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aacdec_usac: parse loudnessInfoV1

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Real-world xHE-AAC streams and the ISO/IEC 23003-3 conformance
sequences carry their loudness metadata exclusively as loudnessInfoV1()
inside loudnessInfoSetExtension(), which was previously rejected with
AVERROR_PATCHWELCOME, making such streams undecodable and loudness
normalization inoperative on them.

loudnessInfoV1() is identical to loudnessInfo() apart from an added
eqSetId field. Parse it, restrict measurement selection to
eqSetId == 0 (in line with the downmixId/drcSetId restrictions), and
skip unknown loudnessInfoSetExtension() payloads using their explicitly
coded size instead of erroring out.
This commit is contained in:
Lynne
2026-06-11 02:25:13 +09:00
parent 8f970a24d5
commit a51ec04adf
2 changed files with 54 additions and 11 deletions
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libavcodec/aac/aacdec.h
+1
View File
@@ -308,6 +308,7 @@ typedef struct ChannelElement {
typedef struct AACUSACLoudnessInfo {
uint8_t drc_set_id : 6;
uint8_t eq_set_id : 6; /* loudnessInfoV1() only, 0 otherwise */
uint8_t downmix_id : 7;
struct {
uint16_t lvl : 12;
libavcodec/aac/aacdec_usac.c
+53 -11
View File
@@ -95,10 +95,13 @@ static int methodvalue_width(int method_def)
}
}
/* ISO/IEC 23003-4, Table 58/60: loudnessInfo(), loudnessInfoV1().
* The only difference in V1 is the added eqSetId field. */
static int decode_loudness_info(AACDecContext *ac, AACUSACLoudnessInfo *info,
GetBitContext *gb)
GetBitContext *gb, int v1)
{
info->drc_set_id = get_bits(gb, 6);
info->eq_set_id = v1 ? get_bits(gb, 6) : 0;
info->downmix_id = get_bits(gb, 7);
if ((info->sample_peak.present = get_bits1(gb))) /* samplePeakLevelPresent */
@@ -122,16 +125,46 @@ static int decode_loudness_info(AACDecContext *ac, AACUSACLoudnessInfo *info,
return 0;
}
/* ISO/IEC 23003-4, Table 61: loudnessInfoSetExtension(), UNIDRCLOUDEXT_EQ */
static int decode_loudness_set_v1(AACDecContext *ac, AACUSACConfig *usac,
GetBitContext *gb)
{
int ret;
int nb_album = get_bits(gb, 6); /* loudnessInfoV1AlbumCount */
int nb_info = get_bits(gb, 6); /* loudnessInfoV1Count */
for (int i = 0; i < nb_album; i++) {
AACUSACLoudnessInfo tmp;
ret = decode_loudness_info(ac, &tmp, gb, 1);
if (ret < 0)
return ret;
if (usac->loudness.nb_album < FF_ARRAY_ELEMS(usac->loudness.album_info))
usac->loudness.album_info[usac->loudness.nb_album++] = tmp;
}
for (int i = 0; i < nb_info; i++) {
AACUSACLoudnessInfo tmp;
ret = decode_loudness_info(ac, &tmp, gb, 1);
if (ret < 0)
return ret;
if (usac->loudness.nb_info < FF_ARRAY_ELEMS(usac->loudness.info))
usac->loudness.info[usac->loudness.nb_info++] = tmp;
}
return 0;
}
/* Pick the bsMethodValue of a program- or anchor-loudness measurement.
* Per ISO/IEC 23003-4 6.1.2.5, downmixId and drcSetId identify the signal a
* loudnessInfo() applies to; only downmixId == 0 (base layout) together with
* drcSetId == 0 (no DRC) describes the unprocessed signal we output, so
* measurements for any other downmix/DRC set must not be used. */
* Per ISO/IEC 23003-4 6.1.2.5, downmixId, drcSetId and eqSetId identify the
* signal a loudnessInfo() applies to; only downmixId == 0 (base layout)
* together with drcSetId == 0 and eqSetId == 0 (no DRC/EQ) describes the
* unprocessed signal we output, so measurements for any other
* downmix/DRC/EQ set must not be used. */
static int select_loudness_measurement(const AACUSACConfig *usac)
{
for (int i = 0; i < usac->loudness.nb_info; i++) {
const AACUSACLoudnessInfo *info = &usac->loudness.info[i];
if (info->downmix_id != 0 || info->drc_set_id != 0)
if (info->downmix_id != 0 || info->drc_set_id != 0 || info->eq_set_id != 0)
continue;
for (int j = 0; j < info->nb_measurements; j++) {
int method = info->measurements[j].method_def;
@@ -151,13 +184,13 @@ static int decode_loudness_set(AACDecContext *ac, AACUSACConfig *usac,
usac->loudness.nb_info = get_bits(gb, 6); /* loudnessInfoCount */
for (int i = 0; i < usac->loudness.nb_album; i++) {
ret = decode_loudness_info(ac, &usac->loudness.album_info[i], gb);
ret = decode_loudness_info(ac, &usac->loudness.album_info[i], gb, 0);
if (ret < 0)
return ret;
}
for (int i = 0; i < usac->loudness.nb_info; i++) {
ret = decode_loudness_info(ac, &usac->loudness.info[i], gb);
ret = decode_loudness_info(ac, &usac->loudness.info[i], gb, 0);
if (ret < 0)
return ret;
}
@@ -167,14 +200,23 @@ static int decode_loudness_set(AACDecContext *ac, AACUSACConfig *usac,
while ((type = get_bits(gb, 4)) != UNIDRCLOUDEXT_TERM) {
uint8_t size_bits = get_bits(gb, 4) + 4; /* bitSizeLen */
uint32_t bit_size = get_bits_long(gb, size_bits) + 1; /* bitSize */
int start = get_bits_count(gb);
int skip;
switch (type) {
case UNIDRCLOUDEXT_EQ:
avpriv_report_missing_feature(ac->avctx, "loudnessInfoV1");
return AVERROR_PATCHWELCOME;
ret = decode_loudness_set_v1(ac, usac, gb);
if (ret < 0)
return ret;
break;
default:
skip_bits_long(gb, bit_size);
break;
}
/* The extension size is explicit, so unparsed (or unknown)
* data can be skipped without desynchronizing. */
skip = bit_size - (get_bits_count(gb) - start);
if (skip < 0)
return AVERROR_INVALIDDATA;
skip_bits_long(gb, skip);
}
}