1/*
2 * MP3 muxer and demuxer
3 * Copyright (c) 2003 Fabrice Bellard
4 *
5 * This file is part of FFmpeg.
6 *
7 * FFmpeg is free software; you can redistribute it and/or
8 * modify it under the terms of the GNU Lesser General Public
9 * License as published by the Free Software Foundation; either
10 * version 2.1 of the License, or (at your option) any later version.
11 *
12 * FFmpeg is distributed in the hope that it will be useful,
13 * but WITHOUT ANY WARRANTY; without even the implied warranty of
14 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
15 * Lesser General Public License for more details.
16 *
17 * You should have received a copy of the GNU Lesser General Public
18 * License along with FFmpeg; if not, write to the Free Software
19 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
20 */
21
22#include <strings.h>
23#include "libavutil/avstring.h"
24#include "libavutil/intreadwrite.h"
25#include "avformat.h"
26#include "id3v2.h"
27#include "id3v1.h"
28
29#if CONFIG_MP3_DEMUXER
30
31#include "libavcodec/mpegaudio.h"
32#include "libavcodec/mpegaudiodecheader.h"
33
34/* mp3 read */
35
36static int mp3_read_probe(AVProbeData *p)
37{
38    int max_frames, first_frames = 0;
39    int fsize, frames, sample_rate;
40    uint32_t header;
41    uint8_t *buf, *buf0, *buf2, *end;
42    AVCodecContext avctx;
43
44    buf0 = p->buf;
45    if(ff_id3v2_match(buf0)) {
46        buf0 += ff_id3v2_tag_len(buf0);
47    }
48    end = p->buf + p->buf_size - sizeof(uint32_t);
49    while(buf0 < end && !*buf0)
50        buf0++;
51
52    max_frames = 0;
53    buf = buf0;
54
55    for(; buf < end; buf= buf2+1) {
56        buf2 = buf;
57
58        for(frames = 0; buf2 < end; frames++) {
59            header = AV_RB32(buf2);
60            fsize = ff_mpa_decode_header(&avctx, header, &sample_rate, &sample_rate, &sample_rate, &sample_rate);
61            if(fsize < 0)
62                break;
63            buf2 += fsize;
64        }
65        max_frames = FFMAX(max_frames, frames);
66        if(buf == buf0)
67            first_frames= frames;
68    }
69    // keep this in sync with ac3 probe, both need to avoid
70    // issues with MPEG-files!
71    if   (first_frames>=4) return AVPROBE_SCORE_MAX/2+1;
72    else if(max_frames>500)return AVPROBE_SCORE_MAX/2;
73    else if(max_frames>=4) return AVPROBE_SCORE_MAX/4;
74    else if(buf0!=p->buf)  return AVPROBE_SCORE_MAX/4-1;
75    else if(max_frames>=1) return 1;
76    else                   return 0;
77//mpegps_mp3_unrecognized_format.mpg has max_frames=3
78}
79
80/**
81 * Try to find Xing/Info/VBRI tags and compute duration from info therein
82 */
83static int mp3_parse_vbr_tags(AVFormatContext *s, AVStream *st, int64_t base)
84{
85    uint32_t v, spf;
86    int frames = -1; /* Total number of frames in file */
87    const int64_t xing_offtbl[2][2] = {{32, 17}, {17,9}};
88    MPADecodeHeader c;
89    int vbrtag_size = 0;
90
91    v = get_be32(s->pb);
92    if(ff_mpa_check_header(v) < 0)
93      return -1;
94
95    if (ff_mpegaudio_decode_header(&c, v) == 0)
96        vbrtag_size = c.frame_size;
97    if(c.layer != 3)
98        return -1;
99
100    /* Check for Xing / Info tag */
101    url_fseek(s->pb, xing_offtbl[c.lsf == 1][c.nb_channels == 1], SEEK_CUR);
102    v = get_be32(s->pb);
103    if(v == MKBETAG('X', 'i', 'n', 'g') || v == MKBETAG('I', 'n', 'f', 'o')) {
104        v = get_be32(s->pb);
105        if(v & 0x1)
106            frames = get_be32(s->pb);
107    }
108
109    /* Check for VBRI tag (always 32 bytes after end of mpegaudio header) */
110    url_fseek(s->pb, base + 4 + 32, SEEK_SET);
111    v = get_be32(s->pb);
112    if(v == MKBETAG('V', 'B', 'R', 'I')) {
113        /* Check tag version */
114        if(get_be16(s->pb) == 1) {
115            /* skip delay, quality and total bytes */
116            url_fseek(s->pb, 8, SEEK_CUR);
117            frames = get_be32(s->pb);
118        }
119    }
120
121    if(frames < 0)
122        return -1;
123
124    /* Skip the vbr tag frame */
125    url_fseek(s->pb, base + vbrtag_size, SEEK_SET);
126
127    spf = c.lsf ? 576 : 1152; /* Samples per frame, layer 3 */
128    st->duration = av_rescale_q(frames, (AVRational){spf, c.sample_rate},
129                                st->time_base);
130    return 0;
131}
132
133static int mp3_read_header(AVFormatContext *s,
134                           AVFormatParameters *ap)
135{
136    AVStream *st;
137    int64_t off;
138
139    st = av_new_stream(s, 0);
140    if (!st)
141        return AVERROR(ENOMEM);
142
143    st->codec->codec_type = AVMEDIA_TYPE_AUDIO;
144    st->codec->codec_id = CODEC_ID_MP3;
145    st->need_parsing = AVSTREAM_PARSE_FULL;
146    st->start_time = 0;
147
148    // lcm of all mp3 sample rates
149    av_set_pts_info(st, 64, 1, 14112000);
150
151    ff_id3v2_read(s);
152    off = url_ftell(s->pb);
153
154    if (!av_metadata_get(s->metadata, "", NULL, AV_METADATA_IGNORE_SUFFIX))
155        ff_id3v1_read(s);
156
157    if (mp3_parse_vbr_tags(s, st, off) < 0)
158        url_fseek(s->pb, off, SEEK_SET);
159
160    /* the parameters will be extracted from the compressed bitstream */
161    return 0;
162}
163
164#define MP3_PACKET_SIZE 1024
165
166static int mp3_read_packet(AVFormatContext *s, AVPacket *pkt)
167{
168    int ret, size;
169    //    AVStream *st = s->streams[0];
170
171    size= MP3_PACKET_SIZE;
172
173    ret= av_get_packet(s->pb, pkt, size);
174
175    pkt->stream_index = 0;
176    if (ret <= 0) {
177        return AVERROR(EIO);
178    }
179    /* note: we need to modify the packet size here to handle the last
180       packet */
181    pkt->size = ret;
182    return ret;
183}
184
185AVInputFormat mp3_demuxer = {
186    "mp3",
187    NULL_IF_CONFIG_SMALL("MPEG audio layer 2/3"),
188    0,
189    mp3_read_probe,
190    mp3_read_header,
191    mp3_read_packet,
192    .flags= AVFMT_GENERIC_INDEX,
193    .extensions = "mp2,mp3,m2a", /* XXX: use probe */
194    .metadata_conv = ff_id3v2_metadata_conv,
195};
196#endif
197
198#if CONFIG_MP2_MUXER || CONFIG_MP3_MUXER
199static int id3v1_set_string(AVFormatContext *s, const char *key,
200                            uint8_t *buf, int buf_size)
201{
202    AVMetadataTag *tag;
203    if ((tag = av_metadata_get(s->metadata, key, NULL, 0)))
204        strncpy(buf, tag->value, buf_size);
205    return !!tag;
206}
207
208static int id3v1_create_tag(AVFormatContext *s, uint8_t *buf)
209{
210    AVMetadataTag *tag;
211    int i, count = 0;
212
213    memset(buf, 0, ID3v1_TAG_SIZE); /* fail safe */
214    buf[0] = 'T';
215    buf[1] = 'A';
216    buf[2] = 'G';
217    count += id3v1_set_string(s, "title",   buf +  3, 30);
218    count += id3v1_set_string(s, "author",  buf + 33, 30);
219    count += id3v1_set_string(s, "album",   buf + 63, 30);
220    count += id3v1_set_string(s, "date",    buf + 93,  4);
221    count += id3v1_set_string(s, "comment", buf + 97, 30);
222    if ((tag = av_metadata_get(s->metadata, "track", NULL, 0))) {
223        buf[125] = 0;
224        buf[126] = atoi(tag->value);
225        count++;
226    }
227    buf[127] = 0xFF; /* default to unknown genre */
228    if ((tag = av_metadata_get(s->metadata, "genre", NULL, 0))) {
229        for(i = 0; i <= ID3v1_GENRE_MAX; i++) {
230            if (!strcasecmp(tag->value, ff_id3v1_genre_str[i])) {
231                buf[127] = i;
232                count++;
233                break;
234            }
235        }
236    }
237    return count;
238}
239
240/* simple formats */
241
242static void id3v2_put_size(AVFormatContext *s, int size)
243{
244    put_byte(s->pb, size >> 21 & 0x7f);
245    put_byte(s->pb, size >> 14 & 0x7f);
246    put_byte(s->pb, size >> 7  & 0x7f);
247    put_byte(s->pb, size       & 0x7f);
248}
249
250static void id3v2_put_ttag(AVFormatContext *s, const char *buf, int len,
251                           uint32_t tag)
252{
253    put_be32(s->pb, tag);
254    id3v2_put_size(s, len + 1);
255    put_be16(s->pb, 0);
256    put_byte(s->pb, 3); /* UTF-8 */
257    put_buffer(s->pb, buf, len);
258}
259
260
261static int mp3_write_packet(struct AVFormatContext *s, AVPacket *pkt)
262{
263    put_buffer(s->pb, pkt->data, pkt->size);
264    put_flush_packet(s->pb);
265    return 0;
266}
267
268static int mp3_write_trailer(struct AVFormatContext *s)
269{
270    uint8_t buf[ID3v1_TAG_SIZE];
271
272    /* write the id3v1 tag */
273    if (id3v1_create_tag(s, buf) > 0) {
274        put_buffer(s->pb, buf, ID3v1_TAG_SIZE);
275        put_flush_packet(s->pb);
276    }
277    return 0;
278}
279#endif /* CONFIG_MP2_MUXER || CONFIG_MP3_MUXER */
280
281#if CONFIG_MP2_MUXER
282AVOutputFormat mp2_muxer = {
283    "mp2",
284    NULL_IF_CONFIG_SMALL("MPEG audio layer 2"),
285    "audio/x-mpeg",
286    "mp2,m2a",
287    0,
288    CODEC_ID_MP2,
289    CODEC_ID_NONE,
290    NULL,
291    mp3_write_packet,
292    mp3_write_trailer,
293};
294#endif
295
296#if CONFIG_MP3_MUXER
297/**
298 * Write an ID3v2.4 header at beginning of stream
299 */
300
301static int mp3_write_header(struct AVFormatContext *s)
302{
303    AVMetadataTag *t = NULL;
304    int totlen = 0;
305    int64_t size_pos, cur_pos;
306
307    put_be32(s->pb, MKBETAG('I', 'D', '3', 0x04)); /* ID3v2.4 */
308    put_byte(s->pb, 0);
309    put_byte(s->pb, 0); /* flags */
310
311    /* reserve space for size */
312    size_pos = url_ftell(s->pb);
313    put_be32(s->pb, 0);
314
315    while ((t = av_metadata_get(s->metadata, "", t, AV_METADATA_IGNORE_SUFFIX))) {
316        uint32_t tag = 0;
317
318        if (t->key[0] == 'T' && strlen(t->key) == 4) {
319            int i;
320            for (i = 0; *ff_id3v2_tags[i]; i++)
321                if (AV_RB32(t->key) == AV_RB32(ff_id3v2_tags[i])) {
322                    int len = strlen(t->value);
323                    tag = AV_RB32(t->key);
324                    totlen += len + ID3v2_HEADER_SIZE + 2;
325                    id3v2_put_ttag(s, t->value, len + 1, tag);
326                    break;
327                }
328        }
329
330        if (!tag) { /* unknown tag, write as TXXX frame */
331            int   len = strlen(t->key), len1 = strlen(t->value);
332            char *buf = av_malloc(len + len1 + 2);
333            if (!buf)
334                return AVERROR(ENOMEM);
335            tag = MKBETAG('T', 'X', 'X', 'X');
336            strcpy(buf,           t->key);
337            strcpy(buf + len + 1, t->value);
338            id3v2_put_ttag(s, buf, len + len1 + 2, tag);
339            totlen += len + len1 + ID3v2_HEADER_SIZE + 3;
340            av_free(buf);
341        }
342    }
343
344    cur_pos = url_ftell(s->pb);
345    url_fseek(s->pb, size_pos, SEEK_SET);
346    id3v2_put_size(s, totlen);
347    url_fseek(s->pb, cur_pos, SEEK_SET);
348
349    return 0;
350}
351
352AVOutputFormat mp3_muxer = {
353    "mp3",
354    NULL_IF_CONFIG_SMALL("MPEG audio layer 3"),
355    "audio/x-mpeg",
356    "mp3",
357    0,
358    CODEC_ID_MP3,
359    CODEC_ID_NONE,
360    mp3_write_header,
361    mp3_write_packet,
362    mp3_write_trailer,
363    AVFMT_NOTIMESTAMPS,
364    .metadata_conv = ff_id3v2_metadata_conv,
365};
366#endif
367