media/base/limits.h

   1 // Copyright (c) 2011 The Chromium Authors. All rights reserved.
   2 // Use of this source code is governed by a BSD-style license that can be
   3 // found in the LICENSE file.
   4
   5 // Contains limit definition constants for the media subsystem.
   6
   7 #ifndef MEDIA_BASE_LIMITS_H_
   8 #define MEDIA_BASE_LIMITS_H_
   9
  10 #include "base/basictypes.h"
  11
  12 namespace media {
  13
  14 namespace limits {
  15
  16 enum {
  17   // Maximum possible dimension (width or height) for any video.
  18   kMaxDimension = (1 << 15) - 1,  // 32767
  19
  20   // Maximum possible canvas size (width multiplied by height) for any video.
  21   kMaxCanvas = (1 << (14 * 2)),  // 16384 x 16384
  22
  23   // Total number of video frames which are populating in the pipeline.
  24   kMaxVideoFrames = 4,
  25
  26   // The following limits are used by AudioParameters::IsValid().
  27   //
  28   // A few notes on sample rates of common formats:
  29   //   - AAC files are limited to 96 kHz.
  30   //   - MP3 files are limited to 48 kHz.
  31   //   - Vorbis used to be limited to 96 KHz, but no longer has that
  32   //     restriction.
  33   //   - Most PC audio hardware is limited to 192 KHz.
  34   kMaxSampleRate = 192000,
  35   kMinSampleRate = 3000,
  36   kMaxChannels = 32,
  37   kMaxBytesPerSample = 4,
  38   kMaxBitsPerSample = kMaxBytesPerSample * 8,
  39   kMaxSamplesPerPacket = kMaxSampleRate,
  40   kMaxPacketSizeInBytes =
  41       kMaxBytesPerSample * kMaxChannels * kMaxSamplesPerPacket,
  42
  43   // This limit is used by ParamTraits<VideoCaptureParams>.
  44   kMaxFramesPerSecond = 1000,
  45
  46   // Maximum lengths for various EME API parameters. These are checks to
  47   // prevent unnecessarily large parameters from being passed around, and the
  48   // lengths are somewhat arbitrary as the EME spec doesn't specify any limits.
  49   kMinCertificateLength = 128,
  50   kMaxCertificateLength = 16 * 1024,
  51   kMaxSessionIdLength = 512,
  52   kMinKeyIdLength = 1,
  53   kMaxKeyIdLength = 512,
  54   kMaxKeyIds = 128,
  55   kMaxInitDataLength = 64 * 1024,         // 64 KB
  56   kMaxSessionResponseLength = 64 * 1024,  // 64 KB
  57   kMaxKeySystemLength = 256,
  58 };
  59
  60 }  // namespace limits
  61
  62 }  // namespace media
  63
  64 #endif  // MEDIA_BASE_LIMITS_H_