Re: [alsa-cvslog] [ALSA GIT]ALSA utilities repository branch master updated. v1.2.4-1-g0c5948e

Re: [alsa-cvslog] [ALSA GIT]ALSA utilities repository branch master updated. v1.2.4-1-g0c5948e

[Takashi Iwai]

On Fri, 23 Oct 2020 11:41:25 +0200,
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> - Log -----------------------------------------------------------------
> commit 0c5948e98a6a8535c89b7bcab13017d7732181c6
> Author: Hui Wang <hui.wang@canonical.com>
> Date:   Fri Oct 23 16:47:10 2020 +0800
> 
>     aplay: try to use 16-bit format to increase capture quality
>     
>     Recently users reported a bug, I tested it and found it is a common
>     issue on Laptop or Desktop machines.
>     
>     The issue is users plug a headset and use "arecord test.wav" to
>     record a sound with default input volume, the recorded sound has
>     poor quality and nearly can't distinguish it is the sound we want
>     to record.
>     
>     This is because the input volume is low and the default format is U8.
>     The driver records sound with 16bit, because the input volume is low,
>     most of samples are within (-256,+256), when converting 16bit to U8,
>     those samples will be 0x7f. This is called quantization noise and we
>     could only workaround it by increase the input volume or adding -f to
>     arecord.
>     
>     But users want to record a better quality sound with default input
>     volume (after installing a new OS, the volume is the default volume),
>     and they don't want to add parameters to the arecord because most of
>     new linux users just use "arecord test.wav".
>     
>     So this patch tries to change the default format from U8 to S16_LE/BE.
>     If the machine doesn't support S16_LE/BE, it still uses U8 as default
>     format.
>     
>     Signed-off-by: Hui Wang <hui.wang@canonical.com>
>     Signed-off-by: Jaroslav Kysela <perex@perex.cz>

This brought a slight concern about the compatibility, as the tool is
very old and used in many places.  But a right usage is always with
the proper option, so maybe this won't break too many things
(hopefully).

Though, this change made me wonder why we don't have any default
configuration for aplay/arecord.  With that, you can adjust it per
user or per distro.  Would it bring more benefit?


thanks,

Takashi