[FFmpeg-devel] [PATCH] DVCPRO HD [1/3] dynamic DV macroblock lookup

Dan Maas dmaas
Thu Jan 3 14:07:46 CET 2008


This is a series of 3 incremental patches that add DVCPRO HD support to 
ffmpeg.

Patch 1 of 3 removes the look-up tables used by the DV codec to 
determine macroblock locations, and replaces them with functions that 
computes the macroblock locations at runtime. I feel this is a necessary 
step before adding DVCPRO HD support, because the look-up tables that 
would be required for the HD format would be very large. DVCPRO HD has 
about four times as many macroblocks as NTSC/PAL formats, and the 
coordinate numbers won't fit in 16-bit entries anymore, so the table 
would have to grow even more than that.

I cannot detect any measurable speed change with this patch compared to 
the current look-up table code. If anything it may be slightly faster 
due to smaller cache footprint.

(apologies for compressing the patch; it's 100KB uncompressed due to the 
removal of large look-up tables)

Regards,
Dan
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