The VideoLAN Forums

Posted: **10 Nov 2006 15:30**

Hi there!

Little problem with AC3 Passthrough! Running suse 10.1 with vlc 0.8.5 from packman repo. Motherboard is a ABIT NF7-S2.0 nforce2. All files play fine, video is good, audio is fine, only constellation where sound is practically non existent is ac3 passthrough with vlc. Hardware Receiver simply starts blinking the input led and only sort of crackles due to the sound problems.

here is the VLC log, starting from when I switch to A/52 over S/PDIF

main debug: removing module "a52tofloat32"
main debug: removing module "bandlimited_resampler"
main debug: removing module "float32_mixer"
main debug: thread 2797091744 joined (alsa.c:714)
main debug: removing module "alsa"
main debug: looking for audio output module: 6 candidates
alsa warning: The rate 44100 Hz is not supported by your hardware. Using 48000 Hz instead.

main warning: couldn't set thread priority (alsa.c:662): Die Operation ist nicht erlaubt
main debug: thread 2797091744 (aout) created at priority 0 (alsa.c:662)
main debug: using audio output module "alsa"
main debug: output 'spdi' 48000 Hz 3F2R/LFE frame=1536 samples/6144 bytes
main debug: mixer 'a52 ' 48000 Hz 3F2R/LFE frame=1536 samples/6144 bytes
main debug: filter(s) 'a52 '->'spdi' 48000 Hz->48000 Hz 3F2R/LFE->3F2R/LFE
main debug: looking for audio filter module: 24 candidates
main debug: using audio filter module "a52tospdif"
main debug: found a filter for the whole conversion
main debug: looking for audio mixer module: 3 candidates
main debug: using audio mixer module "spdif_mixer"
main debug: input 'a52 ' 48000 Hz 3F2R/LFE frame=1536 samples/1536 bytes
main debug: audio output is too slow (-62566), trashing 32000us
main debug: audio output is too slow (-94548), trashing 32000us
main debug: audio output is too slow (-126545), trashing 32000us
main debug: audio output is too slow (-158542), trashing 32000us
main debug: audio output is too slow (-190540), trashing 32000us
main debug: audio output is too slow (-222538), trashing 32000us
main debug: audio output is too slow (-230571), trashing 32000us
alsa debug: recovered from buffer underrun
main debug: audio output is starving (238539), playing silence

liba52 is installed. AC3 Passthrough works fine with Totem & Xine (simply would prefer VLC).

Any suggestions?

greetings, ridewithstyle

Posted: **02 Jan 2007 06:20**

I'm also having this problem with VLC 0.8.6 under Ubuntu 6.10.

Symtpms are exactly as described by various people in various threads going back to VLC 0.8.4. Has anyone found any kind of solution for this yet?

This thread contains more info on it, but it seems there is still no fix? More people with the same problems in this thread.

I have liba52-0.7.4 and SPDIF is working great in MythTV.

I have a Lanparty nForce4 SLI and use ALSA HW:0,0 as my device.

When I select stereo output in VLC everything is fine (goes through SPDIF) but selecting A/52 through S/PDIF I nothing but clicking noises from my Amp as it switches in and out of AC3. I can see VLC is trying to deliver AC3 but it seems to keep failing. CPU and Mem usage is extremely low at all times.

Testing was done with AC3 LotR DVD.

Code: Select all

main debug: removing module "a52tofloat32"
main debug: removing module "bandlimited_resampler"
main debug: removing module "trivial_mixer"
main debug: thread 2924391328 joined (alsa.c:714)
main debug: removing module "alsa"
main debug: removing module "float32tos16"
main debug: looking for audio output module: 5 candidates
main debug: thread 2924391328 (aout) created at priority 0 (alsa.c:662)
main debug: using audio output module "alsa"
main debug: output 'spdi' 48000 Hz 3F2R/LFE frame=1536 samples/6144 bytes
main debug: mixer 'a52 ' 48000 Hz 3F2R/LFE frame=1536 samples/6144 bytes
main debug: filter(s) 'a52 '->'spdi' 48000 Hz->48000 Hz 3F2R/LFE->3F2R/LFE
main debug: looking for audio filter module: 24 candidates
main debug: using audio filter module "a52tospdif"
main debug: found a filter for the whole conversion
main debug: looking for audio mixer module: 3 candidates
main debug: using audio mixer module "spdif_mixer"
main debug: input 'a52 ' 48000 Hz 3F2R/LFE frame=1536 samples/1792 bytes
main debug: audio output is too slow (-57472), trashing 32000us
main debug: audio output is too slow (-89454), trashing 32000us
main debug: audio output is too slow (-121450), trashing 32000us
main debug: audio output is too slow (-153447), trashing 32000us
main debug: audio output is too slow (-185444), trashing 32000us
main debug: audio output is too slow (-217440), trashing 32000us
main debug: audio output is too slow (-249437), trashing 32000us
main debug: audio output is too slow (-281434), trashing 32000us
main debug: audio output is too slow (-289515), trashing 32000us
alsa debug: recovered from buffer underrun
main debug: audio output is starving (273484), playing silence
main debug: audio output is too slow (-61435), trashing 32000us
main debug: audio output is too slow (-93424), trashing 32000us
main debug: audio output is too slow (-125420), trashing 32000us
main debug: audio output is too slow (-157417), trashing 32000us

Posted: **02 Jan 2007 12:11**

Ubuntu version is not VLC 0.8.6 final but a SVN snaphsot, so this can be a problem.

Posted: **09 Jan 2007 20:12**

Ubuntu version is not VLC 0.8.6 final but a SVN snaphsot, so this can be a problem.

I've taken the feisty version (which is a 0.8.6 final) and recompiled it on an edgy pbuilder. The same problem is existing for the final version for me.

Posted: **09 Jan 2007 20:22**

Also, I should not that this does work for me with xine and mythtv spdif output. So its not liba52 either.

Posted: **09 Jan 2007 22:17**

Hi there!
where sound is practically non existent is ac3 passthrough with vlc. Hardware Receiver simply starts blinking the input led and only sort of crackles due to the sound problems.

I have the same problem, and a little workaround. However, I'd prefer to get VLC to pass-through AC3 to the receiver.

My input signal is an MPEG-TS stream coming from an HD receiver. VLC uses the default sound settings (ALSA, device "Default") and sends 2-channel sound to the receiver over the coax digital input. The receiver identifies the type as PCM. However, the input broadcast has 5.1 channel sound. When I hit the "Refresh" in the Audio settings, I get 3 devices. I pick "hw0,2" which is (supposed to be) the pass-through, and I get a blinking iconset on the receiver, where 2 front, 2 back, and LFE icons are blinking.

My workaround is to stream the output over HTTP port 1235, and pick that up with with Gxine. Gxine sends the 5.1 sound to the receiver just fine! The situation is that only VLC is able to tune to the HD stream, and only Gxine can passthrough 5.1 to the receiver. Therefore my CPU is very busy. The same situation occurs with DVDs, however the CPU usage is far less, and Gxine can read the DVDs directly anyway.

Is there a way to make liba52 do passthrough, or is this more of an ALSA issue, in which case, how can you specify a sound device to VLC (I can use the device specified in the Gxine settings for passthrough)?

Posted: **10 Jan 2007 06:28**

Hi there!
where sound is practically non existent is ac3 passthrough with vlc. Hardware Receiver simply starts blinking the input led and only sort of crackles due to the sound problems.
I have the same problem, and a little workaround. However, I'd prefer to get VLC to pass-through AC3 to the receiver.

My input signal is an MPEG-TS stream coming from an HD receiver. VLC uses the default sound settings (ALSA, device "Default") and sends 2-channel sound to the receiver over the coax digital input. The receiver identifies the type as PCM. However, the input broadcast has 5.1 channel sound. When I hit the "Refresh" in the Audio settings, I get 3 devices. I pick "hw0,2" which is (supposed to be) the pass-through, and I get a blinking iconset on the receiver, where 2 front, 2 back, and LFE icons are blinking.

My workaround is to stream the output over HTTP port 1235, and pick that up with with Gxine. Gxine sends the 5.1 sound to the receiver just fine! The situation is that only VLC is able to tune to the HD stream, and only Gxine can passthrough 5.1 to the receiver. Therefore my CPU is very busy. The same situation occurs with DVDs, however the CPU usage is far less, and Gxine can read the DVDs directly anyway.

Is there a way to make liba52 do passthrough, or is this more of an ALSA issue, in which case, how can you specify a sound device to VLC (I can use the device specified in the Gxine settings for passthrough)?

The only problem is that later version of xine-lib have a problem of their own for digital audio output via spdif. It will lag more and more as you progress further into the clip/show. There was a mailing list post indicating that this can be improved by changing the A/V sync method, but its not an entire solution. This is what brought me to vlc in the first place for digital audio needs

I just wish there was an easy way to install 0.8.4 on edgy to work around this. I'm attempting to build the old 0.8.4 dapper package on an edgy pbuilder, but I keep running into troubles that I am attempting to workaround. If I eventually get 0.8.4 built, i'll put it up on a repository for users to use.

Posted: **10 Jan 2007 23:15**

Guys, there appears to be a bug opened about this on trac (about 1 month ago).

http://trac.videolan.org/vlc/ticket/894

Posted: **16 Jan 2007 14:52**

Alright, in the interim - I've got a build put together for ubuntu 6.10 users running into this issue. It's basically the 0.8.4 release with the alsa source file from the 0.8.4a release.

To install it:
1) Set up /etc/apt/preferences

Code: Select all

sudo gedit /etc/apt/preferences

Place:

Package: vlc
Pin: version 0.8.4.*
Pin-Priority: 999

Package: wxvlc
Pin: version 0.8.4.*
Pin-Priority: 999

Package: vlc-plugin-alsa
Pin: version 0.8.4.*
Pin-Priority: 999

2) Add my repository

Code: Select all

sudo gedit /etc/apt/sources.list

Place:

deb http://home.eng.iastate.edu/~superm1 edgy vlc-0.8.4

3) Remove all vlc packages in your system

Code: Select all

sudo apt-get remove --purge vlc libvlc0

4) Add the key my repository is signed with

Code: Select all

wget http://home.eng.iastate.edu/~superm1/80DF6D58.gpg -O- | sudo apt-key add -

5) Update your sources

Code: Select all

sudo apt-get update

6) Install vlc

Code: Select all

sudo apt-get install vlc

The 5.1 sound appears to work correctly with this release.

Posted: **20 Jan 2007 16:29**

How do I install your back port of Feisty's VLC to Edgy? I added your repos, but I still get vlc (0.8.6-svn20061012.debian-1ubuntu1). I'm on Edgy amd64.

TIA

Didjit

Posted: **21 Jan 2007 17:36**

How do I install your back port of Feisty's VLC to Edgy? I added your repos, but I still get vlc (0.8.6-svn20061012.debian-1ubuntu1). I'm on Edgy amd64.

TIA

Didjit

I haven't built for AMD64 - only i386. I can get a build environment setup on my amd64 box too though. It will just take me a little time. I'll post back when I have that together.

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