By Date: <-- -->
By Thread: <-- -->

Two SAA7134 TV Cards and sound over PCI bus



Hi, Michael

Michael Wilke wrote:
Hello List,


i read the list for a while, cause i'm intrested in understanding how v4l work and just wanne learn something :) i read this:

On Fri, 2006-02-10 at 08:36 +0100, Hoeschen, Markus wrote:

This gives me /dev/dsp2 (TV card1) and /dev/dsp3 (TV card2) for the two
audio sources. In this case sound is transferd through PCI bus not
through any "external" cable (remember I've got 2 cards in the same PC).

i've got only one card (Hauppauge WinTV [card=10]), but also 2 dsp devices --- Feb 8 23:07:16 cassandra kernel: [ 456.342584] btaudio: registered device dsp1 [digital] Feb 8 23:07:16 cassandra kernel: [ 456.346799] btaudio: registered device dsp2 [analog] ---

after a few hours there's only dsp1 left, without any dmesg dsp2 left
for a walk or something.

when i try to get sounds over pci bus
(sox -r 32000 -sw -t ossdsp /dev/dsp1 -t ossdsp /dev/dsp)
it works fine, but its not syncron, it starts with ca. 1/2 sec delay and
everytime i zapp around the delay increase.

one night tv runs the whole night and when i wake up, there's a delay
around 5sec or something.

i've got a K7 1800+ / 512 / Geforce puter, so i think it cant be that,
also i try another interrupt and various kernel parameters noapic,
acpi=noirq, ... but it seems that isnt an interrupt problem.

so i wonder, why others could stream videos and i not :)

Now I can use vlc to capture audio and video from this sources and
stream it through my network.


does anyone got a hint for me ?

best regards
michael wilke

The reason for your problem is that the capture card and the sound card
have independent timebases and can't be synchronized. It looks like your
sound card runs a bit slower which causes the increasing delay. We still
need a low latency saple rate converter that replaces the job of sox.

Hartmut

--
video4linux-list mailing list
Unsubscribe mailto:video4linux-list-request (at) redhat.com?subject=unsubscribe
https://www.redhat.com/mailman/listinfo/video4linux-list