System and method for optimizing loudness and dynamic range across different playback devices
Embodiments are directed to a method and system for receiving, in a bitstream, metadata associated with the audio data, and analyzing the metadata to determine whether a loudness parameter for a first group of audio playback devices are available in the bitstream. Responsive to determining that the parameters are present for the first group, the system uses the parameters and audio data to render audio. Responsive to determining that the loudness parameters are not present for the first group, the system analyzes one or more characteristics of the first group, and determines the parameter based on the one or more characteristics.
1. An audio processing unit for decoding one or more frames of an encoded audio bitstream, the encoded audio bitstream including audio data and a metadata container, and the metadata container including one or more metadata payloads, the audio processing unit comprising:
an input buffer for storing the one or more frames of the encoded audio bitstream;
a parser coupled to the input buffer and configured for extracting the audio data from the encoded bitstream; and
an audio decoder coupled to, or integrated with, the parser, and configured for decoding the audio data and applying dynamic range compression (DRC) to the decoded audio data,
wherein the metadata container begins with a syncword identifying the start of the metadata container, the one or more metadata payloads include a parameter specifying a DRC profile selected from a plurality of DRC profiles, wherein each of the plurality of DRC profiles corresponds to a unique compression curve with associated time constants, and the one or more metadata payloads are followed by protection data useful for decryption, authentication, or validation of the one or more metadata payloads,
wherein the specified profile is a DRC profile for portable devices which specifies a compression curve appropriate for portable devices, and
wherein, if the audio processing unit is within a portable device, the DRC is applied according to the specified DRC profile, and, if the audio processing unit is not within a portable device, the DRC is applied according to a different DRC profile of the plurality of DRC profiles.
2. The audio processing unit of claim 1 , wherein the parameter is a DRC gain value computed according to the specified DRC profile.
3. The audio processing unit of claim 1 , wherein the one or more metadata payloads further include a DRC gain value computed according to the specified DRC profile.
4. A method, performed by an audio processing unit, for decoding one or more frames of an encoded audio bitstream, the encoded audio bitstream including audio data and a metadata container, and the metadata container including one or more metadata payloads, comprising:
storing the one or more frames of the encoded audio bitstream;
extracting the audio data from the encoded audio bitstream; and
decoding the audio data and applying dynamic range compression (DRC) to the decoded audio data,
wherein the metadata container begins with a syncword identifying the start of the metadata container, the one or more metadata payloads include a parameter specifying a DRC profile selected from a plurality of DRC profiles, wherein each of the plurality of DRC profiles corresponds to a unique compression curve with associated time constants, and the one or more metadata payloads are followed by protection data useful for decryption, authentication, or validation of the one or more metadata payloads,
wherein the specified profile is a DRC profile for portable devices which specifies a compression curve appropriate for portable devices, and
wherein, if the audio processing unit is within a portable device, the DRC is applied according to the specified DRC profile, and, if the audio processing unit is not within a portable device, the DRC is applied according to a different DRC profile of the plurality of DRC profiles.
5. A non-transitory computer-readable medium comprising a sequence of instructions, which, when performed by an audio processing unit, cause the audio processing unit to perform the method of claim 4 .