ffmpeg | branch: master | Andreas Rheinhardt <andreas.rheinha...@outlook.com> | Wed Mar 12 03:26:09 2025 +0100| [b0af32265430d170458a8365bd1ad293644147c8] | committer: Andreas Rheinhardt
avcodec/vc2enc: Use LUT to assemble interleaved golomb code Up until now, the encoder processed only one bit at a time. With this patch, it is eight bits. Reviewed-by: Lynne <d...@lynne.ee> Signed-off-by: Andreas Rheinhardt <andreas.rheinha...@outlook.com> > http://git.videolan.org/gitweb.cgi/ffmpeg.git/?a=commit;h=b0af32265430d170458a8365bd1ad293644147c8 --- libavcodec/vc2enc.c | 45 +++++++++++++++++++++++++++++++++------------ 1 file changed, 33 insertions(+), 12 deletions(-) diff --git a/libavcodec/vc2enc.c b/libavcodec/vc2enc.c index 4728a48938..1fe973f4cd 100644 --- a/libavcodec/vc2enc.c +++ b/libavcodec/vc2enc.c @@ -22,6 +22,7 @@ #include "libavutil/mem.h" #include "libavutil/pixdesc.h" #include "libavutil/opt.h" +#include "libavutil/thread.h" #include "libavutil/version.h" #include "codec_internal.h" #include "dirac.h" @@ -186,22 +187,39 @@ typedef struct VC2EncContext { enum DiracParseCodes last_parse_code; } VC2EncContext; +/// x_k x_{k-1} ... x_0 -> 0 x_k 0 x_{k - 1} ... 0 x_0 +static uint16_t interleaved_ue_golomb_tab[256]; +/// 1 x_{k-1} ... x_0 -> 0 0 0 x_{k - 1} ... 0 x_0 +static uint16_t top_interleaved_ue_golomb_tab[256]; +/// 1 x_{k-1} ... x_0 -> 2 * k +static uint8_t golomb_len_tab[256]; + +static av_cold void vc2_init_static_data(void) +{ + interleaved_ue_golomb_tab[1] = 1; + for (unsigned i = 2; i < 256; ++i) { + golomb_len_tab[i] = golomb_len_tab[i >> 1] + 2; + interleaved_ue_golomb_tab[i] = (interleaved_ue_golomb_tab[i >> 1] << 2) | (i & 1); + top_interleaved_ue_golomb_tab[i] = interleaved_ue_golomb_tab[i] ^ (1 << golomb_len_tab[i]); + } +} + static av_always_inline void put_vc2_ue_uint(PutBitContext *pb, uint32_t val) { - int i; - int bits = av_log2(++val); - unsigned topbit = 1 << bits; - uint64_t pbits = 0; - - for (i = 0; i < bits; i++) { - topbit >>= 1; - av_assert2(pbits <= UINT64_MAX>>3); - pbits <<= 2; - if (val & topbit) - pbits |= 0x1; + uint64_t pbits = 1; + int bits = 1; + + ++val; + + while (val >> 8) { + pbits |= (uint64_t)interleaved_ue_golomb_tab[val & 0xff] << bits; + val >>= 8; + bits += 16; } + pbits |= (uint64_t)top_interleaved_ue_golomb_tab[val] << bits; + bits += golomb_len_tab[val]; - put_bits63(pb, 2 * bits + 1, (pbits << 1) | 1); + put_bits63(pb, bits, pbits); } static av_always_inline int count_vc2_ue_uint(uint32_t val) @@ -1003,6 +1021,7 @@ static av_cold int vc2_encode_end(AVCodecContext *avctx) static av_cold int vc2_encode_init(AVCodecContext *avctx) { + static AVOnce init_static_once = AV_ONCE_INIT; Plane *p; SubBand *b; int i, level, o, shift; @@ -1165,6 +1184,8 @@ static av_cold int vc2_encode_init(AVCodecContext *avctx) } } + ff_thread_once(&init_static_once, vc2_init_static_data); + return 0; } _______________________________________________ ffmpeg-cvslog mailing list ffmpeg-cvslog@ffmpeg.org https://ffmpeg.org/mailman/listinfo/ffmpeg-cvslog To unsubscribe, visit link above, or email ffmpeg-cvslog-requ...@ffmpeg.org with subject "unsubscribe".
