PulseAudio: Difference between revisions
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{{mininav|[[Audio]]|[[Linux audio]]}} | {{mininav|[[Audio]]|[[Linux audio]]}} | ||
<section begin="intro" />This page goes into detail on using PulseAudio on Linux systems. PulseAudio is used when | <section begin="intro" />This page goes into detail on using PulseAudio on Linux systems. PulseAudio is used when {{name}} is installed in a desktop-environment rather than a dedicated/direct boot setup. PulseAudio allows normal video & audio playback in {{name}} while at the same time allowing the user to get audio in their browser or other applications. It also allows {{name}} playback of video or audio to be paused in order to run a game, Skype or similar. {{name}} is set to only use PulseAudio if you have installed it and running.<section end="intro" /> | ||
== History == | == History == | ||
In the past users have experienced problems with audio not working within XBMC, because they were running a full-blown Ubuntu desktop environment with PulseAudio installed. This happened because PulseAudio blocked the device | In the past users have experienced problems with audio not working within XBMC, because they were running a full-blown Ubuntu desktop environment with PulseAudio installed. This happened because PulseAudio blocked the device {{name}} required, and audio playback only worked reliably when using the virtual Pulse device. | ||
Our workaround for those users has been to uninstall PulseAudio which completely broke desktop audio. | Our workaround for those users has been to uninstall PulseAudio which completely broke desktop audio. | ||
For | For {{name}} 13 'Gotham' and later we wanted this situation to change, so thanks to the new '''PulseAudio Sink''' users now can run a normal Ubuntu desktop. | ||
== PulseAudio Output Configuration == | == PulseAudio Output Configuration == | ||
PulseAudio will be automatically detected and selected in | PulseAudio will be automatically detected and selected in {{name}} when it is running. | ||
PulseAudio can be run in one of two modes these are: | PulseAudio can be run in one of two modes these are: | ||
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Used if you want to passthrough (bitstream) AC3, DTS, and EAC3 to an AVR or other device. In order to allow passthrough to work with PulseAudio then it '''MUST''' be set to use a 2.0 channel configuration, despite the 2.0 setting this will still allow 5.1 audio from AC3, DTS, and EAC3. | Used if you want to passthrough (bitstream) AC3, DTS, and EAC3 to an AVR or other device. In order to allow passthrough to work with PulseAudio then it '''MUST''' be set to use a 2.0 channel configuration, despite the 2.0 setting this will still allow 5.1 audio from AC3, DTS, and EAC3. | ||
{{Note| PulseAudio does not currently allow TrueHD or DTS-MA passthrough, this is a PulseAudio limitation and not a limitation of the | {{Note| PulseAudio does not currently allow TrueHD or DTS-MA passthrough, this is a PulseAudio limitation and not a limitation of the {{name}} implementation.}} | ||
<big>'''Multichannel Mode'''</big> | <big>'''Multichannel Mode'''</big> | ||
Used if you want Multichannel PCM out, in this mode you can configure PulseAudio for up to 7.1 channels. In this mode | Used if you want Multichannel PCM out, in this mode you can configure PulseAudio for up to 7.1 channels. In this mode {{name}} must decode all audio formats to PCM for passing onto the PulseAudio, this can have the advantage of improve audio/video sync. | ||
{{Note| Audio decoded to PCM and sent through PulseAudio the audio will not likely be "bit perfect". Where a video has TrueHD 7.1 audio, this can be decoded by | {{Note| Audio decoded to PCM and sent through PulseAudio the audio will not likely be "bit perfect". Where a video has TrueHD 7.1 audio, this can be decoded by {{name}} to PCM 7.1, however DTS-HD 7.1 audio can't be decoded by XBMC, only the embedded DTS Core 5.1 can be decoded to PCM 5.1 audio.}} | ||
<br /> | <br /> | ||
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=== Setup Guide === | === Setup Guide === | ||
{{orangev|DEVICE ENUMERATION:| | {{orangev|DEVICE ENUMERATION:| {{name}} Enumerates Pulseaudio devices as SPDIF when you have '''Passthrough''' set. Otherwise its '''PCM Device'''.}} | ||
{{bluev|GOOD TO KNOW:|SPDIF has 2 pcm channels but can do virtual 5.1 formats like dts, ac3, eac3.}} | {{bluev|GOOD TO KNOW:|SPDIF has 2 pcm channels but can do virtual 5.1 formats like dts, ac3, eac3.}} | ||
{{greenv|'''NOTICE'''|The following is meant to act as a guide to get you started, thus you may want to adjust things to suit your own particular set of equipment.}} | {{greenv|'''NOTICE'''|The following is meant to act as a guide to get you started, thus you may want to adjust things to suit your own particular set of equipment.}} | ||
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You should use '''PulseAudio''' when: | You should use '''PulseAudio''' when: | ||
* You use your | * You use your {{name}} computer mainly as your Desktop when you don't run XBMC. | ||
* You want other applications audio like Skype, youtube, browser mail notification in parallel with XBMC. | * You want other applications audio like Skype, youtube, browser mail notification in parallel with XBMC. | ||
* You use xbmc in windowed mode as Desktop player | * You use xbmc in windowed mode as Desktop player | ||
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You should use '''ALSA''' when: | You should use '''ALSA''' when: | ||
* You use | * You use {{name}} as your standalone media center. | ||
* You are highly interested in bitperfect exclusive audio output. | * You are highly interested in bitperfect exclusive audio output. | ||
* DTS-HD, TrueHD is something you use daily and is of high importance. | * DTS-HD, TrueHD is something you use daily and is of high importance. |
Revision as of 01:14, 5 June 2014
Audio | Linux audio | PulseAudio |
This page goes into detail on using PulseAudio on Linux systems. PulseAudio is used when XBMC is installed in a desktop-environment rather than a dedicated/direct boot setup. PulseAudio allows normal video & audio playback in XBMC while at the same time allowing the user to get audio in their browser or other applications. It also allows XBMC playback of video or audio to be paused in order to run a game, Skype or similar. XBMC is set to only use PulseAudio if you have installed it and running.
History
In the past users have experienced problems with audio not working within XBMC, because they were running a full-blown Ubuntu desktop environment with PulseAudio installed. This happened because PulseAudio blocked the device XBMC required, and audio playback only worked reliably when using the virtual Pulse device.
Our workaround for those users has been to uninstall PulseAudio which completely broke desktop audio.
For XBMC 13 'Gotham' and later we wanted this situation to change, so thanks to the new PulseAudio Sink users now can run a normal Ubuntu desktop.
PulseAudio Output Configuration
PulseAudio will be automatically detected and selected in XBMC when it is running.
PulseAudio can be run in one of two modes these are:
Passthrough Mode Used if you want to passthrough (bitstream) AC3, DTS, and EAC3 to an AVR or other device. In order to allow passthrough to work with PulseAudio then it MUST be set to use a 2.0 channel configuration, despite the 2.0 setting this will still allow 5.1 audio from AC3, DTS, and EAC3.
Note: PulseAudio does not currently allow TrueHD or DTS-MA passthrough, this is a PulseAudio limitation and not a limitation of the XBMC implementation.
Multichannel Mode
Used if you want Multichannel PCM out, in this mode you can configure PulseAudio for up to 7.1 channels. In this mode XBMC must decode all audio formats to PCM for passing onto the PulseAudio, this can have the advantage of improve audio/video sync.
Note: Audio decoded to PCM and sent through PulseAudio the audio will not likely be "bit perfect". Where a video has TrueHD 7.1 audio, this can be decoded by XBMC to PCM 7.1, however DTS-HD 7.1 audio can't be decoded by XBMC, only the embedded DTS Core 5.1 can be decoded to PCM 5.1 audio.
Setting up pavucontrol
Passthrough Mode
In order to activate Passthrough Codecs, just setup pavucontrol, as in the following:
If you like to do this from the command line, issue:
pactl set-sink-formats 0 "pcm; ac3-iec61937; dts-iec61937; eac3-iec61937"
Where 0 is the sink you want to alter. You can print all sinks, by using:
pactl list sinks
You can leave out the codecs your AVR does not support, always keep pcm.
Multichannel Mode
To configure instead Multi channel mode, do the following settings.
Example setup in xbmc
Setup Guide
PC Speakers 2.0 |
PC Speakers 5.1 |
TV SPDIF 2.0 |
TV SPDIF AC3 (1) |
AVR SPDIF AC3/DTS (2) |
AVR HDMI PCM (3) |
AVR HDMI No HD Audio (4) |
AVR HDMI Decode HD Audio (5) | |
---|---|---|---|---|---|---|---|---|
PusleAudio Mode | ||||||||
Multichannel | Multichannel | Multichannel | Passthrough | Passthrough | Multichannel | Passthrough | Multichannel | |
Pavucontrol - Output Devices | ||||||||
Port | Speakers | Speakers | Digital Output (S/PDIF) | Digital Output (S/PDIF) | Digital Output (S/PDIF) | HDMI/Displayport | HDMI/Displayport | HDMI/Displayport |
AC3 | N/A | N/A | Disabled | Enabled | Enabled | Disabled | Enabled | Disabled |
EAC3 | N/A | N/A | Disabled | Disabled | Disabled | Disabled | Enabled | Disabled |
DTS | N/A | N/A | Disabled | Disabled | Enabled | Disabled | Enabled | Disabled |
Pavucontrol - Configuration | ||||||||
Profile | Analog Stereo Output | Analog Surround 5.1 Output | Digital Stereo (IEC958) Output |
Digital Stereo (IEC958) Output |
Digital Stereo (IEC958) Output |
Digital Surround 5.1 (HDMI) Output |
Digital Stereo (HDMI) Output |
Digital Surround 7.1 (HDMI) Output |
XBMC Settings | ||||||||
Audio Output Device | Speakers | Speakers | SPDIF | SPDIF | SPDIF | HDMI | HDMI | HDMI |
Number of channels | 2.0 | 5.1 | N/A | N/A | N/A | 5.1 | 2.0 | 7.1 |
Enabled passthrough | Disabled | Disabled | Disabled | Enabled | Enabled | Disabled | Enabled | Disabled |
Passthrough output device | N/A | N/A | N/A | SPDIF | SPDIF | N/A | HDMI | N/A |
Dolby Digital (AC3) capable receiver | N/A | N/A | N/A | Enabled | Enabled | Disabled | Enabled | Disabled |
Enabled Dolby Digital transcoding | N/A | N/A | N/A | Enabled | Enabled | Disabled | Enabled | Disabled |
DTS capable receiver | N/A | N/A | N/A | Disabled | Enabled | Disabled | Enabled | Disabled |
TrueHD capable receiver | N/A | N/A | N/A | Disabled | Disabled | Disabled | Disabled | Disabled |
DTS-HD capable receiver | N/A | N/A | N/A | Disabled | Disabled | Disabled | Disabled | Dsiabled |
(1) Where TV can decode 5.1 AC3.
(2) Where AVR only has SPDIF which will support 5.1 AC3 & DTS.
(3) Where AVR can do 5.1 PCM.
(4) Where AVR has HDMI inputs but can't decode TrueHD or DTS-HD but does support 5.1 Ac3 or DTS.
(5) Where AVR has full decode capabilities including 7.1 PCM.
Combined Output aka dual audio
If you want to output to all your attached devices in parallel, e.g. HDMI out, analog out and USB sound card, it is enough to do as below:
Step 1: Edit /etc/pulse/default.pa
load-module module-combine-sink sink_name=combined
Step 2: Restart pulseaudio.
killall pulseaudio
xbmc will then pickup the device, it is named combined.
Audiophile Pulse User
Pulseaudio resamples everything that does not match the underlaying sink, so if you are an audiophile user, you perhaps want to hear your 96 / 192 khz and 24 bit recordings as exact as possible. Therefore you need to tell pulseaudio to use a better resampler in general and second change the default sample rate to 96 or 192 khz. Pulseaudio does not resample audio, that is already in the correct samplerate. Furthermore you need to take care, that your sink has a wide enough output format.
To do this configuration systemwide (96 khz in that example), change /etc/pulse/daemon.conf to include (please replace already existing lines and also remove the commenting):
default-sample-format = s32le default-sample-rate = 96000 resample-method = speex-float-5
Some remark: This will actively make passthrough non working, as we need s16le format for adding ac3 / dts / etc. float to the sink.
The last setting will increase the resample quality from pulse and therefore the CPU load quite a lot. Again: Resampling is only done, when the sink output does not match the data you throw onto it. But as most normal mp3s are in 44.1 khz, you need to take great care when upsampling them. The overwriting of the resample-method is for this use case.
FAQ
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Known issues
When your audio is much too fast or crackles a lot or passthrough only produces noise, you might have a broken driver in use. If this is the case, try to add tsched=0 to the udev loading section in /etc/pulse/default.pa to read like:
load-module module-udev-detect tsched=0
When Pulseaudio is configured to be multi-channel output, e.g. 5.1 profile from within pavucontrol, 2.0 streams are automatically upmixed, no matter what setting you have chosen in xbmc. This is default pulseaudio server behaviour. You can workaround that by disabling enable-remixing in /etc/pulse/daemon.conf
enable-remixing = no
References
Linux - Pulseaudio Sink Discussion and further information. |