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avcodec/mlpdec: parse and use substream info bits

This commit is contained in:
Paul B Mahol 2023-01-30 19:35:36 +01:00
parent 00994e8be1
commit fc9a3b584d
3 changed files with 22 additions and 2 deletions
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6
libavcodec/mlp_parse.c
View File

@ -159,7 +159,11 @@ int ff_mlp_read_major_sync(void *log, MLPHeaderInfo *mh, GetBitContext *gb)
mh->num_substreams = get_bits(gb, 4);
skip_bits_long(gb, 4 + (header_size - 17) * 8);
skip_bits(gb, 2);
mh->extended_substream_info = get_bits(gb, 2);
mh->substream_info = get_bits(gb, 8);
skip_bits_long(gb, (header_size - 18) * 8);
return 0;
}

3
libavcodec/mlp_parse.h
View File

@ -58,6 +58,9 @@ typedef struct MLPHeaderInfo
int peak_bitrate; ///< Peak bitrate for VBR, actual bitrate (==peak) for CBR
int num_substreams; ///< Number of substreams within stream
int extended_substream_info; ///< Which substream of substreams carry 16-channel presentation
int substream_info; ///< Which substream of substreams carry 2/6/8-channel presentation
} MLPHeaderInfo;
static const uint8_t thd_chancount[13] = {

15
libavcodec/mlpdec.c
View File

@ -153,6 +153,12 @@ typedef struct MLPDecodeContext {
/// Number of substreams contained within this stream.
uint8_t num_substreams;
/// Which substream of substreams carry 16-channel presentation
uint8_t extended_substream_info;
/// Which substream of substreams carry 2/6/8-channel presentation
uint8_t substream_info;
/// Index of the last substream to decode - further substreams are skipped.
uint8_t max_decoded_substream;
@ -384,6 +390,7 @@ static int read_major_sync(MLPDecodeContext *m, GetBitContext *gb)
m->access_unit_size_pow2 = mh.access_unit_size_pow2;
m->num_substreams = mh.num_substreams;
m->substream_info = mh.substream_info;
/* limit to decoding 3 substreams, as the 4th is used by Dolby Atmos for non-audio data */
m->max_decoded_substream = FFMIN(m->num_substreams - 1, 2);
@ -1286,7 +1293,13 @@ static int read_access_unit(AVCodecContext *avctx, AVFrame *frame,
if (!s->restart_seen)
goto next_substr;
if (substr > 0 && substr < m->max_decoded_substream &&
if (((avctx->ch_layout.nb_channels == 6 &&
((m->substream_info >> 2) & 0x3) != 0x3) ||
(avctx->ch_layout.nb_channels == 8 &&
((m->substream_info >> 4) & 0x7) != 0x7 &&
((m->substream_info >> 4) & 0x7) != 0x6 &&
((m->substream_info >> 4) & 0x7) != 0x3)) &&
substr > 0 && substr < m->max_decoded_substream &&
(s->min_channel <= m->substream[substr - 1].max_channel)) {
av_log(avctx, AV_LOG_DEBUG,
"Previous substream(%d) channels overlaps current substream(%d) channels, skipping.\n",