stream: 1 format: ac3 (mono) language: en aid: 129.
> 
>    ID_AUDIO_ID=129
>    ID_AID_129_LANG=en
>    number of audio channels on disk: 2.
>    subtitle ( sid ): 2 language: en
> and
>    ID_AUDIO_ID=129
> 
> which last item led me to believe that "-aid 129" would encode the
> audio track that matches "dvd://1"
> 
> But that was incorrect.  It should actually be "-aid 128".  So how does
> one determine the appropriate soundtrack for the main title track?

That information is encoded in the menus, which means there are only very complex ways to figure it out.
You might have a look if anything that lsdvd prints works as a hint, but it won't be 100%.