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mp3enc: write full LAME frame
Most importantly, it contains the encoder delay and replaygain info.
This commit is contained in:
Anton Khirnov
parent
88b32673db
commit
ef363ebd59
@ -370,7 +370,8 @@ to provide the pictures as soon as possible to avoid excessive buffering.
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A Xing/LAME frame right after the ID3v2 header (if present). It is enabled by
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default, but will be written only if the output is seekable. The
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@code{write_xing} private option can be used to disable it. The frame contains
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various information that may be useful to the decoder, like the audio duration.
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various information that may be useful to the decoder, like the audio duration
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or encoder delay.
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@item
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A legacy ID3v1 tag at the end of the file (disabled by default). It may be
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@ -32,6 +32,9 @@
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#include "libavutil/opt.h"
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#include "libavutil/dict.h"
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#include "libavutil/avassert.h"
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#include "libavutil/crc.h"
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#include "libavutil/mathematics.h"
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#include "libavutil/replaygain.h"
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static int id3v1_set_string(AVFormatContext *s, const char *key,
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uint8_t *buf, int buf_size)
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@ -76,8 +79,8 @@ static int id3v1_create_tag(AVFormatContext *s, uint8_t *buf)
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#define XING_NUM_BAGS 400
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#define XING_TOC_SIZE 100
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// maximum size of the xing frame: offset/Xing/flags/frames/size/TOC
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#define XING_MAX_SIZE (32 + 4 + 4 + 4 + 4 + XING_TOC_SIZE)
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// size of the XING/LAME data, starting from the Xing tag
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#define XING_SIZE 156
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typedef struct MP3Context {
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const AVClass *class;
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@ -87,7 +90,18 @@ typedef struct MP3Context {
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int write_xing;
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/* xing header */
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int64_t xing_offset;
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// a buffer containing the whole XING/LAME frame
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uint8_t *xing_frame;
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int xing_frame_size;
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AVCRC audio_crc; // CRC of the audio data
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uint32_t audio_size; // total size of the audio data
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// offset of the XING/LAME frame in the file
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int64_t xing_frame_offset;
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// offset of the XING/INFO tag in the frame
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int xing_offset;
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int32_t frames;
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int32_t size;
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uint32_t want;
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@ -115,13 +129,15 @@ static void mp3_write_xing(AVFormatContext *s)
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{
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MP3Context *mp3 = s->priv_data;
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AVCodecContext *codec = s->streams[mp3->audio_stream_idx]->codec;
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AVDictionaryEntry *enc = av_dict_get(s->streams[mp3->audio_stream_idx]->metadata, "encoder", NULL, 0);
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AVIOContext *dyn_ctx;
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int32_t header;
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MPADecodeHeader mpah;
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int srate_idx, i, channels;
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int bitrate_idx;
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int best_bitrate_idx;
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int best_bitrate_error = INT_MAX;
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int xing_offset;
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int ret;
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int ver = 0;
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int lsf, bytes_needed;
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@ -161,14 +177,8 @@ static void mp3_write_xing(AVFormatContext *s)
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lsf = !((header & (1 << 20) && header & (1 << 19)));
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xing_offset = xing_offtbl[ver != 3][channels == 1];
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bytes_needed = 4 // header
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+ xing_offset
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+ 4 // xing tag
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+ 4 // frames/size/toc flags
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+ 4 // frames
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+ 4 // size
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+ XING_TOC_SIZE; // toc
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mp3->xing_offset = xing_offtbl[ver != 3][channels == 1] + 4;
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bytes_needed = mp3->xing_offset + XING_SIZE;
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for (bitrate_idx = 1; bitrate_idx < 15; bitrate_idx++) {
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int bit_rate = 1000 * avpriv_mpa_bitrate_tab[lsf][3 - 1][bitrate_idx];
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@ -192,28 +202,72 @@ static void mp3_write_xing(AVFormatContext *s)
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header &= ~mask;
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}
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avio_wb32(s->pb, header);
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ret = avio_open_dyn_buf(&dyn_ctx);
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if (ret < 0)
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return;
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avio_wb32(dyn_ctx, header);
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avpriv_mpegaudio_decode_header(&mpah, header);
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av_assert0(mpah.frame_size >= XING_MAX_SIZE);
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av_assert0(mpah.frame_size >= bytes_needed);
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ffio_fill(s->pb, 0, xing_offset);
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mp3->xing_offset = avio_tell(s->pb);
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ffio_wfourcc(s->pb, "Xing");
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avio_wb32(s->pb, 0x01 | 0x02 | 0x04); // frames / size / TOC
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ffio_fill(dyn_ctx, 0, mp3->xing_offset - 4);
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ffio_wfourcc(dyn_ctx, "Xing");
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avio_wb32(dyn_ctx, 0x01 | 0x02 | 0x04 | 0x08); // frames / size / TOC / vbr scale
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mp3->size = mpah.frame_size;
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mp3->want = 1;
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avio_wb32(s->pb, 0); // frames
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avio_wb32(s->pb, 0); // size
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avio_wb32(dyn_ctx, 0); // frames
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avio_wb32(dyn_ctx, 0); // size
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// TOC
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for (i = 0; i < XING_TOC_SIZE; i++)
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avio_w8(s->pb, 255 * i / XING_TOC_SIZE);
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avio_w8(dyn_ctx, 255 * i / XING_TOC_SIZE);
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ffio_fill(s->pb, 0, mpah.frame_size - bytes_needed);
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// vbr quality
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// we write it, because some (broken) tools always expect it to be present
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avio_wb32(dyn_ctx, 0);
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// encoder short version string
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if (enc) {
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uint8_t encoder_str[9] = { 0 };
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memcpy(encoder_str, enc->value, FFMIN(strlen(enc->value), sizeof(encoder_str)));
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avio_write(dyn_ctx, encoder_str, sizeof(encoder_str));
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} else
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ffio_fill(dyn_ctx, 0, 9);
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avio_w8(dyn_ctx, 0); // tag revision 0 / unknown vbr method
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avio_w8(dyn_ctx, 0); // unknown lowpass filter value
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ffio_fill(dyn_ctx, 0, 8); // empty replaygain fields
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avio_w8(dyn_ctx, 0); // unknown encoding flags
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avio_w8(dyn_ctx, 0); // unknown abr/minimal bitrate
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// encoder delay
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if (codec->initial_padding >= 1 << 12) {
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av_log(s, AV_LOG_WARNING, "Too many samples of initial padding.\n");
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avio_wb24(dyn_ctx, 0);
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} else {
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avio_wb24(dyn_ctx, codec->initial_padding << 12);
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}
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avio_w8(dyn_ctx, 0); // misc
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avio_w8(dyn_ctx, 0); // mp3gain
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avio_wb16(dyn_ctx, 0); // preset
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// audio length and CRCs (will be updated later)
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avio_wb32(dyn_ctx, 0); // music length
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avio_wb16(dyn_ctx, 0); // music crc
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avio_wb16(dyn_ctx, 0); // tag crc
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ffio_fill(dyn_ctx, 0, mpah.frame_size - bytes_needed);
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mp3->xing_frame_size = avio_close_dyn_buf(dyn_ctx, &mp3->xing_frame);
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mp3->xing_frame_offset = avio_tell(s->pb);
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avio_write(s->pb, mp3->xing_frame, mp3->xing_frame_size);
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mp3->audio_size = mp3->xing_frame_size;
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}
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/*
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@ -264,6 +318,12 @@ static int mp3_write_audio_packet(AVFormatContext *s, AVPacket *pkt)
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}
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mp3_xing_add_frame(mp3, pkt);
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if (mp3->xing_offset) {
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mp3->audio_size += pkt->size;
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mp3->audio_crc = av_crc(av_crc_get_table(AV_CRC_16_ANSI_LE),
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mp3->audio_crc, pkt->data, pkt->size);
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}
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}
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return ff_raw_write_packet(s, pkt);
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@ -292,26 +352,58 @@ static int mp3_queue_flush(AVFormatContext *s)
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static void mp3_update_xing(AVFormatContext *s)
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{
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MP3Context *mp3 = s->priv_data;
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int i;
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AVReplayGain *rg;
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uint16_t tag_crc;
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uint8_t *toc;
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int i, rg_size;
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/* replace "Xing" identification string with "Info" for CBR files. */
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if (!mp3->has_variable_bitrate) {
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avio_seek(s->pb, mp3->xing_offset, SEEK_SET);
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ffio_wfourcc(s->pb, "Info");
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}
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if (!mp3->has_variable_bitrate)
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AV_WL32(mp3->xing_frame + mp3->xing_offset, MKTAG('I', 'n', 'f', 'o'));
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avio_seek(s->pb, mp3->xing_offset + 8, SEEK_SET);
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avio_wb32(s->pb, mp3->frames);
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avio_wb32(s->pb, mp3->size);
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avio_w8(s->pb, 0); // first toc entry has to be zero.
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AV_WB32(mp3->xing_frame + mp3->xing_offset + 8, mp3->frames);
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AV_WB32(mp3->xing_frame + mp3->xing_offset + 12, mp3->size);
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toc = mp3->xing_frame + mp3->xing_offset + 16;
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toc[0] = 0; // first toc entry has to be zero.
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for (i = 1; i < XING_TOC_SIZE; ++i) {
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int j = i * mp3->pos / XING_TOC_SIZE;
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int seek_point = 256LL * mp3->bag[j] / mp3->size;
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avio_w8(s->pb, FFMIN(seek_point, 255));
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toc[i] = FFMIN(seek_point, 255);
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}
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/* write replaygain */
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rg = (AVReplayGain*)av_stream_get_side_data(s->streams[0], AV_PKT_DATA_REPLAYGAIN,
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&rg_size);
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if (rg && rg_size >= sizeof(*rg)) {
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uint16_t val;
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AV_WB32(mp3->xing_frame + mp3->xing_offset + 131,
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av_rescale(rg->track_peak, 1 << 23, 100000));
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if (rg->track_gain != INT32_MIN) {
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val = FFABS(rg->track_gain / 10000) & ((1 << 9) - 1);
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val |= (rg->track_gain < 0) << 9;
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val |= 1 << 13;
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AV_WB16(mp3->xing_frame + mp3->xing_offset + 135, val);
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}
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if (rg->album_gain != INT32_MIN) {
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val = FFABS(rg->album_gain / 10000) & ((1 << 9) - 1);
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val |= (rg->album_gain < 0) << 9;
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val |= 1 << 14;
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AV_WB16(mp3->xing_frame + mp3->xing_offset + 137, val);
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}
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}
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AV_WB32(mp3->xing_frame + mp3->xing_offset + XING_SIZE - 8, mp3->audio_size);
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AV_WB16(mp3->xing_frame + mp3->xing_offset + XING_SIZE - 4, mp3->audio_crc);
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tag_crc = av_crc(av_crc_get_table(AV_CRC_16_ANSI_LE), 0, mp3->xing_frame, 190);
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AV_WB16(mp3->xing_frame + mp3->xing_offset + XING_SIZE - 2, tag_crc);
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avio_seek(s->pb, mp3->xing_frame_offset, SEEK_SET);
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avio_write(s->pb, mp3->xing_frame, mp3->xing_frame_size);
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avio_seek(s->pb, 0, SEEK_END);
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}
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@ -334,6 +426,8 @@ static int mp3_write_trailer(struct AVFormatContext *s)
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if (mp3->xing_offset)
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mp3_update_xing(s);
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av_freep(&mp3->xing_frame);
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return 0;
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}
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