[mythtv-users] What happened to Lossless Transcoding for Cut Lists?

[mythtv at kosowsky.org]

Ian Evans wrote at about 22:42:50 -0400 on Thursday, April 18, 2019:
 > On Thu, Apr 18, 2019, 10:29 PM , <mythtv at kosowsky.org> wrote:
 > 
 > > I recently upgraded from a very old MythTV to 0.29.1
 > >
 > > Before when creating transcoding profiles, there was a "tickbox" to
 > > allow for lossless compression which was very useful for re-stitching
 > > together the stream after cutting commercials without transcoding to a
 > > new format.
 > >
 > > I see that there are ways to create user jobs via scripts, but this is
 > > much more complicated (and lest robust) than the built-in tickbox.
 > >
 > > - Is there any reason the built-in lossless transcoding option was
 > >   deleted?
 > > - What is the simplest way to re-implement lossless transcoding post
 > >   adding a cut list?
 > >
 > 
 > This might be related. Not near my system right now but thought I'd send to
 > you.
 > 
 > https://lists.gt.net/mythtv/users/611938

Seems like there is a bug...

In my old circa v23 version, I had the following entry in:
'recordingprofiles'
	(58,'Lossless','MPEG-4','MP3',6)
where 6 is the profilegroup id corresponding to 'Transcoders'

'codecparams'
	(58,'transcodelossless','1'),(58,'transcoderesize','0'),(58,'width','480'),(58,'height','480'),(58,'rtjpegquality','170'),(58,'mpeg4bitrate','2200'),(58,'mpeg4maxquality','2'),(58,'mpeg4minquality','15'),(58,'mpeg4qualdiff','3'),(58,'scalebitrate','1'),(58,'mpeg4optionvhq','0'),(58,'mpeg4option4mv','0'),(58,'mpeg4optionidct','0'),(58,'mpeg4optionime','0'),(58,'encodingthreadcount','1'),(58,'mpeg2bitrate','4500'),(58,'hardwaremjpegquality','100'),(58,'hardwaremjpeghdecimation','4'),(58,'hardwaremjpegvdecimation','4'),(58,'mpeg2streamtype','MPEG-2	PS'),(58,'mpeg2aspectratio','4:3'),(58,'mpeg2maxbitrate','6000'),(58,'low_mpeg4avgbitrate','4500'),(58,'low_mpeg4peakbitrate','6000'),(58,'medium_mpeg4avgbitrate','9000'),(58,'medium_mpeg4peakbitrate','11000'),(58,'high_mpeg4avgbitrate','13500'),(58,'high_mpeg4peakbitrate','20200'),(58,'samplerate','32000'),(58,'mp3quality','7'),(58,'volume','90')

In v29.1 fixes, the 'Lossless' profile is missing from
'recordingprofiles' though interestingly it still persists in codecparams.

In any case, I seem to have been able to fix the problem by *manually*
inserting the missing entry into 'recordingprofiles' via mysql.

In particular, when I transcoded 'lossless' after adding a cut-list,
the bitrate determined by ffmpeg was essentially unchanged.

The lack of the 'lossless' tickbox does seem to be a bug...