A device configured to decode a bitstream representative of a higher order ambisonic audio signal, the bitstream comprising a plurality of hierarchical layers including a base layer and one or more enhancement layers, the device comprising: a memory configured to store the bitstream representative of the higher order ambisonic audio signal; and one or more processors configured to: obtain, from the bitstream, an indication of a total number of channels (59A-D, 61A-B) specified in the bitstream; obtain, from the bitstream, an indication of a number of channels specified in each layer of the plurality of layers in the bitstream; obtain, from the bitstream, for each layer of the plurality of layers, an indication of the type of each channel specified in the layer, the indication of the type of the channel indicating if the channel is a foreground channel or a background channel; and obtain the channels specified in the layers in the bitstream based on the indication of the number of channels specified in each of the layers and the indication for each channel of the type of the channel and the indication of the total number of channels specified in the bitstream, wherein the layers are hierarchical such that the base layer is decodable independently of the one or more enhancement layers to provide a first representation of the higher order ambisonic audio signal and the one or more enhancement layers contain additional higher order ambisonic audio data that, when decoded in combination with the base layer, provide a higher resolution representation of the higher order ambisonic audio signal, wherein the channels are higher order ambisonics transport channels. a memory configured to store the bitstream representative of the higher order ambisonic audio signal; and one or more processors configured to: obtain, from the bitstream, an indication of a total number of channels (59A-D, 61A-B) specified in the bitstream; obtain, from the bitstream, an indication of a number of channels specified in each layer of the plurality of layers in the bitstream; obtain, from the bitstream, for each layer of the plurality of layers, an indication of the type of each channel specified in the layer, the indication of the type of the channel indicating if the channel is a foreground channel or a background channel; and obtain the channels specified in the layers in the bitstream based on the indication of the number of channels specified in each of the layers and the indication for each channel of the type of the channel and the indication of the total number of channels specified in the bitstream, obtain, from the bitstream, an indication of a total number of channels (59A-D, 61A-B) specified in the bitstream; obtain, from the bitstream, an indication of a number of channels specified in each layer of the plurality of layers in the bitstream; obtain, from the bitstream, for each layer of the plurality of layers, an indication of the type of each channel specified in the layer, the indication of the type of the channel indicating if the channel is a foreground channel or a background channel; and obtain the channels specified in the layers in the bitstream based on the indication of the number of channels specified in each of the layers and the indication for each channel of the type of the channel and the indication of the total number of channels specified in the bitstream, wherein the layers are hierarchical such that the base layer is decodable independently of the one or more enhancement layers to provide a first representation of the higher order ambisonic audio signal and the one or more enhancement layers contain additional higher order ambisonic audio data that, when decoded in combination with the base layer, provide a higher resolution representation of the higher order ambisonic audio signal, wherein the channels are higher order ambisonics transport channels.