/* * copyright (c) 2006 Michael Niedermayer <michaelni@gmx.at> * * This file is part of FFmpeg. * * 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. * * 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 FFmpeg; if not, write to the Free Software * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA */ #include "libavutil/common.h" #include "libavutil/intreadwrite.h" #include "avcodec.h" #include "mpegaudiodecheader.h" #include "mpegaudiodata.h" static int mp3_header_decompress(AVBitStreamFilterContext *bsfc, AVCodecContext *avctx, const char *args, uint8_t **poutbuf, int *poutbuf_size, const uint8_t *buf, int buf_size, int keyframe){ uint32_t header; int sample_rate= avctx->sample_rate; int sample_rate_index=0; int lsf, mpeg25, bitrate_index, frame_size; header = AV_RB32(buf); if(ff_mpa_check_header(header) >= 0){ *poutbuf= (uint8_t *) buf; *poutbuf_size= buf_size; return 0; } if(avctx->extradata_size != 15 || strcmp(avctx->extradata, "FFCMP3 0.0")){ av_log(avctx, AV_LOG_ERROR, "Extradata invalid %d\n", avctx->extradata_size); return -1; } header= AV_RB32(avctx->extradata+11) & MP3_MASK; lsf = sample_rate < (24000+32000)/2; mpeg25 = sample_rate < (12000+16000)/2; sample_rate_index= (header>>10)&3; sample_rate= avpriv_mpa_freq_tab[sample_rate_index] >> (lsf + mpeg25); //in case sample rate is a little off for(bitrate_index=2; bitrate_index<30; bitrate_index++){ frame_size = avpriv_mpa_bitrate_tab[lsf][2][bitrate_index>>1]; frame_size = (frame_size * 144000) / (sample_rate << lsf) + (bitrate_index&1); if(frame_size == buf_size + 4) break; if(frame_size == buf_size + 6) break; } if(bitrate_index == 30){ av_log(avctx, AV_LOG_ERROR, "Could not find bitrate_index.\n"); return -1; } header |= (bitrate_index&1)<<9; header |= (bitrate_index>>1)<<12; header |= (frame_size == buf_size + 4)<<16; //FIXME actually set a correct crc instead of 0 *poutbuf_size= frame_size; *poutbuf= av_malloc(frame_size + AV_INPUT_BUFFER_PADDING_SIZE); memcpy(*poutbuf + frame_size - buf_size, buf, buf_size + AV_INPUT_BUFFER_PADDING_SIZE); if(avctx->channels==2){ uint8_t *p= *poutbuf + frame_size - buf_size; if(lsf){ FFSWAP(int, p[1], p[2]); header |= (p[1] & 0xC0)>>2; p[1] &= 0x3F; }else{ header |= p[1] & 0x30; p[1] &= 0xCF; } } AV_WB32(*poutbuf, header); return 1; } AVBitStreamFilter ff_mp3_header_decompress_bsf={ .name = "mp3decomp", .filter = mp3_header_decompress, };