Milestone, fix black screen and initial frame issues

src/frame_queue.c

@@ -1,5 +1,6 @@
 #include "frame_queue.h"
 
+#include <libavutil/mem.h>
 #include <stdlib.h>
 #include <string.h>
 
@@ -8,7 +9,7 @@ void frame_data_free(FrameData *frame) {
         return;
     }
 
-    free(frame->pixels);
+    av_freep(&frame->buffer);
     memset(frame, 0, sizeof(*frame));
 }
 
@@ -110,3 +111,41 @@ int frame_queue_pop_latest(FrameQueue *queue, FrameData *out) {
     SDL_UnlockMutex(queue->mutex);
     return 1;
 }
+
+int frame_queue_peek_first(FrameQueue *queue, FrameData *out) {
+    if (!queue || !out || !queue->mutex) {
+        return 0;
+    }
+
+    SDL_LockMutex(queue->mutex);
+    if (queue->count == 0) {
+        SDL_UnlockMutex(queue->mutex);
+        return 0;
+    }
+
+    *out = queue->frames[queue->head];
+    SDL_UnlockMutex(queue->mutex);
+    return 1;
+}
+
+int frame_queue_pop_first(FrameQueue *queue, FrameData *out) {
+    if (!queue || !out || !queue->mutex) {
+        return 0;
+    }
+
+    SDL_LockMutex(queue->mutex);
+    if (queue->count == 0) {
+        SDL_UnlockMutex(queue->mutex);
+        return 0;
+    }
+
+    *out = queue->frames[queue->head];
+    memset(&queue->frames[queue->head], 0, sizeof(queue->frames[queue->head]));
+    queue->head = (queue->head + 1) % FRAME_QUEUE_CAPACITY;
+    queue->count -= 1;
+    if (queue->count == 0) {
+        queue->head = 0;
+    }
+    SDL_UnlockMutex(queue->mutex);
+    return 1;
+}