[mythtvnz] Question about building Pauls Mythtv + Patches

[Steven Ellis]

On 24/08/2008, at 5:10 PM, Steven Ellis wrote:

>
> On 24/08/2008, at 2:57 PM, Steven Ellis wrote:
>
>>
>> On 24/08/2008, at 2:18 PM, Graeme Woollett wrote:
>>
>>> Sorry if I've missed the obvious places for the instructions.  I can
>>> only find references to the tar ball...
>>>
>>> This is the deb for the binary
>>>
>>> deb http://ppa.launchpad.net/paul-kcbbs/ubuntu hardy main
>>>
>>
>> Add the following for getting the source as well
>>
>> deb-src http://ppa.launchpad.net/paul-kcbbs/ubuntu hardy main
>>
>>
>>>
>>> Are there deb-source packages available that can be modified and  
>>> built
>>> into debs the "debian way " rather then the tar ball approach.
>>>
>>> This way all the development file dependencies are taken care of  
>>> making
>>> the source much easier to build
>>>
>>> If so what is the deb-src line I need to use, what does the apt- 
>>> get line
>>> look like?
>>>
>>> My CPU isn't quite fast enough for TV3 so I need to make binaries  
>>> that
>>> have it enabled.
>>
>> Thinking the same myself
>>
>>>
>>> Thats unless somebody else has made some custom debs with it  
>>> enabled?
>>>
>>> I'm quite happy changing files but don't have the time to manually
>>> satisfy all the dev dependencies.
>>
>>
>> mkdir src
>> cd src
>> sudo apt-get source mythtv
>> sudo apt-get build-dep mythtv
>>
>> You should then have an Ubuntu/Debian friendly build tree to play  
>> with.
>>
>
> Well I just had a try with the skip loop filter patch which helped a  
> little bit.
>
> Also tried running the system with a CPU disabled to see how it  
> would affect performance and it made the HD channels unusable on an  
> AMD 3600 X2.
>
> Going to try a rebuild with CODEC_FLAG2_FAST enabled in addition to  
> the skiploopfilter.
>
>

My current patch to  libs/libmythtv/avformatdecoder.cpp around line  
1588  is as follows

                 if (CODEC_ID_H264 == enc->codec_id)
                 {
                    VERBOSE(VB_PLAYBACK, LOC + "Turning off loop  
filter");
                      enc->skip_loop_filter = AVDISCARD_ALL;
                    VERBOSE(VB_PLAYBACK, LOC + "Enabling Fast decode  
mode");
                      enc->flags           |= CODEC_FLAG2_FAST;
                  }

This appears to give me a 4-5 % boost on the SD channels, and possibly  
15-30% on the HD channels. It is hard to tell on TV One HD at the  
moment as the bitrate for the sports is all over the place. TV3 is  
almost watch-able on my CPU so hopefully Graeme will get full support  
on his 5600 X2. Watching TV2 now sits at an average of 70-80% rather  
than close to 100%.

Paul - I'd love to get any additional patches you have to stabilise  
the audio. I haven't had time to play with debug builds to trace the  
audio segfaults yet.

Steve



Steven Ellis - Technical Director
OpenMedia Limited
email   - steven at openmedia.co.nz
website - http://www.openmedia.co.nz

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