// Copyright 2016 The Chromium Authors // Use of this source code is governed by a BSD-style license that can be // found in the LICENSE file. #include "media/base/audio_codecs.h" #include <ostream> #include "base/logging.h" #include "base/strings/string_number_conversions.h" #include "base/strings/string_split.h" #include "base/strings/string_util.h" namespace media { // These names come from src/third_party/ffmpeg/libavcodec/codec_desc.c std::string GetCodecName(AudioCodec codec) { … } std::string GetProfileName(AudioCodecProfile profile) { … } AudioCodec StringToAudioCodec(const std::string& codec_id) { … } std::ostream& operator<<(std::ostream& os, const AudioCodec& codec) { … } #if BUILDFLAG(ENABLE_PLATFORM_AC4_AUDIO) bool ParseDolbyAc4CodecId(const std::string& codec_id, uint8_t* bitstream_versionc, uint8_t* presentation_versionc, uint8_t* presentation_levelc) { // Reference: ETSI Standard: Digital Audio Compression (AC-4) Standard; // Part 2: Immersive and personalized audio // ETSI TS 103 190-2 v1.2.1 (2018-02) // E.13 The MIME codecs parameter // (https://www.etsi.org/deliver/etsi_ts/103100_103199/10319002/01.02.01_60/ts_10319002v010201p.pdf) if (!base::StartsWith(codec_id, "ac-4")) { return false; } const int kMaxAc4CodecIdLength = 4 // FOURCC string "ac-4" + 1 // delimiting period + 2 // bitstream_version version as 2 digit string + 1 // delimiting period + 2 // presentation_version as 2 digit string. + 1 // delimiting period + 2; // presentation_level as 2 digit string. if (codec_id.size() > kMaxAc4CodecIdLength) { DVLOG(4) << __func__ << ": Codec id is too long (" << codec_id << ")"; return false; } std::vector<std::string> elem = base::SplitString( codec_id, ".", base::TRIM_WHITESPACE, base::SPLIT_WANT_ALL); DCHECK(elem[0] == "ac-4"); if (elem.size() != 4) { DVLOG(4) << __func__ << ": invalid Dolby AC-4 codec id:" << codec_id; return false; } if (StringToAudioCodec(elem[0]) != AudioCodec::kAC4) { DVLOG(4) << __func__ << ": invalid Dolby AC-4 codec id:" << codec_id; return false; } // bitstream_version string should be two digits and equals "02". "00","01" // are valid according to spec, but they are not used in real case anymore. unsigned bitstream_version = 0; if (elem[1].size() != 2 || !base::HexStringToUInt(elem[1], &bitstream_version) || bitstream_version != 0x02) { DVLOG(4) << __func__ << ": invalid Dolby AC-4 bitstream version: " << elem[1]; return false; } // If bitstream_version is "02", then "01" and "02" are valid values for // presentation_version. Value "02" is special for AC-4 IMS. // Reference: ETSI Standard: Digital Audio Compression (AC-4) Standard; // Part 2: Immersive and personalized audio // ETSI TS 103 190-2 v1.2.1 (2018-02) // 4.6 Decoder compatibilities // (https://www.etsi.org/deliver/etsi_ts/103100_103199/10319002/01.02.01_60/ts_10319002v010201p.pdf) unsigned presentation_version = 0; if (elem[2].size() != 2 || !base::HexStringToUInt(elem[2], &presentation_version) || !(presentation_version == 0x01 || presentation_version == 0x02)) { DVLOG(4) << __func__ << ": invalid Dolby AC-4 presentation_version: " << elem[1]; return false; } // presentation_level(mdcompat) should be two digits and in range // [0,1,2,3,4,5,6,7]. // Reference: ETSI Standard: Digital Audio Compression (AC-4) Standard; // Part 2: Immersive and personalized audio // ETSI TS 103 190-2 v1.2.1 (2018-02) // 6.3.2.2.3 mdcompat // (https://www.etsi.org/deliver/etsi_ts/103100_103199/10319002/01.02.01_60/ts_10319002v010201p.pdf) unsigned presentation_level = 0; if (elem[3].size() != 2 || !base::HexStringToUInt(elem[3], &presentation_level) || presentation_level > 0x07) { DVLOG(4) << __func__ << ": invalid Dolby AC-4 presentation_level: " << elem[1]; return false; } if (bitstream_versionc) { *bitstream_versionc = bitstream_version; } if (presentation_versionc) { *presentation_versionc = presentation_version; } if (presentation_levelc) { *presentation_levelc = presentation_level; } return true; } #endif // BUILDFLAG(ENABLE_PLATFORM_AC4_AUDIO) #if BUILDFLAG(ENABLE_PLATFORM_IAMF_AUDIO) bool ParseIamfCodecId(std::string_view codec_id, uint8_t* primary_profilec, uint8_t* additional_profilec) { // Reference: Immersive Audio Model and Formats; // v1.0.0 // 6.3. Codecs Parameter String // (https://aomediacodec.github.io/iamf/v1.0.0.html#codecsparameter) if (!codec_id.starts_with("iamf")) { return false; } // For test purposes only, just "iamf" is acceptable. if (codec_id == "iamf") { return true; } constexpr int kMaxIamfCodecIdLength = 4 // FOURCC string "iamf". + 1 // delimiting period. + 3 // primary_profile as 3 digit string. + 1 // delimiting period. + 3 // additional_profile as 3 digit string. + 1 // delimiting period. + 9; // The remaining string is one of // "opus", "mp4a.40.2", "flac", "ipcm". if (codec_id.size() > kMaxIamfCodecIdLength) { DVLOG(4) << __func__ << ": Codec id is too long (" << codec_id << ")"; return false; } std::vector<std::string> elem = base::SplitString( codec_id, ".", base::TRIM_WHITESPACE, base::SPLIT_WANT_ALL); if (elem.size() < 4) { DVLOG(4) << __func__ << ": invalid IAMF codec id:" << codec_id; return false; } DCHECK_EQ(elem[0], "iamf"); if (StringToAudioCodec(elem[0]) != AudioCodec::kIAMF) { DVLOG(4) << __func__ << ": invalid IAMF codec id:" << codec_id; return false; } // The primary profile string should be three digits, and should be between 0 // and 255 inclusive. uint32_t primary_profile = 0; if (elem[1].size() != 3 || !base::StringToUint(elem[1], &primary_profile) || primary_profile > 0xFF) { DVLOG(4) << __func__ << ": invalid IAMF primary profile: " << elem[1]; return false; } // The additional profile string should be three digits, and should be between // 0 and 255 inclusive. uint32_t additional_profile = 0; if (elem[2].size() != 3 || !base::StringToUint(elem[2], &additional_profile) || additional_profile > 0xFF) { DVLOG(4) << __func__ << ": invalid IAMF additional profile: " << elem[2]; return false; } // The codec string should be one of "opus", "mp4a", "flac", or "ipcm". std::string codec = base::ToLowerASCII(elem[3]); if (codec.size() != 4 || ((codec != "opus") && (codec != "mp4a") && (codec != "flac") && (codec != "ipcm"))) { DVLOG(4) << __func__ << ": invalid IAMF stream codec: " << elem[3]; return false; } if (codec == "mp4a") { if (elem.size() != 6) { DVLOG(4) << __func__ << ": incorrect mp4a codec string syntax:" << codec_id; return false; } // The fields following "mp4a" should be "40" and "2" to signal AAC-LC. uint32_t object_type_indication = 0; if (elem[4].size() != 2 || !base::HexStringToUInt(elem[4], &object_type_indication) || object_type_indication != 0x40) { DVLOG(4) << __func__ << ": invalid mp4a Object Type Indication:" << codec_id; return false; } uint32_t audio_object_type = 0; if (elem[5].size() != 1 || !base::HexStringToUInt(elem[5], &audio_object_type) || audio_object_type != 0x02) { DVLOG(4) << __func__ << ": invalid mp4a Audio Object Type:" << codec_id; return false; } } if (primary_profilec) { *primary_profilec = primary_profile; } if (additional_profilec) { *additional_profilec = additional_profile; } return true; } #endif // BUILDFLAG(ENABLE_PLATFORM_IAMF_AUDIO) } // namespace media
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