[mythtv] HD H264 decoding with multiple threads

[Terry Barnaby]

On 12/29/2009 10:25 AM, John wrote:
> Terry Barnaby wrote:
>> I have just "updated" my systems to Fedora 12 and MythTv 0.22 (from
>> RpmFusion RPM's). Previously I was using Fedora 11 with MythTv from
>> SVN from around December 2008.
>> In order to get smooth HD playback on my Intel G45 frontend (from freesat
>> BBC-HD) I had set MythTv to use 2 CPU's in FFMPEG to decode the H264
>> stream.
>> With my current setup MythTv only appears to be using 1 CPU for H264
>> decode.
>> It does appear to use 2 CPU's for SD MPEG2 decode however.
>> Using "mythfrontend -v playback" the log states "Using 2 CPUs for
>> decoding" so
>> all looks to be configure Ok.
>>
>> Any ideas on what is wrong here ?
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>>
> Its not your Setup, its the BBC :-)
>
> BBC-HD has changed their encoders, dropping the bitrate from 18-20 Mb/s
> o about 14 Mb/s. They have as a consequence changed the way the stream
> is encoded, and the ability of ffmpeg to decode multi-threaded :-(
>
> However if you turn of the loopfilter, then ffmpeg can decode
> multi-threaded. This is discussed at
>
> http://svn.mythtv.org/trac/ticket/6986
>
> And patches are available at my long running plea to have this added to
> svn :-)
>
> http://svn.mythtv.org/trac/ticket/4653
>
> you can either use my full patch (updated by jyavenard) rather than the
> full patch, which gives the option to disable the loopfilter,
>
> The smaller 28_skiploop_multithread.dpatch which I now use simply
> assumes that if you are watching H.264 and you have set multi-core you
> want to disable the loopfilter.
>
>
> John
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Thanks for the info John.
I will include one of your patches and have a go.