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
30static 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
117fail:
118    av_packet_free(&in);
119    return ret;
120}
121
122static const enum AVCodecID codec_ids[] = {
123    AV_CODEC_ID_MP3, AV_CODEC_ID_NONE,
124};
125
126const FFBitStreamFilter ff_mp3_header_decompress_bsf = {
127    .p.name      = "mp3decomp",
128    .p.codec_ids = codec_ids,
129    .filter      = mp3_header_decompress,
130};
131