[linux-dvb] hvr-1300 analog audio question

yoshi watanabe yoshi314 at gmail.com
Sat Jul 5 11:18:56 CEST 2008


one small update. when i run the arecord | aplay combo with these parameters :

arecord -D hw:1,0 -c 2 -f S16 --period-size=8192 --buffer-size=524288 | aplay -

or with omitting the --period-size=8192 --buffer-size=524288

i hear noise. but when i start tvtime, right after video appears on
screen i usually get 1-2 seconds of clear audio, and then noise comes
in. i might be on to something. when i discard the buffering
parameters sometimes arecord or aplay complain about buffer underrun.
tvtime does not use cx88 mixes by default, by if i specify /

also this command
 arecord -D hw:1,0 -c 2 -f S16_LE --period-size=65536
--buffer-size=524288 -r 48000| aplay -r 48000 -

gives me very few errors now. noise pick ups when the sounds get
louder though, but feel i'm really close now.

this is on a freshly installed system with mpeg encoder module
disabled. i'll do some more testing.


On 7/1/08, marcin kowalski <yoshi314 at gmail.com> wrote:
> On 01:57 Tue 01 Jul     , hermann pitton wrote:
>  > Hi,
>  >
>  > Am Montag, den 30.06.2008, 10:24 +0100 schrieb Simon Farnsworth:
>  > > yoshi watanabe wrote:
>  > > > hello.
>  > > >
>  > > > i'm using hauppauge hvr-1300 to receive video signal from playstation2
>  > > > console, pal model. video is just fine, but i'm having strange audio
>  > > > issues, but judging by some searching i did - that's pretty common
>  > > > with this card , although people have varied experience with the card.
>  > > >
>  > >
>  > > I've had similar issues with SAA7134 based cards, which were resolved by
>  > >   changing audio parameters.
>  > >
>  > > If your problem is the same as mine was, try:
>  > > arecord --format=S16 \
>  > >          --rate=32000 \
>  > >          --period-size=8192 \
>  > >          --buffer-size=524288 | aplay
>  > >
>  > > This forces 32kHz sampling, and gives the card lots of buffer space to
>  > > play with.
>  >
>  > 32kHz is true for saa713x TV audio dma sampling, saa7130 has no support
>  > at all for it.
>  >
>  > But 48Khz is default on cx88 stuff.
>  >
>  > Cheers,
>  > Hermann
>  >
>
> i guess that means i'm back to square one. it's pretty strange that noise gets more intense when
>  there is more movement in the video (more dynamic scenes = much more noise). but that doesn't mean that when there is
>  static screen displayed it works perfectly. it's more random than that.
>
>  i wonder whether mpeg encoder might be interfering with the audio signal (audio in mpeg stream is always perfectly
>  clear). maybe i should try to disable it (by removing the firmware from /lib/firmware, or the module from the kernel) ?
>
>  i guess i'll have to check around the branches, maybe somebody has some interesting patches that didn't make it into
>  main v4l-dvb tree yet.
>
>  anyway, thanks for your help.
>
>



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