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/* |
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* copyright (c) 2006 Michael Niedermayer <michaelni@gmx.at> |
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* |
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* This file is part of FFmpeg. |
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* |
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* FFmpeg is free software; you can redistribute it and/or |
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* modify it under the terms of the GNU Lesser General Public |
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* License as published by the Free Software Foundation; either |
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* version 2.1 of the License, or (at your option) any later version. |
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* |
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* FFmpeg is distributed in the hope that it will be useful, |
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* but WITHOUT ANY WARRANTY; without even the implied warranty of |
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU |
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* Lesser General Public License for more details. |
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* |
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* You should have received a copy of the GNU Lesser General Public |
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* License along with FFmpeg; if not, write to the Free Software |
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* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA |
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*/ |
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#include "libavutil/common.h" |
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#include "libavutil/intreadwrite.h" |
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#include "avcodec.h" |
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#include "bsf.h" |
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#include "mpegaudiodecheader.h" |
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#include "mpegaudiodata.h" |
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static int mp3_header_decompress(AVBSFContext *ctx, AVPacket *out) |
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{ |
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AVPacket *in; |
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uint32_t header; |
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int sample_rate= ctx->par_in->sample_rate; |
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int sample_rate_index=0; |
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int lsf, mpeg25, bitrate_index, frame_size, ret; |
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uint8_t *buf; |
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int buf_size; |
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ret = ff_bsf_get_packet(ctx, &in); |
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if (ret < 0) |
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return ret; |
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buf = in->data; |
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buf_size = in->size; |
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header = AV_RB32(buf); |
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if(ff_mpa_check_header(header) >= 0){ |
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av_packet_move_ref(out, in); |
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av_packet_free(&in); |
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return 0; |
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} |
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if(ctx->par_in->extradata_size != 15 || strcmp(ctx->par_in->extradata, "FFCMP3 0.0")){ |
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av_log(ctx, AV_LOG_ERROR, "Extradata invalid %d\n", ctx->par_in->extradata_size); |
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ret = AVERROR(EINVAL); |
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goto fail; |
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} |
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header= AV_RB32(ctx->par_in->extradata+11) & MP3_MASK; |
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lsf = sample_rate < (24000+32000)/2; |
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mpeg25 = sample_rate < (12000+16000)/2; |
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sample_rate_index= (header>>10)&3; |
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sample_rate= avpriv_mpa_freq_tab[sample_rate_index] >> (lsf + mpeg25); //in case sample rate is a little off |
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for(bitrate_index=2; bitrate_index<30; bitrate_index++){ |
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frame_size = avpriv_mpa_bitrate_tab[lsf][2][bitrate_index>>1]; |
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frame_size = (frame_size * 144000) / (sample_rate << lsf) + (bitrate_index&1); |
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if(frame_size == buf_size + 4) |
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break; |
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if(frame_size == buf_size + 6) |
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break; |
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} |
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if(bitrate_index == 30){ |
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av_log(ctx, AV_LOG_ERROR, "Could not find bitrate_index.\n"); |
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ret = AVERROR(EINVAL); |
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goto fail; |
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} |
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header |= (bitrate_index&1)<<9; |
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header |= (bitrate_index>>1)<<12; |
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header |= (frame_size == buf_size + 4)<<16; //FIXME actually set a correct crc instead of 0 |
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ret = av_new_packet(out, frame_size); |
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if (ret < 0) |
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goto fail; |
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ret = av_packet_copy_props(out, in); |
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if (ret < 0) { |
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av_packet_unref(out); |
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goto fail; |
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} |
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memcpy(out->data + frame_size - buf_size, buf, buf_size + AV_INPUT_BUFFER_PADDING_SIZE); |
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if(ctx->par_in->channels==2){ |
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uint8_t *p= out->data + frame_size - buf_size; |
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if(lsf){ |
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FFSWAP(int, p[1], p[2]); |
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header |= (p[1] & 0xC0)>>2; |
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p[1] &= 0x3F; |
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}else{ |
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header |= p[1] & 0x30; |
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p[1] &= 0xCF; |
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} |
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} |
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AV_WB32(out->data, header); |
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ret = 0; |
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fail: |
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av_packet_free(&in); |
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return ret; |
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} |
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static const enum AVCodecID codec_ids[] = { |
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AV_CODEC_ID_MP3, AV_CODEC_ID_NONE, |
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}; |
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const AVBitStreamFilter ff_mp3_header_decompress_bsf = { |
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.name = "mp3decomp", |
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.filter = mp3_header_decompress, |
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.codec_ids = codec_ids, |
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}; |