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FFmpeg/libavformat/mp3enc.c

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/*
* MP3 muxer
* Copyright (c) 2003 Fabrice Bellard
*
* This file is part of Libav.
*
* Libav 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.
*
* Libav 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 Libav; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
*/
#include "avformat.h"
#include "avio_internal.h"
#include "id3v1.h"
#include "id3v2.h"
#include "rawenc.h"
#include "libavutil/avstring.h"
#include "libavcodec/mpegaudio.h"
#include "libavcodec/mpegaudiodata.h"
#include "libavcodec/mpegaudiodecheader.h"
#include "libavutil/intreadwrite.h"
#include "libavutil/opt.h"
#include "libavutil/dict.h"
#include "libavutil/avassert.h"
static int id3v1_set_string(AVFormatContext *s, const char *key,
uint8_t *buf, int buf_size)
{
AVDictionaryEntry *tag;
if ((tag = av_dict_get(s->metadata, key, NULL, 0)))
av_strlcpy(buf, tag->value, buf_size);
return !!tag;
}
static int id3v1_create_tag(AVFormatContext *s, uint8_t *buf)
{
AVDictionaryEntry *tag;
int i, count = 0;
memset(buf, 0, ID3v1_TAG_SIZE); /* fail safe */
buf[0] = 'T';
buf[1] = 'A';
buf[2] = 'G';
count += id3v1_set_string(s, "TIT2", buf + 3, 30); //title
count += id3v1_set_string(s, "TPE1", buf + 33, 30); //author|artist
count += id3v1_set_string(s, "TALB", buf + 63, 30); //album
count += id3v1_set_string(s, "TDRL", buf + 93, 4); //date
count += id3v1_set_string(s, "comment", buf + 97, 30);
if ((tag = av_dict_get(s->metadata, "TRCK", NULL, 0))) { //track
buf[125] = 0;
buf[126] = atoi(tag->value);
count++;
}
buf[127] = 0xFF; /* default to unknown genre */
if ((tag = av_dict_get(s->metadata, "TCON", NULL, 0))) { //genre
for(i = 0; i <= ID3v1_GENRE_MAX; i++) {
if (!av_strcasecmp(tag->value, ff_id3v1_genre_str[i])) {
buf[127] = i;
count++;
break;
}
}
}
return count;
}
#define XING_NUM_BAGS 400
#define XING_TOC_SIZE 100
// maximum size of the xing frame: offset/Xing/flags/frames/size/TOC
#define XING_MAX_SIZE (32 + 4 + 4 + 4 + 4 + XING_TOC_SIZE)
typedef struct MP3Context {
const AVClass *class;
ID3v2EncContext id3;
int id3v2_version;
int write_id3v1;
/* xing header */
int64_t xing_offset;
int32_t frames;
int32_t size;
uint32_t want;
uint32_t seen;
uint32_t pos;
uint64_t bag[XING_NUM_BAGS];
int initial_bitrate;
int has_variable_bitrate;
/* index of the audio stream */
int audio_stream_idx;
/* number of attached pictures we still need to write */
int pics_to_write;
/* audio packets are queued here until we get all the attached pictures */
AVPacketList *queue, *queue_end;
} MP3Context;
static const uint8_t xing_offtbl[2][2] = {{32, 17}, {17, 9}};
/*
* Write an empty XING header and initialize respective data.
*/
static void mp3_write_xing(AVFormatContext *s)
{
MP3Context *mp3 = s->priv_data;
AVCodecContext *codec = s->streams[mp3->audio_stream_idx]->codec;
int32_t header;
MPADecodeHeader mpah;
int srate_idx, i, channels;
int bitrate_idx;
int xing_offset;
int ver = 0;
if (!s->pb->seekable)
return;
for (i = 0; i < FF_ARRAY_ELEMS(avpriv_mpa_freq_tab); i++) {
const uint16_t base_freq = avpriv_mpa_freq_tab[i];
if (codec->sample_rate == base_freq) ver = 0x3; // MPEG 1
else if (codec->sample_rate == base_freq / 2) ver = 0x2; // MPEG 2
else if (codec->sample_rate == base_freq / 4) ver = 0x0; // MPEG 2.5
else continue;
srate_idx = i;
break;
}
if (i == FF_ARRAY_ELEMS(avpriv_mpa_freq_tab)) {
av_log(s, AV_LOG_WARNING, "Unsupported sample rate, not writing Xing "
"header.\n");
return;
}
switch (codec->channels) {
case 1: channels = MPA_MONO; break;
case 2: channels = MPA_STEREO; break;
default: av_log(s, AV_LOG_WARNING, "Unsupported number of channels, "
"not writing Xing header.\n");
return;
}
/* 64 kbps frame, should be large enough */
bitrate_idx = (ver == 3) ? 5 : 8;
/* dummy MPEG audio header */
header = 0xff << 24; // sync
header |= (0x7 << 5 | ver << 3 | 0x1 << 1 | 0x1) << 16; // sync/audio-version/layer 3/no crc*/
header |= (bitrate_idx << 4 | srate_idx << 2) << 8;
header |= channels << 6;
avio_wb32(s->pb, header);
avpriv_mpegaudio_decode_header(&mpah, header);
av_assert0(mpah.frame_size >= XING_MAX_SIZE);
xing_offset = xing_offtbl[ver != 3][codec->channels == 1];
ffio_fill(s->pb, 0, xing_offset);
mp3->xing_offset = avio_tell(s->pb);
ffio_wfourcc(s->pb, "Xing");
avio_wb32(s->pb, 0x01 | 0x02 | 0x04); // frames / size / TOC
mp3->size = mpah.frame_size;
mp3->want = 1;
avio_wb32(s->pb, 0); // frames
avio_wb32(s->pb, 0); // size
// TOC
for (i = 0; i < XING_TOC_SIZE; i++)
avio_w8(s->pb, 255 * i / XING_TOC_SIZE);
mpah.frame_size -= 4 + xing_offset + 4 + 4 + 4 + 4 + XING_TOC_SIZE;
ffio_fill(s->pb, 0, mpah.frame_size);
}
/*
* Add a frame to XING data.
* Following lame's "VbrTag.c".
*/
static void mp3_xing_add_frame(MP3Context *mp3, AVPacket *pkt)
{
int i;
mp3->frames++;
mp3->seen++;
mp3->size += pkt->size;
if (mp3->want == mp3->seen) {
mp3->bag[mp3->pos] = mp3->size;
if (XING_NUM_BAGS == ++mp3->pos) {
/* shrink table to half size by throwing away each second bag. */
for (i = 1; i < XING_NUM_BAGS; i += 2)
mp3->bag[i / 2] = mp3->bag[i];
/* double wanted amount per bag. */
mp3->want *= 2;
/* adjust current position to half of table size. */
mp3->pos = XING_NUM_BAGS / 2;
}
mp3->seen = 0;
}
}
static int mp3_write_audio_packet(AVFormatContext *s, AVPacket *pkt)
{
MP3Context *mp3 = s->priv_data;
if (mp3->xing_offset && pkt->size >= 4) {
MPADecodeHeader c;
avpriv_mpegaudio_decode_header(&c, AV_RB32(pkt->data));
if (!mp3->initial_bitrate)
mp3->initial_bitrate = c.bit_rate;
if ((c.bit_rate == 0) || (mp3->initial_bitrate != c.bit_rate))
mp3->has_variable_bitrate = 1;
mp3_xing_add_frame(mp3, pkt);
}
return ff_raw_write_packet(s, pkt);
}
static int mp3_queue_flush(AVFormatContext *s)
{
MP3Context *mp3 = s->priv_data;
AVPacketList *pktl;
int ret = 0, write = 1;
ff_id3v2_finish(&mp3->id3, s->pb);
mp3_write_xing(s);
while ((pktl = mp3->queue)) {
if (write && (ret = mp3_write_audio_packet(s, &pktl->pkt)) < 0)
write = 0;
av_free_packet(&pktl->pkt);
mp3->queue = pktl->next;
av_freep(&pktl);
}
mp3->queue_end = NULL;
return ret;
}
static void mp3_update_xing(AVFormatContext *s)
{
MP3Context *mp3 = s->priv_data;
int i;
/* replace "Xing" identification string with "Info" for CBR files. */
if (!mp3->has_variable_bitrate) {
avio_seek(s->pb, mp3->xing_offset, SEEK_SET);
ffio_wfourcc(s->pb, "Info");
}
avio_seek(s->pb, mp3->xing_offset + 8, SEEK_SET);
avio_wb32(s->pb, mp3->frames);
avio_wb32(s->pb, mp3->size);
avio_w8(s->pb, 0); // first toc entry has to be zero.
for (i = 1; i < XING_TOC_SIZE; ++i) {
int j = i * mp3->pos / XING_TOC_SIZE;
int seek_point = 256LL * mp3->bag[j] / mp3->size;
avio_w8(s->pb, FFMIN(seek_point, 255));
}
avio_seek(s->pb, 0, SEEK_END);
}
static int mp3_write_trailer(struct AVFormatContext *s)
{
uint8_t buf[ID3v1_TAG_SIZE];
MP3Context *mp3 = s->priv_data;
if (mp3->pics_to_write) {
av_log(s, AV_LOG_WARNING, "No packets were sent for some of the "
"attached pictures.\n");
mp3_queue_flush(s);
}
/* write the id3v1 tag */
if (mp3->write_id3v1 && id3v1_create_tag(s, buf) > 0) {
avio_write(s->pb, buf, ID3v1_TAG_SIZE);
}
if (mp3->xing_offset)
mp3_update_xing(s);
return 0;
}
#if CONFIG_MP2_MUXER
AVOutputFormat ff_mp2_muxer = {
.name = "mp2",
.long_name = NULL_IF_CONFIG_SMALL("MP2 (MPEG audio layer 2)"),
.mime_type = "audio/x-mpeg",
.extensions = "mp2,m2a,mpa",
.audio_codec = AV_CODEC_ID_MP2,
.video_codec = AV_CODEC_ID_NONE,
.write_packet = ff_raw_write_packet,
.flags = AVFMT_NOTIMESTAMPS,
};
#endif
#if CONFIG_MP3_MUXER
static const AVOption options[] = {
{ "id3v2_version", "Select ID3v2 version to write. Currently 3 and 4 are supported.",
offsetof(MP3Context, id3v2_version), AV_OPT_TYPE_INT, {.i64 = 4}, 3, 4, AV_OPT_FLAG_ENCODING_PARAM},
{ "write_id3v1", "Enable ID3v1 writing. ID3v1 tags are written in UTF-8 which may not be supported by most software.",
offsetof(MP3Context, write_id3v1), AV_OPT_TYPE_INT, {.i64 = 0}, 0, 1, AV_OPT_FLAG_ENCODING_PARAM},
{ NULL },
};
static const AVClass mp3_muxer_class = {
.class_name = "MP3 muxer",
.item_name = av_default_item_name,
.option = options,
.version = LIBAVUTIL_VERSION_INT,
};
static int mp3_write_packet(AVFormatContext *s, AVPacket *pkt)
{
MP3Context *mp3 = s->priv_data;
if (pkt->stream_index == mp3->audio_stream_idx) {
if (mp3->pics_to_write) {
/* buffer audio packets until we get all the pictures */
AVPacketList *pktl = av_mallocz(sizeof(*pktl));
if (!pktl)
return AVERROR(ENOMEM);
pktl->pkt = *pkt;
pktl->pkt.buf = av_buffer_ref(pkt->buf);
if (!pktl->pkt.buf) {
av_freep(&pktl);
return AVERROR(ENOMEM);
}
if (mp3->queue_end)
mp3->queue_end->next = pktl;
else
mp3->queue = pktl;
mp3->queue_end = pktl;
} else
return mp3_write_audio_packet(s, pkt);
} else {
int ret;
/* warn only once for each stream */
if (s->streams[pkt->stream_index]->nb_frames == 1) {
av_log(s, AV_LOG_WARNING, "Got more than one picture in stream %d,"
" ignoring.\n", pkt->stream_index);
}
if (!mp3->pics_to_write || s->streams[pkt->stream_index]->nb_frames >= 1)
return 0;
if ((ret = ff_id3v2_write_apic(s, &mp3->id3, pkt)) < 0)
return ret;
mp3->pics_to_write--;
/* flush the buffered audio packets */
if (!mp3->pics_to_write &&
(ret = mp3_queue_flush(s)) < 0)
return ret;
}
return 0;
}
/**
* Write an ID3v2 header at beginning of stream
*/
static int mp3_write_header(struct AVFormatContext *s)
{
MP3Context *mp3 = s->priv_data;
int ret, i;
/* check the streams -- we want exactly one audio and arbitrary number of
* video (attached pictures) */
mp3->audio_stream_idx = -1;
for (i = 0; i < s->nb_streams; i++) {
AVStream *st = s->streams[i];
if (st->codec->codec_type == AVMEDIA_TYPE_AUDIO) {
if (mp3->audio_stream_idx >= 0 || st->codec->codec_id != AV_CODEC_ID_MP3) {
av_log(s, AV_LOG_ERROR, "Invalid audio stream. Exactly one MP3 "
"audio stream is required.\n");
return AVERROR(EINVAL);
}
mp3->audio_stream_idx = i;
} else if (st->codec->codec_type != AVMEDIA_TYPE_VIDEO) {
av_log(s, AV_LOG_ERROR, "Only audio streams and pictures are allowed in MP3.\n");
return AVERROR(EINVAL);
}
}
if (mp3->audio_stream_idx < 0) {
av_log(s, AV_LOG_ERROR, "No audio stream present.\n");
return AVERROR(EINVAL);
}
mp3->pics_to_write = s->nb_streams - 1;
ff_id3v2_start(&mp3->id3, s->pb, mp3->id3v2_version, ID3v2_DEFAULT_MAGIC);
ret = ff_id3v2_write_metadata(s, &mp3->id3);
if (ret < 0)
return ret;
if (!mp3->pics_to_write) {
ff_id3v2_finish(&mp3->id3, s->pb);
mp3_write_xing(s);
}
return 0;
}
AVOutputFormat ff_mp3_muxer = {
.name = "mp3",
.long_name = NULL_IF_CONFIG_SMALL("MP3 (MPEG audio layer 3)"),
.mime_type = "audio/x-mpeg",
.extensions = "mp3",
.priv_data_size = sizeof(MP3Context),
.audio_codec = AV_CODEC_ID_MP3,
.video_codec = AV_CODEC_ID_PNG,
.write_header = mp3_write_header,
.write_packet = mp3_write_packet,
.write_trailer = mp3_write_trailer,
.flags = AVFMT_NOTIMESTAMPS,
.priv_class = &mp3_muxer_class,
};
#endif