Open-AVB AVTP Pipeline SDK  1.4
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AAF audio Mapping


Implements AAF (or "AVTP Audio Format") as described in IEEE-1722a.

Works with the ALSA interface and the WAV file interface.

Mapping module configuration parameters

Name Description
map_nv_item_count The number of Media Queue items to hold.
map_nv_tx_rate or map_nv_tx_interval Transmit interval in frames per second. 0 = default for talker class.
The transmit rate for the mapping module should be set according to the sample rate, so that the transmit interval meets the suggested values in 1722a
  • sample rate which are multiple of 8000Hz
    • 8000 for class A
    • 4000 for class B
  • sample rate which are multiple of 44100Hz
    • 7350 for class A
    • 3675 for class B
map_nv_packing_factorHow many AVTP packets worth of audio data to accept in one Media Queue item


There are additional parameters that have to be set by the interface module during the configuration process to ensure all sizes and rates calculate properly inside the mapping module. Those variables have to be set before map_gen_init_cb is being called. Commonly these additional values are set during the interface module configuration which does occur before the gen_init_cb.

These are the fields of the media_q_pub_map_uncmp_audio_info_t structure that have to be set during the interface module configuration:

Name Description
audioRate Rate of the audio avb_audio_rate_t
audioType How the data is organized - what is the data type of samples avb_audio_type_t
audioBitDepth What is the bit depth of audio avb_audio_bit_depth_t
audioChannels How many channels there are avb_audio_channels_t
sparseMode Timestamping mode avb_audio_sparse_mode_t

Below you can find description of how to set up those variables in interfaces

Note: If any of these fields are not set correct the mapping module will not configure the Media Queue correctly.

Note: Both the talker and listener must be configured with matching audio parameters. If the received data on the listener does not match the configured parameters the stream will still be started and data will still flow but no audio will be played.