avdevice/decklink: move AVPacketQueue into decklink_common and rename it to DecklinkPacketQueue

Move the AVPacketQueue functionality that is currently only used
for the decklink decode module into decklink_common, so it can
be shared by the decklink encoder (i.e. for VANC insertion when
we receive data packets separate from video).

The threadsafe queue used within the decklink module was named
"AVPacketQueue" which implies that it is part of the public API,
which it is not.

Rename the functions and the name of the queue struct to make
clear it is used exclusively by decklink, per Marton Balint's
suggestion.

Signed-off-by: Devin Heitmueller <dheitmueller@ltnglobal.com>
Signed-off-by: Marton Balint <cus@passwd.hu>

libavdevice/decklink_common.cpp

@@ -390,6 +390,121 @@ int ff_decklink_set_format(AVFormatContext *avctx, decklink_direction_t directio
     return ff_decklink_set_format(avctx, 0, 0, 0, 0, AV_FIELD_UNKNOWN, direction);
 }
 
+void ff_decklink_packet_queue_init(AVFormatContext *avctx, DecklinkPacketQueue *q)
+{
+    struct decklink_cctx *ctx = (struct decklink_cctx *)avctx->priv_data;
+    memset(q, 0, sizeof(DecklinkPacketQueue));
+    pthread_mutex_init(&q->mutex, NULL);
+    pthread_cond_init(&q->cond, NULL);
+    q->avctx = avctx;
+    q->max_q_size = ctx->queue_size;
+}
+
+void ff_decklink_packet_queue_flush(DecklinkPacketQueue *q)
+{
+    PacketListEntry *pkt, *pkt1;
+
+    pthread_mutex_lock(&q->mutex);
+    for (pkt = q->pkt_list.head; pkt != NULL; pkt = pkt1) {
+        pkt1 = pkt->next;
+        av_packet_unref(&pkt->pkt);
+        av_freep(&pkt);
+    }
+    q->pkt_list.head = NULL;
+    q->pkt_list.tail = NULL;
+    q->nb_packets = 0;
+    q->size       = 0;
+    pthread_mutex_unlock(&q->mutex);
+}
+
+void ff_decklink_packet_queue_end(DecklinkPacketQueue *q)
+{
+    ff_decklink_packet_queue_flush(q);
+    pthread_mutex_destroy(&q->mutex);
+    pthread_cond_destroy(&q->cond);
+}
+
+unsigned long long ff_decklink_packet_queue_size(DecklinkPacketQueue *q)
+{
+    unsigned long long size;
+    pthread_mutex_lock(&q->mutex);
+    size = q->size;
+    pthread_mutex_unlock(&q->mutex);
+    return size;
+}
+
+int ff_decklink_packet_queue_put(DecklinkPacketQueue *q, AVPacket *pkt)
+{
+    PacketListEntry *pkt1;
+
+    // Drop Packet if queue size is > maximum queue size
+    if (ff_decklink_packet_queue_size(q) > (uint64_t)q->max_q_size) {
+        av_packet_unref(pkt);
+        av_log(q->avctx, AV_LOG_WARNING,  "Decklink input buffer overrun!\n");
+        return -1;
+    }
+    /* ensure the packet is reference counted */
+    if (av_packet_make_refcounted(pkt) < 0) {
+        av_packet_unref(pkt);
+        return -1;
+    }
+
+    pkt1 = (PacketListEntry *)av_malloc(sizeof(*pkt1));
+    if (!pkt1) {
+        av_packet_unref(pkt);
+        return -1;
+    }
+    av_packet_move_ref(&pkt1->pkt, pkt);
+    pkt1->next = NULL;
+
+    pthread_mutex_lock(&q->mutex);
+
+    if (!q->pkt_list.tail) {
+        q->pkt_list.head = pkt1;
+    } else {
+        q->pkt_list.tail->next = pkt1;
+    }
+
+    q->pkt_list.tail = pkt1;
+    q->nb_packets++;
+    q->size += pkt1->pkt.size + sizeof(*pkt1);
+
+    pthread_cond_signal(&q->cond);
+
+    pthread_mutex_unlock(&q->mutex);
+    return 0;
+}
+
+int ff_decklink_packet_queue_get(DecklinkPacketQueue *q, AVPacket *pkt, int block)
+{
+    int ret;
+
+    pthread_mutex_lock(&q->mutex);
+
+    for (;; ) {
+        PacketListEntry *pkt1 = q->pkt_list.head;
+        if (pkt1) {
+            q->pkt_list.head = pkt1->next;
+            if (!q->pkt_list.head) {
+                q->pkt_list.tail = NULL;
+            }
+            q->nb_packets--;
+            q->size -= pkt1->pkt.size + sizeof(*pkt1);
+            *pkt     = pkt1->pkt;
+            av_free(pkt1);
+            ret = 1;
+            break;
+        } else if (!block) {
+            ret = 0;
+            break;
+        } else {
+            pthread_cond_wait(&q->cond, &q->mutex);
+        }
+    }
+    pthread_mutex_unlock(&q->mutex);
+    return ret;
+}
+
 int ff_decklink_list_devices(AVFormatContext *avctx,
                              struct AVDeviceInfoList *device_list,
                              int show_inputs, int show_outputs)