@@ -796,6 +796,8 @@ typedef struct AVChapter {

     AVDictionary *metadata;

 } AVChapter;

+typedef struct AVFormatInternal AVFormatInternal;

+

 /**

  * Format I/O context.

  * New fields can be added to the end with minor version bumps.

@@ -1049,6 +1051,11 @@ typedef struct AVFormatContext {

      */

     AVRational offset_timebase;

+    /**

+     * An opaque field for libavformat internal usage.

+     * Must not be accessed in any way by callers.

+     */

+    AVFormatInternal *internal;

 } AVFormatContext;

 typedef struct AVPacketList {

@@ -42,6 +42,14 @@ typedef struct CodecMime{

     enum AVCodecID id;

 } CodecMime;

+struct AVFormatInternal {

+    /**

+     * Number of streams relevant for interleaving.

+     * Muxing only.

+     */

+    int nb_interleaved_streams;

+};

+

 void ff_dynarray_add(intptr_t **tab_ptr, int *nb_ptr, intptr_t elem);

 #ifdef __GNUC__

@@ -232,6 +232,9 @@ static int init_muxer(AVFormatContext *s, AVDictionary **options)

             av_log(s, AV_LOG_WARNING,

                    "Codec for stream %d does not use global headers "

                    "but container format requires global headers\n", i);

+

+        if (codec->codec_type != AVMEDIA_TYPE_ATTACHMENT)

+            s->internal->nb_interleaved_streams++;

     }

     if (!s->priv_data && of->priv_data_size > 0) {

@@ -541,7 +544,7 @@ int ff_interleave_packet_per_dts(AVFormatContext *s, AVPacket *out,

     for (i = 0; i < s->nb_streams; i++)

         stream_count += !!s->streams[i]->last_in_packet_buffer;

-    if (stream_count && (s->nb_streams == stream_count || flush)) {

+    if (stream_count && (s->internal->nb_interleaved_streams == stream_count || flush)) {

         pktl = s->packet_buffer;

         *out = pktl->pkt;

@@ -19,6 +19,7 @@

  */

 #include "avformat.h"

 #include "avio_internal.h"

+#include "internal.h"

 #include "libavutil/opt.h"

 /**

@@ -100,6 +101,13 @@ AVFormatContext *avformat_alloc_context(void)

     ic = av_malloc(sizeof(AVFormatContext));

     if (!ic) return ic;

     avformat_get_context_defaults(ic);

+

+    ic->internal = av_mallocz(sizeof(*ic->internal));

+    if (!ic->internal) {

+        avformat_free_context(ic);

+        return NULL;

+    }

+

     return ic;

 }

@@ -2633,6 +2633,7 @@ void avformat_free_context(AVFormatContext *s)

     av_freep(&s->chapters);

     av_dict_free(&s->metadata);

     av_freep(&s->streams);

+    av_freep(&s->internal);

     av_free(s);

 }