[MPlayer-dev-eng] Re: monkeyaudio dshow codec

[Jindrich Makovicka]

On Sun, 18 Mar 2007 13:48:29 -0500
Rich Felker <dalias at aerifal.cx> wrote:

> On Mon, Mar 19, 2007 at 12:34:55AM +0600, Vladimir Voroshilov wrote:
> > Hi, All.
> > 
> > Here is my reply to Compn's private mail.
> > I post it here, because somebody, perhaphs, can give me some clever
> > ideas.
> > 
> > 
> > 2007/3/14, Patriot ACT <patriotact at gmail.com>:
> > >
> > >currently mplayer has no demuxer/decoder for ape...
> > >i dont think its important
> > >just bored :)
> > >
> > >
> > >http://samples.mplayerhq.hu/A-codecs/lossless/luckynight.ape
> > >
> > >radlight one which in graphedit requires a file to graph, i think
> > >it doesnt have input pin? i wonder if this can be emulated around
> > >to use mplayer as input?
> > >
> > >http://www.rarewares.org/files/lossless/RadLightAPE.exe
> > >
> > >audiocodec radlightape
> > >  info "blah"
> > >  status working
> > >  format 0x1
> > >  driver dshow
> > >  dll "RLAPEDec.ax"
> > >  guid 0x41faf0f4, 0xdcec, 0x4f6a, 0x82, 0xd2, 0x56, 0xe1, 0x00,
> > > 0xf2,
> > >0xa8, 0xe5
> > 
> > Well.
> > Good news:
> > 1. Under MinGW i can hear sound from provided sample file with
> > mplayer. That's all :)
> > 
> > Bad News:
> > 1. Under Linux it requires MSVCR71.dll (or it's emulation in
> > win32.c) 2. Even with (1) mplayer crashes under Linux (something
> > wrong in WINAPI emulation, i guess)
> > 3. Decoder starts decoding exact after IBaseFilter::Start is called
> > and does not stop till source file end riched.
> > 4.Due to (3) input mplayer data is totally ignored (codec reads
> > file by itself). So timestamps is broken.
> > 5. (3) also requires large ringbuffer to store data.
> > 6. playing filename is required for codec.
> > 
> > i hope, 3-6 can be solved if i move 1-pin dshow filter wrapper from
> > decoding stage to stream level and connect such stream to rawaudio
> > demuxer. Large buffer, perhaps, can be solved with call to
> > IBasefilter::Pause in proper places, but this requires more
> > investigations, though.
> 
> IMO hacks like this are not welcome. Decoding in the stream or demuxer
> stage is not acceptable. Aren't there public specs (or non-free source
> someone could read) available for monkey audio? If so, a proper
> decoder should be written and added to ffmpeg, rather than throwing in
> more and more evil hacks for the sake of using binary decoders (which
> should be seen as deprecated).

The source code is available with a fairly permissive license (not GPL
compatible though). APE decoder shouldn't be so hard to port for anyone
willing to read the Hungarian notation :)

http://www.monkeysaudio.com/developers.html

http://www.monkeysaudio.com/license.html

-- 
Jindrich Makovicka