diff options
| author | Clément Bœsch <ubitux@gmail.com> | 2012-05-09 22:39:40 +0200 |
|---|---|---|
| committer | Anton Khirnov <anton@khirnov.net> | 2012-09-15 18:25:22 +0200 |
| commit | ca8e39dd0d2ed737bcf025236be9fdd1bd05cc4d (patch) | |
| tree | 6909d728f793be4a6993115d5abe8befd0b78526 /libavformat/mp3enc.c | |
| parent | 6365e4db79cc1a8c2c153e73828e922962d1086e (diff) | |
mp3enc: support MPEG-2 and MPEG-2.5 in Xing header.
Diffstat (limited to 'libavformat/mp3enc.c')
| -rw-r--r-- | libavformat/mp3enc.c | 24 |
1 files changed, 17 insertions, 7 deletions
diff --git a/libavformat/mp3enc.c b/libavformat/mp3enc.c index 602071cf05..6a6e60226e 100644 --- a/libavformat/mp3enc.c +++ b/libavformat/mp3enc.c @@ -90,25 +90,34 @@ typedef struct MP3Context { AVPacketList *queue, *queue_end; } MP3Context; +static const uint8_t xing_offtbl[2][2] = {{32, 17}, {17, 9}}; + /* insert a dummy frame containing number of frames */ 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 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_WARNING, "Unsupported sample rate, not writing Xing " "header.\n"); @@ -125,13 +134,14 @@ static void mp3_write_xing(AVFormatContext *s) /* 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); + xing_offset = xing_offtbl[ver != 3][codec->channels == 1]; ffio_fill(s->pb, 0, xing_offset); ffio_wfourcc(s->pb, "Xing"); avio_wb32(s->pb, 0x1); // only number of frames |