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8da0a6cda1
ffmpeg/libavformat/mp3enc.c
Tobias Rapp 8da0a6cda1 mp3enc: Fix Xing tag identification string for CBR files 
Fixes the Xing tag identification string to be "Info" for MP3 files with
constant bitrate. The previous "Xing" caused some decoders to recognize the
file as VBR.

Signed-off-by: Michael Niedermayer <michaelni@gmx.at>
2012-05-07 16:24:19 +02:00

512 lines
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/*
* MP3 muxer
* Copyright (c) 2003 Fabrice Bellard
*
* This file is part of FFmpeg.
*
* FFmpeg 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.
*
* FFmpeg 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 FFmpeg; 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 "libavcodec/mpegaudio.h"
#include "libavcodec/mpegaudiodata.h"
#include "libavcodec/mpegaudiodecheader.h"
#include "libavformat/avio_internal.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';
/* we knowingly overspecify each tag length by one byte to compensate for the mandatory null byte added by av_strlcpy */
count += id3v1_set_string(s, "TIT2", buf + 3, 30 + 1); //title
count += id3v1_set_string(s, "TPE1", buf + 33, 30 + 1); //author|artist
count += id3v1_set_string(s, "TALB", buf + 63, 30 + 1); //album
count += id3v1_set_string(s, "TDRL", buf + 93, 4 + 1); //date
count += id3v1_set_string(s, "comment", buf + 97, 30 + 1);
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 VBR_NUM_BAGS 400
#define VBR_TOC_SIZE 100
typedef struct MP3Context {
const AVClass *class;
ID3v2EncContext id3;
int id3v2_version;
int write_id3v1;
int64_t frames_offset;
int32_t frames;
int32_t size;
uint32_t want;
uint32_t seen;
uint32_t pos;
uint64_t bag[VBR_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 int64_t xing_offtbl[2][2] = {{32, 17}, {17,9}};
/*
* Write an empty XING header and initialize respective data.
*/
static int mp3_write_xing(AVFormatContext *s)
{
MP3Context *mp3 = s->priv_data;
AVCodecContext *codec = s->streams[mp3->audio_stream_idx]->codec;
int bitrate_idx;
int best_bitrate_idx = -1;
int best_bitrate_error= INT_MAX;
int64_t xing_offset;
int32_t header, mask;
MPADecodeHeader c;
int srate_idx, i, channels;
int needed;
if (!s->pb->seekable)
return 0;
for (i = 0; i < FF_ARRAY_ELEMS(avpriv_mpa_freq_tab); i++)
if (avpriv_mpa_freq_tab[i] == codec->sample_rate) {
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 -1;
}
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 -1;
}
/* dummy MPEG audio header */
header = 0xff << 24; // sync
header |= (0x7 << 5 | 0x3 << 3 | 0x1 << 1 | 0x1) << 16; // sync/mpeg-1/layer 3/no crc*/
header |= (srate_idx << 2) << 8;
header |= channels << 6;
for (bitrate_idx=1; bitrate_idx<15; bitrate_idx++) {
int error;
avpriv_mpegaudio_decode_header(&c, header | (bitrate_idx << (4+8)));
error= FFABS(c.bit_rate - codec->bit_rate);
if(error < best_bitrate_error){
best_bitrate_error= error;
best_bitrate_idx = bitrate_idx;
}
}
av_assert0(best_bitrate_idx >= 0);
for (bitrate_idx= best_bitrate_idx;; bitrate_idx++) {
if (15 == bitrate_idx)
return -1;
mask = bitrate_idx << (4+8);
header |= mask;
avpriv_mpegaudio_decode_header(&c, header);
xing_offset=xing_offtbl[c.lsf == 1][c.nb_channels == 1];
needed = 4 // header
+ xing_offset
+ 4 // xing tag
+ 4 // frames/size/toc flags
+ 4 // frames
+ 4 // size
+ VBR_TOC_SIZE; // toc
if (needed <= c.frame_size)
break;
header &= ~mask;
}
avio_wb32(s->pb, header);
ffio_fill(s->pb, 0, xing_offset);
avio_wb32(s->pb, MKBETAG('X', 'i', 'n', 'g'));
avio_wb32(s->pb, 0x01 | 0x02 | 0x04); // frames/size/toc
mp3->frames_offset = avio_tell(s->pb);
mp3->size = c.frame_size;
mp3->want=1;
mp3->seen=0;
mp3->pos=0;
avio_wb32(s->pb, 0); // frames
avio_wb32(s->pb, 0); // size
// toc
for (i = 0; i < VBR_TOC_SIZE; ++i)
avio_w8(s->pb, (uint8_t)(255 * i / VBR_TOC_SIZE));
ffio_fill(s->pb, 0, c.frame_size - needed);
avio_flush(s->pb);
return 0;
}
/*
* Add a frame to XING data.
* Following lame's "VbrTag.c".
*/
static void mp3_xing_add_frame(AVFormatContext *s, AVPacket *pkt)
{
MP3Context *mp3 = s->priv_data;
int i;
++mp3->frames;
mp3->size += pkt->size;
if (mp3->want == ++mp3->seen) {
mp3->bag[mp3->pos] = mp3->size;
if (VBR_NUM_BAGS == ++mp3->pos) {
/* shrink table to half size by throwing away each second bag. */
for (i = 1; i < VBR_NUM_BAGS; i += 2)
mp3->bag[i >> 1] = mp3->bag[i];
/* double wanted amount per bag. */
mp3->want <<= 1;
/* adjust current position to half of table size. */
mp3->pos >>= 1;
}
mp3->seen = 0;
}
}
static void mp3_fix_xing(AVFormatContext *s)
{
MP3Context *mp3 = s->priv_data;
int i;
avio_flush(s->pb);
/* replace "Xing" identification string with "Info" for CBR files. */
if (!mp3->has_variable_bitrate) {
int64_t tag_offset = mp3->frames_offset
- 4 // frames/size/toc flags
- 4; // xing tag
avio_seek(s->pb, tag_offset, SEEK_SET);
avio_wb32(s->pb, MKBETAG('I', 'n', 'f', 'o'));
}
avio_seek(s->pb, mp3->frames_offset, 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 < VBR_TOC_SIZE; ++i) {
int j = i * mp3->pos / VBR_TOC_SIZE;
int seek_point = 256LL * mp3->bag[j] / mp3->size;
avio_w8(s->pb, FFMIN(seek_point, 255));
}
avio_flush(s->pb);
avio_seek(s->pb, 0, SEEK_END);
}
static int mp3_write_packet_internal(AVFormatContext *s, AVPacket *pkt)
{
if (! pkt || ! pkt->data || pkt->size < 4)
return ff_raw_write_packet(s, pkt);
else {
MP3Context *mp3 = s->priv_data;
MPADecodeHeader c;
#ifdef FILTER_VBR_HEADERS
int base;
#endif
avpriv_mpegaudio_decode_header(&c, AV_RB32(pkt->data));
if (!mp3->initial_bitrate)
mp3->initial_bitrate = c.bit_rate;
if (!mp3->has_variable_bitrate) {
if ((c.bit_rate == 0) || (mp3->initial_bitrate != c.bit_rate))
mp3->has_variable_bitrate = 1;
}
#ifdef FILTER_VBR_HEADERS
/* filter out XING and INFO headers. */
base = 4 + xing_offtbl[c.lsf == 1][c.nb_channels == 1];
if (base + 4 <= pkt->size) {
uint32_t v = AV_RB32(pkt->data + base);
if (MKBETAG('X','i','n','g') == v || MKBETAG('I','n','f','o') == v)
return 0;
}
/* filter out VBRI headers. */
base = 4 + 32;
if (base + 4 <= pkt->size && MKBETAG('V','B','R','I') == AV_RB32(pkt->data + base))
return 0;
#endif
if (mp3->frames_offset)
mp3_xing_add_frame(s, 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_packet_internal(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 int mp2_write_trailer(struct AVFormatContext *s)
{
uint8_t buf[ID3v1_TAG_SIZE];
MP3Context *mp3 = s->priv_data;
if (mp3 && 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 && mp3->write_id3v1 && id3v1_create_tag(s, buf) > 0) {
avio_write(s->pb, buf, ID3v1_TAG_SIZE);
}
/* write number of frames */
if (mp3 && mp3->frames_offset) {
avio_seek(s->pb, mp3->frames_offset, SEEK_SET);
avio_wb32(s->pb, s->streams[mp3->audio_stream_idx]->nb_frames);
avio_seek(s->pb, 0, SEEK_END);
}
avio_flush(s->pb);
return 0;
}
#if CONFIG_MP2_MUXER
AVOutputFormat ff_mp2_muxer = {
.name = "mp2",
.long_name = NULL_IF_CONFIG_SMALL("MPEG audio layer 2"),
.mime_type = "audio/x-mpeg",
.extensions = "mp2,m2a",
.audio_codec = CODEC_ID_MP2,
.video_codec = CODEC_ID_NONE,
.write_packet = ff_raw_write_packet,
.write_trailer = mp2_write_trailer,
.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, {.dbl = 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, {.dbl = 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;
pkt->destruct = NULL;
if (mp3->queue_end)
mp3->queue_end->next = pktl;
else
mp3->queue = pktl;
mp3->queue_end = pktl;
} else
return mp3_write_packet_internal(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 != 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;
}
static int mp3_write_trailer(AVFormatContext *s)
{
MP3Context *mp3 = s->priv_data;
int ret=mp2_write_trailer(s);
if (ret < 0)
return ret;
if (mp3->frames_offset)
mp3_fix_xing(s);
return 0;
}
AVOutputFormat ff_mp3_muxer = {
.name = "mp3",
.long_name = NULL_IF_CONFIG_SMALL("MPEG audio layer 3"),
.mime_type = "audio/x-mpeg",
.extensions = "mp3",
.priv_data_size = sizeof(MP3Context),
.audio_codec = CODEC_ID_MP3,
.video_codec = 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
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