diff options
Diffstat (limited to 'src/output/plugins')
| -rw-r--r-- | src/output/plugins/AlsaOutputPlugin.cxx | 41 |
1 files changed, 21 insertions, 20 deletions
diff --git a/src/output/plugins/AlsaOutputPlugin.cxx b/src/output/plugins/AlsaOutputPlugin.cxx index 0ebf3ddbe..33a090274 100644 --- a/src/output/plugins/AlsaOutputPlugin.cxx +++ b/src/output/plugins/AlsaOutputPlugin.cxx @@ -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 ¶m, 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; } |