[mythtv-users] Transcoding and aspect ratio (DVB-T)

[Ian Grant]

Chris Pinkham wrote:
>> Okay, so I found the following code in nuvinfo:
>>
>>              # Make some corrections for myth bugs
>> 156             $info{'audio_sample_rate'} = 44100 if
>> ($info{'audio_sample_rate'} == 42501 || $info{'audio_sample_rate'} =~
>> /^44\d\d\d$/);
>> 157             $info{'aspect'} = '4:3';
>>     
>
> Sounds like an old nuvinfo, where id you get it from?
>   

Well, it's actually the newest version, AFAIK:
http://forevermore.net/files/nuvexport/nuvexport-0.3-0.20060302.svn.src.rpm
Although the SVN source does show that the last time nuvinfo.pm was
updated was 2 months ago.

>   
>> Unfortunately they still play as 4:3 in VLC/MPC, so I must assume that
>> the error is in the detection with the player.
>>     
>
> I believe so.
>
>   
>> On a side note, it appears nuvinfo uses 'mplayer -identify' to get the
>> aspect ratio for mpg files (or nuvs which are really mpeg).
>> When I do mplayer -identify on a transcoded nuv file, it reports
>> 'ID_VIDEO_ASPECT=0.0000'
>>     
>
> Definitely sounds like an old version of nuvinfo.  The version I have
> reads directly from the .nuv file and unpacks the header data itself.
>   

This version of nuvinfo does that too, but if it cannot find the text
'MythTVVideo' it thinks the file is an MPEG file and falls back to using
mplayer -identify instead (see
https://svn.forevermore.net/nuvexport/browser/trunk/mythtv/nuvinfo.pm).

> Also, there is an updated patch for mplayer that properly detects the
> aspect ratio in a Myth .nuv file, where did you get your mplayer from and
> did you patch it yourself or is it able to play Myth's .nuv files 
> "out of the box"
My mplayer is from ATrpms (mplayer-1.0-51_pre7try2.el4.at), as far as I
can see it plays Myth .nuv files fine, with the correct aspect ratio.
As I said though, I don't have a dedicated Myth frontend, so any testing
of mplayer has been using frontend on the same machine as the backend
with VNC (no monitor on server, it's in a cupboard).

I've come to think that the problem lies with the dsmyth filters on
Windows. Unless I can get mythtranscode to write the aspect ratio into
the MPEG4 stream (like it is for MPEG2 recordings) as well as the .nuv
container (correct me if I'm wrong on this line of thinking, please).


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