From: Michael Niedermayer <mich...@niedermayer.cc> This avoids closing and opening the bit reader
Signed-off-by: Michael Niedermayer <mich...@niedermayer.cc> --- libavcodec/diracdec.c | 37 ++++++++++++++++++++++++++++++++++--- 1 file changed, 34 insertions(+), 3 deletions(-) diff --git a/libavcodec/diracdec.c b/libavcodec/diracdec.c index c67f845..fe879bb 100644 --- a/libavcodec/diracdec.c +++ b/libavcodec/diracdec.c @@ -485,13 +485,44 @@ static av_cold int dirac_decode_end(AVCodecContext *avctx) static inline int coeff_unpack_golomb(GetBitContext *gb, int qfactor, int qoffset) { int sign, coeff; + uint32_t buf; - coeff = svq3_get_ue_golomb(gb); + OPEN_READER(re, gb); + UPDATE_CACHE(re, gb); + buf = GET_CACHE(re, gb); + + if (buf & 0xAA800000) { + buf >>= 32 - 8; + SKIP_BITS(re, gb, ff_interleaved_golomb_vlc_len[buf]); + + coeff = ff_interleaved_ue_golomb_vlc_code[buf]; + } else { + unsigned ret = 1; + + do { + buf >>= 32 - 8; + SKIP_BITS(re, gb, + FFMIN(ff_interleaved_golomb_vlc_len[buf], 8)); + + if (ff_interleaved_golomb_vlc_len[buf] != 9) { + ret <<= (ff_interleaved_golomb_vlc_len[buf] - 1) >> 1; + ret |= ff_interleaved_dirac_golomb_vlc_code[buf]; + break; + } + ret = (ret << 4) | ff_interleaved_dirac_golomb_vlc_code[buf]; + UPDATE_CACHE(re, gb); + buf = GET_CACHE(re, gb); + } while (ret<0x8000000U && BITS_AVAILABLE(re, gb)); + + coeff = ret - 1; + } if (coeff) { coeff = (coeff * qfactor + qoffset + 2) >> 2; - sign = get_bits1(gb); - coeff = (coeff ^ -sign) + sign; + sign = SHOW_SBITS(re, gb, 1); + LAST_SKIP_BITS(re, gb, 1); + coeff = (coeff ^ sign) - sign; } + CLOSE_READER(re, gb); return coeff; } -- 1.7.9.5 _______________________________________________ ffmpeg-devel mailing list ffmpeg-devel@ffmpeg.org http://ffmpeg.org/mailman/listinfo/ffmpeg-devel