mirror of
https://github.com/mpv-player/mpv
synced 2024-12-27 01:22:30 +00:00
bca917f6d2
Ancient Linux audio output. Apparently it survived until now, because some BSDs (but not all) had use of this. But these should work with ao_sdl or ao_openal too (that's why these AOs exist after all). ao_oss itself has the problem that it's virtually unmaintainable from my point of view due to all the subtle (or non-subtle) difference. Look at the ifdef mess and the multiple code paths (that shouldn't exist) in the removed source code.
225 lines
9.4 KiB
ReStructuredText
225 lines
9.4 KiB
ReStructuredText
AUDIO OUTPUT DRIVERS
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====================
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Audio output drivers are interfaces to different audio output facilities. The
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syntax is:
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``--ao=<driver1,driver2,...[,]>``
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Specify a priority list of audio output drivers to be used.
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If the list has a trailing ',', mpv will fall back on drivers not contained
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in the list.
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.. note::
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See ``--ao=help`` for a list of compiled-in audio output drivers. The
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driver ``--ao=alsa`` is preferred. ``--ao=pulse`` is preferred on systems
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where PulseAudio is used.
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Available audio output drivers are:
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``alsa`` (Linux only)
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ALSA audio output driver
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See `ALSA audio output options`_ for options specific to this AO.
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.. warning::
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To get multichannel/surround audio, use ``--audio-channels=auto``. The
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default for this option is ``auto-safe``, which makes this audio output
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explicitly reject multichannel output, as there is no way to detect
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whether a certain channel layout is actually supported.
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You can also try `using the upmix plugin <http://git.io/vfuAy>`_.
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This setup enables multichannel audio on the ``default`` device
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with automatic upmixing with shared access, so playing stereo
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and multichannel audio at the same time will work as expected.
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``jack``
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JACK (Jack Audio Connection Kit) audio output driver.
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The following global options are supported by this audio output:
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``--jack-port=<name>``
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Connects to the ports with the given name (default: physical ports).
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``--jack-name=<client>``
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Client name that is passed to JACK (default: ``mpv``). Useful
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if you want to have certain connections established automatically.
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``--jack-autostart=<yes|no>``
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Automatically start jackd if necessary (default: disabled). Note that
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this tends to be unreliable and will flood stdout with server messages.
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``--jack-connect=<yes|no>``
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Automatically create connections to output ports (default: enabled).
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When enabled, the maximum number of output channels will be limited to
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the number of available output ports.
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``--jack-std-channel-layout=<waveext|any>``
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Select the standard channel layout (default: waveext). JACK itself has no
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notion of channel layouts (i.e. assigning which speaker a given
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channel is supposed to map to) - it just takes whatever the application
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outputs, and reroutes it to whatever the user defines. This means the
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user and the application are in charge of dealing with the channel
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layout. ``waveext`` uses WAVE_FORMAT_EXTENSIBLE order, which, even
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though it was defined by Microsoft, is the standard on many systems.
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The value ``any`` makes JACK accept whatever comes from the audio
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filter chain, regardless of channel layout and without reordering. This
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mode is probably not very useful, other than for debugging or when used
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with fixed setups.
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``coreaudio`` (Mac OS X only)
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Native Mac OS X audio output driver using AudioUnits and the CoreAudio
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sound server.
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Automatically redirects to ``coreaudio_exclusive`` when playing compressed
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formats.
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The following global options are supported by this audio output:
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``--coreaudio-change-physical-format=<yes|no>``
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Change the physical format to one similar to the requested audio format
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(default: no). This has the advantage that multichannel audio output
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will actually work. The disadvantage is that it will change the
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system-wide audio settings. This is equivalent to changing the ``Format``
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setting in the ``Audio Devices`` dialog in the ``Audio MIDI Setup``
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utility. Note that this does not affect the selected speaker setup.
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``--coreaudio-spdif-hack=<yes|no>``
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Try to pass through AC3/DTS data as PCM. This is useful for drivers
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which do not report AC3 support. It converts the AC3 data to float,
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and assumes the driver will do the inverse conversion, which means
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a typical A/V receiver will pick it up as compressed IEC framed AC3
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stream, ignoring that it's marked as PCM. This disables normal AC3
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passthrough (even if the device reports it as supported). Use with
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extreme care.
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``coreaudio_exclusive`` (Mac OS X only)
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Native Mac OS X audio output driver using direct device access and
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exclusive mode (bypasses the sound server).
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``openal``
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OpenAL audio output driver
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``--openal-num-buffers=<2-128>``
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Specify the number of audio buffers to use. Lower values are better for
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lower CPU usage. Default: 4.
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``--openal-num-samples=<256-32768>``
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Specify the number of complete samples to use for each buffer. Higher
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values are better for lower CPU usage. Default: 8192.
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``--openal-direct-channels=<yes|no>``
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Enable OpenAL Soft's direct channel extension when available to avoid
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tinting the sound with ambisonics or HRTF.
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Channels are dropped when when they are not available as downmixing
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will be disabled. Default: no.
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``pulse``
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PulseAudio audio output driver
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The following global options are supported by this audio output:
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``--pulse-host=<host>``
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Specify the host to use. An empty <host> string uses a local connection,
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"localhost" uses network transfer (most likely not what you want).
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``--pulse-buffer=<1-2000|native>``
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Set the audio buffer size in milliseconds. A higher value buffers
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more data, and has a lower probability of buffer underruns. A smaller
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value makes the audio stream react faster, e.g. to playback speed
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changes.
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``--pulse-latency-hacks=<yes|no>``
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Enable hacks to workaround PulseAudio timing bugs (default: no). If
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enabled, mpv will do elaborate latency calculations on its own. If
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disabled, it will use PulseAudio automatically updated timing
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information. Disabling this might help with e.g. networked audio or
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some plugins, while enabling it might help in some unknown situations
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(it used to be required to get good behavior on old PulseAudio versions).
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If you have stuttering video when using pulse, try to enable this
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option. (Or try to update PulseAudio.)
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``--pulse-allow-suspended=<yes|no>``
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Allow mpv to use PulseAudio even if the sink is suspended (default: no).
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Can be useful if PulseAudio is running as a bridge to jack and mpv has its sink-input set to the one jack is using.
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``sdl``
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SDL 1.2+ audio output driver. Should work on any platform supported by SDL
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1.2, but may require the ``SDL_AUDIODRIVER`` environment variable to be set
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appropriately for your system.
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.. note:: This driver is for compatibility with extremely foreign
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environments, such as systems where none of the other drivers
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are available.
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The following global options are supported by this audio output:
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``--sdl-buflen=<length>``
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Sets the audio buffer length in seconds. Is used only as a hint by the
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sound system. Playing a file with ``-v`` will show the requested and
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obtained exact buffer size. A value of 0 selects the sound system
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default.
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``--sdl-bufcnt=<count>``
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Sets the number of extra audio buffers in mpv. Usually needs not be
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changed.
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``null``
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Produces no audio output but maintains video playback speed. You can use
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``--ao=null --ao-null-untimed`` for benchmarking.
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The following global options are supported by this audio output:
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``--ao-null-untimed``
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Do not simulate timing of a perfect audio device. This means audio
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decoding will go as fast as possible, instead of timing it to the
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system clock.
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``--ao-null-buffer``
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Simulated buffer length in seconds.
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``--ao-null-outburst``
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Simulated chunk size in samples.
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``--ao-null-speed``
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Simulated audio playback speed as a multiplier. Usually, a real audio
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device will not go exactly as fast as the system clock. It will deviate
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just a little, and this option helps to simulate this.
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``--ao-null-latency``
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Simulated device latency. This is additional to EOF.
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``--ao-null-broken-eof``
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Simulate broken audio drivers, which always add the fixed device
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latency to the reported audio playback position.
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``--ao-null-broken-delay``
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Simulate broken audio drivers, which don't report latency correctly.
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``--ao-null-channel-layouts``
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If not empty, this is a ``,`` separated list of channel layouts the
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AO allows. This can be used to test channel layout selection.
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``--ao-null-format``
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Force the audio output format the AO will accept. If unset accepts any.
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``pcm``
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Raw PCM/WAVE file writer audio output
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The following global options are supported by this audio output:
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``--ao-pcm-waveheader=<yes|no>``
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Include or do not include the WAVE header (default: included). When
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not included, raw PCM will be generated.
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``--ao-pcm-file=<filename>``
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Write the sound to ``<filename>`` instead of the default
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``audiodump.wav``. If ``no-waveheader`` is specified, the default is
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``audiodump.pcm``.
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``--ao-pcm-append=<yes|no>``
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Append to the file, instead of overwriting it. Always use this with the
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``no-waveheader`` option - with ``waveheader`` it's broken, because
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it will write a WAVE header every time the file is opened.
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``wasapi``
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Audio output to the Windows Audio Session API.
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