avfilter/vf_framerate: calculate delta from scaled pts instead of unscaled

Signed-off-by: Paul B Mahol <onemda@gmail.com>

libavfilter/vf_framerate.c

@@ -476,28 +476,23 @@ static void set_work_frame_pts(AVFilterContext *ctx)
     average_srce_pts_delta = s->average_srce_pts_dest_delta;
     ff_dlog(ctx, "set_work_frame_pts() initial average srce pts:%"PRId64"\n", average_srce_pts_delta);
 
+    set_srce_frame_dest_pts(ctx);
+
     // calculate the PTS delta
-    if ((pts = (s->srce[s->next]->pts - s->srce[s->crnt]->pts))) {
+    if ((pts = (s->srce_pts_dest[s->next] - s->srce_pts_dest[s->crnt]))) {
         average_srce_pts_delta = average_srce_pts_delta?((average_srce_pts_delta+pts)>>1):pts;
-    } else if (s->srce[s->prev] && (pts = (s->srce[s->crnt]->pts - s->srce[s->prev]->pts))) {
+    } else if (s->srce[s->prev] && (pts = (s->srce_pts_dest[s->crnt] - s->srce_pts_dest[s->prev]))) {
         average_srce_pts_delta = average_srce_pts_delta?((average_srce_pts_delta+pts)>>1):pts;
     }
 
-    s->average_srce_pts_dest_delta = av_rescale_q(average_srce_pts_delta, s->srce_time_base, s->dest_time_base);
+    s->average_srce_pts_dest_delta = average_srce_pts_delta;
     ff_dlog(ctx, "set_work_frame_pts() average srce pts:%"PRId64"\n", average_srce_pts_delta);
     ff_dlog(ctx, "set_work_frame_pts() average srce pts:%"PRId64" at dest time base:%u/%u\n",
             s->average_srce_pts_dest_delta, s->dest_time_base.num, s->dest_time_base.den);
 
-    set_srce_frame_dest_pts(ctx);
-
     if (ctx->inputs[0] && !s->average_dest_pts_delta) {
-        int64_t d = av_q2d(av_inv_q(av_mul_q(s->srce_time_base, s->dest_frame_rate)));
-        if (d == 0) { // FIXME
-            av_log(ctx, AV_LOG_WARNING, "Buggy path reached, use settb filter before this filter!\n");
-            d = av_q2d(av_mul_q(ctx->inputs[0]->time_base, s->dest_frame_rate));
-        }
-        s->average_dest_pts_delta = av_rescale_q(d, s->srce_time_base, s->dest_time_base);
-        ff_dlog(ctx, "set_frame_pts() average output pts from input timebase\n");
+        int64_t d = av_q2d(av_inv_q(av_mul_q(s->dest_time_base, s->dest_frame_rate)));
+        s->average_dest_pts_delta = d;
         ff_dlog(ctx, "set_work_frame_pts() average dest pts delta:%"PRId64"\n", s->average_dest_pts_delta);
     }