From cd92ef77c95d3483b29089d09142bc1eb0b1df2b Mon Sep 17 00:00:00 2001
From: James Almer <jamrial@gmail.com>
Date: Thu, 28 May 2026 12:03:01 -0300
Subject: [PATCH] avformat/mov: add support for version 1 of chnl box

Fixes ticket #11183.

Signed-off-by: James Almer <jamrial@gmail.com>
---
 libavformat/mov.c      |  4 ++--
 libavformat/mov_chan.c | 43 ++++++++++++++++++++++++++++++++++++------
 libavformat/mov_chan.h |  3 ++-
 libavformat/version.h  |  2 +-
 4 files changed, 42 insertions(+), 10 deletions(-)

diff --git a/libavformat/mov.c b/libavformat/mov.c
index 3ab73d8747..5f8be009c4 100644
--- a/libavformat/mov.c
+++ b/libavformat/mov.c
@@ -1237,14 +1237,14 @@ static int mov_read_chnl(MOVContext *c, AVIOContext *pb, MOVAtom atom)
 
     version = avio_r8(pb);
     flags   = avio_rb24(pb);
-    if (version != 0 || flags != 0) {
+    if (version > 1 || flags != 0) {
         av_log(c->fc, AV_LOG_ERROR,
                "Unsupported 'chnl' box with version %d, flags: %#x",
                version, flags);
         return AVERROR_INVALIDDATA;
     }
 
-    ret = ff_mov_read_chnl(c->fc, pb, st);
+    ret = ff_mov_read_chnl(c->fc, pb, st, version);
     if (ret < 0)
         return ret;
 
diff --git a/libavformat/mov_chan.c b/libavformat/mov_chan.c
index e45b58af24..bfe566e74e 100644
--- a/libavformat/mov_chan.c
+++ b/libavformat/mov_chan.c
@@ -752,11 +752,18 @@ int ff_mov_get_channel_positions_from_layout(const AVChannelLayout *layout,
     return 0;
 }
 
-int ff_mov_read_chnl(AVFormatContext *s, AVIOContext *pb, AVStream *st)
+int ff_mov_read_chnl(AVFormatContext *s, AVIOContext *pb, AVStream *st, int version)
 {
     int stream_structure = avio_r8(pb);
+    int base_channel_count;
+    int obj_count = 0;
     int ret;
 
+    if (version == 1) {
+        stream_structure >>= 4;
+        base_channel_count = avio_r8(pb);
+    }
+
     // stream carries channels
     if (stream_structure & 1) {
         int layout = avio_r8(pb);
@@ -766,6 +773,13 @@ int ff_mov_read_chnl(AVFormatContext *s, AVIOContext *pb, AVStream *st)
             AVChannelLayout *ch_layout = &st->codecpar->ch_layout;
             int nb_channels = ch_layout->nb_channels;
 
+            if (version == 1) {
+                nb_channels = avio_r8(pb);
+                obj_count = base_channel_count - nb_channels;
+                if (obj_count < 0)
+                    return AVERROR_INVALIDDATA;
+            }
+
             av_channel_layout_uninit(ch_layout);
             ret = av_channel_layout_custom_init(ch_layout, nb_channels);
             if (ret < 0)
@@ -795,16 +809,33 @@ int ff_mov_read_chnl(AVFormatContext *s, AVIOContext *pb, AVStream *st)
             if (ret < 0)
                 return ret;
         } else {
-            uint64_t omitted_channel_map = avio_rb64(pb);
-            ret = mov_get_channel_layout_from_config(layout, &st->codecpar->ch_layout, omitted_channel_map);
-            if (ret < 0)
-                return ret;
+            uint64_t omitted_channel_map = 0;
+            int omitted_channel_present = 1, channel_order_definition = 0;
+
+            if (version == 1) {
+                int byte = avio_r8(pb);
+                omitted_channel_present  =  byte       & 1;
+                channel_order_definition = (byte >> 1) & 0x7;
+            }
+
+            if (omitted_channel_present)
+                omitted_channel_map = avio_rb64(pb);
+            if (!channel_order_definition) {
+                ret = mov_get_channel_layout_from_config(layout, &st->codecpar->ch_layout, omitted_channel_map);
+                if (ret < 0)
+                    return ret;
+            } else
+                av_log(s, AV_LOG_TRACE, "'chnl' with channel_order_definition %d\n", channel_order_definition);
+
+            if (version == 1)
+                obj_count = base_channel_count - st->codecpar->ch_layout.nb_channels;
         }
     }
 
     // stream carries objects
     if (stream_structure & 2) {
-        int obj_count = avio_r8(pb);
+        if (version == 0)
+            obj_count = avio_r8(pb);
         av_log(s, AV_LOG_TRACE, "'chnl' with object_count %d\n", obj_count);
     }
 
diff --git a/libavformat/mov_chan.h b/libavformat/mov_chan.h
index b901538279..51f24176f6 100644
--- a/libavformat/mov_chan.h
+++ b/libavformat/mov_chan.h
@@ -181,8 +181,9 @@ int ff_mov_get_channel_positions_from_layout(const AVChannelLayout *layout,
  * @param s     AVFormatContext
  * @param pb    AVIOContext
  * @param st    The stream to set codec values for
+ * @param version Version of the tag
  * @return      0 if ok, or negative AVERROR code on failure
  */
-int ff_mov_read_chnl(AVFormatContext *s, AVIOContext *pb, AVStream *st);
+int ff_mov_read_chnl(AVFormatContext *s, AVIOContext *pb, AVStream *st, int version);
 
 #endif /* AVFORMAT_MOV_CHAN_H */
diff --git a/libavformat/version.h b/libavformat/version.h
index e063e12b98..bbb2fc7d87 100644
--- a/libavformat/version.h
+++ b/libavformat/version.h
@@ -32,7 +32,7 @@
 #include "version_major.h"
 
 #define LIBAVFORMAT_VERSION_MINOR  19
-#define LIBAVFORMAT_VERSION_MICRO 100
+#define LIBAVFORMAT_VERSION_MICRO 101
 
 #define LIBAVFORMAT_VERSION_INT AV_VERSION_INT(LIBAVFORMAT_VERSION_MAJOR, \
                                                LIBAVFORMAT_VERSION_MINOR, \