/* * copyright (c) 2006 Michael Niedermayer <michaelni@gmx.at> * * This file is part of Libav. * * Libav 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, * 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 * 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" static int mp3_header_compress(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, extraheader; int mode_extension, header_size; if(avctx->strict_std_compliance > FF_COMPLIANCE_EXPERIMENTAL){ av_log(avctx, AV_LOG_ERROR, "not standards compliant\n"); return -1; } header = AV_RB32(buf); mode_extension= (header>>4)&3; if(ff_mpa_check_header(header) < 0 || (header&0x60000) != 0x20000){ output_unchanged: *poutbuf= (uint8_t *) buf; *poutbuf_size= buf_size; av_log(avctx, AV_LOG_INFO, "cannot compress %08X\n", header); return 0; } if(avctx->extradata_size == 0){ avctx->extradata_size=15; avctx->extradata= av_malloc(avctx->extradata_size); strcpy(avctx->extradata, "FFCMP3 0.0"); memcpy(avctx->extradata+11, buf, 4); } if(avctx->extradata_size != 15){ av_log(avctx, AV_LOG_ERROR, "Extradata invalid\n"); return -1; } extraheader = AV_RB32(avctx->extradata+11); if((extraheader&MP3_MASK) != (header&MP3_MASK)) goto output_unchanged; header_size= (header&0x10000) ? 4 : 6; *poutbuf_size= buf_size - header_size; *poutbuf= av_malloc(buf_size - header_size + FF_INPUT_BUFFER_PADDING_SIZE); memcpy(*poutbuf, buf + header_size, buf_size - header_size + FF_INPUT_BUFFER_PADDING_SIZE); if(avctx->channels==2){ if((header & (3<<19)) != 3<<19){ (*poutbuf)[1] &= 0x3F; (*poutbuf)[1] |= mode_extension<<6; FFSWAP(int, (*poutbuf)[1], (*poutbuf)[2]); }else{ (*poutbuf)[1] &= 0x8F; (*poutbuf)[1] |= mode_extension<<4; } } return 1; } AVBitStreamFilter ff_mp3_header_compress_bsf={ "mp3comp", 0, mp3_header_compress, };