• Daniel Mack's avatar
    ALSA: add DSD formats · ef7a4f97
    Daniel Mack authored
    This patch adds two formats for Direct Stream Digital (DSD), a
    pulse-density encoding format which is described here:
    https://en.wikipedia.org/wiki/Direct_Stream_Digital
    
    DSD operates on 2.8, 5.6 or 11.2MHz sample rates and as a 1-bit
    stream.
    
    The two new types added by this patch describe streams that are capable
    of handling DSD samples in DOP format as 8-bit or in 16-bit (or at a x8
    or x16 data rate, respectively).
    
    DSD itself specifies samples in *bit*, while DOP and ALSA handle them
    as *bytes*. Hence, a factor of 8 or 16 has to be applied for the sample
    rare configuration, according to the following table:
    
                                                      configured hardware
            176.4KHz   352.8kHz   705.6KHz     <----       sample rate
    
    8-bit                2.8MHz     5.6MHz
    16-bit    2.8Mhz     5.6MHz    11.2MHz
    
             `-----------------------------'
                 actual DSD sample rates
    Signed-off-by: default avatarDaniel Mack <zonque@gmail.com>
    Signed-off-by: default avatarTakashi Iwai <tiwai@suse.de>
    ef7a4f97
pcm_misc.c 13.2 KB