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output/alsa, pcm: rename "DSD over USB" to "DoP"

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The standard has been renamed since the early draft that was
implemented in MPD.
This commit is contained in:
Max Kellermann
2014-08-31 16:12:26 +02:00
parent 6e04d66a35
commit e5a28bfd8d
10 changed files with 60 additions and 59 deletions
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41
src/output/plugins/AlsaOutputPlugin.cxx
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@@ -62,12 +62,11 @@ struct AlsaOutput {
bool use_mmap;
/**
* Enable DSD over USB according to the dCS suggested
* standard?
* Enable DSD over PCM according to the DoP standard standard?
*
* @see http://www.dcsltd.co.uk/page/assets/DSDoverUSB.pdf
* @see http://dsd-guide.com/dop-open-standard
*/
bool dsd_usb;
bool dop;
/** libasound's buffer_time setting (in microseconds) */
unsigned int buffer_time;
@@ -153,7 +152,9 @@ AlsaOutput::Configure(const config_param &param, Error &error)
use_mmap = param.GetBlockValue("use_mmap", false);
dsd_usb = param.GetBlockValue("dsd_usb", false);
dop = param.GetBlockValue("dop", false) ||
/* legacy name from MPD 0.18 and older: */
param.GetBlockValue("dsd_usb", false);
buffer_time = param.GetBlockValue("buffer_time",
MPD_ALSA_BUFFER_TIME_US);
@@ -639,34 +640,34 @@ alsa_setup_dsd(AlsaOutput *ad, const AudioFormat audio_format,
bool *shift8_r, bool *packed_r, bool *reverse_endian_r,
Error &error)
{
assert(ad->dsd_usb);
assert(ad->dop);
assert(audio_format.format == SampleFormat::DSD);
/* pass 24 bit to alsa_setup() */
AudioFormat usb_format = audio_format;
usb_format.format = SampleFormat::S24_P32;
usb_format.sample_rate /= 2;
AudioFormat dop_format = audio_format;
dop_format.format = SampleFormat::S24_P32;
dop_format.sample_rate /= 2;
const AudioFormat check = usb_format;
const AudioFormat check = dop_format;
if (!alsa_setup(ad, usb_format, packed_r, reverse_endian_r, error))
if (!alsa_setup(ad, dop_format, packed_r, reverse_endian_r, error))
return false;
/* if the device allows only 32 bit, shift all DSD-over-USB
/* if the device allows only 32 bit, shift all DoP
samples left by 8 bit and leave the lower 8 bit cleared;
the DSD-over-USB documentation does not specify whether
this is legal, but there is anecdotical evidence that this
is possible (and the only option for some devices) */
*shift8_r = usb_format.format == SampleFormat::S32;
if (usb_format.format == SampleFormat::S32)
usb_format.format = SampleFormat::S24_P32;
*shift8_r = dop_format.format == SampleFormat::S32;
if (dop_format.format == SampleFormat::S32)
dop_format.format = SampleFormat::S24_P32;
if (usb_format != check) {
if (dop_format != check) {
/* no bit-perfect playback, which is required
for DSD over USB */
error.Format(alsa_output_domain,
"Failed to configure DSD-over-USB on ALSA device \"%s\"",
"Failed to configure DSD-over-PCM on ALSA device \"%s\"",
alsa_device(ad));
delete[] ad->silence;
return false;
@@ -681,9 +682,9 @@ alsa_setup_or_dsd(AlsaOutput *ad, AudioFormat &audio_format,
{
bool shift8 = false, packed, reverse_endian;
const bool dsd_usb = ad->dsd_usb &&
const bool dop = ad->dop &&
audio_format.format == SampleFormat::DSD;
const bool success = dsd_usb
const bool success = dop
? alsa_setup_dsd(ad, audio_format,
&shift8, &packed, &reverse_endian,
error)
@@ -694,7 +695,7 @@ alsa_setup_or_dsd(AlsaOutput *ad, AudioFormat &audio_format,
ad->pcm_export->Open(audio_format.format,
audio_format.channels,
dsd_usb, shift8, packed, reverse_endian);
dop, shift8, packed, reverse_endian);
return true;
}