lavfi: initialize pts to AV_NOPTS_VALUE when creating new buffer refs.

libavfilter/audio.c

@@ -129,6 +129,8 @@ AVFilterBufferRef* avfilter_get_audio_buffer_ref_from_arrays(uint8_t **data,
         samplesref->extended_data = samplesref->data;
     }
 
+    samplesref->pts = AV_NOPTS_VALUE;
+
     return samplesref;
 
 fail:

libavfilter/video.c

@@ -125,6 +125,8 @@ avfilter_get_video_buffer_ref_from_arrays(uint8_t *data[4], int linesize[4], int
     pic->   extended_data = pic->data;
     picref->extended_data = picref->data;
 
+    picref->pts = AV_NOPTS_VALUE;
+
     return picref;
 
 fail: