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// Copyright (c) 2011 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.
// Contains limit definition constants for the media subsystem.
#ifndef MEDIA_BASE_LIMITS_H_
#define MEDIA_BASE_LIMITS_H_
#include "build/build_config.h"
namespace media {
namespace limits {
enum {
// Maximum possible dimension (width or height) for any video.
kMaxDimension = (1 << 15) - 1, // 32767
// Maximum possible canvas size (width multiplied by height) for any video.
kMaxCanvas = (1 << (14 * 2)), // 16384 x 16384
// Total number of video frames which are populating in the pipeline.
kMaxVideoFrames = 4,
// The following limits are used by AudioParameters::IsValid().
//
// A few notes on sample rates of common formats:
// - AAC files are limited to 96 kHz.
// - MP3 files are limited to 48 kHz.
// - Vorbis used to be limited to 96 kHz, but no longer has that
// restriction.
// - Most PC audio hardware is limited to 192 kHz, some specialized DAC
// devices will use 768 kHz though.
//
// kMaxSampleRate should be updated with
// blink::audio_utilities::MaxAudioBufferSampleRate()
kMaxSampleRate = 768000,
kMinSampleRate = 3000,
kMaxChannels = 32,
kMaxBytesPerSample = 4,
kMaxBitsPerSample = kMaxBytesPerSample * 8,
kMaxSamplesPerPacket = kMaxSampleRate,
kMaxPacketSizeInBytes =
kMaxBytesPerSample * kMaxChannels * kMaxSamplesPerPacket,
// This limit is used by ParamTraits<VideoCaptureParams>.
kMaxFramesPerSecond = 1000,
// The minimum elapsed amount of time (in seconds) for a playback to be
// considered as having active engagement.
kMinimumElapsedWatchTimeSecs = 7,
// Maximum lengths for various EME API parameters. These are checks to
// prevent unnecessarily large parameters from being passed around, and the
// lengths are somewhat arbitrary as the EME spec doesn't specify any limits.
kMinCertificateLength = 128,
kMaxCertificateLength = 16 * 1024,
kMaxSessionIdLength = 512,
kMinKeyIdLength = 1,
kMaxKeyIdLength = 512,
kMaxKeyIds = 128,
kMaxInitDataLength = 64 * 1024, // 64 KB
kMaxSessionResponseLength = 64 * 1024, // 64 KB
kMaxKeySystemLength = 256,
// Minimum and maximum buffer sizes for certain audio platforms.
#if BUILDFLAG(IS_MAC)
kMinAudioBufferSize = 128,
kMaxAudioBufferSize = 4096,
#elif defined(USE_CRAS)
// Though CRAS has different per-board defaults, allow explicitly requesting
// this buffer size on any board.
kMinAudioBufferSize = 256,
kMaxAudioBufferSize = 8192,
#endif
// Maximum buffer size supported by Web Audio.
kMaxWebAudioBufferSize = 8192,
// Bounds for the number of threads used for software video decoding.
kMinVideoDecodeThreads = 2,
kMaxVideoDecodeThreads =
16, // Matches ffmpeg's MAX_AUTO_THREADS. Higher values can result in
// immediate out of memory errors for high resolution content. See
// https://crbug.com/893984
};
} // namespace limits
} // namespace media
#endif // MEDIA_BASE_LIMITS_H_
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