diff options
Diffstat (limited to 'libavformat/h261dec.c')
| -rw-r--r-- | libavformat/h261dec.c | 45 |
1 files changed, 21 insertions, 24 deletions
diff --git a/libavformat/h261dec.c b/libavformat/h261dec.c index 4a5805020f..a1d682128d 100644 --- a/libavformat/h261dec.c +++ b/libavformat/h261dec.c @@ -2,20 +2,20 @@ * RAW H.261 video demuxer * Copyright (c) 2009 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 */ @@ -25,33 +25,30 @@ static int h261_probe(AVProbeData *p) { - uint32_t code= -1; int i; int valid_psc=0; int invalid_psc=0; int next_gn=0; int src_fmt=0; - GetBitContext gb; - init_get_bits(&gb, p->buf, p->buf_size*8); + for(i=0; i<p->buf_size; i++){ + if ((AV_RB16(&p->buf[i]) - 1) < 0xFFU) { + int shift = av_log2_16bit(p->buf[i+1]); + uint32_t code = AV_RB64(&p->buf[FFMAX(i-1, 0)]) >> (24+shift); + if ((code & 0xffff0000) == 0x10000) { + int gn= (code>>12)&0xf; + if(!gn) + src_fmt= code&8; + if(gn != next_gn) invalid_psc++; + else valid_psc++; - for(i=0; i<p->buf_size*8; i++){ - if ((code & 0x01ff0000) || !(code & 0xff00)) { - code = (code<<8) + get_bits(&gb, 8); - i += 7; - } else - code = (code<<1) + get_bits1(&gb); - if ((code & 0xffff0000) == 0x10000) { - int gn= (code>>12)&0xf; - if(!gn) - src_fmt= code&8; - if(gn != next_gn) invalid_psc++; - else valid_psc++; - - if(src_fmt){ // CIF - next_gn= (gn+1 )%13; - }else{ //QCIF - next_gn= (gn+1+!!gn)% 7; + if(src_fmt){ // CIF + static const int lut[16]={1,2,3,4,5,6,7,8,9,10,11,12,0,16,16,16}; + next_gn = lut[gn]; + }else{ //QCIF + static const int lut[16]={1,3,16,5,16,0,16,16,16,16,16,16,16,16,16,16}; + next_gn = lut[gn]; + } } } } |