1 /*
2 * copyright (c) 2006 Michael Niedermayer <michaelni@gmx.at>
3 *
4 * This file is part of FFmpeg.
5 *
6 * FFmpeg is free software; you can redistribute it and/or
7 * modify it under the terms of the GNU Lesser General Public
8 * License as published by the Free Software Foundation; either
9 * version 2.1 of the License, or (at your option) any later version.
10 *
11 * FFmpeg is distributed in the hope that it will be useful,
12 * but WITHOUT ANY WARRANTY; without even the implied warranty of
13 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
14 * Lesser General Public License for more details.
15 *
16 * You should have received a copy of the GNU Lesser General Public
17 * License along with FFmpeg; if not, write to the Free Software
18 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
19 */
20
21 #include "libavutil/common.h"
22 #include "libavutil/intreadwrite.h"
23 #include "bsf.h"
24 #include "bsf_internal.h"
25 #include "mpegaudiodecheader.h"
26 #include "mpegaudiodata.h"
27
28
mp3_header_decompress(AVBSFContext * ctx,AVPacket * out)29 static int mp3_header_decompress(AVBSFContext *ctx, AVPacket *out)
30 {
31 AVPacket *in;
32 uint32_t header;
33 int sample_rate= ctx->par_in->sample_rate;
34 int sample_rate_index=0;
35 int lsf, mpeg25, bitrate_index, frame_size, ret;
36 uint8_t *buf;
37 int buf_size;
38
39 ret = ff_bsf_get_packet(ctx, &in);
40 if (ret < 0)
41 return ret;
42
43 buf = in->data;
44 buf_size = in->size;
45
46 header = AV_RB32(buf);
47 if(ff_mpa_check_header(header) >= 0){
48 av_packet_move_ref(out, in);
49 av_packet_free(&in);
50
51 return 0;
52 }
53
54 if(ctx->par_in->extradata_size != 15 || strcmp(ctx->par_in->extradata, "FFCMP3 0.0")){
55 av_log(ctx, AV_LOG_ERROR, "Extradata invalid %d\n", ctx->par_in->extradata_size);
56 ret = AVERROR(EINVAL);
57 goto fail;
58 }
59
60 header= AV_RB32(ctx->par_in->extradata+11) & MP3_MASK;
61
62 lsf = sample_rate < (24000+32000)/2;
63 mpeg25 = sample_rate < (12000+16000)/2;
64 sample_rate_index= (header>>10)&3;
65 if (sample_rate_index == 3) {
66 ret = AVERROR_INVALIDDATA;
67 goto fail;
68 }
69
70 sample_rate= avpriv_mpa_freq_tab[sample_rate_index] >> (lsf + mpeg25); //in case sample rate is a little off
71
72 for(bitrate_index=2; bitrate_index<30; bitrate_index++){
73 frame_size = avpriv_mpa_bitrate_tab[lsf][2][bitrate_index>>1];
74 frame_size = (frame_size * 144000) / (sample_rate << lsf) + (bitrate_index&1);
75 if(frame_size == buf_size + 4)
76 break;
77 if(frame_size == buf_size + 6)
78 break;
79 }
80 if(bitrate_index == 30){
81 av_log(ctx, AV_LOG_ERROR, "Could not find bitrate_index.\n");
82 ret = AVERROR(EINVAL);
83 goto fail;
84 }
85
86 header |= (bitrate_index&1)<<9;
87 header |= (bitrate_index>>1)<<12;
88 header |= (frame_size == buf_size + 4)<<16; //FIXME actually set a correct crc instead of 0
89
90 ret = av_new_packet(out, frame_size);
91 if (ret < 0)
92 goto fail;
93 ret = av_packet_copy_props(out, in);
94 if (ret < 0) {
95 av_packet_unref(out);
96 goto fail;
97 }
98 memcpy(out->data + frame_size - buf_size, buf, buf_size + AV_INPUT_BUFFER_PADDING_SIZE);
99
100 if(ctx->par_in->channels==2){
101 uint8_t *p= out->data + frame_size - buf_size;
102 if(lsf){
103 FFSWAP(int, p[1], p[2]);
104 header |= (p[1] & 0xC0)>>2;
105 p[1] &= 0x3F;
106 }else{
107 header |= p[1] & 0x30;
108 p[1] &= 0xCF;
109 }
110 }
111
112 AV_WB32(out->data, header);
113
114 ret = 0;
115
116 fail:
117 av_packet_free(&in);
118 return ret;
119 }
120
121 static const enum AVCodecID codec_ids[] = {
122 AV_CODEC_ID_MP3, AV_CODEC_ID_NONE,
123 };
124
125 const AVBitStreamFilter ff_mp3_header_decompress_bsf = {
126 .name = "mp3decomp",
127 .filter = mp3_header_decompress,
128 .codec_ids = codec_ids,
129 };
130