lavfi: loop on request_frame if necessary.

Some filters need several input frames before producing output. For these filter, it becomes simpler to return 0 in request_frame() and let the framework call it again until output has been produced.

Nicolas George committed 13 years ago

Commit 79d8cfa1 parent c2085763 files · +40 −2Browse files

Unified · Split

3 files

libavfilter/avfilter.c +15 −2
libavfilter/avfilter.h +11 −0
libavfilter/internal.h +14 −0

libavfilter/avfilter.c+15−2

     if (link->closed)
         return AVERROR_EOF;
+    av_assert0(!link->frame_requested);
+    link->frame_requested = 1;
+    while (link->frame_requested) {
+        /* TODO reindent */
     if (link->srcpad->request_frame)
         ret = link->srcpad->request_frame(link);
     else if (link->src->inputs[0])
         link->partial_buf = NULL;
         ret = ff_filter_frame_framed(link, pbuf);
     }
-    if (ret == AVERROR_EOF)
+        if (ret < 0) {
-        link->closed = 1;
+            link->frame_requested = 0;
+            if (ret == AVERROR_EOF)
+                link->closed = 1;
+        } else {
+            av_assert0(!link->frame_requested ||
+                       link->flags & FF_LINK_FLAG_REQUEST_LOOP);
+        }
+    }
     return ret;
 }
     pts = out->pts;
     ret = filter_frame(link, out);
+    link->frame_requested = 0;
     ff_update_link_current_pts(link, pts);
     return ret;
 }
     int nb_channels = av_frame_get_channels(frame);
     int ret = 0;
+    link->flags |= FF_LINK_FLAG_REQUEST_LOOP;
     /* Handle framing (min_samples, max_samples) */
     while (insamples) {
         if (!pbuf) {

libavfilter/avfilter.h+11−0

@@ -682,6 +682,17 @@ struct AVFilterLink { · 681 unmodified lines
682	* Number of channels.	682	* Number of channels.
683	*/	683	*/
684	int channels;	684	int channels;
		685
		686	/**
		687	* True if a frame is being requested on the link.
		688	* Used internally by the framework.
		689	*/
		690	unsigned frame_requested;
		691
		692	/**
		693	* Link processing flags.
		694	*/
		695	unsigned flags;
685	};	696	};
686		697
687	/**	698	/**

libavfilter/internal.h+14−0

@@ -325,4 +325,18 @@ int ff_buffersink_read_samples_compat(AVFilterContext ctx, AVFilterBufferRef * · 324 unmodified lines
325	*/	325	*/
326	int ff_filter_frame(AVFilterLink link, AVFrame frame);	326	int ff_filter_frame(AVFilterLink link, AVFrame frame);
327		327
		328	/**
		329	* Flags for AVFilterLink.flags.
		330	*/
		331	enum {
		332
		333	/**
		334	* Frame requests may need to loop in order to be fulfilled.
		335	* A filter must set this flags on an output link if it may return 0 in
		336	* request_frame() without filtering a frame.
		337	*/
		338	FF_LINK_FLAG_REQUEST_LOOP = 1,
		339
		340	};
		341
328	#endif /* AVFILTER_INTERNAL_H */	342	#endif /* AVFILTER_INTERNAL_H */

lavfi: loop on request_frame if necessary.

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