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;
- int64_t nb_frames_offset;
+
+ /* 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;
AVPacketList *queue, *queue_end;
} MP3Context;
-/* insert a dummy frame containing number of frames */
+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;
- 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;
+ int xing_offset;
+ int ver = 0;
if (!s->pb->seekable)
return;
- 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;
- }
+ 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_ERROR, "Unsupported sample rate.\n");
+ 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_ERROR, "Unsupported number of channels.\n"); return;
+ 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 | 0x3 << 3 | 0x1 << 1 | 0x1) << 16; // sync/mpeg-1/layer 3/no crc*/
+ 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, 0x1); // only number of frames
- mp3->nb_frames_offset = avio_tell(s->pb);
- avio_wb32(s->pb, 0);
+ 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
- mpah.frame_size -= 4 + xing_offset + 4 + 4 + 4;
+ // 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;
mp3_write_xing(s);
while ((pktl = mp3->queue)) {
- if (write && (ret = ff_raw_write_packet(s, &pktl->pkt)) < 0)
+ if (write && (ret = mp3_write_audio_packet(s, &pktl->pkt)) < 0)
write = 0;
av_free_packet(&pktl->pkt);
mp3->queue = pktl->next;
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 && mp3->pics_to_write) {
+ 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 && mp3->write_id3v1 && id3v1_create_tag(s, buf) > 0) {
+ if (mp3->write_id3v1 && id3v1_create_tag(s, buf) > 0) {
avio_write(s->pb, buf, ID3v1_TAG_SIZE);
}
- /* write number of frames */
- if (mp3 && mp3->nb_frames_offset) {
- avio_seek(s->pb, mp3->nb_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);
+ if (mp3->xing_offset)
+ mp3_update_xing(s);
return 0;
}
.audio_codec = AV_CODEC_ID_MP2,
.video_codec = AV_CODEC_ID_NONE,
.write_packet = ff_raw_write_packet,
- .write_trailer = mp3_write_trailer,
+ .flags = AVFMT_NOTIMESTAMPS,
};
#endif
mp3->queue = pktl;
mp3->queue_end = pktl;
} else
- return ff_raw_write_packet(s, pkt);
+ return mp3_write_audio_packet(s, pkt);
} else {
int ret;
projects / ffmpeg / blobdiff