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List:       wine-devel
Subject:    Re: wineqtdecoder: initial commit of the video decoder using Mac
From:       Aric Stewart <aric () codeweavers ! com>
Date:       2010-11-30 17:02:20
Message-ID: 4CF52E1C.2000907 () codeweavers ! com
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Sent a revised patch using the ICMDecompression apis just before seeing 
your e-mail.  So I figured out that part.

I will have to look into the pixel buffer copying improvement once the 
base framework is in place.

thanks!
-aric


On 11/30/10 10:33 AM, Ken Thomases wrote:
> On Nov 30, 2010, at 6:52 AM, Alexandre Julliard wrote:
> 
> > Aric Stewart<aric@codeweavers.com>  writes:
> > 
> > > ---
> > > configure                             |    8 +-
> > > configure.ac                          |    5 +
> > > dlls/wineqtdecoder/Makefile.in        |   11 +
> > > dlls/wineqtdecoder/main.c             |  135 +++++++++
> > > dlls/wineqtdecoder/qtvdecoder.c       |  536
> > > +++++++++++++++++++++++++++++++++
> > > dlls/wineqtdecoder/version.rc         |   26 ++
> > > dlls/wineqtdecoder/wineqtdecoder.spec |    4 +
> > > 7 files changed, 724 insertions(+), 1 deletions(-)
> > > create mode 100644 dlls/wineqtdecoder/Makefile.in
> > > create mode 100644 dlls/wineqtdecoder/main.c
> > > create mode 100644 dlls/wineqtdecoder/qtvdecoder.c
> > > create mode 100644 dlls/wineqtdecoder/version.rc
> > > create mode 100644 dlls/wineqtdecoder/wineqtdecoder.spec
> > 
> > This is showing many deprecated function warnings even on Leopard. We
> > should try to avoid that in new code.
> 
> Aric,
> 
> The DecompressSequenceBeginS takes a CGrafPort or GWorld.  These are QuickDraw \
> concepts and are very, very obsolete.  DecompressSequenceBeginS should be \
> deprecated, itself, since it depends on them, but doesn't appear to be.  The \
> documentation on this whole area is terrible.  Apple seems to have blackholed even \
> the documentation of the more modern APIs.  (You can still get it from within Xcode \
> 3.2.x if you go into preferences and subscribe to the Leopard docset.  But it seems \
> largely gone from their website.) 
> As is often the case, the headers provide what documentation there is.  According \
> to the headers (/System/Library/Frameworks/QuickTime.framework/Headers/ImageCompression.h), \
> the replacement is ICMDecompressionSessionCreate() and friends, also in that \
> header.  (That header has both old APIs and new.  You want the ones introduced with \
> Mac OS X 10.4 or later, or QuickTime 7 or later.) 
> The ICMDecompression... functions feed you CVPixelBuffer objects through a \
> callback.  Those are documented \
> here<http://developer.apple.com/library/mac/#documentation/QuartzCore/Reference/CVPixelBufferRef/>. \
> (Take note of the "Derived from" info at the top of that page.  If you feel that \
> CVPixelBuffer is missing some important API, it may be provided by the base \
> classes.) 
> The ICMDecompression... API seems kind of asynchronous in nature, but I think you \
> can force it to fully decompress frames immediately via the frameTime parameter to \
> ICMDecompressionSessionDecodeFrame().  The flags field of ICMFrameTimeRecord can \
> include icmFrameTimeDecodeImmediately. 
> The next thing that might be useful are some techniques to avoid doing the pixel \
> copying manually.  Depending on the output format you require (This->outputDepth \
> and This->rowBytes), you may be able to create a CGBitmapContext to wrap the output \
> buffer.  Then, you can create a CGImage from the CVPixelBuffer, and draw the image \
> into the context.  (The modern Mac APIs don't really have blit operations, they \
> copy and/or convert images by drawing.)  Some of these techniques are illustrated \
> in this sample code:<http://developer.apple.com/library/mac/#samplecode/CaptureAndCompressIPBMovie/>. \
> Actually, it sort of does the reverse.  It wraps the CVPixelBuffer in the bitmap \
> context and draws onto it, but the principle is similar. 
> I hope that helps.
> 
> -Ken
> 


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