[mythtv] Using CoreAVC with myth (better h264 performance)

[Mark Buechler]

This is an excellent piece of work! It's a shame ffmpeg isn't as efficient
as coreavc for h.264 content.

Thanks for sharing this!!

- Mark.

On 4/13/06, Alan Nisota <alannisota at gmail.com> wrote:
>
> In order to be able to view h264 encoded material in HD on my machine,
> I have been searching for a solution.  ffh264 is too slow to handle
> 720p on my 2.8GHz P4, which I use as my frontend.  I thought I was out
> of luck, until someone pointed out CoreAVCDecoder, which is a
> DirectShow filter for Windows, and can play HD h.264 material capably
> on my hardware.  the only problem was, of course, that it only exists
> for Windows.  Well, mplayer can use DirectShow filters, so i thought
> perhaps I could use that to play my videos in linux.  Of course, the
> directshow capability in mplayer is basically unsupported, and
> coreavcdecoder didn't work out of the box.  After a bit of mucking
> around though, I was able to get it working.  And then the CoreCodec
> team released version 1.0, which does much more significant input
> validation, as well as including a registration key, and some other
> difficulties.  After a lot more work, I was able to get 1.0 working
> with mplayer as well.  I then moved on to incorporating the decoder
> into myth, which turned out not to be difficult at all.
>
> So, I now have myth using a Windows DirectShow filter to playback H264
> media, and it is actually able to do so in real time with HD content!
>
> I am not sure what the myth developers' take on this will be.  The
> interface code is all based on wine, and is GPL, however the actual
> driver is non-free (costs between $10 and $20 depending on which
> version you buy).  the old codec 0.0.4 is still meandering about the
> net, but I would expect that without a license it cannot be legally
> redistributed.
>
> the directshow code could certainly be made to work with other filters
> as well, though, in general, the free codecs are good enough, so there
> is no need.  Also, since libavformat is still used to split the
> streams, it is unlikely it would be useful for handling codecs that
> aren't available in ffmpeg.  If there is any interest in getting this
> type of functionality into myth, I'll be happy to clean up the patches
> and submit them, though.
>
> So, with all that in mind, here is what I've got:
>
> apply the patch located here:
> http://www.files.bz/files/9309/Mythtv/directshow.patch.20060413.bz2
>
> copy the following file into ~mythtv/.mythtv (or whatever user runs
> the forntend):
> http://www.files.bz/files/9309/Mythtv/dshowcodecs
>
> Purchase CoreAVCDecoder (coreavc.corecodec.org) and install via wine
> (or if you already have 0.0.4 you can use that instead).
> copy CoreAVCDecoder.ax to /usr/lib/win32/
> edit dshowcodecs and change the user-id and product-key to the values
> found in your wine registry (~/.wine/system.reg)
>
> from your mythtv dir:
> cd libs/libdshowloader && make && cd dshow && make && cd ../../..
> build myth as usual.
>
> You should be good to go.
> Caveats:
> It is likely to only work with linux and gcc/glibc, as I played some
> tricks with the exception handler in order to load the module.
> It has only been tested on 32bit machines, I have no idea what will
> happen if you try to compile on a 64bit one.
> The code is still very rough.  a lot of work would be needed to make
> it copile without warnings and as a proper library
> Because we are using a binary, if it crashes, it is likely there is
> nothing I can do to help.
>
> If you are interested in the mplayer version, it can be found here:
> http://www.files.bz/files/9309/Mythtv/mplayer_coreavc.patch.20060413.bz2
> you need to directly edit DS_VideoDecoder.c and add your user-id/key
> there (search for 'Joe User' to find where), and you need to add
> something like this to your codecs.conf file:
> videocodec coreavc
>   info "CoreAVC DShow H264 decoder for x86 - http://corecodec.org/"
>   status untested
>   format 0x10000005
> ;  format 0x31637661 ; avc1
>   fourcc H264,h264
>   fourcc X264,x264
>   fourcc avc1
>   fourcc davc,DAVC
>   driver dshow
>   dll "CoreAVCDecoder.ax"
>   guid 0x09571a4b, 0xf1fe, 0x4c60, 0x97, 0x60, 0xde, 0x6d, 0x31, 0x0c,
> 0x7c, 0x31
>   out YV12,IYUV,I420,YUY2
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