Documentation clarification for MF_MT_AUDIO_AVG_BYTES_PER_SECOND for AAC encoder

mb 0

The documentation here:

https://learn.microsoft.com/en-us/windows/win32/medfound/aac-encoder

States that for AAC encoding the valid values for **MF_MT_AUDIO_AVG_BYTES_PER_SECOND **are 12000, 16000, 20000, 24000. It then says that * 6 those values should be used for 6 channel audio.

However, it then says the default value for 6 channels is 60000, which doesn't match any of the above statements. Trying to use 60000 also causes the encoder initialization to fail.

Can anyone shed light on what is correct here? Thanks

Jeanine Zhang-MSFT 9,431 Reputation points Microsoft Vendor

2024-06-19T05:38:00.4766667+00:00

According to the computational logic of the document, as far as I'm concerned, the default value for 6 channels is 72000. If you try to use 72000, whether it works?
mb 0 Reputation points

2024-06-19T15:44:12.92+00:00

Yes, 72000 bytes works along with other multiples of 6 of the other listed items. So the question is what is the 60000 for, and why is it in the docs.

Ideally I'd like a lower bit rate than 72000, since for 6 channel AAC the suggested bit rate is 64kb/ per channel, not 96kb/s.
Jeanine Zhang-MSFT 9,431 Reputation points Microsoft Vendor

2024-06-20T02:54:33.68+00:00

It is a document issue. I suggest you could feedback the issue base on the document link.

The default bit rate for 6 channel AAC is 96 Kbps/ per channel.

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Documentation clarification for MF_MT_AUDIO_AVG_BYTES_PER_SECOND for AAC encoder