lavf: generic code for exporting attached pictures.

libavformat/avformat.h

@@ -530,6 +530,13 @@ typedef struct AVIndexEntry {
 #define AV_DISPOSITION_HEARING_IMPAIRED  0x0080  /**< stream for hearing impaired audiences */
 #define AV_DISPOSITION_VISUAL_IMPAIRED   0x0100  /**< stream for visual impaired audiences */
 #define AV_DISPOSITION_CLEAN_EFFECTS     0x0200  /**< stream without voice */
+/**
+ * The stream is stored in the file as an attached picture/"cover art" (e.g.
+ * APIC frame in ID3v2). The single packet associated with it will be returned
+ * among the first few packets read from the file unless seeking takes place.
+ * It can also be accessed at any time in AVStream.attached_pic.
+ */
+#define AV_DISPOSITION_ATTACHED_PIC      0x0400
 
 /**
  * Stream structure.
@@ -602,6 +609,15 @@ typedef struct AVStream {
      */
     AVRational avg_frame_rate;
 
+    /**
+     * For streams with AV_DISPOSITION_ATTACHED_PIC disposition, this packet
+     * will contain the attached picture.
+     *
+     * decoding: set by libavformat, must not be modified by the caller.
+     * encoding: unused
+     */
+    AVPacket attached_pic;
+
     /*****************************************************************
      * All fields below this line are not part of the public API. They
      * may not be used outside of libavformat and can be changed and

libavformat/utils.c

@@ -498,10 +498,27 @@ static int init_input(AVFormatContext *s, const char *filename, AVDictionary **o
     return av_probe_input_buffer(s->pb, &s->iformat, filename, s, 0, 0);
 }
 
+static AVPacket *add_to_pktbuf(AVPacketList **packet_buffer, AVPacket *pkt,
+                               AVPacketList **plast_pktl){
+    AVPacketList *pktl = av_mallocz(sizeof(AVPacketList));
+    if (!pktl)
+        return NULL;
+
+    if (*packet_buffer)
+        (*plast_pktl)->next = pktl;
+    else
+        *packet_buffer = pktl;
+
+    /* add the packet in the buffered packet list */
+    *plast_pktl = pktl;
+    pktl->pkt= *pkt;
+    return &pktl->pkt;
+}
+
 int avformat_open_input(AVFormatContext **ps, const char *filename, AVInputFormat *fmt, AVDictionary **options)
 {
     AVFormatContext *s = *ps;
-    int ret = 0;
+    int i, ret = 0;
     AVDictionary *tmp = NULL;
 
     if (!s && !(s = avformat_alloc_context()))
@@ -551,6 +568,14 @@ int avformat_open_input(AVFormatContext **ps, const char *filename, AVInputForma
         if ((ret = s->iformat->read_header(s)) < 0)
             goto fail;
 
+    /* queue attached pictures */
+    for (i = 0; i < s->nb_streams; i++)
+        if (s->streams[i]->disposition & AV_DISPOSITION_ATTACHED_PIC) {
+            AVPacket copy = s->streams[i]->attached_pic;
+            copy.destruct = NULL;
+            add_to_pktbuf(&s->raw_packet_buffer, &copy, &s->raw_packet_buffer_end);
+        }
+
     if (s->pb && !s->data_offset)
         s->data_offset = avio_tell(s->pb);
 
@@ -574,23 +599,6 @@ fail:
 
 /*******************************************************/
 
-static AVPacket *add_to_pktbuf(AVPacketList **packet_buffer, AVPacket *pkt,
-                               AVPacketList **plast_pktl){
-    AVPacketList *pktl = av_mallocz(sizeof(AVPacketList));
-    if (!pktl)
-        return NULL;
-
-    if (*packet_buffer)
-        (*plast_pktl)->next = pktl;
-    else
-        *packet_buffer = pktl;
-
-    /* add the packet in the buffered packet list */
-    *plast_pktl = pktl;
-    pktl->pkt= *pkt;
-    return &pktl->pkt;
-}
-
 int av_read_packet(AVFormatContext *s, AVPacket *pkt)
 {
     int ret, i;
@@ -2547,6 +2555,8 @@ void avformat_free_context(AVFormatContext *s)
             av_parser_close(st->parser);
             av_free_packet(&st->cur_pkt);
         }
+        if (st->attached_pic.data)
+            av_free_packet(&st->attached_pic);
         av_dict_free(&st->metadata);
         av_free(st->index_entries);
         av_free(st->codec->extradata);