/* * Copyright (c) 2023, Alliance for Open Media. All rights reserved * * This source code is subject to the terms of the BSD 3-Clause Clear License * and the Alliance for Open Media Patent License 1.0. If the BSD 3-Clause Clear * License was not distributed with this source code in the LICENSE file, you * can obtain it at www.aomedia.org/license/software-license/bsd-3-c-c. If the * Alliance for Open Media Patent License 1.0 was not distributed with this * source code in the PATENTS file, you can obtain it at * www.aomedia.org/license/patent. */ #ifndef OBU_CODEC_CONFIG_H_ #define OBU_CODEC_CONFIG_H_ #include #include #include #include "absl/status/status.h" #include "absl/status/statusor.h" #include "absl/strings/str_cat.h" #include "iamf/common/read_bit_buffer.h" #include "iamf/common/write_bit_buffer.h" #include "iamf/obu/decoder_config/aac_decoder_config.h" #include "iamf/obu/decoder_config/flac_decoder_config.h" #include "iamf/obu/decoder_config/lpcm_decoder_config.h" #include "iamf/obu/decoder_config/opus_decoder_config.h" #include "iamf/obu/obu_base.h" #include "iamf/obu/obu_header.h" #include "iamf/obu/types.h" namespace iamf_tools { // TODO(b/305752871): Port this `std::variant` to a virtual class. typedef std::variant DecoderConfig; struct CodecConfig { enum CodecId : uint32_t { kCodecIdOpus = 0x4f707573, // "Opus" kCodecIdFlac = 0x664c6143, // "fLaC" kCodecIdLpcm = 0x6970636d, // "ipcm" kCodecIdAacLc = 0x6d703461, // "mp4a" }; template friend void AbslStringify(Sink& sink, const CodecId& codec_id) { std::string human_readable_codec_id; switch (codec_id) { case kCodecIdOpus: human_readable_codec_id = "Opus"; break; case kCodecIdFlac: human_readable_codec_id = "FLAC"; break; case kCodecIdLpcm: human_readable_codec_id = "LPCM"; break; case kCodecIdAacLc: human_readable_codec_id = "AAC LC"; break; default: human_readable_codec_id = "Unknown"; break; } sink.Append(absl::StrCat("0x", absl::Hex(codec_id, absl::kZeroPad8), " ( ", human_readable_codec_id, " )")); } friend bool operator==(const CodecConfig& lhs, const CodecConfig& rhs) = default; CodecId codec_id; DecodedUleb128 num_samples_per_frame; int16_t audio_roll_distance; // Active field depends on `codec_id`. DecoderConfig decoder_config; }; class CodecConfigObu : public ObuBase { public: /*!\brief Constructor. * * \param header `ObuHeader` of the OBU. * \param input_codec_config `codec_config_id` in the OBU. * \param codec_config `codec_config` in the OBU. * \return `CodecConfigObu` on success. A specific status on failure. */ static absl::StatusOr Create( const ObuHeader& header, DecodedUleb128 codec_config_id, const CodecConfig& input_codec_config, bool automatically_override_roll_distance = true); /*!\brief Creates a `CodecConfigObu` from a `ReadBitBuffer`. * * This function is designed to be used from the perspective of the decoder. * It will call `ReadAndValidatePayload` in order to read from the buffer; * therefore it can fail. * * \param header `ObuHeader` of the OBU. * \param payload_size Size of the obu payload in bytes. * \param rb `ReadBitBuffer` where the `CodecConfigObu` data is stored. Data * read from the buffer is consumed. * \return a `CodecConfigObu` on success. A specific status on failure. */ static absl::StatusOr CreateFromBuffer( const ObuHeader& header, int64_t payload_size, ReadBitBuffer& rb); /*!\brief Destructor. */ ~CodecConfigObu() override = default; friend bool operator==(const CodecConfigObu& lhs, const CodecConfigObu& rhs) = default; /*!\brief Prints logging information about the OBU.*/ void PrintObu() const override; /*!\brief Sets the codec delay in the underlying `decoder_config`. * * In some codecs, like Opus, the codec delay is called "pre-skip". * * \param codec_delay Codec delay to set in the underlying `decoder_config`. * \return `absl::OkStatus()` on success. Succeed may be a no-op when the * underlying `decoder_config` does not have a field for codec delay. * A specific status on failure. */ absl::Status SetCodecDelay(uint16_t codec_delay); /*!\brief Gets the output sample rate associated with the OBU. * * This sample rate is used for timing and offset calculations as per * section 3.11 of the IAMF spec. * * - AAC, FLAC, LPCM: Based on the sample rate of the input stream. * - Opus: Always 48kHz ("The sample rate used for computing offsets SHALL * be 48 kHz."). * * \return Output sample rate in Hz. */ uint32_t GetOutputSampleRate() const { return output_sample_rate_; } /*!\brief Gets the input sample rate associated with the OBU. * * The sample rate of the data before being passed to the underlying codec * libraries. * * \return Input sample rate in Hz. */ uint32_t GetInputSampleRate() const { return input_sample_rate_; } /*!\brief Gets the bit-depth of the PCM to be used to measure loudness. * * This typically is the highest bit-depth associated substreams should be * decoded to. * * \return Bit-depth of the PCM which will be used to measure loudness. */ uint32_t GetBitDepthToMeasureLoudness() const { return bit_depth_to_measure_loudness_; } /*!\brief Gets the number of samples per frame of the OBU. * * \return Num samples per frame of the OBU. */ uint32_t GetNumSamplesPerFrame() const { return codec_config_.num_samples_per_frame; } /*!\brief Gets the codec config id of the OBU. * * \return codec config id of the OBU. */ DecodedUleb128 GetCodecConfigId() const { return codec_config_id_; } /*!\brief Gets the codec config of the OBU. * * \return codec config of the OBU. */ const CodecConfig& GetCodecConfig() const { return codec_config_; } bool IsLossless() const; private: /*!\brief Used only by the factory `Create()` function. * * \param header `ObuHeader` of the OBU. * \param codec_config_id `codec_config_id` in the OBU. * \param codec_config `codec_config` in the OBU. * \param output_sample_rate Output sample rate in Hz. * \param input_sample_rate Input sample rate in Hz. * \param bit_depth_to_measure_loudness Bit-depth of the PCM which will be * used to measure loudness. */ CodecConfigObu(const ObuHeader& header, DecodedUleb128 codec_config_id, const CodecConfig& codec_config, uint32_t output_sample_rate, uint32_t input_sample_rate, uint8_t bit_depth_to_measure_loudness); // Used only by the factory `CreateFromBuffer` function. explicit CodecConfigObu(const ObuHeader& header) : CodecConfigObu(header, DecodedUleb128(), CodecConfig(), 0, 0, 0) {} // Fields in the OBU as per the IAMF specification. DecodedUleb128 codec_config_id_; CodecConfig codec_config_; // Metadata fields. uint32_t input_sample_rate_ = 0; uint32_t output_sample_rate_ = 0; uint8_t bit_depth_to_measure_loudness_ = 0; /*!\brief Writes the OBU payload to the buffer. * * \param wb Buffer to write to. * \return `absl::OkStatus()` if the OBU is valid. A specific status on * failure. */ absl::Status ValidateAndWritePayload(WriteBitBuffer& wb) const override; /*!\brief Reads the OBU payload from the buffer. * * \param payload_size Size of the obu payload in bytes. * \param rb Buffer to read from. * \return `absl::OkStatus()` if the payload is valid. A specific status on * failure. */ absl::Status ReadAndValidatePayloadDerived(int64_t payload_size, ReadBitBuffer& rb) override; }; } // namespace iamf_tools #endif // OBU_CODEC_CONFIG_H_