[mythtv-users] Transcoded file is bigger

Michael T. Dean mtdean at thirdcontact.com
Sat Mar 22 18:04:38 UTC 2008


On 03/22/2008 12:57 PM, Krzysztof Adamski wrote:
> I don't know if this is due to upgrade to 0.21, but I don't remember
> seeing this before.
> I just recorded a SD program from ATSC OTA (a subchannel) the transcoder
> is set to autodetect and the file size went from 565.5MB to 596.0MB.
>   

And what bitrate did you have in the original file?  And what resolution 
was the original file?  And what recording profile did you use (SQL at 
the bottom can be used to output your profiles).

> Is there a flag I could pass the trancoder that would keep the original
> file AND delete the new file if the new file is bigger. I know I can
> keep the original file, but I want this to be automatic.

Nope.

There was a bug that caused any NUV to be created (i.e. by software 
encoders or when transcoding, but not using the MPEG2->MPEG2 transcoder) 
to use twice the bitrate specified, but, IIRC, it was fixed before 0.21 
was released (or at least in 0.21-fixes shortly after release).  You may 
want to try upgrading to the most recent 0.21-fixes.

Mike


  SELECT recordingprofiles.name as Profile,
         max(if(codecparams.name = 'width', codecparams.value, '')) as 
Width,
         max(if(codecparams.name = 'height', codecparams.value, '')) as 
Height,
         max(if(codecparams.name = 'mpeg2streamtype', codecparams.value, 
'')) as StreamType,
         max(if(codecparams.name = 'mpeg2aspectratio', 
codecparams.value, '')) as AspectRatio,
         max(if(codecparams.name = 'mpeg2bitrate', codecparams.value, 
'')) as AvgBitrate,
         max(if(codecparams.name = 'mpeg2maxbitrate', codecparams.value, 
'')) as MaxBitrate,
         max(if(codecparams.name = 'samplerate', codecparams.value, '')) 
as AudioSampleRate,
         max(if(codecparams.name = 'mp3quality', codecparams.value, '')) 
as MP3Quality,
         max(if(codecparams.name = 'mpeg2audtype', codecparams.value, 
'')) as MPEG2AudioType,
         max(if(codecparams.name = 'mpeg2audbitratel1', 
codecparams.value, '')) as AudioBitrateL1,
         max(if(codecparams.name = 'mpeg2audbitratel2', 
codecparams.value, '')) as AudioBitrateL2
    FROM recordingprofiles, codecparams
   WHERE recordingprofiles.id = codecparams.profile
     AND codecparams.name IN ('width', 'height', 'mpeg2streamtype',
                              'mpeg2aspectratio', 'mpeg2bitrate',
                              'mpeg2maxbitrate', 'samplerate', 'mp3quality',
                              'mpeg2audtype', 'mpeg2audbitratel1',
                              'mpeg2audbitratel2')
GROUP BY codecparams.profile\G



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