Add patches for block-level quant in theora, -O2 on build, and statically link pthread on Windows

README.chromium

 Contains the sources used to compile FFmpeg binaries used by Google Chrome and
 Chromium.
 
 The FFmpeg source is from Alexander Strange's ffmpeg-mt branch:
   git://gitorious.org/~astrange/ffmpeg/ffmpeg-mt.git
   Commit: 42b521db9177ed2d4e62845659fdcd44c59757f9
 
+The Theora patches are also from the ffmpeg-mt branch above.  The git commit
+numbers and the corresponding svn revisions for them from ffmpeg mainline can
+be found at the top of each patch.
+
 The libswscale source is from the public libswscale repository:
   git://git.ffmpeg.org/libswscale
   Commit: 69fc1002e2c92aac84dccc5047141feefc94b309
 
+The static_pthread_O2.patch does two things.  First, it uses -O2 instead of
+-O3 to build ffmpeg.  This yields a significant savings in binary size, and
+also seems to improve performance (lower CPU usage).  Second, the patch adds
+a modification that statically links pthreadGC2 into avcodec-52.dll on an
+MSYS/MinGW build in Windows.  This reduces the number of DLLs required for
+distribution, and lowers the total size of the binaries.
+
 Steps for extracting:
   1) Extract ffmpeg-mt, which creates the directory ffmpeg-mt:
        tar xzvf ffmpeg-mt.tar.gz
   2) Descend into the newly created ffmpeg-mt directory:
        cd ffmpeg-mt
   3) Extract libswscale in place:
        tar xzvf ../libswscale.tar.gz
+  4) Apply the Theora patches:
+       patch -p1 < ../r18986_theora_block_quant.patch
+       patch -p1 < ../r19351_theora_decode_tables_limit127.patch
+       patch -p1 < ../r19356_theora_decode_init_error_passing.patch
+       patch -p1 < ../r19350_init_loop_filter_127fix.patch
+       patch -p1 < ../r19355_invalid_huffman_table.patch
+  5) Apply the static_pthread_O2.patch:
+       patch -p1 < ../static_pthread_O2.patch
+  6) If on mac, apply the mac_install_name.patch:
+       patch -p1 < ../mac_install_name.patch
 
 NOTE: Under Windows it is recommended to use Chromium's MinGW/MSYS environment
 or 7-Zip to extract the archives.  We've experienced issues when using WinRAR.
 
 Since FFmpeg is sandboxed inside the render process, we're only interested in
 building the absolute minimum.
 
 Example configure flags suitable for Chromium (Ogg+Theora+Vorbis), which will
 build and install to the directory ./chromium-ffmpeg:
   ./configure --disable-ffmpeg --disable-ffplay --disable-ffserver             \
@@ skipping 17 matching lines @@
               --enable-decoder=aac --enable-decoder=h264                 \
               --enable-decoder=mp3 --enable-decoder=theora               \
               --enable-decoder=vorbis --enable-demuxer=mp3               \
               --enable-demuxer=mov --enable-demuxer=ogg                  \
               --enable-parser=mpegaudio                                  \
               --prefix=./chrome-ffmpeg
 
 If building on Windows with Chromium's MinGW/MSYS environment, add the following:
               --target-os=mingw32 --enable-memalign-hack --cc=gcc-sjlj
 
-If building on Mac, apply the mac_install_name.patch first so that the configure
-script will generate dylibs that know how to locate themselves in an application
-package.
-  patch -p1 < mac_install_name.patch
+If building on Mac, do not forget to do step (6) of the extraction to apply the
+mac_install_name.patch first so that the configure script will generate dylibs
+that know how to locate themselves in an application package.
 
 To build:
   make
 
 To install:
   make install
 
 On Windows, copy the resulting avcodec-52.dll, avformat-52.dll, and
 avutil-50.dll alongside chrome.exe for windows.
 
 On Mac, copy the resulting libavcodec.52.dylib, libavformat.52.dylib, and
 libavutil.50.dylib into the Chromium.app/Contents/MacOS folder alongside the
 Chromium binary.
 
 On Linux, copy the resulting libavcodec.so.52, libavformat.so.52, and
 libavutil.so.50 alongside the chrome executable.