path: root/media/base/mime_util.cc

// Copyright 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 <map>

#include "base/containers/hash_tables.h"
#include "base/lazy_instance.h"
#include "base/strings/string_number_conversions.h"
#include "base/strings/string_split.h"
#include "base/strings/string_util.h"
#include "build/build_config.h"
#include "media/base/mime_util.h"

#if defined(OS_ANDROID)
#include "base/android/build_info.h"
#endif

namespace media {

// Singleton utility class for mime types.
class MimeUtil {
 public:
  enum Codec {
    INVALID_CODEC,
    PCM,
    MP3,
    MPEG2_AAC_LC,
    MPEG2_AAC_MAIN,
    MPEG2_AAC_SSR,
    MPEG4_AAC_LC,
    MPEG4_AAC_SBR_v1,
    MPEG4_AAC_SBR_PS_v2,
    VORBIS,
    OPUS,
    H264_BASELINE,
    H264_MAIN,
    H264_HIGH,
    VP8,
    VP9,
    THEORA
  };

  bool IsSupportedMediaMimeType(const std::string& mime_type) const;

  bool AreSupportedMediaCodecs(const std::vector<std::string>& codecs) const;

  void ParseCodecString(const std::string& codecs,
                        std::vector<std::string>* codecs_out,
                        bool strip);

  bool IsStrictMediaMimeType(const std::string& mime_type) const;
  SupportsType IsSupportedStrictMediaMimeType(
      const std::string& mime_type,
      const std::vector<std::string>& codecs) const;

  void RemoveProprietaryMediaTypesAndCodecsForTests();

 private:
  friend struct base::DefaultLazyInstanceTraits<MimeUtil>;

  typedef base::hash_set<int> CodecSet;
  typedef std::map<std::string, CodecSet> StrictMappings;
  struct CodecEntry {
    CodecEntry() : codec(INVALID_CODEC), is_ambiguous(true) {}
    CodecEntry(Codec c, bool ambiguous) : codec(c), is_ambiguous(ambiguous) {}
    Codec codec;
    bool is_ambiguous;
  };
  typedef std::map<std::string, CodecEntry> StringToCodecMappings;

  MimeUtil();

  // For faster lookup, keep hash sets.
  void InitializeMimeTypeMaps();

  // Returns IsSupported if all codec IDs in |codecs| are unambiguous
  // and are supported by the platform. MayBeSupported is returned if
  // at least one codec ID in |codecs| is ambiguous but all the codecs
  // are supported by the platform. IsNotSupported is returned if at
  // least one codec ID  is not supported by the platform.
  SupportsType AreSupportedCodecs(
      const CodecSet& supported_codecs,
      const std::vector<std::string>& codecs) const;

  // Converts a codec ID into an Codec enum value and indicates
  // whether the conversion was ambiguous.
  // Returns true if this method was able to map |codec_id| to a specific
  // Codec enum value. |codec| and |is_ambiguous| are only valid if true
  // is returned. Otherwise their value is undefined after the call.
  // |is_ambiguous| is true if |codec_id| did not have enough information to
  // unambiguously determine the proper Codec enum value. If |is_ambiguous|
  // is true |codec| contains the best guess for the intended Codec enum value.
  bool StringToCodec(const std::string& codec_id,
                     Codec* codec,
                     bool* is_ambiguous) const;

  // Returns true if |codec| is supported by the platform.
  // Note: This method will return false if the platform supports proprietary
  // codecs but |allow_proprietary_codecs_| is set to false.
  bool IsCodecSupported(Codec codec) const;

  // Returns true if |codec| refers to a proprietary codec.
  bool IsCodecProprietary(Codec codec) const;

  // Returns true and sets |*default_codec| if |mime_type| has a  default codec
  // associated with it. Returns false otherwise and the value of
  // |*default_codec| is undefined.
  bool GetDefaultCodecLowerCase(const std::string& mime_type_lower_case,
                                Codec* default_codec) const;

  // Returns true if |mime_type_lower_case| has a default codec associated with
  // it and IsCodecSupported() returns true for that particular codec.
  bool IsDefaultCodecSupportedLowerCase(
      const std::string& mime_type_lower_case) const;

  using MimeTypes = base::hash_set<std::string>;
  MimeTypes media_map_;

  // A map of mime_types and hash map of the supported codecs for the mime_type.
  StrictMappings strict_format_map_;

  // Keeps track of whether proprietary codec support should be
  // advertised to callers.
  bool allow_proprietary_codecs_;

  // Lookup table for string compare based string -> Codec mappings.
  StringToCodecMappings string_to_codec_map_;

  DISALLOW_COPY_AND_ASSIGN(MimeUtil);
};  // class MimeUtil

// This variable is Leaky because it is accessed from WorkerPool threads.
static base::LazyInstance<MimeUtil>::Leaky g_media_mime_util =
    LAZY_INSTANCE_INITIALIZER;


// A list of media types: http://en.wikipedia.org/wiki/Internet_media_type
// A comprehensive mime type list: http://plugindoc.mozdev.org/winmime.php
// This set of codecs is supported by all variations of Chromium.
static const char* const common_media_types[] = {
  // Ogg.
  "audio/ogg",
  "application/ogg",
#if !defined(OS_ANDROID)  // Android doesn't support Ogg Theora.
  "video/ogg",
#endif

  // WebM.
  "video/webm",
  "audio/webm",

  // Wav.
  "audio/wav",
  "audio/x-wav",

#if defined(OS_ANDROID)
  // HLS.
  "application/vnd.apple.mpegurl",
  "application/x-mpegurl",
#endif
};

// List of proprietary types only supported by Google Chrome.
static const char* const proprietary_media_types[] = {
  // MPEG-4.
  "video/mp4",
  "video/x-m4v",
  "audio/mp4",
  "audio/x-m4a",

  // MP3.
  "audio/mp3",
  "audio/x-mp3",
  "audio/mpeg",
  "audio/aac",

#if defined(ENABLE_MPEG2TS_STREAM_PARSER)
  // MPEG-2 TS.
  "video/mp2t",
#endif
};

#if defined(OS_ANDROID)
static bool IsCodecSupportedOnAndroid(MimeUtil::Codec codec) {
  switch (codec) {
    case MimeUtil::INVALID_CODEC:
      return false;

    case MimeUtil::PCM:
    case MimeUtil::MP3:
    case MimeUtil::MPEG4_AAC_LC:
    case MimeUtil::MPEG4_AAC_SBR_v1:
    case MimeUtil::MPEG4_AAC_SBR_PS_v2:
    case MimeUtil::H264_BASELINE:
    case MimeUtil::H264_MAIN:
    case MimeUtil::H264_HIGH:
    case MimeUtil::VP8:
    case MimeUtil::VORBIS:
      return true;

    case MimeUtil::MPEG2_AAC_LC:
    case MimeUtil::MPEG2_AAC_MAIN:
    case MimeUtil::MPEG2_AAC_SSR:
      // MPEG-2 variants of AAC are not supported on Android.
      return false;

    case MimeUtil::VP9:
      // VP9 is supported only in KitKat+ (API Level 19).
      return base::android::BuildInfo::GetInstance()->sdk_int() >= 19;

    case MimeUtil::OPUS:
      // Opus is supported only in Lollipop+ (API Level 21).
      return base::android::BuildInfo::GetInstance()->sdk_int() >= 21;

    case MimeUtil::THEORA:
      return false;
  }

  return false;
}
#endif

struct MediaFormatStrict {
  const char* const mime_type;
  const char* const codecs_list;
};

// Following is the list of RFC 6381 compliant codecs:
//   mp4a.66     - MPEG-2 AAC MAIN
//   mp4a.67     - MPEG-2 AAC LC
//   mp4a.68     - MPEG-2 AAC SSR
//   mp4a.69     - MPEG-2 extension to MPEG-1
//   mp4a.6B     - MPEG-1 audio
//   mp4a.40.2   - MPEG-4 AAC LC
//   mp4a.40.02  - MPEG-4 AAC LC (leading 0 in aud-oti for compatibility)
//   mp4a.40.5   - MPEG-4 HE-AAC v1 (AAC LC + SBR)
//   mp4a.40.05  - MPEG-4 HE-AAC v1 (AAC LC + SBR) (leading 0 in aud-oti for
//                 compatibility)
//   mp4a.40.29  - MPEG-4 HE-AAC v2 (AAC LC + SBR + PS)
//
//   avc1.42E0xx - H.264 Baseline
//   avc1.4D40xx - H.264 Main
//   avc1.6400xx - H.264 High
static const char kMP4AudioCodecsExpression[] =
    "mp4a.66,mp4a.67,mp4a.68,mp4a.69,mp4a.6B,mp4a.40.2,mp4a.40.02,mp4a.40.5,"
    "mp4a.40.05,mp4a.40.29";
static const char kMP4VideoCodecsExpression[] =
    // This is not a complete list of supported avc1 codecs. It is simply used
    // to register support for the corresponding Codec enum. Instead of using
    // strings in these three arrays, we should use the Codec enum values.
    // This will avoid confusion and unnecessary parsing at runtime.
    // kUnambiguousCodecStringMap/kAmbiguousCodecStringMap should be the only
    // mapping from strings to codecs. See crbug.com/461009.
    "avc1.42E00A,avc1.4D400A,avc1.64000A,"
    "mp4a.66,mp4a.67,mp4a.68,mp4a.69,mp4a.6B,mp4a.40.2,mp4a.40.02,mp4a.40.5,"
    "mp4a.40.05,mp4a.40.29";

// These containers are also included in
// common_media_types/proprietary_media_types. See crbug.com/461012.
static const MediaFormatStrict format_codec_mappings[] = {
    {"video/webm", "opus,vorbis,vp8,vp8.0,vp9,vp9.0"},
    {"audio/webm", "opus,vorbis"},
    {"audio/wav", "1"},
    {"audio/x-wav", "1"},
// Android does not support Opus in Ogg container.
#if defined(OS_ANDROID)
    {"video/ogg", "theora,vorbis"},
    {"audio/ogg", "vorbis"},
    {"application/ogg", "theora,vorbis"},
#else
    {"video/ogg", "opus,theora,vorbis"},
    {"audio/ogg", "opus,vorbis"},
    {"application/ogg", "opus,theora,vorbis"},
#endif
    {"audio/mpeg", "mp3"},
    {"audio/mp3", ""},
    {"audio/x-mp3", ""},
    {"audio/mp4", kMP4AudioCodecsExpression},
    {"audio/x-m4a", kMP4AudioCodecsExpression},
    {"video/mp4", kMP4VideoCodecsExpression},
    {"video/x-m4v", kMP4VideoCodecsExpression},
    {"application/x-mpegurl", kMP4VideoCodecsExpression},
    {"application/vnd.apple.mpegurl", kMP4VideoCodecsExpression}};

struct CodecIDMappings {
  const char* const codec_id;
  MimeUtil::Codec codec;
};

// List of codec IDs that provide enough information to determine the
// codec and profile being requested.
//
// The "mp4a" strings come from RFC 6381.
static const CodecIDMappings kUnambiguousCodecStringMap[] = {
    {"1", MimeUtil::PCM},  // We only allow this for WAV so it isn't ambiguous.
    // avc1/avc3.XXXXXX may be unambiguous; handled by ParseH264CodecID().
    {"mp3", MimeUtil::MP3},
    {"mp4a.66", MimeUtil::MPEG2_AAC_MAIN},
    {"mp4a.67", MimeUtil::MPEG2_AAC_LC},
    {"mp4a.68", MimeUtil::MPEG2_AAC_SSR},
    {"mp4a.69", MimeUtil::MP3},
    {"mp4a.6B", MimeUtil::MP3},
    {"mp4a.40.2", MimeUtil::MPEG4_AAC_LC},
    {"mp4a.40.02", MimeUtil::MPEG4_AAC_LC},
    {"mp4a.40.5", MimeUtil::MPEG4_AAC_SBR_v1},
    {"mp4a.40.05", MimeUtil::MPEG4_AAC_SBR_v1},
    {"mp4a.40.29", MimeUtil::MPEG4_AAC_SBR_PS_v2},
    {"vorbis", MimeUtil::VORBIS},
    {"opus", MimeUtil::OPUS},
    {"vp8", MimeUtil::VP8},
    {"vp8.0", MimeUtil::VP8},
    {"vp9", MimeUtil::VP9},
    {"vp9.0", MimeUtil::VP9},
    {"theora", MimeUtil::THEORA}};

// List of codec IDs that are ambiguous and don't provide
// enough information to determine the codec and profile.
// The codec in these entries indicate the codec and profile
// we assume the user is trying to indicate.
static const CodecIDMappings kAmbiguousCodecStringMap[] = {
    {"mp4a.40", MimeUtil::MPEG4_AAC_LC},
    {"avc1", MimeUtil::H264_BASELINE},
    {"avc3", MimeUtil::H264_BASELINE},
    // avc1/avc3.XXXXXX may be ambiguous; handled by ParseH264CodecID().
};

MimeUtil::MimeUtil() : allow_proprietary_codecs_(false) {
  InitializeMimeTypeMaps();
}

SupportsType MimeUtil::AreSupportedCodecs(
    const CodecSet& supported_codecs,
    const std::vector<std::string>& codecs) const {
  DCHECK(!supported_codecs.empty());
  DCHECK(!codecs.empty());

  SupportsType result = IsSupported;
  for (size_t i = 0; i < codecs.size(); ++i) {
    bool is_ambiguous = true;
    Codec codec = INVALID_CODEC;
    if (!StringToCodec(codecs[i], &codec, &is_ambiguous))
      return IsNotSupported;

    if (!IsCodecSupported(codec) ||
        supported_codecs.find(codec) == supported_codecs.end()) {
      return IsNotSupported;
    }

    if (is_ambiguous)
      result = MayBeSupported;
  }

  return result;
}

void MimeUtil::InitializeMimeTypeMaps() {
  // Initialize the supported media types.
  for (size_t i = 0; i < arraysize(common_media_types); ++i)
    media_map_.insert(common_media_types[i]);
#if defined(USE_PROPRIETARY_CODECS)
  allow_proprietary_codecs_ = true;

  for (size_t i = 0; i < arraysize(proprietary_media_types); ++i)
    media_map_.insert(proprietary_media_types[i]);
#endif

  for (size_t i = 0; i < arraysize(kUnambiguousCodecStringMap); ++i) {
    string_to_codec_map_[kUnambiguousCodecStringMap[i].codec_id] =
        CodecEntry(kUnambiguousCodecStringMap[i].codec, false);
  }

  for (size_t i = 0; i < arraysize(kAmbiguousCodecStringMap); ++i) {
    string_to_codec_map_[kAmbiguousCodecStringMap[i].codec_id] =
        CodecEntry(kAmbiguousCodecStringMap[i].codec, true);
  }

  // Initialize the strict supported media types.
  for (size_t i = 0; i < arraysize(format_codec_mappings); ++i) {
    std::vector<std::string> mime_type_codecs;
    ParseCodecString(format_codec_mappings[i].codecs_list,
                     &mime_type_codecs,
                     false);

    CodecSet codecs;
    for (size_t j = 0; j < mime_type_codecs.size(); ++j) {
      Codec codec = INVALID_CODEC;
      bool is_ambiguous = true;
      CHECK(StringToCodec(mime_type_codecs[j], &codec, &is_ambiguous));
      DCHECK(!is_ambiguous);
      codecs.insert(codec);
    }

    strict_format_map_[format_codec_mappings[i].mime_type] = codecs;
  }
}

bool MimeUtil::IsSupportedMediaMimeType(const std::string& mime_type) const {
  return media_map_.find(base::StringToLowerASCII(mime_type)) !=
         media_map_.end();
}


bool MimeUtil::AreSupportedMediaCodecs(
    const std::vector<std::string>& codecs) const {
  for (size_t i = 0; i < codecs.size(); ++i) {
    Codec codec = INVALID_CODEC;
    bool is_ambiguous = true;
    if (!StringToCodec(codecs[i], &codec, &is_ambiguous) ||
        !IsCodecSupported(codec)) {
      return false;
    }
  }
  return true;
}

void MimeUtil::ParseCodecString(const std::string& codecs,
                                std::vector<std::string>* codecs_out,
                                bool strip) {
  std::string no_quote_codecs;
  base::TrimString(codecs, "\"", &no_quote_codecs);
  base::SplitString(no_quote_codecs, ',', codecs_out);

  if (!strip)
    return;

  // Strip everything past the first '.'
  for (std::vector<std::string>::iterator it = codecs_out->begin();
       it != codecs_out->end();
       ++it) {
    size_t found = it->find_first_of('.');
    if (found != std::string::npos)
      it->resize(found);
  }
}

bool MimeUtil::IsStrictMediaMimeType(const std::string& mime_type) const {
  return strict_format_map_.find(base::StringToLowerASCII(mime_type)) !=
         strict_format_map_.end();
}

SupportsType MimeUtil::IsSupportedStrictMediaMimeType(
    const std::string& mime_type,
    const std::vector<std::string>& codecs) const {
  const std::string mime_type_lower_case = base::StringToLowerASCII(mime_type);
  StrictMappings::const_iterator it_strict_map =
      strict_format_map_.find(mime_type_lower_case);
  if (it_strict_map == strict_format_map_.end())
    return codecs.empty() ? MayBeSupported : IsNotSupported;

  if (it_strict_map->second.empty()) {
    // We get here if the mimetype does not expect a codecs parameter.
    return (codecs.empty() &&
            IsDefaultCodecSupportedLowerCase(mime_type_lower_case))
               ? IsSupported
               : IsNotSupported;
  }

  if (codecs.empty()) {
    // We get here if the mimetype expects to get a codecs parameter,
    // but didn't get one. If |mime_type_lower_case| does not have a default
    // codec the best we can do is say "maybe" because we don't have enough
    // information.
    Codec default_codec = INVALID_CODEC;
    if (!GetDefaultCodecLowerCase(mime_type_lower_case, &default_codec))
      return MayBeSupported;

    return IsCodecSupported(default_codec) ? IsSupported : IsNotSupported;
  }

  return AreSupportedCodecs(it_strict_map->second, codecs);
}

void MimeUtil::RemoveProprietaryMediaTypesAndCodecsForTests() {
  for (size_t i = 0; i < arraysize(proprietary_media_types); ++i)
    media_map_.erase(proprietary_media_types[i]);
  allow_proprietary_codecs_ = false;
}

// Returns true iff |profile_str| conforms to hex string "42y0".
//
// |profile_str| is the first four characters of the H.264 suffix string. From
// ISO-14496-10 7.3.2.1, it consists of:
//   8 bits: profile_idc; required to be 0x42 here.
//   1 bit: constraint_set0_flag; ignored here.
//   1 bit: constraint_set1_flag; ignored here.
//   1 bit: constraint_set2_flag; ignored here.
//   1 bit: constraint_set3_flag; ignored here.
//   4 bits: reserved; required to be 0 here.
//
// The spec indicates other ways, not implemented here, that a |profile_str|
// can indicate a baseline conforming decoder is sufficient for decode in Annex
// A.2.1: "[profile_idc not necessarily 0x42] with constraint_set0_flag set and
// in which level_idc and constraint_set3_flag represent a level less than or
// equal to the specified level."
static bool IsValidH264BaselineProfile(const std::string& profile_str) {
  return (profile_str.size() == 4 && profile_str[0] == '4' &&
          profile_str[1] == '2' && base::IsHexDigit(profile_str[2]) &&
          profile_str[3] == '0');
}

static bool IsValidH264Level(const std::string& level_str) {
  uint32 level;
  if (level_str.size() != 2 || !base::HexStringToUInt(level_str, &level))
    return false;

  // Valid levels taken from Table A-1 in ISO-14496-10.
  // Essentially |level_str| is toHex(10 * level).
  return ((level >= 10 && level <= 13) ||
          (level >= 20 && level <= 22) ||
          (level >= 30 && level <= 32) ||
          (level >= 40 && level <= 42) ||
          (level >= 50 && level <= 51));
}

// Handle parsing H.264 codec IDs as outlined in RFC 6381 and ISO-14496-10.
//   avc1.42y0xx, y >= 8 - H.264 Baseline
//   avc1.4D40xx         - H.264 Main
//   avc1.6400xx         - H.264 High
//
//   avc1.xxxxxx & avc3.xxxxxx are considered ambiguous forms that are trying to
//   signal H.264 Baseline. For example, the idc_level, profile_idc and
//   constraint_set3_flag pieces may explicitly require decoder to conform to
//   baseline profile at the specified level (see Annex A and constraint_set0 in
//   ISO-14496-10).
static bool ParseH264CodecID(const std::string& codec_id,
                             MimeUtil::Codec* codec,
                             bool* is_ambiguous) {
  // Make sure we have avc1.xxxxxx or avc3.xxxxxx
  if (codec_id.size() != 11 ||
      (!base::StartsWith(codec_id, "avc1.", base::CompareCase::SENSITIVE) &&
       !base::StartsWith(codec_id, "avc3.", base::CompareCase::SENSITIVE))) {
    return false;
  }

  std::string profile = base::StringToUpperASCII(codec_id.substr(5, 4));
  if (IsValidH264BaselineProfile(profile)) {
    *codec = MimeUtil::H264_BASELINE;
  } else if (profile == "4D40") {
    *codec = MimeUtil::H264_MAIN;
  } else if (profile == "6400") {
    *codec = MimeUtil::H264_HIGH;
  } else {
    *codec = MimeUtil::H264_BASELINE;
    *is_ambiguous = true;
    return true;
  }

  *is_ambiguous =
      !IsValidH264Level(base::StringToUpperASCII(codec_id.substr(9)));
  return true;
}

bool MimeUtil::StringToCodec(const std::string& codec_id,
                             Codec* codec,
                             bool* is_ambiguous) const {
  StringToCodecMappings::const_iterator itr =
      string_to_codec_map_.find(codec_id);
  if (itr != string_to_codec_map_.end()) {
    *codec = itr->second.codec;
    *is_ambiguous = itr->second.is_ambiguous;
    return true;
  }

  // If |codec_id| is not in |string_to_codec_map_|, then we assume that it is
  // an H.264 codec ID because currently those are the only ones that can't be
  // stored in the |string_to_codec_map_| and require parsing.
  return ParseH264CodecID(codec_id, codec, is_ambiguous);
}

bool MimeUtil::IsCodecSupported(Codec codec) const {
  DCHECK_NE(codec, INVALID_CODEC);

#if defined(OS_ANDROID)
  if (!IsCodecSupportedOnAndroid(codec))
    return false;
#endif

  return allow_proprietary_codecs_ || !IsCodecProprietary(codec);
}

bool MimeUtil::IsCodecProprietary(Codec codec) const {
  switch (codec) {
    case INVALID_CODEC:
    case MP3:
    case MPEG2_AAC_LC:
    case MPEG2_AAC_MAIN:
    case MPEG2_AAC_SSR:
    case MPEG4_AAC_LC:
    case MPEG4_AAC_SBR_v1:
    case MPEG4_AAC_SBR_PS_v2:
    case H264_BASELINE:
    case H264_MAIN:
    case H264_HIGH:
      return true;

    case PCM:
    case VORBIS:
    case OPUS:
    case VP8:
    case VP9:
    case THEORA:
      return false;
  }

  return true;
}

bool MimeUtil::GetDefaultCodecLowerCase(const std::string& mime_type_lower_case,
                                        Codec* default_codec) const {
  if (mime_type_lower_case == "audio/mpeg" ||
      mime_type_lower_case == "audio/mp3" ||
      mime_type_lower_case == "audio/x-mp3") {
    *default_codec = MimeUtil::MP3;
    return true;
  }

  return false;
}

bool MimeUtil::IsDefaultCodecSupportedLowerCase(
    const std::string& mime_type_lower_case) const {
  Codec default_codec = Codec::INVALID_CODEC;
  if (!GetDefaultCodecLowerCase(mime_type_lower_case, &default_codec))
    return false;
  return IsCodecSupported(default_codec);
}

bool IsSupportedMediaMimeType(const std::string& mime_type) {
  return g_media_mime_util.Get().IsSupportedMediaMimeType(mime_type);
}

bool AreSupportedMediaCodecs(const std::vector<std::string>& codecs) {
  return g_media_mime_util.Get().AreSupportedMediaCodecs(codecs);
}

bool IsStrictMediaMimeType(const std::string& mime_type) {
  return g_media_mime_util.Get().IsStrictMediaMimeType(mime_type);
}

SupportsType IsSupportedStrictMediaMimeType(
    const std::string& mime_type,
    const std::vector<std::string>& codecs) {
  return g_media_mime_util.Get().IsSupportedStrictMediaMimeType(
      mime_type, codecs);
}

void ParseCodecString(const std::string& codecs,
                      std::vector<std::string>* codecs_out,
                      const bool strip) {
  g_media_mime_util.Get().ParseCodecString(codecs, codecs_out, strip);
}

void RemoveProprietaryMediaTypesAndCodecsForTests() {
  g_media_mime_util.Get().RemoveProprietaryMediaTypesAndCodecsForTests();
}

}  // namespace media