* MP3 muxer
* Copyright (c) 2003 Fabrice Bellard
*
- * This file is part of Libav.
+ * This file is part of FFmpeg.
*
- * Libav is free software; you can redistribute it and/or
+ * 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.
*
- * Libav is distributed in the hope that it will be useful,
+ * 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 Libav; if not, write to the Free Software
+ * License along with FFmpeg; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
*/
#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"
static int id3v1_set_string(AVFormatContext *s, const char *key,
return len + ID3v2_HEADER_SIZE;
}
+#define VBR_NUM_BAGS 400
+#define VBR_TOC_SIZE 100
typedef struct MP3Context {
const AVClass *class;
int id3v2_version;
int write_id3v1;
- int64_t nb_frames_offset;
+ 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];
} MP3Context;
-static int mp3_write_trailer(struct AVFormatContext *s)
+static int mp2_write_trailer(struct AVFormatContext *s)
{
uint8_t buf[ID3v1_TAG_SIZE];
MP3Context *mp3 = s->priv_data;
}
/* write number of frames */
- if (mp3 && mp3->nb_frames_offset) {
- avio_seek(s->pb, mp3->nb_frames_offset, SEEK_SET);
+ if (mp3 && mp3->frames_offset) {
+ avio_seek(s->pb, mp3->frames_offset, SEEK_SET);
avio_wb32(s->pb, s->streams[0]->nb_frames);
avio_seek(s->pb, 0, SEEK_END);
}
.audio_codec = CODEC_ID_MP2,
.video_codec = CODEC_ID_NONE,
.write_packet = ff_raw_write_packet,
- .write_trailer = mp3_write_trailer,
+ .write_trailer = mp2_write_trailer,
};
#endif
return -1;
}
-/* insert a dummy frame containing number of frames */
-static void mp3_write_xing(AVFormatContext *s)
+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)
{
- AVCodecContext *codec = s->streams[0]->codec;
+ AVCodecContext *codec = s->streams[0]->codec;
MP3Context *mp3 = s->priv_data;
- int bitrate_idx = 1; // 32 kbps
- int64_t xing_offset = (codec->channels == 2) ? 32 : 17;
- int32_t header;
- MPADecodeHeader mpah;
- int srate_idx, i, channels;
+ int bitrate_idx = 3;
+ int64_t xing_offset;
+ int32_t mask, header;
+ MPADecodeHeader c;
+ int srate_idx, i, channels;
+ int needed;
for (i = 0; i < FF_ARRAY_ELEMS(ff_mpa_freq_tab); i++)
if (ff_mpa_freq_tab[i] == codec->sample_rate) {
}
if (i == FF_ARRAY_ELEMS(ff_mpa_freq_tab)) {
av_log(s, AV_LOG_ERROR, "Unsupported sample rate.\n");
- return;
+ return -1;
}
switch (codec->channels) {
case 1: channels = MPA_MONO; break;
case 2: channels = MPA_STEREO; break;
- default: av_log(s, AV_LOG_ERROR, "Unsupported number of channels.\n"); return;
+ default: av_log(s, AV_LOG_ERROR, "Unsupported number of channels.\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 |= (bitrate_idx << 4 | srate_idx << 2) << 8;
+ header |= (srate_idx << 2) << 8;
header |= channels << 6;
- avio_wb32(s->pb, header);
- ff_mpegaudio_decode_header(&mpah, header);
+ for (;;) {
+ if (15 == bitrate_idx)
+ return -1;
+
+ mask = (bitrate_idx << 4) << 8;
+ header |= mask;
+ ff_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;
+ ++bitrate_idx;
+ }
+ avio_wb32(s->pb, header);
ffio_fill(s->pb, 0, xing_offset);
- ffio_wfourcc(s->pb, "Xing");
- avio_wb32(s->pb, 0x1); // only number of frames
- mp3->nb_frames_offset = avio_tell(s->pb);
- avio_wb32(s->pb, 0);
+ avio_wb32(s->pb, MKBETAG('X', 'i', 'n', 'g'));
+ avio_wb32(s->pb, 0x01 | 0x02 | 0x04); // frames/size/toc
- mpah.frame_size -= 4 + xing_offset + 4 + 4 + 4;
- ffio_fill(s->pb, 0, mpah.frame_size);
+ 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);
+ 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);
}
/**
return 0;
}
+static int mp3_write_packet(AVFormatContext *s, AVPacket *pkt)
+{
+ if (! pkt || ! pkt->data || pkt->size < 4)
+ return ff_raw_write_packet(s, pkt);
+ else {
+ MP3Context *mp3 = s->priv_data;
+#ifdef FILTER_VBR_HEADERS
+ MPADecodeHeader c;
+ int base;
+
+ ff_mpegaudio_decode_header(&c, AV_RB32(pkt->data));
+
+ /* 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_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"),
.audio_codec = CODEC_ID_MP3,
.video_codec = CODEC_ID_NONE,
.write_header = mp3_write_header,
- .write_packet = ff_raw_write_packet,
+ .write_packet = mp3_write_packet,
.write_trailer = mp3_write_trailer,
.flags = AVFMT_NOTIMESTAMPS,
.priv_class = &mp3_muxer_class,
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