From 70c12a33220903962c3d4acdcfc37f6984eadb7d Mon Sep 17 00:00:00 2001 From: Christopher Snowhill Date: Thu, 27 Jan 2022 18:16:08 -0800 Subject: [PATCH] avformat/mp3dec: Parse iTunes gapless info X-Unsent: 1 To: ffmpeg-devel@ffmpeg.org Parse the ID3v2 iTunSMPB comment tag containing gapless decoding info, and also add the expected test results for the implementation. Signed-off-by: Christopher Snowhill --- libavformat/mp3dec.c | 86 ++++++++++++++++++++++++++++++- tests/fate/gapless.mak | 3 ++ tests/ref/fate/gapless-mp3-itunes | 5 ++ 3 files changed, 93 insertions(+), 1 deletion(-) create mode 100644 tests/ref/fate/gapless-mp3-itunes diff --git a/libavformat/mp3dec.c b/libavformat/mp3dec.c index f617348b2e..d03174db03 100644 --- a/libavformat/mp3dec.c +++ b/libavformat/mp3dec.c @@ -313,6 +313,75 @@ static void mp3_parse_vbri_tag(AVFormatContext *s, AVStream *st, int64_t base) } } +static void mp3_parse_itunes_tag(AVFormatContext *s, AVStream *st, MPADecodeHeader *c, int64_t base, int vbrtag_size, unsigned int *size, uint64_t *duration, uint32_t spf) +{ + uint32_t v; + AVDictionaryEntry *de; + FFStream *const sti = ffstream(st); + MP3DecContext *mp3 = s->priv_data; + size_t length; + uint32_t zero, start_pad, end_pad; + uint64_t last_eight_frames_offset; + int64_t temp_duration, file_size; + int i; + + if (!s->metadata || !(de = av_dict_get(s->metadata, "iTunSMPB", NULL, 0))) + return; + + length = strlen(de->value); + + /* Minimum length is one digit per field plus the whitespace, maximum length should depend on field type + * There are four fields we need in the first six, the rest are currently zero padding */ + if (length < (12 + 11) || length > (10 * 8 + 2 * 16 + 11)) + return; + + file_size = avio_size(s->pb); + if (file_size < 0) + file_size = 0; + + if (sscanf(de->value, "%"PRIx32" %"PRIx32" %"PRIx32" %"PRIx64" %"PRIx32" %"PRIx64, &zero, &start_pad, &end_pad, &temp_duration, &zero, &last_eight_frames_offset) < 6 || + temp_duration < 0 || + start_pad > (576 * 2 * 32) || + end_pad > (576 * 2 * 64) || + (file_size && (last_eight_frames_offset >= (file_size - base - vbrtag_size)))) { + *duration = 0; + return; + } + + *duration = temp_duration; + + if (end_pad >= 528 + 1) { + mp3->start_pad = start_pad; + mp3->end_pad = end_pad - (528 + 1); + sti->start_skip_samples = mp3->start_pad + 528 + 1; + if (mp3->frames) { + sti->first_discard_sample = -mp3->end_pad + 528 + 1 + mp3->frames * (int64_t)spf; + sti->last_discard_sample = mp3->frames * (int64_t)spf; + } + if (!st->start_time) + st->start_time = av_rescale_q(sti->start_skip_samples, + (AVRational){1, c->sample_rate}, + st->time_base); + av_log(s, AV_LOG_DEBUG, "pad %d %d\n", mp3->start_pad, mp3-> end_pad); + } + if (!s->pb->seekable) + return; + + *size = (unsigned int) last_eight_frames_offset; + if (avio_seek(s->pb, base + vbrtag_size + last_eight_frames_offset, SEEK_SET) < 0) + return; + + for (i = 0; i < 8; i++) { + v = avio_rb32(s->pb); + if (ff_mpa_check_header(v) < 0) + return; + if (avpriv_mpegaudio_decode_header(c, v) != 0) + break; + *size += c->frame_size; + avio_skip(s->pb, c->frame_size - 4); + } +} + /** * Try to find Xing/Info/VBRI tags and compute duration from info therein */ @@ -321,8 +390,10 @@ static int mp3_parse_vbr_tags(AVFormatContext *s, AVStream *st, int64_t base) uint32_t v, spf; MPADecodeHeader c; int vbrtag_size = 0; + unsigned int size = 0; MP3DecContext *mp3 = s->priv_data; int ret; + uint64_t duration = 0; ffio_init_checksum(s->pb, ff_crcA001_update, 0); @@ -345,16 +416,29 @@ static int mp3_parse_vbr_tags(AVFormatContext *s, AVStream *st, int64_t base) mp3_parse_vbri_tag(s, st, base); if (!mp3->frames && !mp3->header_filesize) + vbrtag_size = 0; + + mp3_parse_itunes_tag(s, st, &c, base, vbrtag_size, &size, &duration, spf); + + if (!mp3->frames && !size && !duration) return -1; /* Skip the vbr tag frame */ avio_seek(s->pb, base + vbrtag_size, SEEK_SET); - if (mp3->frames) + if (duration) + st->duration = av_rescale_q(duration, (AVRational){1, c.sample_rate}, st->time_base); + else if (mp3->frames) st->duration = av_rescale_q(mp3->frames, (AVRational){spf, c.sample_rate}, st->time_base); if (mp3->header_filesize && mp3->frames && !mp3->is_cbr) st->codecpar->bit_rate = av_rescale(mp3->header_filesize, 8 * c.sample_rate, mp3->frames * (int64_t)spf); + if (size) { + if (duration) + st->codecpar->bit_rate = av_rescale(size, 8 * c.sample_rate, duration); + else if (mp3->frames) + st->codecpar->bit_rate = av_rescale(size, 8 * c.sample_rate, mp3->frames * (int64_t)spf); + } return 0; } diff --git a/tests/fate/gapless.mak b/tests/fate/gapless.mak index 68a396e187..b8c93b984c 100644 --- a/tests/fate/gapless.mak +++ b/tests/fate/gapless.mak @@ -1,6 +1,9 @@ FATE_GAPLESS-$(CONFIG_MP3_DEMUXER) += fate-gapless-mp3 fate-gapless-mp3: CMD = gapless $(TARGET_SAMPLES)/gapless/gapless.mp3 "-c:a mp3" +FATE_GAPLESS-$(CONFIG_MP3_DEMUXER) += fate-gapless-mp3-itunes +fate-gapless-mp3-itunes: CMD = gapless $(TARGET_SAMPLES)/gapless/gapless-itunes.mp3 "-c:a mp3" + FATE_GAPLESSINFO_PROBE-$(CONFIG_MP3_DEMUXER) += fate-gapless-mp3-side-data fate-gapless-mp3-side-data: CMD = ffprobe_demux $(TARGET_SAMPLES)/gapless/gapless.mp3 diff --git a/tests/ref/fate/gapless-mp3-itunes b/tests/ref/fate/gapless-mp3-itunes new file mode 100644 index 0000000000..f3295e2652 --- /dev/null +++ b/tests/ref/fate/gapless-mp3-itunes @@ -0,0 +1,5 @@ +1e285368a8a176bc729712b06f724f21 *tests/data/fate/gapless-mp3-itunes.out-1 +cde648358dcd59911c4990ed59bf7d40 +4a39c54de9687ea8f66ea8204133c5c0 *tests/data/fate/gapless-mp3-itunes.out-2 +cde648358dcd59911c4990ed59bf7d40 +c8cd71407ac5bbfadf5ccf7b5a64430c *tests/data/fate/gapless-mp3-itunes.out-3 -- 2.34.1