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 /* check for fixed fields in ADX header for possible match */ 00054 if ((state & 0xFFFF0000FFFFFF00) == 0x8000000003120400ULL) { 00055 int channels = state & 0xFF; 00056 int header_size = ((state >> 32) & 0xFFFF) + 4; 00057 if (channels > 0 && header_size >= 8) { 00058 s->header_size = header_size; 00059 s->block_size = BLOCK_SIZE * channels; 00060 s->remaining = i - 7 + s->header_size + s->block_size; 00061 break; 00062 } 00063 } 00064 } 00065 pc->state64 = state; 00066 } 00067 00068 if (s->header_size) { 00069 if (!s->remaining) 00070 s->remaining = s->block_size; 00071 if (s->remaining <= buf_size) { 00072 next = s->remaining; 00073 s->remaining = 0; 00074 } else 00075 s->remaining -= buf_size; 00076 } 00077 00078 if (ff_combine_frame(pc, next, &buf, &buf_size) < 0 || !buf_size) { 00079 *poutbuf = NULL; 00080 *poutbuf_size = 0; 00081 return buf_size; 00082 } 00083 00084 s1->duration = BLOCK_SAMPLES; 00085 00086 *poutbuf = buf; 00087 *poutbuf_size = buf_size; 00088 return next; 00089 } 00090 00091 AVCodecParser ff_adx_parser = { 00092 .codec_ids = { AV_CODEC_ID_ADPCM_ADX }, 00093 .priv_data_size = sizeof(ADXParseContext), 00094 .parser_parse = adx_parse, 00095 .parser_close = ff_parse_close, 00096 };