avformat/mov: factorize reading the main part of the chnl atom to mov_chan

Signed-off-by: Marton Balint <cus@passwd.hu>

libavformat/mov.c

@@ -953,9 +953,8 @@ static int mov_read_chan(MOVContext *c, AVIOContext *pb, MOVAtom atom)
 static int mov_read_chnl(MOVContext *c, AVIOContext *pb, MOVAtom atom)
 {
     int64_t end = av_sat_add64(avio_tell(pb), atom.size);
-    int stream_structure;
     int version, flags;
-    int ret = 0;
+    int ret;
     AVStream *st;
 
     if (c->fc->nb_streams < 1)
@@ -971,58 +970,9 @@ static int mov_read_chnl(MOVContext *c, AVIOContext *pb, MOVAtom atom)
         return AVERROR_INVALIDDATA;
     }
 
-    stream_structure = avio_r8(pb);
-
-    // stream carries channels
-    if (stream_structure & 1) {
-        int layout = avio_r8(pb);
-
-        av_log(c->fc, AV_LOG_TRACE, "'chnl' layout %d\n", layout);
-        if (!layout) {
-            uint8_t *positions = av_malloc(st->codecpar->ch_layout.nb_channels);
-
-            if (!positions)
-                return AVERROR(ENOMEM);
-            for (int i = 0; i < st->codecpar->ch_layout.nb_channels; i++) {
-                int speaker_pos = avio_r8(pb);
-
-                av_log(c->fc, AV_LOG_TRACE, "speaker_position %d\n", speaker_pos);
-                if (speaker_pos == 126) { // explicit position
-                    avpriv_request_sample(c->fc, "explicit position");
-                    av_freep(&positions);
-                    return AVERROR_PATCHWELCOME;
-                } else {
-                    positions[i] = speaker_pos;
-                }
-            }
-
-            ret = ff_mov_get_layout_from_channel_positions(positions,
-                    st->codecpar->ch_layout.nb_channels,
-                    &st->codecpar->ch_layout);
-            av_freep(&positions);
-            if (ret) {
-                av_log(c->fc, AV_LOG_ERROR,
-                        "get channel layout from speaker positions failed, %s\n",
-                        av_err2str(ret));
-                return ret;
-            }
-        } else {
-            uint64_t omitted_channel_map = avio_rb64(pb);
-
-            if (omitted_channel_map) {
-                avpriv_request_sample(c->fc, "omitted_channel_map 0x%" PRIx64 " != 0",
-                                      omitted_channel_map);
-                return AVERROR_PATCHWELCOME;
-            }
-            ff_mov_get_channel_layout_from_config(layout, &st->codecpar->ch_layout);
-        }
-    }
-
-    // stream carries objects
-    if (stream_structure & 2) {
-        int obj_count = avio_r8(pb);
-        av_log(c->fc, AV_LOG_TRACE, "'chnl' with object_count %d\n", obj_count);
-    }
+    ret = ff_mov_read_chnl(c->fc, pb, st);
+    if (ret < 0)
+        return ret;
 
     if (avio_tell(pb) != end) {
         av_log(c->fc, AV_LOG_WARNING, "skip %" PRId64 " bytes of unknown data inside chnl\n",

libavformat/mov_chan.c

@@ -863,3 +863,62 @@ error:
     av_channel_layout_uninit(layout);
     return ret;
 }
+
+int ff_mov_read_chnl(AVFormatContext *s, AVIOContext *pb, AVStream *st)
+{
+    int stream_structure = avio_r8(pb);
+    int ret;
+
+    // stream carries channels
+    if (stream_structure & 1) {
+        int layout = avio_r8(pb);
+
+        av_log(s, AV_LOG_TRACE, "'chnl' layout %d\n", layout);
+        if (!layout) {
+            uint8_t *positions = av_malloc(st->codecpar->ch_layout.nb_channels);
+
+            if (!positions)
+                return AVERROR(ENOMEM);
+            for (int i = 0; i < st->codecpar->ch_layout.nb_channels; i++) {
+                int speaker_pos = avio_r8(pb);
+
+                av_log(s, AV_LOG_TRACE, "speaker_position %d\n", speaker_pos);
+                if (speaker_pos == 126) { // explicit position
+                    avpriv_request_sample(s, "explicit position");
+                    av_freep(&positions);
+                    return AVERROR_PATCHWELCOME;
+                } else {
+                    positions[i] = speaker_pos;
+                }
+            }
+
+            ret = ff_mov_get_layout_from_channel_positions(positions,
+                    st->codecpar->ch_layout.nb_channels,
+                    &st->codecpar->ch_layout);
+            av_freep(&positions);
+            if (ret) {
+                av_log(s, AV_LOG_ERROR,
+                        "get channel layout from speaker positions failed, %s\n",
+                        av_err2str(ret));
+                return ret;
+            }
+        } else {
+            uint64_t omitted_channel_map = avio_rb64(pb);
+
+            if (omitted_channel_map) {
+                avpriv_request_sample(s, "omitted_channel_map 0x%" PRIx64 " != 0",
+                                      omitted_channel_map);
+                return AVERROR_PATCHWELCOME;
+            }
+            ff_mov_get_channel_layout_from_config(layout, &st->codecpar->ch_layout);
+        }
+    }
+
+    // stream carries objects
+    if (stream_structure & 2) {
+        int obj_count = avio_r8(pb);
+        av_log(s, AV_LOG_TRACE, "'chnl' with object_count %d\n", obj_count);
+    }
+
+    return 0;
+}

libavformat/mov_chan.h

@@ -189,4 +189,14 @@ int ff_mov_get_channel_positions_from_layout(const AVChannelLayout *layout,
 int ff_mov_get_layout_from_channel_positions(const uint8_t *position, int position_num,
                                              AVChannelLayout *layout);
 
+/**
+ * Read 'chnl' tag from the input stream.
+ *
+ * @param s     AVFormatContext
+ * @param pb    AVIOContext
+ * @param st    The stream to set codec values for
+ * @return      0 if ok, or negative AVERROR code on failure
+ */
+int ff_mov_read_chnl(AVFormatContext *s, AVIOContext *pb, AVStream *st);
+
 #endif /* AVFORMAT_MOV_CHAN_H */