From: Niklas Haas <g...@haasn.dev> Changes since v1: - Greatly simplified EMDF implementation, after gaining insight to the specification (which states that the emdf header must used certain hard-coded values) - Tested and validated on official samples
--- Instead of the nal_prefix, this profile inside wraps the RPU inside an EMDF container, as specified in ETSI TS 102 366. However, this DV-specific EMDF container is restricted (by the specification) to a fixed set of hard-coded parameters, which we can effecitvely treat as a magic byte sequence. Validated and tested using official Dolby sample files, which I unfortunately cannot share. However, there are public sample files available at the merge request link below. Relevant links: - https://www.etsi.org/deliver/etsi_ts/102300_102399/102366/01.04.01_60/ts_102366v010401p.pdf - https://patentimages.storage.googleapis.com/8a/0b/da/28294acaed2182/EP3588964A1.pdf - https://www.etsi.org/deliver/etsi_ts/103500_103599/103572/01.03.01_60/ts_103572v010301p.pdf - https://gitlab.com/mbunkus/mkvtoolnix/-/merge_requests/2254 --- libavcodec/dovi_rpu.c | 45 ++++++++++++++++++++++++++++++++++++++++--- 1 file changed, 42 insertions(+), 3 deletions(-) diff --git a/libavcodec/dovi_rpu.c b/libavcodec/dovi_rpu.c index a6b23f4dd11..529062be30a 100644 --- a/libavcodec/dovi_rpu.c +++ b/libavcodec/dovi_rpu.c @@ -174,6 +174,18 @@ static inline int64_t get_se_coef(GetBitContext *gb, const AVDOVIRpuDataHeader * return 0; /* unreachable */ } +static inline unsigned get_variable_bits(GetBitContext *gb, int n) +{ + unsigned int value = get_bits(gb, n); + int read_more = get_bits1(gb); + while (read_more) { + value = (value + 1) << n; + value |= get_bits(gb, n); + read_more = get_bits1(gb); + } + return value; +} + #define VALIDATE(VAR, MIN, MAX) \ do { \ if (VAR < MIN || VAR > MAX) { \ @@ -200,9 +212,36 @@ int ff_dovi_rpu_parse(DOVIContext *s, const uint8_t *rpu, size_t rpu_size) if ((ret = init_get_bits8(gb, rpu, rpu_size)) < 0) return ret; - /* RPU header, common values */ - nal_prefix = get_bits(gb, 8); - VALIDATE(nal_prefix, 25, 25); + /* Container header */ + if (s->dv_profile == 10 /* dav1.10 */) { + /* DV inside AV1 re-uses an EMDF container skeleton, but with fixed + * values - so we can effectively treat this as a magic byte sequence. + * + * The exact fields are, as follows: + * emdf_version : f(2) = 0 + * key_id : f(3) = 6 + * emdf_payload_id : f(5) = 31 + * emdf_payload_id_ext : var(5) = 225 + * smploffste : f(1) = 0 + * duratione : f(1) = 0 + * groupide : f(1) = 0 + * codecdatae : f(1) = 0 + * discard_unknown_payload : f(1) = 1 + */ + const unsigned header_magic = 0x01be6841u; + unsigned header, emdf_payload_size; + header = get_bits_long(gb, 27); + VALIDATE(header, header_magic, header_magic); + emdf_payload_size = get_variable_bits(gb, 8); + VALIDATE(emdf_payload_size, 6, 512); + if (emdf_payload_size * 8 > get_bits_left(gb)) + return AVERROR_INVALIDDATA; + } else { + nal_prefix = get_bits(gb, 8); + VALIDATE(nal_prefix, 25, 25); + } + + /* RPU header */ rpu_type = get_bits(gb, 6); if (rpu_type != 2) { av_log(s->logctx, AV_LOG_WARNING, "Unrecognized RPU type " -- 2.44.0 _______________________________________________ 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".
