diff options
Diffstat (limited to 'libavcodec/cabac.c')
| -rw-r--r-- | libavcodec/cabac.c | 38 |
1 files changed, 32 insertions, 6 deletions
diff --git a/libavcodec/cabac.c b/libavcodec/cabac.c index 5c590030f1..c0abe834cf 100644 --- a/libavcodec/cabac.c +++ b/libavcodec/cabac.c @@ -2,20 +2,20 @@ * H.26L/H.264/AVC/JVT/14496-10/... encoder/decoder * Copyright (c) 2003 Michael Niedermayer <michaelni@gmx.at> * - * This file is part of Libav. + * This file is part of FFmpeg. * - * Libav is free software; you can redistribute it and/or + * FFmpeg is free software; you can redistribute it and/or * modify it under the terms of the GNU Lesser General Public * License as published by the Free Software Foundation; either * version 2.1 of the License, or (at your option) any later version. * - * Libav is distributed in the hope that it will be useful, + * FFmpeg is distributed in the hope that it will be useful, * but WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU * Lesser General Public License for more details. * * You should have received a copy of the GNU Lesser General Public - * License along with Libav; if not, write to the Free Software + * License along with FFmpeg; if not, write to the Free Software * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA */ @@ -27,6 +27,7 @@ #include <string.h> #include "libavutil/common.h" +#include "libavutil/timer.h" #include "cabac.h" #include "cabac_functions.h" @@ -160,7 +161,20 @@ const uint8_t ff_h264_cabac_tables[512 + 4*2*64 + 4*64 + 63] = { /** * @param buf_size size of buf in bits */ -void ff_init_cabac_decoder(CABACContext *c, const uint8_t *buf, int buf_size){ +void ff_init_cabac_encoder(CABACContext *c, uint8_t *buf, int buf_size){ + init_put_bits(&c->pb, buf, buf_size); + + c->low= 0; + c->range= 0x1FE; + c->outstanding_count= 0; + c->pb.bit_left++; //avoids firstBitFlag +} + +/** + * + * @param buf_size size of buf in bits + */ +int ff_init_cabac_decoder(CABACContext *c, const uint8_t *buf, int buf_size){ c->bytestream_start= c->bytestream= buf; c->bytestream_end= buf + buf_size; @@ -168,9 +182,21 @@ void ff_init_cabac_decoder(CABACContext *c, const uint8_t *buf, int buf_size){ #if CABAC_BITS == 16 c->low = (*c->bytestream++)<<18; c->low+= (*c->bytestream++)<<10; + // Keep our fetches on a 2-byte boundry as this should avoid ever having to + // do unaligned loads if the compiler (or asm) optimises the double byte + // load into a single instruction + if(((uintptr_t)c->bytestream & 1) == 0) { + c->low += (1 << 9); + } + else { + c->low += ((*c->bytestream++) << 2) + 2; + } #else c->low = (*c->bytestream++)<<10; -#endif c->low+= ((*c->bytestream++)<<2) + 2; +#endif c->range= 0x1FE; + if ((c->range<<(CABAC_BITS+1)) < c->low) + return AVERROR_INVALIDDATA; + return 0; } |