FFmpeg: libavcodec/adx_parser.c Source File

00001 /*
00002  * Copyright (c) 2011  Justin Ruggles
00003  *
00004  * This file is part of Libav.
00005  *
00006  * Libav is free software; you can redistribute it and/or
00007  * modify it under the terms of the GNU Lesser General Public
00008  * License as published by the Free Software Foundation; either
00009  * version 2.1 of the License, or (at your option) any later version.
00010  *
00011  * Libav is distributed in the hope that it will be useful,
00012  * but WITHOUT ANY WARRANTY; without even the implied warranty of
00013  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
00014  * Lesser General Public License for more details.
00015  *
00016  * You should have received a copy of the GNU Lesser General Public
00017  * License along with Libav; if not, write to the Free Software
00018  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
00019  */
00020 
00028 #include "libavutil/intreadwrite.h"
00029 #include "parser.h"
00030 #include "adx.h"
00031 
00032 typedef struct ADXParseContext {
00033     ParseContext pc;
00034     int header_size;
00035     int block_size;
00036     int remaining;
00037 } ADXParseContext;
00038 
00039 static int adx_parse(AVCodecParserContext *s1,
00040                            AVCodecContext *avctx,
00041                            const uint8_t **poutbuf, int *poutbuf_size,
00042                            const uint8_t *buf, int buf_size)
00043 {
00044     ADXParseContext *s = s1->priv_data;
00045     ParseContext *pc = &s->pc;
00046     int next = END_NOT_FOUND;
00047     int i;
00048     uint64_t state= pc->state64;
00049 
00050     if(!s->header_size){
00051         for(i=0; i<buf_size; i++){
00052             state= (state<<8) | buf[i];
00053             if((state&0xFFFF0000FFFFFF00) == 0x8000000003120400ULL && (state&0xFF) && ((state>>32)&0xFFFF)>=4){
00054                 s->header_size= ((state>>32)&0xFFFF) + 4;
00055                 s->block_size = BLOCK_SIZE * (state&0xFF);
00056                 s->remaining  = i - 7 + s->header_size + s->block_size;
00057                 break;
00058             }
00059         }
00060         pc->state64= state;
00061     }
00062 
00063     if (s->header_size) {
00064         if (!s->remaining) {
00065             s->remaining = s->block_size;
00066         }
00067         if (s->remaining<=buf_size) {
00068             next= s->remaining;
00069             s->remaining = 0;
00070         } else
00071             s->remaining -= buf_size;
00072     }
00073 
00074     if (ff_combine_frame(pc, next, &buf, &buf_size) < 0 || !buf_size) {
00075         *poutbuf      = NULL;
00076         *poutbuf_size = 0;
00077         return buf_size;
00078     }
00079     *poutbuf = buf;
00080     *poutbuf_size = buf_size;
00081     return next;
00082 }
00083 
00084 AVCodecParser ff_adx_parser = {
00085     .codec_ids      = { CODEC_ID_ADPCM_ADX },
00086     .priv_data_size = sizeof(ADXParseContext),
00087     .parser_parse   = adx_parse,
00088     .parser_close   = ff_parse_close,
00089 };