shithub: libvpx

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vp9-svc: Fix to frame dropping in svc mode.

Don't advance the svc frame counters on dropped frame,
since this can break the referencing scheme and lead
to a crash/assert.

Updated svc-datarate unittest to add a lower bitrate test.

Change only affects 1 pass cbr svc, with frame dropper enabled.

Change-Id: Ibb7530b7a587a9344d46898d9286fd9e2ef0779c

--- a/test/datarate_test.cc

+++ b/test/datarate_test.cc

@@ -905,8 +905,8 @@

   ::libvpx_test::I420VideoSource video("hantro_collage_w352h288.yuv", 352, 288,

                                        30, 1, 0, 200);

   // TODO(wonkap/marpan): Check that effective_datarate for each layer hits the

-  // layer target_bitrate. Also check if test can pass at lower bitrate (~200k).

-  for (int i = 400; i <= 800; i += 200) {

+  // layer target_bitrate.

+  for (int i = 200; i <= 800; i += 200) {

     cfg_.rc_target_bitrate = i;

     ResetModel();

     assign_layer_bitrates(&cfg_, &svc_params_, cfg_.ss_number_layers,

--- a/vp9/encoder/vp9_encoder.c

+++ b/vp9/encoder/vp9_encoder.c

@@ -3999,8 +3999,12 @@

       ++cm->current_video_frame;

       cpi->ext_refresh_frame_flags_pending = 0;

       cpi->svc.rc_drop_superframe = 1;

-      if (cpi->use_svc)

-        vp9_inc_frame_in_layer(cpi);

+      // TODO(marpan): Advancing the svc counters on dropped frames can break

+      // the referencing scheme for the fixed svc patterns defined in

+      // vp9_one_pass_cbr_svc_start_layer(). Look into fixing this issue, but

+      // for now, don't advance the svc frame counters on dropped frame.

+      // if (cpi->use_svc)

+      //   vp9_inc_frame_in_layer(cpi);

       return;

     }

   }