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 "defs.h"
26 #include "mpegaudiodecheader.h"
27 #include "mpegaudiodata.h"
28
29
mp3_header_decompress(AVBSFContext *ctx, AVPacket *out)30 static int mp3_header_decompress(AVBSFContext *ctx, AVPacket *out)
31 {
32 AVPacket *in;
33 uint32_t header;
34 int sample_rate= ctx->par_in->sample_rate;
35 int sample_rate_index=0;
36 int lsf, mpeg25, bitrate_index, frame_size, ret;
37 uint8_t *buf;
38 int buf_size;
39
40 ret = ff_bsf_get_packet(ctx, &in);
41 if (ret < 0)
42 return ret;
43
44 buf = in->data;
45 buf_size = in->size;
46
47 header = AV_RB32(buf);
48 if(ff_mpa_check_header(header) >= 0){
49 av_packet_move_ref(out, in);
50 av_packet_free(&in);
51
52 return 0;
53 }
54
55 if(ctx->par_in->extradata_size != 15 || strcmp(ctx->par_in->extradata, "FFCMP3 0.0")){
56 av_log(ctx, AV_LOG_ERROR, "Extradata invalid %d\n", ctx->par_in->extradata_size);
57 ret = AVERROR(EINVAL);
58 goto fail;
59 }
60
61 header= AV_RB32(ctx->par_in->extradata+11) & MP3_MASK;
62
63 lsf = sample_rate < (24000+32000)/2;
64 mpeg25 = sample_rate < (12000+16000)/2;
65 sample_rate_index= (header>>10)&3;
66 if (sample_rate_index == 3) {
67 ret = AVERROR_INVALIDDATA;
68 goto fail;
69 }
70
71 sample_rate = ff_mpa_freq_tab[sample_rate_index] >> (lsf + mpeg25); //in case sample rate is a little off
72
73 for(bitrate_index=2; bitrate_index<30; bitrate_index++){
74 frame_size = ff_mpa_bitrate_tab[lsf][2][bitrate_index>>1];
75 frame_size = (frame_size * 144000) / (sample_rate << lsf) + (bitrate_index&1);
76 if(frame_size == buf_size + 4)
77 break;
78 if(frame_size == buf_size + 6)
79 break;
80 }
81 if(bitrate_index == 30){
82 av_log(ctx, AV_LOG_ERROR, "Could not find bitrate_index.\n");
83 ret = AVERROR(EINVAL);
84 goto fail;
85 }
86
87 header |= (bitrate_index&1)<<9;
88 header |= (bitrate_index>>1)<<12;
89 header |= (frame_size == buf_size + 4)<<16; //FIXME actually set a correct crc instead of 0
90
91 ret = av_new_packet(out, frame_size);
92 if (ret < 0)
93 goto fail;
94 ret = av_packet_copy_props(out, in);
95 if (ret < 0) {
96 av_packet_unref(out);
97 goto fail;
98 }
99 memcpy(out->data + frame_size - buf_size, buf, buf_size + AV_INPUT_BUFFER_PADDING_SIZE);
100
101 if (ctx->par_in->ch_layout.nb_channels == 2){
102 uint8_t *p= out->data + frame_size - buf_size;
103 if(lsf){
104 FFSWAP(int, p[1], p[2]);
105 header |= (p[1] & 0xC0)>>2;
106 p[1] &= 0x3F;
107 }else{
108 header |= p[1] & 0x30;
109 p[1] &= 0xCF;
110 }
111 }
112
113 AV_WB32(out->data, header);
114
115 ret = 0;
116
117 fail:
118 av_packet_free(&in);
119 return ret;
120 }
121
122 static const enum AVCodecID codec_ids[] = {
123 AV_CODEC_ID_MP3, AV_CODEC_ID_NONE,
124 };
125
126 const FFBitStreamFilter ff_mp3_header_decompress_bsf = {
127 .p.name = "mp3decomp",
128 .p.codec_ids = codec_ids,
129 .filter = mp3_header_decompress,
130 };
131