Fix AAC bitrate computation and add missing parameters (b6b96789) · Commits · e / os / android_packages_modules_Bluetooth

system/stack/a2dp/a2dp_aac.cc

+43 −4

Original line number	Diff line number	Diff line
		@@ -497,6 +497,40 @@ int A2DP_GetBitRateAac(const uint8_t* p_codec_info) {
		return aac_cie.bitRate;
		}

		int A2DP_ComputeMaxBitRateAac(const uint8_t* p_codec_info, uint16_t mtu) {
		tA2DP_AAC_CIE aac_cie;

		// Check whether the codec info contains valid data
		tA2DP_STATUS a2dp_status = A2DP_ParseInfoAac(&aac_cie, p_codec_info, false);
		if (a2dp_status != A2DP_SUCCESS) {
		LOG_ERROR(LOG_TAG, "%s: cannot decode codec information: %d", __func__,
		a2dp_status);
		return -1;
		}

		int sampling_freq = A2DP_GetTrackSampleRateAac(p_codec_info);
		if (sampling_freq == -1) return -1;

		int pcm_channel_samples_per_frame = 0;
		switch (aac_cie.objectType) {
		case A2DP_AAC_OBJECT_TYPE_MPEG2_LC:
		case A2DP_AAC_OBJECT_TYPE_MPEG4_LC:
		pcm_channel_samples_per_frame = 1024;
		break;
		case A2DP_AAC_OBJECT_TYPE_MPEG4_LTP:
		case A2DP_AAC_OBJECT_TYPE_MPEG4_SCALABLE:
		// TODO: The MPEG documentation doesn't specify the value.
		break;
		default:
		break;
		}
		if (pcm_channel_samples_per_frame == 0) return -1;

		// See Section 3.2.1 Estimating Average Frame Size from
		// the aacEncoder.pdf document included with the AAC source code.
		return (8 * mtu * sampling_freq) / pcm_channel_samples_per_frame;
		}

		bool A2DP_GetPacketTimestampAac(const uint8_t* p_codec_info,
		const uint8_t* p_data, uint32_t* p_timestamp) {
		// TODO: Is this function really codec-specific?
		@@ -928,10 +962,15 @@ bool A2dpCodecConfigAac::setCodecConfig(const uint8_t* p_peer_codec_info,

		// Set the bit rate to the smaller of the local and peer bit rate
		// However, make sure the bit rate doesn't go beyond a certain threshold
		if (sink_info_cie.bitRate == 0) {
		// NOTE: Some devices report bitRate of zero - in that case use our bitRate
		result_config_cie.bitRate = a2dp_aac_caps.bitRate;
		} else {
		result_config_cie.bitRate =
		std::min(a2dp_aac_caps.bitRate, sink_info_cie.bitRate);
		result_config_cie.bitRate = std::max(
		result_config_cie.bitRate, static_cast<uint32_t>(A2DP_AAC_MIN_BITRATE));
		}

		//
		// Select the sample frequency

system/stack/a2dp/a2dp_aac_encoder.cc

+52 −26

Original line number	Diff line number	Diff line
		@@ -187,7 +187,7 @@ static void a2dp_aac_encoder_update(uint16_t peer_mtu,
		&a2dp_aac_encoder_cb.aac_encoder_params;
		uint8_t codec_info[AVDT_CODEC_SIZE];
		AACENC_ERROR aac_error;
		int aac_param_value;
		int aac_param_value, aac_sampling_freq, aac_bit_rate;

		*p_restart_input = false;
		*p_restart_output = false;
		@@ -277,20 +277,25 @@ static void a2dp_aac_encoder_update(uint16_t peer_mtu,
		return; // TODO: Return an error?
		}

		// Set the encoder's parameters: Bit Rate - MANDATORY
		aac_param_value = A2DP_GetBitRateAac(p_codec_info);
		if (aac_param_value == -1) {
		// Set the encoder's parameters: audioMuxVersion
		aac_param_value = 1; // audioMuxVersion = 1
		aac_error = aacEncoder_SetParam(a2dp_aac_encoder_cb.aac_handle,
		AACENC_AUDIOMUXVER, aac_param_value);
		if (aac_error != AACENC_OK) {
		LOG_ERROR(LOG_TAG,
		"%s: Cannot set AAC parameter AACENC_BITRATE: "
		"invalid codec bit rate",
		__func__);
		"%s: Cannot set AAC parameter AACENC_AUDIOMUXVER to %d: "
		"AAC error 0x%x",
		__func__, aac_param_value, aac_error);
		return; // TODO: Return an error?
		}

		// Set the encoder's parameters: Signaling mode of the extension AOT
		aac_param_value = 1; // Signaling mode of the extension AOT = 1
		aac_error = aacEncoder_SetParam(a2dp_aac_encoder_cb.aac_handle,
		AACENC_BITRATE, aac_param_value);
		AACENC_SIGNALING_MODE, aac_param_value);
		if (aac_error != AACENC_OK) {
		LOG_ERROR(LOG_TAG,
		"%s: Cannot set AAC parameter AACENC_BITRATE to %d: "
		"%s: Cannot set AAC parameter AACENC_SIGNALING_MODE to %d: "
		"AAC error 0x%x",
		__func__, aac_param_value, aac_error);
		return; // TODO: Return an error?
		@@ -307,6 +312,44 @@ static void a2dp_aac_encoder_update(uint16_t peer_mtu,
		__func__, aac_param_value, aac_error);
		return; // TODO: Return an error?
		}
		aac_sampling_freq = aac_param_value; // Save for extra usage below

		// Set the encoder's parameters: Bit Rate - MANDATORY
		aac_param_value = A2DP_GetBitRateAac(p_codec_info);
		// Calculate the bit rate from MTU and sampling frequency
		aac_bit_rate =
		A2DP_ComputeMaxBitRateAac(p_codec_info, a2dp_aac_encoder_cb.TxAaMtuSize);
		aac_bit_rate = std::min(aac_param_value, aac_bit_rate);
		LOG_DEBUG(LOG_TAG, "%s: MTU = %d Sampling Frequency = %d Bit Rate = %d",
		__func__, a2dp_aac_encoder_cb.TxAaMtuSize, aac_sampling_freq,
		aac_bit_rate);
		if (aac_bit_rate == -1) {
		LOG_ERROR(LOG_TAG,
		"%s: Cannot set AAC parameter AACENC_BITRATE: "
		"invalid codec bit rate",
		__func__);
		return; // TODO: Return an error?
		}
		aac_error = aacEncoder_SetParam(a2dp_aac_encoder_cb.aac_handle,
		AACENC_BITRATE, aac_bit_rate);
		if (aac_error != AACENC_OK) {
		LOG_ERROR(LOG_TAG,
		"%s: Cannot set AAC parameter AACENC_BITRATE to %d: "
		"AAC error 0x%x",
		__func__, aac_bit_rate, aac_error);
		return; // TODO: Return an error?
		}

		// Set the encoder's parameters: PEAK Bit Rate
		aac_error = aacEncoder_SetParam(a2dp_aac_encoder_cb.aac_handle,
		AACENC_PEAK_BITRATE, aac_bit_rate);
		if (aac_error != AACENC_OK) {
		LOG_ERROR(LOG_TAG,
		"%s: Cannot set AAC parameter AACENC_PEAK_BITRATE to %d: "
		"AAC error 0x%x",
		__func__, aac_bit_rate, aac_error);
		return; // TODO: Return an error?
		}

		// Set the encoder's parameters: Channel Mode - MANDATORY
		if (A2DP_GetTrackChannelCountAac(p_codec_info) == 1) {
		@@ -470,7 +513,6 @@ static void a2dp_aac_get_num_frame_iteration(uint8_t* num_of_iterations,
		a2dp_aac_encoder_cb.aac_feeding_state.bytes_per_tick * us_this_tick /
		(A2DP_AAC_ENCODER_INTERVAL_MS * 1000);

		#if 1
		result = a2dp_aac_encoder_cb.aac_feeding_state.counter / pcm_bytes_per_frame;
		a2dp_aac_encoder_cb.aac_feeding_state.counter -= result * pcm_bytes_per_frame;
		nof = result;
		@@ -480,22 +522,6 @@ static void a2dp_aac_get_num_frame_iteration(uint8_t* num_of_iterations,

		*num_of_frames = nof;
		*num_of_iterations = noi;

		#else
		pcm_bytes_per_frame = 800;
		result = a2dp_aac_encoder_cb.aac_feeding_state.counter / pcm_bytes_per_frame;
		nof = result;
		noi = 1;

		a2dp_aac_encoder_cb.aac_feeding_state.counter -= result * pcm_bytes_per_frame;

		LOG_VERBOSE(LOG_TAG, "%s: effective num of frames %u, iterations %u",
		__func__, nof, noi);

		*num_of_frames = nof;
		*num_of_iterations = noi;

		#endif
		}

		static void a2dp_aac_encode_frames(uint8_t nb_frame) {

system/stack/include/a2dp_aac.h

+8 −0

Original line number	Diff line number	Diff line
		@@ -174,6 +174,14 @@ int A2DP_GetVariableBitRateSupportAac(const uint8_t* p_codec_info);
		// contains invalid codec information.
		int A2DP_GetBitRateAac(const uint8_t* p_codec_info);

		// Computes the maximum bit rate for the A2DP AAC codec based on the MTU.
		// The actual value is codec-specific - for AAC it is in bits per second.
		// \|p_codec_info\| is a pointer to the AAC codec_info to decode.
		// \|mtu\| is the MTU to use for the computation.
		// Returns the maximum bit rate on success, or -1 if \|p_codec_info\|
		// contains invalid codec information.
		int A2DP_ComputeMaxBitRateAac(const uint8_t* p_codec_info, uint16_t mtu);

		// Gets the A2DP AAC audio data timestamp from an audio packet.
		// \|p_codec_info\| contains the codec information.
		// \|p_data\| contains the audio data.