avcodec/decode: split ProgressFrame allocator into two functions

Signed-off-by: James Almer <jamrial@gmail.com>

libavcodec/decode.c

@@ -1725,7 +1725,7 @@ static void check_progress_consistency(const ProgressFrame *f)
     av_assert1(!f->progress || f->progress->f == f->f);
 }
 
-static int progress_frame_get(AVCodecContext *avctx, ProgressFrame *f)
+int ff_progress_frame_alloc(AVCodecContext *avctx, ProgressFrame *f)
 {
     FFRefStructPool *pool = avctx->internal->progress_frame_pool;
 
@@ -1743,9 +1743,12 @@ int ff_progress_frame_get_buffer(AVCodecContext *avctx, ProgressFrame *f, int fl
 {
     int ret;
 
-    ret = progress_frame_get(avctx, f);
-    if (ret < 0)
-        return ret;
+    check_progress_consistency(f);
+    if (!f->f) {
+        ret = ff_progress_frame_alloc(avctx, f);
+        if (ret < 0)
+            return ret;
+    }
 
     ret = ff_thread_get_buffer(avctx, f->progress->f, flags);
     if (ret < 0) {

libavcodec/progressframe.h

@@ -102,12 +102,24 @@ void ff_progress_frame_report(ProgressFrame *f, int progress);
 void ff_progress_frame_await(const ProgressFrame *f, int progress);
 
 /**
- * This function sets up the ProgressFrame, i.e. gets ProgressFrame.f
- * and also calls ff_thread_get_buffer() on the frame.
+ * This function allocates ProgressFrame.f
+ * May be called before ff_progress_frame_get_buffer() in the cases where the
+ * AVFrame needs to be accessed before the ff_thread_get_buffer() call in
+ * ff_progress_frame_alloc().
  *
  * @note: This must only be called by codecs with the
  *        FF_CODEC_CAP_USES_PROGRESSFRAMES internal cap.
  */
+int ff_progress_frame_alloc(struct AVCodecContext *avctx, ProgressFrame *f);
+
+/**
+ * This function sets up the ProgressFrame, i.e. allocates ProgressFrame.f
+ * if needed, and also calls ff_thread_get_buffer() on the frame.
+ *
+ * @note: This must only be called by codecs with the
+ *        FF_CODEC_CAP_USES_PROGRESSFRAMES internal cap.
+ * @see ff_progress_frame_alloc
+ */
 int ff_progress_frame_get_buffer(struct AVCodecContext *avctx,
                                  ProgressFrame *f, int flags);