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Allow extremely low resolution for simulcast path

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Some screen capturers may occasionally send an extremely small frame,
e.g. 2x2. If a scale_resolution_down_by is specified, WebrtcVideoEngine
would enforce configured resolution to be at least 16x16, which would
then break VideoStreamEncoder and cause a crash.

This changes disables scaling and alignment for extremely low resolutions.

Bug: chromium:1265303, webrtc:13371
Change-Id: Icdb736043e1fdf91fdde5a8e4b3c6a89f6b90577
Reviewed-on: https://webrtc-review.googlesource.com/c/src/+/236850
Reviewed-by: Niels Moller <nisse@webrtc.org>
Commit-Queue: Ilya Nikolaevskiy <ilnik@webrtc.org>
Cr-Commit-Position: refs/heads/main@{#35420}
This commit is contained in:
Ilya Nikolaevskiy
2021-11-25 16:12:58 +01:00
committed by WebRTC LUCI CQ
parent e1bbef1e6b
commit a40e6de242
1 changed files with 26 additions and 15 deletions
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41
media/engine/webrtc_video_engine.cc
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@ -57,6 +57,18 @@ constexpr int64_t kUnsignaledSsrcCooldownMs = rtc::kNumMillisecsPerSec / 2;
// needed.
constexpr char kAv1xCodecName[] = "AV1X";
int ScaleDownResolution(int resolution,
double scale_down_by,
int min_resolution) {
// Resolution is never scalied down to smaller than min_resolution.
// If the input resolution is already smaller than min_resolution,
// no scaling should be done at all.
if (resolution <= min_resolution)
return resolution;
return std::max(static_cast<int>(resolution / scale_down_by + 0.5),
min_resolution);
}
const char* StreamTypeToString(
webrtc::VideoSendStream::StreamStats::StreamType type) {
switch (type) {
@ -3584,13 +3596,13 @@ EncoderStreamFactory::CreateDefaultVideoStreams(
layer.max_framerate = max_framerate;
if (encoder_config.simulcast_layers[0].scale_resolution_down_by > 1.) {
layer.width = std::max<size_t>(
layer.width /
encoder_config.simulcast_layers[0].scale_resolution_down_by,
layer.width = ScaleDownResolution(
layer.width,
encoder_config.simulcast_layers[0].scale_resolution_down_by,
kMinLayerSize);
layer.height = std::max<size_t>(
layer.height /
encoder_config.simulcast_layers[0].scale_resolution_down_by,
layer.height = ScaleDownResolution(
layer.height,
encoder_config.simulcast_layers[0].scale_resolution_down_by,
kMinLayerSize);
}
@ -3666,14 +3678,15 @@ EncoderStreamFactory::CreateSimulcastOrConferenceModeScreenshareStreams(
const bool norm_size_configured =
webrtc::NormalizeSimulcastSizeExperiment::GetBase2Exponent().has_value();
const int normalized_width =
(default_scale_factors_used || norm_size_configured)
(default_scale_factors_used || norm_size_configured) &&
(width >= kMinLayerSize)
? NormalizeSimulcastSize(width, encoder_config.number_of_streams)
: width;
const int normalized_height =
(default_scale_factors_used || norm_size_configured)
(default_scale_factors_used || norm_size_configured) &&
(height >= kMinLayerSize)
? NormalizeSimulcastSize(height, encoder_config.number_of_streams)
: height;
for (size_t i = 0; i < layers.size(); ++i) {
layers[i].active = encoder_config.simulcast_layers[i].active;
layers[i].scalability_mode =
@ -3691,12 +3704,10 @@ EncoderStreamFactory::CreateSimulcastOrConferenceModeScreenshareStreams(
if (has_scale_resolution_down_by) {
const double scale_resolution_down_by = std::max(
encoder_config.simulcast_layers[i].scale_resolution_down_by, 1.0);
layers[i].width = std::max(
static_cast<int>(normalized_width / scale_resolution_down_by),
kMinLayerSize);
layers[i].height = std::max(
static_cast<int>(normalized_height / scale_resolution_down_by),
kMinLayerSize);
layers[i].width = ScaleDownResolution(
normalized_width, scale_resolution_down_by, kMinLayerSize);
layers[i].height = ScaleDownResolution(
normalized_height, scale_resolution_down_by, kMinLayerSize);
}
// Update simulcast bitrates with configured min and max bitrate.
if (encoder_config.simulcast_layers[i].min_bitrate_bps > 0) {