Re: [Alsa-user] 'Supported bit depths' according to alsa-lib seem to differ from real values
Hello Clemens,Thank you so much! This is valuable information.I was working with the API reference. I guess I should start reading a book or tutorial. :)Kind regards,Feli___ Alsa-user mailing list Alsa-user@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/alsa-user
Re: [Alsa-user] 'Supported bit depths' according to alsa-lib seem to differ from real values
f...@interkatz.de wrote: > according to hda-verb, the supported capturing parameters are 16/20/24 > bits per sample These are the sample formats that are transmitted on the HDA bus. > Alsa-lib, on the other hand, claims that the supported formats (for > `hw:0,0` in this case) are S16LE and S32LE These are the sample formats that the HDA controller writes into memory, and that your application sees in the buffer. > I expected that ALSA returns something like: S16LE, S20LE, S24LE. S20 and S24 are smaller samples that are aligned at the least significant bit in the 32-bit memory word. This would make them harder to handle, and almost no DMA controller is stupid enough to use them. The 20- or 24-bit samples you get from HDA are aligned at the most significant bit, i.e., you can handle them like 32-bit values. If you really want to know how many bits are actually significant, call snd_pcm_hw_params_get_sbits() after you've set the hw params. Regards, Clemens ___ Alsa-user mailing list Alsa-user@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/alsa-user
[Alsa-user] 'Supported bit depths' according to alsa-lib seem to differ from real values
Hello, I have tried using alsa-lib to query hardware capabilities in order to capture sound at natively supported settings using the built-in sound card (ALC269VC). However, I have found that `snd_pcm_hw_params_get_format_mask()` returns different results from what is shown in the /proc/asound/card[...]/codec#[...] file or what is returned by calling `hda-verb /dev/snd/hw[...] 0x[...] 0xF00 0x0A`. Namely, according to hda-verb, the supported capturing parameters are 16/20/24 bits per sample, as well as sampling rates of 44.1/48/96/192 kHz. Alsa-lib, on the other hand, claims that the supported formats (for `hw:0,0` in this case) are S16LE and S32LE, while the sampling rates are the same. Is this normal ALSA behavior, or is that a bug in ALSA? I expected that ALSA returns something like: S16LE, S20LE, S24LE. Kind regards, Feli Kramer ___ Alsa-user mailing list Alsa-user@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/alsa-user
