Streaming to Airport Express from VLC 1.1.0

[fulldecent]

Hello, I heard that the 1.1.0 release of VLC support streaming to Apple Airport Express and that there was a simplified interface to do this. Information appears to be sparse on this, so I started a stub wiki page at http://wiki.videolan.org/Airport_Express

If you could please explain this process to me, I will update this wiki page.

Thanks,
Will

[ajmas]

I am not aware of such functionality. The only approach that I know is to use a third party application.

[Jean-Baptiste Kempf]

There is no interface to do so, but the functionnality is present

[ajmas]

I learn something new. Is it command line accessible?

[Jean-Baptiste Kempf]

Yes, it is named RAOP

[crzyhanko]

This is discussed a bit in a few other threads.
viewtopic.php?f=14&t=62267
viewtopic.php?f=12&t=63324

From what I can tell, the easiest way to make it work is to go into preferences>all>stream output
then, in the box for "default stream output chain", you type

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#transcode{acodec=alac,channels=2,samplerate=44100}:raop{host=<ip address of airport express>,volume=175}

This will stream audio to the airport express. You must delete this when you want to normally play files on your computer.

If you want to stream audio to the airport express whenever you play media files, but also have them display on your computer screen (and have audio through the computer speakers) you can instead type

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#duplicate{dst="transcode{acodec=alac,channels=2,samplerate=44100}:raop{host=<ip address of airport express>,volume=175}",dst=display{delay=1000}}

where the "delay" value is in milliseconds and can be used to try and synchronize the video/sound from the computer with the airport express. If you don't want VLC to play sound out of your computer you can use

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#duplicate{dst="transcode{acodec=alac,channels=2,samplerate=44100}:raop{host=<ip address of airport express>,volume=175}",dst=display{no-audio,delay=1000}}

The ip address of the airport express can be found using the AirPort Utility. Usually it's of the form 10.0.1.x where x is between 1 and 254.

If you correctly set the values under the preferences for transcode, raop, and display (preferences>all>stream output>sout stream>*transcode/raop/display*) then you can use the short option of

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#duplicate{dst="transcode:raop",dst=display}

to control generating streams to the airport and display.

Hope this helps.

[brucegraphics]

Thank you crzyhanko, those instructions successfully work on my Airport Express.

[gnippiks]

Thanks crzyhanko, that was very helpful.

But the above doesn't work for me when the input audio stream only has one channel. When I try to play a video with a mono audio stream, I get the following error message:

stream_out_raop error: The Apple Lossless audio stream must be encoded with 44100 Hz and 2 channels

I am using #transcode{acodec=alac,channels=2,samplerate=44100} as above, but the single-channel input is not being converted to the two-channel output required by the raop module.

Does anyone know how to transcode a mono audio stream to a stereo audio stream? Is it even possible with VLC?

Here's a larger excerpt from my log messages:

mpeg_audio debug: MPGA channels:1 samplerate:48000 bitrate:128
stream_out_transcode debug: creating audio transcoding from fcc=`mpga' to fcc=`alac'
stream_out_transcode debug: Looking for filter (mpga->s16l, channels 1->1, rate 48000->44100)
mpgatofixed32 debug: mpga->f32l, bits per sample: 0
bandlimited_resampler debug: f32l/48000KHz/1->f32l/44100KHz/1
audio_format debug: f32l->s16l, bits per sample: 32->16
stream_out_transcode debug: Got complete audio filter chain
stream_out_raop error: The Apple Lossless audio stream must be encoded with 44100 Hz and 2 channels

[Jean-Baptiste Kempf]

Thanks crzyhanko, that was very helpful.

But the above doesn't work for me when the input audio stream only has one channel. When I try to play a video with a mono audio stream, I get the following error message:

stream_out_raop error: The Apple Lossless audio stream must be encoded with 44100 Hz and 2 channels

I am using #transcode{acodec=alac,channels=2,samplerate=44100} as above, but the single-channel input is not being converted to the two-channel output required by the raop module.

Does anyone know how to transcode a mono audio stream to a stereo audio stream? Is it even possible with VLC?

Here's a larger excerpt from my log messages:

mpeg_audio debug: MPGA channels:1 samplerate:48000 bitrate:128
stream_out_transcode debug: creating audio transcoding from fcc=`mpga' to fcc=`alac'
stream_out_transcode debug: Looking for filter (mpga->s16l, channels 1->1, rate 48000->44100)
mpgatofixed32 debug: mpga->f32l, bits per sample: 0
bandlimited_resampler debug: f32l/48000KHz/1->f32l/44100KHz/1
audio_format debug: f32l->s16l, bits per sample: 32->16
stream_out_transcode debug: Got complete audio filter chain
stream_out_raop error: The Apple Lossless audio stream must be encoded with 44100 Hz and 2 channels

Force channels to 2?

[gnippiks]

Force channels to 2?

How can I do this?

I am using the transcode module with the channels=2 option, but that does not change the number of output channels to 2 if the input stream is mono. Thanks.

[Jean-Baptiste Kempf]

Ok, then, some code is missing to do a filter to have mono => stereo.

[crzyhanko]

Does anyone know how to transcode a mono audio stream to a stereo audio stream? Is it even possible with VLC?

Sorry, no idea. I can't find anything that suggests a way to upmix. The only thought I have is maybe you could force something out of the headphone surround effect, but I don't know enough about it to even begin to guess if that is actually doable.

[chrisrp]

Hi

With the help of this board i have managed to get my vlc to stream audio to my airport express! Thank you very much! I actually had to use:

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#duplicate{dst=display{noaudio,delay=4000},dst="transcode{acodec=alac,channels=2,samplerate=44100}: raop{host=10.0.1.1,volume=175}"}

I switched the order of the commands, without switching the video delay wasn't working.

However i have another question. First let me say i have no knowledge of vlc command lines. But i would like to be able to control the volume from vlc and not the speakers. As it stands now the volume is fixed at whatever value is in the string.

Can anyone help me with this?

Thank you very much!

Chris

[Jean-Baptiste Kempf]

I am not sure this is implemented.

[nickdjones]

Thanks for these instructions - the abbreviated form with specific settings under each area works well for me, though I had to upgrade from 1.0.5 to 1.1.11 before it would find the alac audio encoder.

thanks!

[mlte]

Hi,
Thanks for the tip, it almost works...but i'm having an issue using this code :
#transcode{acodec=alac,channels=2,samplerate=44100}:raop{host=<ip address of airport express>,volume=175}

I have an orange triangle, which i think is due to the password i put for the airport connection. I guess there might be a code line where you can add the password after the "host=<ip address of airport express>" part, but i have no idea of what it could be.

Anyone for an idea ?