Hello Srinivas, On 08/01/2017 02:52 PM, Srinivas Kandagatla wrote: >>>> As example, if you configure bus in Left justified format with 24 bits >>>> sample length, 32 bits application samples should be truncated to 24 >>>> bits samples at ADV7533 I2S interface level (LSB dropped). >> >>> May be we can do that to make the user happy but isn't this just truncate >>> the resolution to 24Bit then? >> >>> And it's a false indication that we are supporting 32bit samples. >>> Which am not very happy with. >> >> This is what the sample_bits field in the DAI structure is for.ya. > But still reporting that driver supports 32 bit samples when it does not > really support all 32 bits, is kinda misleading to user. > Isn't it? > > And the driver would be end up with hacked up code for each case. By experience, this is usual. As example, if you have a look to codec ad193x (i take one randomly) it support 16, 20, 24 and 32 bits frames. But if you have a look to AD1939 data-sheet it supports 24-bits conversion. Some other examples could be 13-bits DAC/ADC with 16 bits samples. In term of audio quality, truncation to a 24 bits sample should generate an negligible additional error equal to the LSB bit: -20log(2^24)= -144dB. It is just a personal opinion, but if have the choice between do truncation in software (application or alsa-lib) and in hardware, i would prefer the second one. Regards arnaud _______________________________________________ Alsa-devel mailing list Alsa-devel@xxxxxxxxxxxxxxxx http://mailman.alsa-project.org/mailman/listinfo/alsa-devel
