Results 1 to 3 of 3

Thread: TV Video audio sync issue

  1. #1

    Default TV Video audio sync issue

    There seems to be a bug, or issue where any PCI TV card does not easily configure to play sound through the speakers via the buss. Many cards do NOT have an audio out port and those cards are the problem. The Yaast2 configuration does not work. Even though you select no audio out. There is no sound. The only way I have been able to get ANY sound at all is to pipe it as follows:
    arecord -D hw:1,0 -r 32000 -c 2 -f S16_LE | aplay -

    Doing so produces sound, but there is at least a 1 second delay in the sound. I have found nothing anywhere on why this happens, or how to fix it.

    It seems that I need to configure some sort of loopback for the audio to grab the audio coming from the bus, but I am not seeing anything on it.

    If I install a card with an audio port, it is simple. Just plug the audio out on the card, to the audio in on the sound card, and it works and is in sync.

  2. #2
    Join Date
    Mar 2008
    Location
    Phuket, Thailand
    Posts
    27,109
    Blog Entries
    40

    Default Re: TV Video audio sync issue

    Quote Originally Posted by lshantz View Post
    There seems to be a bug, or issue where any PCI TV card does not easily configure to play sound through the speakers via the buss. Many cards do NOT have an audio out port and those cards are the problem.
    If you are using openSUSE-11.4, you may find pulse audio provides this capability to play sound. If you have pulse audio in use, then install the application 'pavucontrol'. That provides control over ALL audio that comes into one's PC, and allows one to redirect that audio anywhere, whether it be to an application input, or to a set of speakers, or to a sink.

    For example, I was playing with it here ... Looking (maybe) for audio mixer for use with Pulse Audio Take a look at post#4 and #5 in that thread.

    That might mean you need to try :
    Code:
    arecord -D pulse -r 32000 -c 2 -f S16_LE
    and then tune pulse audio to redirect the audio to an application ...

    or
    Code:
    arecord -D pulse -r 32000 -c 2 -f S16_LE | aplay -
    if you wish to reduce the pulse audio overhead.

    I'm assuming you will be able to detect the audio with pulse audio.

    Reference pavucontrol, you will need to have that running at the same time as arecord and aplay the first time you set this up. After it is setup you should not need to run it again unless you wish to change the configuration, record levels, etc ...

    Of course 'jack' will do this, but I 'don't know jack' about jack, and find it too time consuming to try to learn. Pulse is easier by comparison and a LOT of the bugs that plagued pulse in the earlier days are gone, and now the main problem with pulse is a total lack of user familiarity (although I think there are still a number of bugs to be squashed).

    If you are really masochistic (and have fast CPU and don't mind recoding the entire video) you could reprocess it with ffmpeg as noted in this fedora thread where I was trying to help a user: [SOLVED] Which device to use for ffmpeg sound input? Fedora 14 - FedoraForum.org

    As you know avidemux also offers the capability to resync audio and for such resync I find avidemux pretty fast.

  3. #3

    Default Re: TV Video audio sync issue

    Awesome! Thanks for the informative answer. I'm sure many others are having the same issues, based on the number of pleas for help out in the wild.

    I currently have a card in that has audio out and it is working, but I'd like to try this and see what happens. The confusing part is that it is difficult to figure out which audio goes to what to configure it. I thought this was the whole idea behind the automagic config utility in Yasst2. But for what ever reason, it does not.

    I'm really looking forward to tinkering with the audio sync issues. That has a huge number of folks throwing up their hands in frustration. Thanks again for the reply.

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •