[mythtv-users] Re: More HD stuttering

Jason Sharpe mythtv.list at gmail.com
Fri Dec 2 09:14:31 EST 2005


Thanks Mudit!

You have given me something to play with this weekend!

Perfect job for a slave backend..:)


> ------------------------------
>
> Message: 6
> Date: Thu, 1 Dec 2005 18:30:16 -0800
> From: Mudit Wahal <mwahal at gmail.com>
> Subject: Re: [mythtv-users] Re: More HD stuttering
> To: Discussion about mythtv <mythtv-users at mythtv.org>
> Message-ID:
>        <be5fa62d0512011830h39036855p3c1c823eb621a37e at mail.gmail.com>
> Content-Type: text/plain; charset=ISO-8859-1
>
> Here is the mencoder script I use to transcode 1920x1080i mpeg2 to
> 1280x720p mpeg4. I use two passes and very high bit rate. I've 50"
> Panny DLP connected to IOData LP2. When I play the original mpeg2 and
> transcoded mpeg4, I can't tell any difference. All movies and shows
> actually look better in mpeg4. Its very cpu intensive. One hour of
> recording takes about 8 hours on my sempron 3000+. I usually cut the
> commercials using commercial_cut program. That cut down 1hr of program
> to 40-42 mins, and about 2 hrs of transcoding time.
>
> ##### no error checking is done #####
>
> set oac="-oac copy" ## can substitute for mp3
> set pp="pp=ci/hb/vb/dr/tn:1:2:3,"
> set scale="1280:720:1" ## can change it to lower for non HD shows
> set profile="dxnhdtv" ## change it to dxnhtntsc for 720x480 resolution or
> lower
> set cartoon=":" ## set it to :cartoon: if you transcode kids cartoon
> shows or simpsons
> set oac="-oac copy"
> set bitrate="9000" ## usually lower for non HD shows
> set infile="$1" ## this is ur input file, 1st argument
> set outfile="$2" ## this is ur output file, 2nd argument
> set logfile="$infile".log
>
> ####### 1st pass #######
> mencoder $oac -noaspect -vf ${pp}scale=${scale} -ovc xvid -xvidencopts
> turbo${cartoon}pass=1:profile=${profile}:bitrate=${bitrate}:max_bframes=1:
> -o /dev/null -passlogfile $logfile $infile
>
> ###### 2nd pass #########
> mencoder $oac -noaspect -vf ${pp}scale=${scale} -ovc xvid -xvidencopts
> pass=2${cartoon}profile=${profile}:bitrate=${bitrate}:max_bframes=1:
> -o $outfile -passlogfile $logfile $infile
>
>
> ######## for 1280x720p recordings I use the following #####
> set ofps="-ofps 30000/1001"
> mencoder $oac -noaspect -vf pp=hb/vb/dr/tn:1:2:3 -ovc xvid
> -xvidencopts
> turbo:pass=1:profile=${profile}:bitrate=${bitrate}:max_bframes=1:
> -o /dev/null -passlogfile $logfile $infile $ofps
> mencoder $oac -noaspect -vf pp=hb/vb/dr/tn:1:2:3 -ovc xvid
> -xvidencopts pass=2:profile=${profile}:bitrate=${bitrate}:max_bframes=1:
> $infile -o $outfile -passlogfile $logfile $infile $ofps
>
> Hope it helps.
>
> Thanks
>
> Mudit
>
>
> On 12/1/05, Jason Sharpe <mythtv.list at gmail.com> wrote:
> > I agree, very VERY frustrating.
> >
> > I have built a couple of standalone front ends and both of them are
> > stuttering (one worse then the other). SD plays back pretty well,
> however HD
> > is a different story. Sometimes I can get decent performance however
> most of
> > the time I want to jump out of the window.
> >
> > Specs:
> >
> > MSI 915G Mobo
> > P4 3.0
> > 1 Gig DDR400
> > Nvidia 6600 GT PCIx
> >
> > I am also seeing combing, however from the previous comment I agree that
> it
> > is probly showing 1080i content on in 720p. My guess is that is probly
> > causing some other issues as well, not just combing, the front end has
> to
> > scale down the picture to display it, I am sure that the processing
> power
> > used to do that could improve playback.
> >
> > Since my theater and the plasma are only going to show 720p does anyone
> know
> > of a good way  to set it up so myth looks at every show after recording
> > finishes and automatically transcodes shows in 1080i to 720p? (user job
> > perhaps?)
> > I am new to myth (and Linux) so I haven't explored everything yet..:)
> >
> > I am looking forward to solving the problems, I can't WAIT to ditch my
> Tivo.
> >
> > Jason
>
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