I don’t have any idea who makes software nowadays, but how can it expected to be reliable?

Intel DG33FBC motherboard, onboard Realtek ALC888 High Definition Audio. I am tracing AUDIO_STREAM_CONFIG_CAPS capabilities reported by onboard audio capture board, one of them:


majortype {73647561-0000-0010-8000-00AA00389B71}, subtype {00000001-0000-0010-8000-00AA00389B71}, pUnk 0x00000000
bFixedSizeSamples 1, bTemporalCompression 0, lSampleSize 4
formattype {05589F81-C356-11CE-BF01-00AA0055595A}, cbFormat 18, pbFormat 0x002911a8
  wFormatTag 1
  nChannels 2
  nSamplesPerSec 8000
  nAvgBytesPerSec 32000
  nBlockAlign 4
  wBitsPerSample 16
  cbSize 0


guid {73647561-0000-0010-8000-00AA00389B71}
MinimumChannels 1, MaximumChannels 2, ChannelsGranularity 1
MinimumBitsPerSample 8, MaximumBitsPerSample 16, BitsPerSampleGranularity 8
MinimumSampleFrequency 11025, MaximumSampleFrequency 44100, SampleFrequencyGranularity 11025

Media type sampling frequency is 8 KHz (correct) but associated capabilities structure still report different sampling rates and granularity (crap), it is in fact 11025..44100 Hz for all capabilities, including those with sampling frequencies from a different row.

3 Replies to “Confusing AUDIO_STREAM_CONFIG_CAPS”

  1. I believe the bug here is actually in the Audio Capture Source, not the audio driver. AFAIK the Audio Capture Source has no viable method to directly inquire the hardware capabilities and so sets its own arbitrary caps. You should see the same results with all hardware.

  2. Hi Chris, I am glad you registered here to comment, thanks. I also noticed today that I receive the same caps when I connected USB Audio Input device. I supports 8, 11, 16… 96 KHz sampling rates and the capabilities were just the same, with rates 11025 to 44100, step 11025. It seems these figured are just stubbes there and should be ignored. Perhaps bits per sample and channel count numbers are also inaccurate.

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