iamf-tools

What is IAMF?

The Immersive Audio Model and Formats (IAMF) standard is defined by the Alliance for Open Media (AOM).

What is iamf-tools?

iamf-tools implements tools to help users process and work with the IAMF format. These tools can be used as a complement to the libiamf reference decoder and other tools such as ffmpeg and MP4Box.

Encoding IAMF files

There are multiple workflows for creating IAMF files, supporting different types of inputs.

• Encode an ADM-BWF file to IAMF
• Encode wav files to IAMF using the iamf-tools encoder
• Merge IAMF files and video into an mp4 file
• Encode wav files to IAMF using ffmpeg

Decoding IAMF files

The libiamf reference decoder is available at https://github.com/AOMediaCodec/libiamf/.

Web Demo

The web demo hosted in the GitHub Pages of this repo decodes and renders standalone IAMF files to stereo and binaural wav files for preview and comparison.

Encoder

The encoder can be used to encode a standalone IAMF Sequence (.iamf) file from a set of multichannel wav files or an ADM-BWF file.

Building the encoder

See Build instructions to build from source.

Using the encoder with wav files and proto input

The iamf-tools encoder can be used to encode a set of multichannel wav files into an IAMF file. An accompanying input textproto file serves as the configuration file, specifying details such as channel layout, mix gains and codec to use for the underlying audio elements.

Prepare up to two multichannel wav files and the input textproto file. See Textproto templates for some example input textprotos and details on how to customize them.

Run the encoder. Specify the input file with --user_metadata_filename.

Optional flags:

• --input_wav_directory controls the directory wav files are read from (default iamf/cli/testdata/).
• --output_iamf_directory controls the output directory of the IAMF files.

Using the encoder:

bazel-bin/iamf/cli/encoder_main --user_metadata_filename=iamf/cli/testdata/test_000002.textproto --output_iamf_directory=.

If this example is successful the encoder will produce an output test_000002.iamf file in the current directory.

Using the encoder with ADM-BWF input

Run the encoder. Specify the input file with --adm_filename. See the adm_to_user_metadata README.md for details on the conversion.

[!WARNING]

Some ADM conversions are a work in progress and are experimental (b/392958726).

Optional flags:

• --output_iamf_directory controls the output directory of the IAMF files.
• --adm_importance_threshold controls the threshold below which ADM audioObjects are omitted (default 0).
• --adm_frame_duration_ms controls the frame size of the output IAMF in ms (default 10).

bazel-bin/iamf/cli/encoder_main --adm_filename=path/to/adm.wav --output_iamf_directory=.

The encoder will produce an output .iamf file in the output directory, where the underlying audio streams are encoded with PCM.

License

Released under the BSD 3-Clause Clear License. See LICENSE for details.