diff mbox series

[FFmpeg-devel] avcodec/mlpdec: fix decoding of overlapping channels in substreams

Message ID CAPYw7P4FxQ1QFWXseAgbw1EEbav6B60Sp4FQXmO+_bVAcNvO9w@mail.gmail.com
State New
Headers show
Series [FFmpeg-devel] avcodec/mlpdec: fix decoding of overlapping channels in substreams | expand

Checks

Context Check Description
yinshiyou/configure_loongarch64 warning Failed to apply patch
andriy/make_x86 success Make finished
andriy/make_fate_x86 success Make fate finished

Commit Message

Paul B Mahol Sept. 15, 2022, 3:27 p.m. UTC 
Patch attached.

There are cases when previously decoded substreams
would, if they have overlapping channels with final substream, cause
incorrect decoding results.
diff mbox series

Patch

From adf5fd3bdb397f88a52d7ce0cf76491a55d33eef Mon Sep 17 00:00:00 2001
From: Paul B Mahol <onemda@gmail.com>
Date: Thu, 15 Sep 2022 16:14:08 +0200
Subject: [PATCH] avcodec/mlpdec: fix decoding of overlapping channels in
 substreams

Fixes #5039

Signed-off-by: Paul B Mahol <onemda@gmail.com>
---
 libavcodec/mlpdec.c | 25 +++++++++++++++++++------
 1 file changed, 19 insertions(+), 6 deletions(-)

diff --git a/libavcodec/mlpdec.c b/libavcodec/mlpdec.c
index 0a97fae26c..bb72134b09 100644
--- a/libavcodec/mlpdec.c
+++ b/libavcodec/mlpdec.c
@@ -67,6 +67,8 @@  typedef struct SubStream {
     uint8_t     min_channel;
     /// The index of the last channel coded in this substream.
     uint8_t     max_channel;
+    /// The coded channels mask in this substream.
+    uint64_t    coded_channels;
     /// The number of channels input into the rematrix stage.
     uint8_t     max_matrix_channel;
     /// For each channel output by the matrix, the output channel to map it to
@@ -563,6 +565,7 @@  static int read_restart_header(MLPDecodeContext *m, GetBitContext *gbp,
 
     s->min_channel        = min_channel;
     s->max_channel        = max_channel;
+    s->coded_channels     = ((1LL << (max_channel - min_channel + 1)) - 1) << min_channel;
     s->max_matrix_channel = max_matrix_channel;
     s->noise_type         = noise_type;
 
@@ -1272,11 +1275,6 @@  static int read_access_unit(AVCodecContext *avctx, AVFrame *frame,
     for (substr = 0; substr <= m->max_decoded_substream; substr++) {
         SubStream *s = &m->substream[substr];
 
-        if (substr != m->max_decoded_substream &&
-            m->substream[m->max_decoded_substream].min_channel == 0 &&
-            m->substream[m->max_decoded_substream].max_channel == avctx->ch_layout.nb_channels - 1)
-            goto skip_substr;
-
         init_get_bits(&gb, buf, substream_data_len[substr] * 8);
 
         m->matrix_changed = 0;
@@ -1301,6 +1299,22 @@  static int read_access_unit(AVCodecContext *avctx, AVFrame *frame,
             if (!s->restart_seen)
                 goto next_substr;
 
+            if (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",
+                       substr - 1, substr);
+                goto next_substr;
+            }
+
+            if (substr != m->max_decoded_substream &&
+                ((s->coded_channels & m->substream[m->max_decoded_substream].coded_channels) != 0)) {
+                av_log(avctx, AV_LOG_DEBUG,
+                       "Current substream(%d) channels overlaps final substream(%d) channels, skipping.\n",
+                       substr, m->max_decoded_substream);
+                goto next_substr;
+            }
+
             if ((ret = read_block_data(m, &gb, substr)) < 0)
                 return ret;
 
@@ -1350,7 +1364,6 @@  next_substr:
             av_log(m->avctx, AV_LOG_ERROR,
                    "No restart header present in substream %d.\n", substr);
 
-skip_substr:
         buf += substream_data_len[substr];
     }
 
-- 
2.37.2