| /* |
| * 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 "bsf.h" |
| #include "mpegaudiodecheader.h" |
| #include "mpegaudiodata.h" |
| |
| |
| static int mp3_header_decompress(AVBSFContext *ctx, AVPacket *out) |
| { |
| AVPacket *in; |
| uint32_t header; |
| int sample_rate= ctx->par_in->sample_rate; |
| int sample_rate_index=0; |
| int lsf, mpeg25, bitrate_index, frame_size, ret; |
| uint8_t *buf; |
| int buf_size; |
| |
| ret = ff_bsf_get_packet(ctx, &in); |
| if (ret < 0) |
| return ret; |
| |
| buf = in->data; |
| buf_size = in->size; |
| |
| header = AV_RB32(buf); |
| if(ff_mpa_check_header(header) >= 0){ |
| av_packet_move_ref(out, in); |
| av_packet_free(&in); |
| |
| return 0; |
| } |
| |
| if(ctx->par_in->extradata_size != 15 || strcmp(ctx->par_in->extradata, "FFCMP3 0.0")){ |
| av_log(ctx, AV_LOG_ERROR, "Extradata invalid %d\n", ctx->par_in->extradata_size); |
| ret = AVERROR(EINVAL); |
| goto fail; |
| } |
| |
| header= AV_RB32(ctx->par_in->extradata+11) & MP3_MASK; |
| |
| lsf = sample_rate < (24000+32000)/2; |
| mpeg25 = sample_rate < (12000+16000)/2; |
| sample_rate_index= (header>>10)&3; |
| if (sample_rate_index == 3) { |
| ret = AVERROR_INVALIDDATA; |
| goto fail; |
| } |
| |
| 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(ctx, AV_LOG_ERROR, "Could not find bitrate_index.\n"); |
| ret = AVERROR(EINVAL); |
| goto fail; |
| } |
| |
| 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 |
| |
| ret = av_new_packet(out, frame_size); |
| if (ret < 0) |
| goto fail; |
| ret = av_packet_copy_props(out, in); |
| if (ret < 0) { |
| av_packet_unref(out); |
| goto fail; |
| } |
| memcpy(out->data + frame_size - buf_size, buf, buf_size + AV_INPUT_BUFFER_PADDING_SIZE); |
| |
| if(ctx->par_in->channels==2){ |
| uint8_t *p= out->data + 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(out->data, header); |
| |
| ret = 0; |
| |
| fail: |
| av_packet_free(&in); |
| return ret; |
| } |
| |
| static const enum AVCodecID codec_ids[] = { |
| AV_CODEC_ID_MP3, AV_CODEC_ID_NONE, |
| }; |
| |
| const AVBitStreamFilter ff_mp3_header_decompress_bsf = { |
| .name = "mp3decomp", |
| .filter = mp3_header_decompress, |
| .codec_ids = codec_ids, |
| }; |