tor-browser

commit cb867d5a618117c7b73716d917e938b36dfc4029
parent 7a84f98d6e88d76945bf88baba69b10089b565f5
Author: Dan Baker <dbaker@mozilla.com>
Date:   Mon, 27 Oct 2025 12:16:48 -0600

Bug 1995393 - Vendor libwebrtc from c530e64f66

Upstream commit: https://webrtc.googlesource.com/src/+/c530e64f660f3a10db47baf576b86031336f639c
    Fix wraparound issue in FrameInstrumentationGenerator.

    This prevents an RTC_CHECK from triggering if the sequence index
    wraparound happens on a delta frame.

    Bug: webrtc:440978611, chromium:440989756
    Change-Id: I4d893687391e87a0d2a8476d0db70153b0e8a768
    Reviewed-on: https://webrtc-review.googlesource.com/c/src/+/406100
    Commit-Queue: Erik Språng <sprang@webrtc.org>
    Reviewed-by: Fanny Linderborg <linderborg@webrtc.org>
    Auto-Submit: Erik Språng <sprang@webrtc.org>
    Cr-Commit-Position: refs/heads/main@{#45426}

Diffstat:
M
third_party/libwebrtc/README.mozilla.last-vendor
 | 
4
++--
M
third_party/libwebrtc/video/corruption_detection/frame_instrumentation_generator.cc
 | 
20
++++++++++----------
M
third_party/libwebrtc/video/corruption_detection/frame_instrumentation_generator_unittest.cc
 | 
48
++++++++++++++++++++++++++++++++++++++++++++++++

3 files changed, 60 insertions(+), 12 deletions(-)
diff --git a/third_party/libwebrtc/README.mozilla.last-vendor b/third_party/libwebrtc/README.mozilla.last-vendor
@@ -1,4 +1,4 @@
 # ./mach python dom/media/webrtc/third_party_build/vendor-libwebrtc.py --from-local /Users/danielbaker/elm/.moz-fast-forward/moz-libwebrtc --commit mozpatches libwebrtc
-libwebrtc updated from /Users/danielbaker/elm/.moz-fast-forward/moz-libwebrtc commit mozpatches on 2025-10-27T18:14:02.272854+00:00.
+libwebrtc updated from /Users/danielbaker/elm/.moz-fast-forward/moz-libwebrtc commit mozpatches on 2025-10-27T18:16:31.261057+00:00.
 # base of lastest vendoring
-a2dab3cb79
+c530e64f66
diff --git a/third_party/libwebrtc/video/corruption_detection/frame_instrumentation_generator.cc b/third_party/libwebrtc/video/corruption_detection/frame_instrumentation_generator.cc
@@ -140,17 +140,17 @@ FrameInstrumentationGenerator::OnEncodedImage(
     }
 
     int sequence_index = contexts_[layer_id].frame_sampler.GetCurrentIndex();
-    if (is_key_frame) {
+    if (is_key_frame && ((sequence_index & 0b0111'1111) != 0)) {
       // Increase until all the last 7 bits are zeroes.
-      // If this would overflow to 15 bits, reset to 0.
-      if (sequence_index > 0b0011'1111'1000'0000) {
-        sequence_index = 0;
-      } else if ((sequence_index & 0b0111'1111) != 0) {
-        // Last 7 bits are not all zeroes.
-        sequence_index >>= 7;
-        sequence_index += 1;
-        sequence_index <<= 7;
-      }
+      sequence_index >>= 7;
+      sequence_index += 1;
+      sequence_index <<= 7;
+      contexts_[layer_id].frame_sampler.SetCurrentIndex(sequence_index);
+    }
+
+    if (sequence_index >= (1 << 14)) {
+      // Overflow of 14 bit counter, reset to 0.
+      sequence_index = 0;
       contexts_[layer_id].frame_sampler.SetCurrentIndex(sequence_index);
     }
 
diff --git a/third_party/libwebrtc/video/corruption_detection/frame_instrumentation_generator_unittest.cc b/third_party/libwebrtc/video/corruption_detection/frame_instrumentation_generator_unittest.cc
@@ -581,6 +581,54 @@ TEST(FrameInstrumentationGeneratorTest,
   EXPECT_EQ(data1->sequence_index(), 0b0000'1000'0000);
   EXPECT_EQ(data2->sequence_index(), 0b0001'0000'0000);
 }
+TEST(FrameInstrumentationGeneratorTest,
+     SequenceIndexThatWouldOverflowTo15BitsIncreasesCorrectlyAtNewDeltaFrame) {
+  FrameInstrumentationGenerator generator(VideoCodecType::kVideoCodecVP8);
+  generator.OnCapturedFrame(
+      VideoFrame::Builder()
+          .set_video_frame_buffer(MakeI420FrameBufferWithDifferentPixelValues())
+          .set_rtp_timestamp(1)
+          .build());
+  EncodedImage encoded_image;
+  encoded_image.SetRtpTimestamp(1);
+  encoded_image.SetFrameType(VideoFrameType::kVideoFrameDelta);
+  encoded_image.qp_ = 10;
+  encoded_image._encodedWidth = kDefaultScaledWidth;
+  encoded_image._encodedHeight = kDefaultScaledHeight;
+  encoded_image.SetSimulcastIndex(0);
+
+  constexpr int kMaxSequenceIndex = 0b11'1111'1111'1111;
+
+  generator.SetHaltonSequenceIndex(kMaxSequenceIndex,
+                                   generator.GetLayerId(encoded_image));
+  std::optional<FrameInstrumentationData> data =
+      generator.OnEncodedImage(encoded_image);
+
+  ASSERT_TRUE(data.has_value());
+  EXPECT_EQ(data->sequence_index(), kMaxSequenceIndex);
+
+  // Loop until we get a new delta frame.
+  bool has_found_delta_frame = false;
+  for (int i = 0; i < 34; ++i) {
+    generator.OnCapturedFrame(
+        VideoFrame::Builder()
+            .set_video_frame_buffer(
+                MakeI420FrameBufferWithDifferentPixelValues())
+            .set_rtp_timestamp(i + 2)
+            .build());
+
+    encoded_image.SetRtpTimestamp(i + 2);
+
+    std::optional<FrameInstrumentationData> frame_instrumentation_data =
+        generator.OnEncodedImage(encoded_image);
+    if (frame_instrumentation_data.has_value()) {
+      has_found_delta_frame = true;
+      EXPECT_EQ(frame_instrumentation_data->sequence_index(), 0);
+      break;
+    }
+  }
+  EXPECT_TRUE(has_found_delta_frame);
+}
 
 TEST(FrameInstrumentationGeneratorTest, GetterAndSetterOperatesAsExpected) {
   FrameInstrumentationGenerator generator(VideoCodecType::kVideoCodecVP8);