vpxdec: request a sync point on decoder errors

Part-of: <https://gitlab.freedesktop.org/gstreamer/gst-plugins-good/-/merge_requests/725>

ext/vpx/gstvp8dec.c

@@ -59,6 +59,7 @@ static void gst_vp8_dec_set_default_format (GstVPXDec * dec, GstVideoFormat fmt,
     int width, int height);
 static void gst_vp8_dec_handle_resolution_change (GstVPXDec * dec,
     vpx_image_t * img, GstVideoFormat fmt);
+static gboolean gst_vp8_dec_get_needs_sync_point (GstVPXDec * dec);
 
 static GstStaticPadTemplate gst_vp8_dec_sink_template =
 GST_STATIC_PAD_TEMPLATE ("sink",
@@ -103,6 +104,8 @@ gst_vp8_dec_class_init (GstVP8DecClass * klass)
       GST_DEBUG_FUNCPTR (gst_vp8_dec_set_default_format);
   vpx_class->handle_resolution_change =
       GST_DEBUG_FUNCPTR (gst_vp8_dec_handle_resolution_change);
+  vpx_class->get_needs_sync_point =
+      GST_DEBUG_FUNCPTR (gst_vp8_dec_get_needs_sync_point);
 
   GST_DEBUG_CATEGORY_INIT (gst_vp8dec_debug, "vp8dec", 0, "VP8 Decoder");
 }
@@ -153,4 +156,10 @@ gst_vp8_dec_handle_resolution_change (GstVPXDec * dec, vpx_image_t * img,
   }
 }
 
+static gboolean
+gst_vp8_dec_get_needs_sync_point (GstVPXDec * dec)
+{
+  return FALSE;
+}
+
 #endif /* HAVE_VP8_DECODER */

ext/vpx/gstvp9dec.c

@@ -61,6 +61,7 @@ static gboolean gst_vp9_dec_get_valid_format (GstVPXDec * dec,
     vpx_image_t * img, GstVideoFormat * fmt);
 static void gst_vp9_dec_handle_resolution_change (GstVPXDec * dec,
     vpx_image_t * img, GstVideoFormat fmt);
+static gboolean gst_vp9_dec_get_needs_sync_point (GstVPXDec * dec);
 
 static GstStaticPadTemplate gst_vp9_dec_sink_template =
 GST_STATIC_PAD_TEMPLATE ("sink",
@@ -107,6 +108,8 @@ gst_vp9_dec_class_init (GstVP9DecClass * klass)
       GST_DEBUG_FUNCPTR (gst_vp9_dec_get_valid_format);
   vpx_class->handle_resolution_change =
       GST_DEBUG_FUNCPTR (gst_vp9_dec_handle_resolution_change);
+  vpx_class->get_needs_sync_point =
+      GST_DEBUG_FUNCPTR (gst_vp9_dec_get_needs_sync_point);
 
   GST_DEBUG_CATEGORY_INIT (gst_vp9dec_debug, "vp9dec", 0, "VP9 Decoder");
 }
@@ -223,4 +226,10 @@ gst_vp9_dec_handle_resolution_change (GstVPXDec * dec, vpx_image_t * img,
   }
 }
 
+static gboolean
+gst_vp9_dec_get_needs_sync_point (GstVPXDec * dec)
+{
+  return TRUE;
+}
+
 #endif /* HAVE_VP9_DECODER */

ext/vpx/gstvpxdec.c

@@ -197,6 +197,7 @@ static void
 gst_vpx_dec_init (GstVPXDec * gst_vpx_dec)
 {
   GstVideoDecoder *decoder = (GstVideoDecoder *) gst_vpx_dec;
+  GstVPXDecClass *vpxclass = GST_VPX_DEC_GET_CLASS (gst_vpx_dec);
 
   GST_DEBUG_OBJECT (gst_vpx_dec, "gst_vpx_dec_init");
   gst_video_decoder_set_packetized (decoder, TRUE);
@@ -205,6 +206,11 @@ gst_vpx_dec_init (GstVPXDec * gst_vpx_dec)
   gst_vpx_dec->deblocking_level = DEFAULT_DEBLOCKING_LEVEL;
   gst_vpx_dec->noise_level = DEFAULT_NOISE_LEVEL;
 
+  if (vpxclass->get_needs_sync_point) {
+    gst_video_decoder_set_needs_sync_point (GST_VIDEO_DECODER (gst_vpx_dec),
+        vpxclass->get_needs_sync_point (gst_vpx_dec));
+  }
+
   gst_video_decoder_set_needs_format (decoder, TRUE);
   gst_video_decoder_set_use_default_pad_acceptcaps (decoder, TRUE);
   GST_PAD_SET_ACCEPT_TEMPLATE (GST_VIDEO_DECODER_SINK_PAD (decoder));
@@ -581,12 +587,12 @@ gst_vpx_dec_open_codec (GstVPXDec * dec, GstVideoCodecFrame * frame)
   gst_buffer_unmap (frame->input_buffer, &minfo);
 
   if (status != VPX_CODEC_OK) {
-    GST_WARNING_OBJECT (dec, "VPX preprocessing error: %s",
+    GST_INFO_OBJECT (dec, "VPX preprocessing error: %s",
         gst_vpx_error_name (status));
     return GST_FLOW_CUSTOM_SUCCESS_1;
   }
   if (!stream_info.is_kf) {
-    GST_WARNING_OBJECT (dec, "No keyframe, skipping");
+    GST_INFO_OBJECT (dec, "No keyframe, skipping");
     return GST_FLOW_CUSTOM_SUCCESS_1;
   }
   if (stream_info.w == 0 || stream_info.h == 0) {
@@ -672,6 +678,12 @@ gst_vpx_dec_handle_frame (GstVideoDecoder * decoder, GstVideoCodecFrame * frame)
   if (!dec->decoder_inited) {
     ret = vpxclass->open_codec (dec, frame);
     if (ret == GST_FLOW_CUSTOM_SUCCESS_1) {
+      GstVideoDecoderRequestSyncPointFlags flags = 0;
+
+      if (gst_video_decoder_get_needs_sync_point (decoder))
+        flags |= GST_VIDEO_DECODER_REQUEST_SYNC_POINT_DISCARD_INPUT;
+
+      gst_video_decoder_request_sync_point (decoder, frame, flags);
       gst_video_decoder_drop_frame (decoder, frame);
       return GST_FLOW_OK;
     } else if (ret != GST_FLOW_OK) {
@@ -701,8 +713,15 @@ gst_vpx_dec_handle_frame (GstVideoDecoder * decoder, GstVideoCodecFrame * frame)
   gst_buffer_unmap (frame->input_buffer, &minfo);
 
   if (status) {
+    GstVideoDecoderRequestSyncPointFlags flags = 0;
+
     GST_VIDEO_DECODER_ERROR (decoder, 1, LIBRARY, ENCODE,
         ("Failed to decode frame"), ("%s", gst_vpx_error_name (status)), ret);
+
+    if (gst_video_decoder_get_needs_sync_point (decoder))
+      flags |= GST_VIDEO_DECODER_REQUEST_SYNC_POINT_DISCARD_INPUT;
+
+    gst_video_decoder_request_sync_point (decoder, frame, flags);
     gst_video_codec_frame_unref (frame);
     return ret;
   }

ext/vpx/gstvpxdec.h

@@ -102,6 +102,11 @@ struct _GstVPXDecClass
   void (*handle_resolution_change) (GstVPXDec *dec, vpx_image_t *img, GstVideoFormat fmt);
   /*virtual function to check valid format*/
   gboolean (*get_frame_format)(GstVPXDec *dec, vpx_image_t *img, GstVideoFormat* fmt);
+  /* virtual function to check whether the decoder can handle data
+   * before receiving a sync_point, either at the start of after a
+   * decoding error
+   */
+  gboolean (*get_needs_sync_point)(GstVPXDec *dec);
 };
 
 GType gst_vpx_dec_get_type (void);