On Fri, Jun 3, 2022 at 8:11 PM Andreas Rheinhardt <andreas.rheinha...@outlook.com> wrote: > > Martijn van Beurden: > > The afconvert utility shipped with MacOS supports muxing of FLAC > > in CAF, see afconvert help output on a recent Mac here: > > https://hydrogenaud.io/index.php?topic=122509.0 A file created > > with afconvert free of copyright (licensed CC0) can be found here: > > http://www.audiograaf.nl/misc_stuff/afconvert-FLAC-in-CAF.caf > > > > This patch implements parsing of such a file > > --- > > libavformat/caf.c | 1 + > > libavformat/cafdec.c | 41 +++++++++++++++++++++++++++++++++++++++++ > > 2 files changed, 42 insertions(+) > > > > diff --git a/libavformat/caf.c b/libavformat/caf.c > > index a700e4055b..a61c39fae5 100644 > > --- a/libavformat/caf.c > > +++ b/libavformat/caf.c > > @@ -46,6 +46,7 @@ const AVCodecTag ff_codec_caf_tags[] = { > > { AV_CODEC_ID_GSM, MKTAG('a','g','s','m') }, > > { AV_CODEC_ID_GSM_MS, MKTAG('m','s', 0, '1') }, > > { AV_CODEC_ID_ILBC, MKTAG('i','l','b','c') }, > > + { AV_CODEC_ID_FLAC, MKTAG('f','l','a','c') }, > > { AV_CODEC_ID_MACE3, MKTAG('M','A','C','3') }, > > { AV_CODEC_ID_MACE6, MKTAG('M','A','C','6') }, > > { AV_CODEC_ID_MP1, MKTAG('.','m','p','1') }, > > diff --git a/libavformat/cafdec.c b/libavformat/cafdec.c > > index 168f69f20b..72a74ab297 100644 > > --- a/libavformat/cafdec.c > > +++ b/libavformat/cafdec.c > > @@ -31,6 +31,7 @@ > > #include "demux.h" > > #include "internal.h" > > #include "isom.h" > > +#include "libavcodec/flac.h" > > #include "mov_chan.h" > > #include "libavutil/intreadwrite.h" > > #include "libavutil/intfloat.h" > > @@ -170,6 +171,46 @@ static int read_kuki_chunk(AVFormatContext *s, int64_t > > size) > > } > > avio_skip(pb, size - ALAC_NEW_KUKI); > > } > > + } else if (st->codecpar->codec_id == AV_CODEC_ID_FLAC) { > > + int last, type, flac_metadata_size; > > + uint8_t buf[4]; > > + /* The magic cookie format for FLAC consists mostly of an mp4 dfLa > > atom. */ > > + if (size < (16 + FLAC_STREAMINFO_SIZE)) { > > + av_log(s, AV_LOG_ERROR, "invalid FLAC magic cookie\n"); > > + return AVERROR_INVALIDDATA; > > + } > > + /* Check cookie version. */ > > + if (avio_r8(pb) != 0) { > > + av_log(s, AV_LOG_ERROR, "unknown FLAC magic cookie\n"); > > + return AVERROR_INVALIDDATA; > > + } > > + avio_rb24(pb); /* Flags */ > > + /* read dfLa fourcc */ > > + if (avio_read(pb, buf, 4) != 4) { > > + av_log(s, AV_LOG_ERROR, "failed to read FLAC magic cookie\n"); > > + return AVERROR_INVALIDDATA; > > + } > > + if (memcmp(buf,"dfLa",4)) { > > + av_log(s, AV_LOG_ERROR, "invalid FLAC magic cookie\n"); > > + return AVERROR_INVALIDDATA; > > + } > > + /* Check dfLa version. */ > > + if (avio_r8(pb) != 0) { > > + av_log(s, AV_LOG_ERROR, "unknown dfLa version\n"); > > + return AVERROR_INVALIDDATA; > > + } > > + avio_rb24(pb); /* Flags */ > > + avio_read(pb, buf, sizeof(buf)); > > You are not checking this; this could lead to uninitialized values being > used in flac_parse_block_header() below. > > > + flac_parse_block_header(buf, &last, &type, &flac_metadata_size); > > + if (type != FLAC_METADATA_TYPE_STREAMINFO || flac_metadata_size != > > FLAC_STREAMINFO_SIZE) { > > + av_log(s, AV_LOG_ERROR, "STREAMINFO must be first > > FLACMetadataBlock\n"); > > + return AVERROR_INVALIDDATA; > > + } > > + ret = ff_get_extradata(s, st->codecpar, pb, FLAC_STREAMINFO_SIZE); > > + if (ret < 0) > > + return ret; > > + if (!last) > > + av_log(s, AV_LOG_WARNING, "non-STREAMINFO FLACMetadataBlock(s) > > ignored\n"); > > } else if (st->codecpar->codec_id == AV_CODEC_ID_OPUS) { > > // The data layout for Opus is currently unknown, so we do not > > export > > // extradata at all. Multichannel streams are not supported. > > Is there an official spec for this?
CAF mostly follows ISOBMFF in these things, so https://github.com/xiph/flac/blob/master/doc/isoflac.txt is probably the source of truth for dfLa FLACSpecificBox and such. Base CAF specification is at https://developer.apple.com/library/archive/documentation/MusicAudio/Reference/CAFSpec/CAF_spec/CAF_spec.html , but it stops at AAC, and ignores both Opus and FLAC. Jan _______________________________________________ ffmpeg-devel mailing list ffmpeg-devel@ffmpeg.org https://ffmpeg.org/mailman/listinfo/ffmpeg-devel To unsubscribe, visit link above, or email ffmpeg-devel-requ...@ffmpeg.org with subject "unsubscribe".
