The encoder, for content having a bitdepth higher than 16, stores the LSBs uncompressed. To do so, it performs first channel rematrixing then extract these MSBs.
However, these 2 steps are inverted, as can be seen in the decoder, or in the official encoder: http://alac.macosforge.org/trac/browser/trunk/codec/matrix_enc.c#L170 This patch set fixes that by: 1) Increasing the predictor buffer to hold 2 channels worth of data 2) Storing the extracted MSBs temporary in this buffer before performing rematrixing, as the rematrixing generates information that needs to be written before the raw MSBs. It would possible to detect bitstreams before this change and achieve correct decoding if need be. Christophe Gisquet (2): alacenc: increase predictor buffer alacenc: fix extra bits extraction libavcodec/alacenc.c | 35 ++++++++++++++++++++++++----------- 1 file changed, 24 insertions(+), 11 deletions(-) -- 1.9.2.msysgit.0 _______________________________________________ ffmpeg-devel mailing list ffmpeg-devel@ffmpeg.org http://ffmpeg.org/mailman/listinfo/ffmpeg-devel
