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// Copyright (c) 2012 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
#include "media/base/media_switches.h"
#include "base/command_line.h"
#include "build/build_config.h"
namespace switches {
// Allow users to specify a custom buffer size for debugging purpose.
const char kAudioBufferSize[] = "audio-buffer-size";
// Command line flag name to set the autoplay policy.
const char kAutoplayPolicy[] = "autoplay-policy";
// Set number of threads to use for video decoding.
const char kVideoThreads[] = "video-threads";
// Suspend media pipeline on background tabs.
const char kEnableMediaSuspend[] = "enable-media-suspend";
const char kDisableMediaSuspend[] = "disable-media-suspend";
// Force to report VP9 as an unsupported MIME type.
const char kReportVp9AsAnUnsupportedMimeType[] =
#if defined(OS_LINUX) || defined(OS_FREEBSD) || defined(OS_SOLARIS)
// The Alsa device to use when opening an audio input stream.
const char kAlsaInputDevice[] = "alsa-input-device";
// The Alsa device to use when opening an audio stream.
const char kAlsaOutputDevice[] = "alsa-output-device";
#if defined(OS_WIN)
// Use exclusive mode audio streaming for Windows Vista and higher.
// Leads to lower latencies for audio streams which uses the
// AudioParameters::AUDIO_PCM_LOW_LATENCY audio path.
// See
// for details.
const char kEnableExclusiveAudio[] = "enable-exclusive-audio";
// Force the use of MediaFoundation for video capture. This is only supported in
// Windows 7 and above. Used, like |kForceDirectShowVideoCapture|, to
// troubleshoot problems in Windows platforms.
const char kForceMediaFoundationVideoCapture[] = "force-mediafoundation";
// Use Windows WaveOut/In audio API even if Core Audio is supported.
const char kForceWaveAudio[] = "force-wave-audio";
// Instead of always using the hardware channel layout, check if a driver
// supports the source channel layout. Avoids outputting empty channels and
// permits drivers to enable stereo to multichannel expansion. Kept behind a
// flag since some drivers lie about supported layouts and hang when used. See
// for more details.
const char kTrySupportedChannelLayouts[] = "try-supported-channel-layouts";
// Number of buffers to use for WaveOut.
const char kWaveOutBuffers[] = "waveout-buffers";
#if defined(USE_CRAS)
// Use CRAS, the ChromeOS audio server.
const char kUseCras[] = "use-cras";
// For automated testing of protected content, this switch allows specific
// domains (e.g. to skip asking the user for permission to share
// the protected media identifier. In this context, domain does not include the
// port number. User's content settings will not be affected by enabling this
// switch.
// Reference:
// Example:
const char kUnsafelyAllowProtectedMediaIdentifierForDomain[] =
// Enable a internal audio focus management between tabs in such a way that two
// tabs can't play on top of each other.
// The allowed values are: "" (empty) or |kEnableAudioFocusDuckFlash|.
const char kEnableAudioFocus[] = "enable-audio-focus";
// This value is used as an option for |kEnableAudioFocus|. Flash will
// be ducked when losing audio focus.
const char kEnableAudioFocusDuckFlash[] = "duck-flash";
// Rather than use the renderer hosted remotely in the media service, fall back
// to the default renderer within content_renderer. Does not change the behavior
// of the media service.
const char kDisableMojoRenderer[] = "disable-mojo-renderer";
// Use fake device for Media Stream to replace actual camera and microphone.
const char kUseFakeDeviceForMediaStream[] = "use-fake-device-for-media-stream";
// Use an .y4m file to play as the webcam. See the comments in
// media/capture/video/file_video_capture_device.h for more details.
const char kUseFileForFakeVideoCapture[] = "use-file-for-fake-video-capture";
// Play a .wav file as the microphone. Note that for WebRTC calls we'll treat
// the bits as if they came from the microphone, which means you should disable
// audio processing (lest your audio file will play back distorted). The input
// file is converted to suit Chrome's audio buses if necessary, so most sane
// .wav files should work. You can pass either <path> to play the file looping
// or <path>%noloop to stop after playing the file to completion.
const char kUseFileForFakeAudioCapture[] = "use-file-for-fake-audio-capture";
// Use fake device for accelerated decoding of JPEG. This allows, for example,
// testing of the communication to the GPU service without requiring actual
// accelerator hardware to be present.
const char kUseFakeJpegDecodeAccelerator[] = "use-fake-jpeg-decode-accelerator";
// Enables support for inband text tracks in media content.
const char kEnableInbandTextTracks[] = "enable-inband-text-tracks";
// When running tests on a system without the required hardware or libraries,
// this flag will cause the tests to fail. Otherwise, they silently succeed.
const char kRequireAudioHardwareForTesting[] =
// Allows clients to override the threshold for when the media renderer will
// declare the underflow state for the video stream when audio is present.
// TODO(dalecurtis): Remove once experiments for finish.
const char kVideoUnderflowThresholdMs[] = "video-underflow-threshold-ms";
// Disables the new rendering algorithm for webrtc, which is designed to improve
// the rendering smoothness.
const char kDisableRTCSmoothnessAlgorithm[] =
// Force media player using SurfaceView instead of SurfaceTexture on Android.
const char kForceVideoOverlays[] = "force-video-overlays";
// Allows explicitly specifying MSE audio/video buffer sizes.
// Default values are 150M for video and 12M for audio.
const char kMSEAudioBufferSizeLimit[] = "mse-audio-buffer-size-limit";
const char kMSEVideoBufferSizeLimit[] = "mse-video-buffer-size-limit";
// Specifies the path to the Clear Key CDM for testing, which is necessary to
// support External Clear Key key system when library CDM is enabled. Note that
// External Clear Key key system support is also controlled by feature
// kExternalClearKeyForTesting.
const char kClearKeyCdmPathForTesting[] = "clear-key-cdm-path-for-testing";
#if !defined(OS_ANDROID)
// Turns on the internal media session backend. This should be used by embedders
// that want to control the media playback with the media session interfaces.
const char kEnableInternalMediaSession[] = "enable-internal-media-session";
#endif // !defined(OS_ANDROID)
namespace autoplay {
// Autoplay policy that requires a document user activation.
const char kDocumentUserActivationRequiredPolicy[] =
// Autoplay policy that does not require any user gesture.
const char kNoUserGestureRequiredPolicy[] = "no-user-gesture-required";
// Autoplay policy to require a user gesture in order to play.
const char kUserGestureRequiredPolicy[] = "user-gesture-required";
// Autoplay policy to require a user gesture in order to play for cross origin
// iframes.
const char kUserGestureRequiredForCrossOriginPolicy[] =
} // namespace autoplay
} // namespace switches
namespace media {
// Use new audio rendering mixer.
const base::Feature kNewAudioRenderingMixingStrategy{
"NewAudioRenderingMixingStrategy", base::FEATURE_DISABLED_BY_DEFAULT};
// Only used for disabling overlay fullscreen (aka SurfaceView) in Clank.
const base::Feature kOverlayFullscreenVideo{"overlay-fullscreen-video",
// Enable Picture in Picture.
const base::Feature kPictureInPicture{"PictureInPicture",
// Let videos be resumed via remote controls (for example, the notification)
// when in background.
const base::Feature kResumeBackgroundVideo {
#if defined(OS_ANDROID)
// Display the Cast overlay button on the media controls.
const base::Feature kMediaCastOverlayButton{"MediaCastOverlayButton",
// Use AndroidOverlay rather than ContentVideoView in clank?
const base::Feature kUseAndroidOverlay{"UseAndroidOverlay",
// Use AndroidOverlay for more cases than just player-element fullscreen? This
// requires that |kUseAndroidOverlay| is true, else it is ignored.
const base::Feature kUseAndroidOverlayAggressively{
"UseAndroidOverlayAggressively", base::FEATURE_ENABLED_BY_DEFAULT};
// Enables playback of AV1 video files.
const base::Feature kAv1Decoder{"Av1Decoder",
// Let video track be unselected when video is playing in the background.
const base::Feature kBackgroundVideoTrackOptimization{
"BackgroundVideoTrackOptimization", base::FEATURE_ENABLED_BY_DEFAULT};
// Let video without audio be paused when it is playing in the background.
const base::Feature kBackgroundVideoPauseOptimization{
"BackgroundVideoPauseOptimization", base::FEATURE_ENABLED_BY_DEFAULT};
const base::Feature kComplexityBasedVideoBuffering{
"ComplexityBasedVideoBuffering", base::FEATURE_DISABLED_BY_DEFAULT};
// Make MSE garbage collection algorithm more aggressive when we are under
// moderate or critical memory pressure. This will relieve memory pressure by
// releasing stale data from MSE buffers.
const base::Feature kMemoryPressureBasedSourceBufferGC{
"MemoryPressureBasedSourceBufferGC", base::FEATURE_DISABLED_BY_DEFAULT};
// On systems where pepper CDMs are enabled, use mojo CDM instead of PPAPI CDM.
// Note that mojo CDM support is still under development. Some features are
// still missing and this feature should only be enabled for testing.
const base::Feature kMojoCdm{"MojoCdm", base::FEATURE_DISABLED_BY_DEFAULT};
// Enable MojoVideoDecoder. Has no effect except on Android currently.
const base::Feature kMojoVideoDecoder{"MojoVideoDecoder",
// Manage and report MSE buffered ranges by PTS intervals, not DTS intervals.
const base::Feature kMseBufferByPts{"MseBufferByPts",
// Support FLAC codec within ISOBMFF streams used with Media Source Extensions.
const base::Feature kMseFlacInIsobmff{"MseFlacInIsobmff",
// Use the new Remote Playback / media flinging pipeline.
const base::Feature kNewRemotePlaybackPipeline{
"NewRemotePlaybackPipeline", base::FEATURE_DISABLED_BY_DEFAULT};
// CanPlayThrough issued according to standard.
const base::Feature kSpecCompliantCanPlayThrough{
"SpecCompliantCanPlayThrough", base::FEATURE_ENABLED_BY_DEFAULT};
// Use shared block-based buffering for media.
const base::Feature kUseNewMediaCache{"use-new-media-cache",
// Use R16 texture for 9-16 bit channel instead of half-float conversion by CPU.
const base::Feature kUseR16Texture{"use-r16-texture",
// Enables the Unified Autoplay policy by overriding the platform's default
// autoplay policy.
const base::Feature kUnifiedAutoplay{"UnifiedAutoplay",
// Use SurfaceLayer instead of VideoLayer.
const base::Feature kUseSurfaceLayerForVideo{"UseSurfaceLayerForVideo",
// Inform video blitter of video color space.
const base::Feature kVideoBlitColorAccuracy{"video-blit-color-accuracy",
// Enables support for External Clear Key (ECK) key system for testing on
// supported platforms. On platforms that do not support ECK, this feature has
// no effect.
const base::Feature kExternalClearKeyForTesting{
"ExternalClearKeyForTesting", base::FEATURE_DISABLED_BY_DEFAULT};
// Enables support of experimental CDM interface version(s). This is usually
// used to enable new CDM interface support for testing while it's still in
// development. This switch may not be used anywhere if there's no experimental
// CDM interface being developed.
const base::Feature kSupportExperimentalCdmInterface{
"SupportExperimentalCdmInterface", base::FEATURE_DISABLED_BY_DEFAULT};
// Enables low-delay video rendering in media pipeline on "live" stream.
const base::Feature kLowDelayVideoRenderingOnLiveStream{
// Enables Media Engagement Index recording. The data from which will
// be used to bypass autoplay policies.
const base::Feature kRecordMediaEngagementScores{
"RecordMediaEngagementScores", base::FEATURE_ENABLED_BY_DEFAULT};
// Enables the Media Engagement Index to override autoplay policies if an
// origins engagement score is high enough.
const base::Feature kMediaEngagementBypassAutoplayPolicies{
"MediaEngagementBypassAutoplayPolicies", base::FEATURE_DISABLED_BY_DEFAULT};
#if defined(OS_ANDROID)
// Lock the screen orientation when a video goes fullscreen.
const base::Feature kVideoFullscreenOrientationLock{
"VideoFullscreenOrientationLock", base::FEATURE_ENABLED_BY_DEFAULT};
// Enter/exit fullscreen when device is rotated to/from the video orientation.
const base::Feature kVideoRotateToFullscreen{"VideoRotateToFullscreen",
// An experimental feature to enable persistent-license type support in MediaDrm
// when using Encrypted Media Extensions (EME) API.
// TODO(xhwang): Remove this after feature launch. See
const base::Feature kMediaDrmPersistentLicense{
"MediaDrmPersistentLicense", base::FEATURE_ENABLED_BY_DEFAULT};
#if defined(OS_WIN)
// Enables video decode acceleration using the D3D11 video decoder api.
// This is completely insecure - DO NOT USE except for testing.
const base::Feature kD3D11VideoDecoding{"D3D11VideoDecoding",
// Does NV12->NV12 video copy on the main thread right before the texture's
// used by GL.
const base::Feature kDelayCopyNV12Textures{"DelayCopyNV12Textures",
// Enables H264 HW encode acceleration using Media Foundation for Windows.
const base::Feature kMediaFoundationH264Encoding{
"MediaFoundationH264Encoding", base::FEATURE_ENABLED_BY_DEFAULT};
#endif // defined(OS_WIN)
std::string GetEffectiveAutoplayPolicy(const base::CommandLine& command_line) {
// Return the autoplay policy set in the command line, if any.
if (command_line.HasSwitch(switches::kAutoplayPolicy))
return command_line.GetSwitchValueASCII(switches::kAutoplayPolicy);
if (base::FeatureList::IsEnabled(media::kUnifiedAutoplay))
return switches::autoplay::kDocumentUserActivationRequiredPolicy;
// The default value is platform dependent.
#if defined(OS_ANDROID)
return switches::autoplay::kUserGestureRequiredPolicy;
return switches::autoplay::kNoUserGestureRequiredPolicy;
MEDIA_EXPORT bool IsAudioFocusDuckFlashEnabled() {
return base::CommandLine::ForCurrentProcess()->GetSwitchValueASCII(
switches::kEnableAudioFocus) ==
// Adds icons to the overflow menu on the native media controls.
// For experiment:
const base::Feature kOverflowIconsForMediaControls{
"OverflowIconsForMediaControls", base::FEATURE_DISABLED_BY_DEFAULT};
// Enables the new redesigned media controls.
const base::Feature kUseModernMediaControls{"UseModernMediaControls",
// Allows Media Engagement to use preloaded data to decide whether an origin has
// a high media engagement.
const base::Feature kPreloadMediaEngagementData{
"PreloadMediaEngagementData", base::FEATURE_DISABLED_BY_DEFAULT};
} // namespace media