ogg/vorbis: implement header packet skip in chained ogg bitstreams.

doc/APIchanges

@@ -2,6 +2,10 @@ The last version increases of all libraries were on 2025-03-28
 
 API changes, most recent first:
 
+2025-08-xx - xxxxxxxxxx - lavf 62.6.100 - oggparsevorbis.h oggparseopus.h oggparseflac.h
+  Drop header packets from secondary chained ogg/{flac, opus, vorbis} streams
+  from demuxer output.
+
 2025-09-xx - xxxxxxxxxx - lavu 60.13.100 - hwcontext_d3d12va.h
   Add resource_flags and heap_flags to AVD3D12VADeviceContext
   Add heap_flags to AVD3D12VAFramesContext

libavformat/oggparsevorbis.c

@@ -215,6 +215,12 @@ struct oggvorbis_private {
     AVVorbisParseContext *vp;
     int64_t final_pts;
     int final_duration;
+    uint8_t *header;
+    int header_size;
+    uint8_t *comment;
+    int comment_size;
+    uint8_t *setup;
+    int setup_size;
 };
 
 static int fixup_vorbis_headers(AVFormatContext *as,
@@ -260,6 +266,10 @@ static void vorbis_cleanup(AVFormatContext *s, int idx)
         av_vorbis_parse_free(&priv->vp);
         for (i = 0; i < 3; i++)
             av_freep(&priv->packet[i]);
+
+        av_freep(&priv->header);
+        av_freep(&priv->comment);
+        av_freep(&priv->setup);
     }
 }
 
@@ -434,6 +444,9 @@ static int vorbis_packet(AVFormatContext *s, int idx)
     struct ogg_stream *os = ogg->streams + idx;
     struct oggvorbis_private *priv = os->private;
     int duration, flags = 0;
+    int skip_packet = 0;
+    int ret, new_extradata_size;
+    PutByteContext pb;
 
     if (!priv->vp)
         return AVERROR_INVALIDDATA;
@@ -496,10 +509,50 @@ static int vorbis_packet(AVFormatContext *s, int idx)
         if (duration < 0) {
             os->pflags |= AV_PKT_FLAG_CORRUPT;
             return 0;
-        } else if (flags & VORBIS_FLAG_COMMENT) {
-            vorbis_update_metadata(s, idx);
-            flags = 0;
         }
+
+        if (flags & VORBIS_FLAG_HEADER) {
+            ret = vorbis_parse_header(s, s->streams[idx], os->buf + os->pstart, os->psize);
+            if (ret < 0)
+                return ret;
+
+            ret = av_reallocp(&priv->header, os->psize);
+            if (ret < 0)
+                return ret;
+
+            memcpy(priv->header, os->buf + os->pstart, os->psize);
+            priv->header_size = os->psize;
+
+            skip_packet = 1;
+        }
+
+        if (flags & VORBIS_FLAG_COMMENT) {
+            ret = vorbis_update_metadata(s, idx);
+            if (ret < 0)
+                return ret;
+
+            ret = av_reallocp(&priv->comment, os->psize);
+            if (ret < 0)
+                return ret;
+
+            memcpy(priv->comment, os->buf + os->pstart, os->psize);
+            priv->comment_size = os->psize;
+
+            flags = 0;
+            skip_packet = 1;
+        }
+
+        if (flags & VORBIS_FLAG_SETUP) {
+            ret = av_reallocp(&priv->setup, os->psize);
+            if (ret < 0)
+                return ret;
+
+            memcpy(priv->setup, os->buf + os->pstart, os->psize);
+            priv->setup_size = os->psize;
+
+            skip_packet = 1;
+        }
+
         os->pduration = duration;
     }
 
@@ -521,7 +574,31 @@ static int vorbis_packet(AVFormatContext *s, int idx)
         priv->final_duration += os->pduration;
     }
 
-    return 0;
+    if (priv->header && priv->comment && priv->setup) {
+        new_extradata_size = priv->header_size + priv->comment_size + priv->setup_size + 6;
+
+        ret = av_reallocp(&os->new_extradata, new_extradata_size);
+        if (ret < 0)
+            return ret;
+
+        os->new_extradata_size = new_extradata_size;
+        bytestream2_init_writer(&pb, os->new_extradata, new_extradata_size);
+        bytestream2_put_be16(&pb, priv->header_size);
+        bytestream2_put_buffer(&pb, priv->header, priv->header_size);
+        bytestream2_put_be16(&pb, priv->comment_size);
+        bytestream2_put_buffer(&pb, priv->comment, priv->comment_size);
+        bytestream2_put_be16(&pb, priv->setup_size);
+        bytestream2_put_buffer(&pb, priv->setup, priv->setup_size);
+
+        av_freep(&priv->header);
+        priv->header_size = 0;
+        av_freep(&priv->comment);
+        priv->comment_size = 0;
+        av_freep(&priv->setup);
+        priv->setup_size = 0;
+    }
+
+    return skip_packet;
 }
 
 const struct ogg_codec ff_vorbis_codec = {

tests/ref/fate/ogg-vorbis-chained-meta.txt

@@ -6,10 +6,7 @@ Stream ID: 0, frame PTS: 128, metadata: N/A
 Stream ID: 0, packet PTS: 704, packet DTS: 704
 Stream ID: 0, frame PTS: 704, metadata: N/A
 Stream ID: 0, packet PTS: 0, packet DTS: 0
-Stream ID: 0, packet PTS: 0, packet DTS: 0
 Stream ID: 0, new metadata: encoder=Lavc61.19.100 libvorbis:title=Second Stream
-Stream ID: 0, packet PTS: 0, packet DTS: 0
-Stream ID: 0, packet PTS: 0, packet DTS: 0
 Stream ID: 0, frame PTS: 0, metadata: N/A
 Stream ID: 0, packet PTS: 128, packet DTS: 128
 Stream ID: 0, frame PTS: 128, metadata: N/A