On Wed, Oct 16, 2024 at 03:26:39PM +0200, Michael Niedermayer wrote: > This makes a 16bit RGB raw sample 25% faster at a 2% loss of compression with > rawlsb=4 > > Please test and comment > > This stores the LSB through non binary range coding, this is simpler than > using a > separate coder > For cases where range coding is not wanted its probably best to use golomb > rice > for everything. > > We also pass the LSB through the decorrelation and context stages (which is > basically free) > this leads to slightly better compression than separating them earlier. > > Signed-off-by: Michael Niedermayer <mich...@niedermayer.cc> > --- > libavcodec/ffv1.h | 2 ++ > libavcodec/ffv1_template.c | 19 ++++++++++--------- > libavcodec/ffv1dec.c | 2 ++ > libavcodec/ffv1dec_template.c | 16 +++++++++++++--- > libavcodec/ffv1enc.c | 15 ++++++++++++++- > libavcodec/ffv1enc_template.c | 17 +++++++++++++++-- > 6 files changed, 56 insertions(+), 15 deletions(-)
3rd implemantation :) you might ask why i implement this 4?! times Heres why: (tests done with 4 rawlsb bits, 16bit per sample input) The original (no decompression supported, bits riped out before context model and decorrelation, seperate buffer) -rw-r----- 1 michael michael 91403202 Oct 15 22:48 film4st.nut I dont remember -rw-r----- 1 michael michael 91253765 Oct 15 23:14 film4st-new.nut bits extracted after decorrelation and context model, interleaved range coder, simple but not efficient rangecoder implemantation -rw-r----- 1 michael michael 91080109 Oct 16 00:14 film4st-new2.nut This current, bits extracted after decorrelation and context model, simplest and most efficient range coder implemantation -rw-r----- 1 michael michael 90996813 Oct 16 15:14 film4st-new3.nut same but with quantization table 1 -rw-r----- 1 michael michael 89883371 Oct 16 15:50 film4st-new3q1.nut Heres the reference without rawlsb: -rw-r----- 1 michael michael 88090676 Oct 15 22:49 film0st.nut -rw-r----- 1 michael michael 88168254 Oct 16 15:50 film0st-q1.nut So this implemantation so far performs best and is also very simple thx [...] -- Michael GnuPG fingerprint: 9FF2128B147EF6730BADF133611EC787040B0FAB Many things microsoft did are stupid, but not doing something just because microsoft did it is even more stupid. If everything ms did were stupid they would be bankrupt already.
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