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How to programmatically get info about e.g. the streams in a file before decoding it. #131
Description
Hello,
Thanks for the tremendous effort on IAMF.
I am integrating support into my project @SpatialAudioKit . I would like to be able to probe an iamf or mp4 file with iamf stream before decoding it, in order to set up audio routings. It's not immediately obvious how i can do this. Can you provide any pointers?
thanks
oli
Activity
yilun-zhangs commentedon Feb 5, 2025
Hi @olilarkin
Unfortunately, even there is one interface IAMF_decoder_get_stream_info() already, but it could not provide more detail information.
We will consider to expand IAMF_StreamInfo{} to include elements numbers, element type, channels, layout, ambisonics orders, etc..
yilun-zhangs commentedon Feb 5, 2025
Hi @olilarkin
I have checked that ffmpeg supports to probe basic information
I am not sure if ffmpeg could satisfy your requirement before libiamf support it.
Thanks.
olilarkin commentedon Feb 5, 2025
Thanks, i am aware of ffprobe/libavformat, unfortunately the license is probably too prohibitive. It would be great to get that functionality in libaimf!
Whilst i have your attention i wondered if AOMediaCodec/iamf-tools@c6521c7 indicates that another IAMF decoder will be open sourced?
yilun-zhangs commentedon Feb 6, 2025
Hi @jwcullen
The decoder mentioned in that commit will be open sourced? I think the decoder is used to generated rendered reference file for each TC in
testsdirectory, right?Hi @olilarkin
Regarding the probe function, we will continue to consider it.
Thanks.
jwcullen commentedon Feb 26, 2025
So the encoder in
iamf-toolsneeded a lot of decoder components in order to measure loudness and produce the test rendered wav files. Some things were closed source, but it made sense to open-source it and provide an API around it (currently WIP). It should be treated as an alternative implementation, not the reference decoder.@olilarkin What type of stuff would you specifically want to probe?
olilarkin commentedon Feb 26, 2025
I want to be able to visualize the spatial signal in an iamf file, using my engine @SpatialAudioKit, so i need to know how to configure the routing and hook e.g. the ambisonic stream if it exists.
trsonic commentedon Jul 31, 2026
Hi @olilarkin! A while ago we added a probe function in iamf-tools. See https://github.com/AOMediaCodec/iamf-tools/blob/main/docs/iamf_probe_main.md .
yilun-zhangs commentedon Aug 3, 2026
Hi @olilarkin
I also made a PR: #172 to output detail iamf stream info at decoder side.
olilarkin commentedon Aug 3, 2026
thanks, i will check them out!