From 1715a7f4b0487c9ecebfedfc796377022a85baec Mon Sep 17 00:00:00 2001
From: Paul B Mahol <onemda@gmail.com>
Date: Mon, 30 Jan 2023 19:35:36 +0100
Subject: [PATCH] avcodec/mlpdec: parse and use substream info bits
Signed-off-by: Paul B Mahol <onemda@gmail.com>
---
libavcodec/mlp_parse.c | 6 +++++-
libavcodec/mlp_parse.h | 3 +++
libavcodec/mlpdec.c | 15 ++++++++++++++-
3 files changed, 22 insertions(+), 2 deletions(-)
@@ -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;
}
@@ -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] = {
@@ -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",
--
2.39.1