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Avoid undefined behavior in vp8 screenshare_layers

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active_layer_ could be dereferenced while being -1...
Also added som DCHECKs

BUG=webrtc:5490

Review URL: https://codereview.webrtc.org/1656233002

Cr-Commit-Position: refs/heads/master@{#11486}
This commit is contained in:
sprang
2016-02-04 03:59:52 -08:00
committed by Commit bot
parent 08582ff075
commit 2ddb8bd359
2 changed files with 15 additions and 7 deletions
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18
webrtc/modules/video_coding/codecs/vp8/screenshare_layers.cc
View File

@ -57,8 +57,8 @@ ScreenshareLayers::ScreenshareLayers(int num_temporal_layers,
max_qp_(-1),
max_debt_bytes_(0),
frame_rate_(-1) {
assert(num_temporal_layers > 0);
assert(num_temporal_layers <= 2);
RTC_CHECK_GT(num_temporal_layers, 0);
RTC_CHECK_LE(num_temporal_layers, 2);
}
int ScreenshareLayers::CurrentLayerId() const {
@ -147,7 +147,8 @@ bool ScreenshareLayers::ConfigureBitrates(int bitrate_kbps,
}
// Don't reconfigure qp limits during quality boost frames.
if (layers_[active_layer_].state != TemporalLayer::State::kQualityBoost) {
if (active_layer_ == -1 ||
layers_[active_layer_].state != TemporalLayer::State::kQualityBoost) {
min_qp_ = cfg->rc_min_quantizer;
max_qp_ = cfg->rc_max_quantizer;
// After a dropped frame, a frame with max qp will be encoded and the
@ -169,6 +170,10 @@ bool ScreenshareLayers::ConfigureBitrates(int bitrate_kbps,
void ScreenshareLayers::FrameEncoded(unsigned int size,
uint32_t timestamp,
int qp) {
if (number_of_temporal_layers_ == 1)
return;
RTC_DCHECK_NE(-1, active_layer_);
if (size == 0) {
layers_[active_layer_].state = TemporalLayer::State::kDropped;
return;
@ -198,6 +203,7 @@ void ScreenshareLayers::PopulateCodecSpecific(bool base_layer_sync,
vp8_info->layerSync = false;
vp8_info->tl0PicIdx = kNoTl0PicIdx;
} else {
RTC_DCHECK_NE(-1, active_layer_);
vp8_info->temporalIdx = active_layer_;
if (base_layer_sync) {
vp8_info->temporalIdx = 0;
@ -218,10 +224,7 @@ void ScreenshareLayers::PopulateCodecSpecific(bool base_layer_sync,
}
bool ScreenshareLayers::TimeToSync(int64_t timestamp) const {
if (active_layer_ != 1) {
RTC_NOTREACHED();
return false;
}
RTC_DCHECK_EQ(1, active_layer_);
RTC_DCHECK_NE(-1, layers_[0].last_qp);
if (layers_[1].last_qp == -1) {
// First frame in TL1 should only depend on TL0 since there are no
@ -248,6 +251,7 @@ bool ScreenshareLayers::TimeToSync(int64_t timestamp) const {
bool ScreenshareLayers::UpdateConfiguration(vpx_codec_enc_cfg_t* cfg) {
if (max_qp_ == -1 || number_of_temporal_layers_ <= 1)
return false;
RTC_DCHECK_NE(-1, active_layer_);
// If layer is in the quality boost state (following a dropped frame), update
// the configuration with the adjusted (lower) qp and set the state back to

4
webrtc/modules/video_coding/codecs/vp8/screenshare_layers_unittest.cc
View File

@ -8,6 +8,8 @@
* be found in the AUTHORS file in the root of the source tree.
*/
#include <vector>
#include "gtest/gtest.h"
#include "vpx/vpx_encoder.h"
#include "vpx/vp8cx.h"
@ -41,6 +43,8 @@ class ScreenshareLayerTest : public ::testing::Test {
CodecSpecificInfoVP8* vp8_info,
int* flags) {
*flags = layers_->EncodeFlags(timestamp);
if (*flags == -1)
return;
layers_->PopulateCodecSpecific(base_sync, vp8_info, timestamp);
ASSERT_NE(-1, frame_size_);
layers_->FrameEncoded(frame_size_, timestamp, kDefaultQp);