The VideoLAN Forums

I wanted to play DVDs from my Mac, with the video connected to the VGA input on my projector and the audio being streamed to my AV receiver wirelessly via my airport express.

First problem: only itunes streams audio to the airport express. I got around that with airfoil. (iTunes will play video, but won't output the video's audio to the airport express.)

Second problem: there is a delay for audio streamed to an airport express. VLC allows one to delay the video, to let the audio catch up.

Third problem: it seems VLC only sees the stereo ccapabilities of my Mac, so outputs only stereo even though my AV receiver can do 5.1. I don't have a solution for this.

Anyone have good results with this? I had a hard time figuring out how much to delay the video, and then it still seemed to get out of sync over time.

Should I just get an M-Audio Transit and connect the audio over the USB-optical adapter?

I still haven't been able to get VLC sync controls to work for me AT ALL. This isn't a fine tuning issue. I've tried seting the video delay to various values without any impact. Can you tell me precisely what you're doing so I might at least catch up to you?

Thanks in advance.

Third problem: it seems VLC only sees the stereo ccapabilities of my Mac, so outputs only stereo even though my AV receiver can do 5.1. I don't have a solution for this.

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Should I just get an M-Audio Transit and connect the audio over the USB-optical adapter?

I also can get Stereo only with Tiger 10.4.2, although I have full 5.1 surround with the same setup under Panther 10.3.9.

I have the M-audio Sonica Theater, but connected analogically to Logitech Z5300 boxes.

It would be nice if other user would contribute by reporting their results.

i have the same delay problem with streaming the sound,

i've fixed it by choosing a negative value for the "Audio desynchronization compensation" value, in miliseconds, under the Audio (Advanced) tab of VLC for OS X.

Hello--

We have VLC version 0.8.4 running on a 12" Powerbook G4 using Tiger 10.4.4 connected via DVI cable to our video projector. We are using AirFoil V2.0.1 to transmit the audio across the room to our Airport Express connected to our stereo amplifier and speakers.

I launched AirFoil, used it to launch VLC, opened a DVD disc, set the video device to Screen 2, started the movie, set the subtitles to English, and heard the audio over our speakers. I found that these things had to be done in exactly this order. (For example, I cannot set the video device until I have opened the DVD, and I cannot set the subtitles until the movie has started.) After some practice, I could perform this sequence in a few minutes without getting any error messages.

I rebooted my machine and performed this procedure without any error messages. As predicted by the Airfoil documentation, the lipsync was way off. According to the Airfoil documentation, I need a 2400 millisecond (that's 2.4 seconds) delay in the video to compensate for a similar delay in the audio introduced by the AirTunes transmission mechanism.

Again using the AirFoil documentation, I pressed the "f" key, and a message, "Audio delay -50 ms" appeared. I pressed the "f" key repeatedly and the delay incremented... until the sound stopped. I found that at -250 ms the sound was OK, but at -300 ms the sound got "bursty" -- unintelligible tiny bursts of sound every second or so. Beyond -300 ms delay, there was no sound at all. Pressing the "g" key to reduce the delay to -250 ms made the sound come back. Using the "f" and "g" keys, I could move the delay back and forth across the -250/-300 ms boundary and the sound would come and go reliably.

Would anyone have any suggestions on how to make VLC work on our equipment with the -2400 ms delay recommended in the AirFoil documentation?

--Gil

Gil - Same problem here. VLC 0.8.4 running on G4 powerbook, beyond 250ms my sound goes... Not sure what the problem is but it's bugging the $hit out of me cuz this is the last hurdle. Tried mplayer also but it doesn't seem to interact as well with airfoil. Someone must have run into this before...

-Dave

The problem is simple.
VLCs buffer is only 300ms of packets on normal files. The audio delay cannot cross that boundary. Sometimes (due to the interleaving) there is more audio, sometimes there is less (audio for time 50 is stored at time 20 vs. stored at time 80).

When the delay > buffer, there is no audio, so there is stuttering or silence.

You can increase the -*-caching options (all the caching options for all the input methods. file/dvd/vcd/cdda/http/mms/etc). However larger caches means that it will take longer for play/pause/stop and all other actions to be processed as well.

DJ

thanks for the info DJ, after a little more tinkering my setup is working well. for anyone who didn't catch how to do it (i know it took me a while) the process is as follows. go to the VLC preferences>input/codecs>access modules>file. make sure the advanced checkbox is checked so you can see the "caching value in ms" field. set this to something larger than the delay you want (i used 3000). after making that adjustment and saving i could hit the "f" key during playback until the delay was set to -2400ms. the adui is all synched up! i then set the default delay in the VLC preferences>audio to -2400 so it starts this way. thanks for the help in figuring this out everyone

ok everything is in sync for me. now can someone please tell me the airfoil registration code?

ok everything is in sync for me. now can someone please tell me the airfoil registration code?

Try this link!

It's not working for me. I'm very sorry and I'm not very experienced with VLC either. I recently purchase an Airport Express for this purpose. I don't understand the various panels and what they mean. I've spent a few hours playing around with the settings, but to no avail.
I would really appreciate some help. Thanks in advance.

Bear54LA, DJ & gt4726a info is all good and very useful and helpful..

Airfoil is not needed.:
iTune uses a stream called 'Shoutcast' and Shoutcast's ICY protocol is so simple that you can replicate it just by telling VLC to stream an MP3 or MPEG2 to HTTP with (raw/no) encapsulation.
Example.: We deciphered their MURL scheme enough to write our own streaming MURL. Here it is: Note.: the above should be one long line, and do not add a space after the comma at the line break... As so... What this says is to transcode audio to 192 bit/sec MPEG layer 2 (the MP3 encoder is much slower), to display the video only, and to stream the audio to HTTP port 8080. Copy and paste this MURL to the "Choose a stream output" input box of the Stream output page of VLC's preferences. You'll need to check "Advanced" to see this page. Don't change any other streaming controls.

or try to bypass Transcoding by.: Play a DVD with these settings, and you should see video with no audio. Open iTunes and go to Advanced -> Open Stream. Tune to icy://localhost:8080 and select your AirTunes speakers. You should hear your movie with a considerable delay. On my computer, this delay is reliably 2.4 to 2.85 seconds. On the audio page of VLC's prefs, put in -2400 to -2850 for the desynchronization compensation. Close your movie and open it again (you have to do this for any preference change to take effect, it seems). When your movie opens, it should be more closely synchronized. If it's not perfect, you may need to fiddle with the compensation. Pausing the movie, or clicking through menus, will require some patience since everything is affected by the audio delay but after setting it up generally if the sound is still a little out you can in VLC just hit F and J to tweak audio delay to - and +..

The volume control in VLC seems to have no effect, so you'll need to use the one in iTunes. Seeking in a movie is VLC's weakest point; in the beta version, you'll need to pause before you seek or it will probably crash though release 0.8.6b may be better at this now (fingers -crossed).

Note.: Incidentally, playing VLC's streaming video sound via your Airport, Firewire or LAN is easy - just tell another iTunes to look at your video-serving-computer's local ip, port 8080 (eg, http://192.168.1.3:8080/) and iTunes will pick up the stream easy as pie.

Hi,

I'm really excited to try this, but I can't seem to find the "Choose a stream output" input box in VLC's prefs.

Can you give me a little more info about where it is?

Thanks!

Copy and paste this MURL to the "Choose a stream output" input box of the Stream output page of VLC's preferences. You'll need to check "Advanced" to see this page. Don't change any other streaming controls.

The string posted by dfc came probably originally from here: http://www.macosxhints.com/article.php? ... 4910602%20).

Here everything summed up: How to stream the audio channel from VLC via iTunes to the AirPort Express.

1) In VLC enter the following MURL in Preferences, (check Advanced check-box) Stream output -> General, 'Default stream output chain'. and start playing (and thus streaming) your media file.

2) Open URL in iTunes (Menu Advanced>Open Stream) icy://localhost:8080

Now you can forward the audio from iTunes to the AirPort Express and hear the sound with a considerable delay.

3) increase VLC cache to make space for a big delay:
VLC preferences>input/codecs>access modules>file. make sure the advanced checkbox is checked so you can see the "caching value in ms" field. set this to something larger than the delay you want (i used 3000)

4) In VLC adjust the delay with the 'f' and 'g' keys while playing to around -2400ms
to make the delay permanent enter the value into the VLC preferences>Audio>desynchronization compensation field

It works for me! However, I'd love to stream the audio from VLC directly to the AirPort without the detour via iTunes. However, the AirPort accepts only encrypted streams. DVD-Jon figured out how the AirPort's streaming-protocol works (http://nanocrew.net/software/justeport/) but I doubt you can make VLC stream in that format.