0.5sec delay in S/PDIF output stream causes loss of audio

I am using an ABIT IC-7G motherboard with an AC7 compatible audio chipset by
Realtek which is connected to my AV amp via an S/PDIF optical cable. I have
all the latest drivers and Windows XP update installed.

According to the AV amp the input is PCM even when the computer is idle (ie.
not playing anything) but every time I try to play a file or Windows XP
tries to play a sound effect such as a mouse click there is a 0.5 second
delay before the sound comes out from the AV amp which causes the complete
loss of the first 0.5 seconds of everything I try to play, including the
total loss of every Windows XP sound effect and the first 0.5 seconds of
every audio sample in my play lists even if they are set to play
automatically one after the other. At the same time the sound from the
analogue speakers on my monitor which are connected to the same motherboard
comes out fine without any delay or any loss.

The only way I can find of stopping this delay and loss of audio is to play
a file in one audio player and then pause it indefinitely as soon as it
begins and then use another player to play my audio files.

The Dolby Digital and Dolby 5.1 output was working properly when I tested it
with the Star Wars DVD.

Is this a bug in my audio chip set, or the driver or with Windows XP and how
do I fix it so that the S/PDIF output is always streaming with no activation
delay without having to play a file and pause it an leave it on pause
indefinitely.

"Agamemnon" wrote in message
...
I am using an ABIT IC-7G motherboard with an AC7 compatible audio chipset
by Realtek which is connected to my AV amp via an S/PDIF optical cable. I
have all the latest drivers and Windows XP update installed.

According to the AV amp the input is PCM even when the computer is idle
(ie. not playing anything) but every time I try to play a file or Windows
XP tries to play a sound effect such as a mouse click there is a 0.5
second delay before the sound comes out from the AV amp which causes the
complete loss of the first 0.5 seconds of everything I try to play,
including the total loss of every Windows XP sound effect and the first
0.5 seconds of every audio sample in my play lists even if they are set to
play automatically one after the other. At the same time the sound from
the analogue speakers on my monitor which are connected to the same
motherboard comes out fine without any delay or any loss.

PS. This is not a problem with the AV amp because the same problem also
occurs when I use my MiniDisc player as the decoder. I dont have this
problem with my old computer which has a SB Live sound card and is using
Windows 98.


The only way I can find of stopping this delay and loss of audio is to
play a file in one audio player and then pause it indefinitely as soon as
it begins and then use another player to play my audio files.

The Dolby Digital and Dolby 5.1 output was working properly when I tested
it with the Star Wars DVD.

Is this a bug in my audio chip set, or the driver or with Windows XP and
how do I fix it so that the S/PDIF output is always streaming with no
activation delay without having to play a file and pause it an leave it on
pause indefinitely.

"Agamemnon" wrote in message...
I am using an ABIT IC-7G motherboard with an AC7 compatible audio
chipset by Realtek which is connected to my AV amp via an S/PDIF
optical cable. I have all the latest drivers

Do you want to tell us what sound codec driver build you're running? The
problem with people saying that they've got the "latest"-something or other
is that all it really means is that you're running the latest driver *that
you know about*. It's possible that there may be a newer one that you don't
know about, if you see what I mean.

According to the AV amp the input is PCM even when the computer is idle
(ie. not playing anything)

Does it tell you what bit rate and sample frequency this is? What make and
model is the amplifier?

but every time I try to play a file or Windows XP tries to play
a sound effect such as a mouse click there is a 0.5 second delay before
the sound comes out from the AV amp

If you look at the amplifier's display during this delay, do you see it
unlocking/relocking onto the digital signal at all?

At the same time the sound from the analogue speakers on my monitor which
are connected to the same motherboard comes out fine without any delay or
any loss.

....which is to be expected, as they're driven from the audio codec's analog
outputs.

The only way I can find of stopping this delay and loss of audio is
to play a file in one audio player and then pause it indefinitely as
soon as it begins and then use another player to play my audio files.

This does imply that the amplifier needs time to lock onto the signal for
some reason. Do you have any intermediate codec or converter - AC3Filter,
for example, installed on your PC?

The Dolby Digital and Dolby 5.1 output was working properly
when I tested it with the Star Wars DVD.

Unfortunately this doesn't tell you a huge amount, other than that the sound
hardware on the motherboard is successfully streaming the AC3 packetstream.

Is this a bug in my audio chip set, or the driver or with Windows XP

It is unlikely to be a fault in the chipset, as these tend either to work
perfectly or not at all. It could be with the driver, and it could be with
Windows XP. It could also be an issue/errata in your amplifier. Many of them
mute for a fraction of a second when the digital input resyncs or changes
format (like when swapping from PCM to AC3 and back).

and how do I fix it so that the S/PDIF output is always streaming
with no activation delay

Not something we can offer a miracle fix for unfortunately. Answer the
questions above and more assistance should be forthcoming.

Followup set.
--


Richard Hopkins
Cardiff, Wales, United Kingdom
(replace nospam with pipex in reply address)

The UK's leading technology reseller www.dabs.com

"Richard Hopkins" wrote in message
...
"Agamemnon" wrote in message...
I am using an ABIT IC-7G motherboard with an AC7 compatible audio
chipset by Realtek which is connected to my AV amp via an S/PDIF
optical cable. I have all the latest drivers

Do you want to tell us what sound codec driver build you're running? The
problem with people saying that they've got the "latest"-something or
other is that all it really means is that you're running the latest driver
*that you know about*. It's possible that there may be a newer one that
you don't know about, if you see what I mean.

Realtek AC'97 Audio
Realtek Semiconductor Corp.
5.10.0.5650
02/08/2004
Microsoft Windows Hardware Compatibility Publisher

(the date is in UK format dd/mm/yyyy)


According to the AV amp the input is PCM even when the computer is idle
(ie. not playing anything)

Does it tell you what bit rate and sample frequency this is? What make and
model is the amplifier?

No it doesn't and its not a problem with the amp since my MD player has the
same problem. This problem does not occur with my SB Live connected to the
same equipment under W98. (Yamaha RXV650 and Sony MDS-JE510)


but every time I try to play a file or Windows XP tries to play
a sound effect such as a mouse click there is a 0.5 second delay before
the sound comes out from the AV amp

If you look at the amplifier's display during this delay, do you see it
unlocking/relocking onto the digital signal at all?

No. The only time the display changes is if I mute the S/PDIF channel on the
volume mixer control on the PC (because it switches the LED off) or when it
switches to Dolby Digital or 5/7.1 mode when I'm playing a DVD. When I'm
playing PCM audio the display remains locked and is always locked even when
the computer is idle. There is not even a flicker when I start to play a
audio file.


At the same time the sound from the analogue speakers on my monitor which
are connected to the same motherboard comes out fine without any delay or
any loss.

...which is to be expected, as they're driven from the audio codec's
analog outputs.

The only way I can find of stopping this delay and loss of audio is
to play a file in one audio player and then pause it indefinitely as
soon as it begins and then use another player to play my audio files.

This does imply that the amplifier needs time to lock onto the signal for
some reason. Do you have any intermediate codec or converter - AC3Filter,
for example, installed on your PC?

AC'97 Audio


The Dolby Digital and Dolby 5.1 output was working properly
when I tested it with the Star Wars DVD.

Unfortunately this doesn't tell you a huge amount, other than that the
sound hardware on the motherboard is successfully streaming the AC3
packetstream.

Is this a bug in my audio chip set, or the driver or with Windows XP

It is unlikely to be a fault in the chipset, as these tend either to work
perfectly or not at all. It could be with the driver, and it could be with
Windows XP. It could also be an issue/errata in your amplifier. Many of
them mute for a fraction of a second when the digital input resyncs or
changes format (like when swapping from PCM to AC3 and back).

Its not the amplifier (nor my MD player). It works perfectly well with no
delay or loss when I have my CD player connected optically through the same
input. And just to make sure I set the amp to Pure Direct mode so there is
no processing don on the input signal.


and how do I fix it so that the S/PDIF output is always streaming
with no activation delay

Not something we can offer a miracle fix for unfortunately. Answer the
questions above and more assistance should be forthcoming.

Followup set.

Can you please leave the follow ups to
alt.comp.mainboards.abit,alt.comp.periphs.mainboar d.abit,comp.sys.ibm.pc.soundcard.tech

I am monitoring in
comp.sys.ibm.pc.soundcard.tech


--


Richard Hopkins
Cardiff, Wales, United Kingdom
(replace nospam with pipex in reply address)

The UK's leading technology reseller www.dabs.com

On Thu, 20 Jan 2005 16:57:32 -0000, "Agamemnon"
wrote:

No. The only time the display changes is if I mute the S/PDIF channel on the
volume mixer control on the PC (because it switches the LED off) or when it
switches to Dolby Digital or 5/7.1 mode when I'm playing a DVD. When I'm
playing PCM audio the display remains locked and is always locked even when
the computer is idle. There is not even a flicker when I start to play a
audio file.

Is it possible that while the PC is idling, the SPDIF output runs at a
default rate (say 48kHz), and then if you start playing an audio file
at a different rate (eg. 44.1kHz), either the PC or the AV amp briefly
mutes while the clock rate is changed? I see you say that there isn't
a flicker when you start to play a file, but that might just mean the
AV amp is always seeing a valid SPDIF signal: it (or the PC) might
still mute briefly if the rate changes.
--
Clive Backham

"Clive Backham" wrote in message
...
On Thu, 20 Jan 2005 16:57:32 -0000, "Agamemnon"
wrote:

No. The only time the display changes is if I mute the S/PDIF channel on
the
volume mixer control on the PC (because it switches the LED off) or when
it
switches to Dolby Digital or 5/7.1 mode when I'm playing a DVD. When I'm
playing PCM audio the display remains locked and is always locked even
when
the computer is idle. There is not even a flicker when I start to play a
audio file.

Is it possible that while the PC is idling, the SPDIF output runs at a
default rate (say 48kHz), and then if you start playing an audio file
at a different rate (eg. 44.1kHz), either the PC or the AV amp briefly
mutes while the clock rate is changed? I see you say that there isn't
a flicker when you start to play a file, but that might just mean the
AV amp is always seeing a valid SPDIF signal: it (or the PC) might
still mute briefly if the rate changes.

It not that because I've just played back a 48kHz sample using CoolEdit Pro
and the delay and loss is still there. (If it was a 24 bit sample my amp
should tell me this and my MD player is not even capable of playing it back,
but it can, so its not 24 bit.)

Does anyone else with the same motherboard (ABIT IC7-G) have the same
problem ?

Is there any way I can tell Windows XP to open the audio output channel on
start up and keep it open, ie. make it think is playing back a sequence of
0's all the time, then at least I'll be able to hear the mouse clicks, which
I cannot hear now because they last least then 0.5s.

--
Clive Backham

It sounds like a buffer problem and might be latency related to Windows
Kmixer...based on the WDM -- as opposed to ASIO -- driver model. Do a Google
search for "Kmixer+latency" and you should find some info.

Check this thread too:

http://makeashorterlink.com/?S1054394A

Your Win98 machine uses .vxd drivers which don't introduce latency like the
WDMs.
--
Robert J. Salvi, Ambiance Acoustics
http://www.ambianceacoustics.com
San Diego, CA USA
(858) 485-7514
"Agamemnon" wrote in message
...
I am using an ABIT IC-7G motherboard with an AC7 compatible audio chipset
by Realtek which is connected to my AV amp via an S/PDIF optical cable. I
have all the latest drivers and Windows XP update installed.

According to the AV amp the input is PCM even when the computer is idle
(ie. not playing anything) but every time I try to play a file or Windows
XP tries to play a sound effect such as a mouse click there is a 0.5
second delay before the sound comes out from the AV amp which causes the
complete loss of the first 0.5 seconds of everything I try to play,
including the total loss of every Windows XP sound effect and the first
0.5 seconds of every audio sample in my play lists even if they are set to
play automatically one after the other. At the same time the sound from
the analogue speakers on my monitor which are connected to the same
motherboard comes out fine without any delay or any loss.

The only way I can find of stopping this delay and loss of audio is to
play a file in one audio player and then pause it indefinitely as soon as
it begins and then use another player to play my audio files.

The Dolby Digital and Dolby 5.1 output was working properly when I tested
it with the Star Wars DVD.

Is this a bug in my audio chip set, or the driver or with Windows XP and
how do I fix it so that the S/PDIF output is always streaming with no
activation delay without having to play a file and pause it an leave it on
pause indefinitely.

"R. J. Salvi" wrote in message
...
It sounds like a buffer problem and might be latency related to Windows
Kmixer...based on the WDM -- as opposed to ASIO -- driver model. Do a
Google search for "Kmixer+latency" and you should find some info.

The latency with Kmixer is 30ms which is nothing unless you are looking for
accurate lip sync and it says nothing about this causing a loss of signal
only its dely. The delay that I am experiencing in 0.5s ie. 500ms and I
completely loose all of that length of audio on the S/PDIF output.


Check this thread too:

http://makeashorterlink.com/?S1054394A

Your Win98 machine uses .vxd drivers which don't introduce latency like
the WDMs.

Does Windows XP have a command which opens up the S/PDIF audio channel on
the mixer and keeps it open. If so what is it so I can put it in my AUTOEXEC
file so as to open the channel when Windows starts.

--
Robert J. Salvi, Ambiance Acoustics
http://www.ambianceacoustics.com
San Diego, CA USA
(858) 485-7514
"Agamemnon" wrote in message
...
I am using an ABIT IC-7G motherboard with an AC7 compatible audio chipset
by Realtek which is connected to my AV amp via an S/PDIF optical cable. I
have all the latest drivers and Windows XP update installed.

According to the AV amp the input is PCM even when the computer is idle
(ie. not playing anything) but every time I try to play a file or Windows
XP tries to play a sound effect such as a mouse click there is a 0.5
second delay before the sound comes out from the AV amp which causes the
complete loss of the first 0.5 seconds of everything I try to play,
including the total loss of every Windows XP sound effect and the first
0.5 seconds of every audio sample in my play lists even if they are set
to play automatically one after the other. At the same time the sound
from the analogue speakers on my monitor which are connected to the same
motherboard comes out fine without any delay or any loss.

The only way I can find of stopping this delay and loss of audio is to
play a file in one audio player and then pause it indefinitely as soon as
it begins and then use another player to play my audio files.

The Dolby Digital and Dolby 5.1 output was working properly when I tested
it with the Star Wars DVD.

Is this a bug in my audio chip set, or the driver or with Windows XP and
how do I fix it so that the S/PDIF output is always streaming with no
activation delay without having to play a file and pause it an leave it
on pause indefinitely.

"Agamemnon" wrote in message
...

"Richard Hopkins" wrote in message
...
"Agamemnon" wrote in message...
I am using an ABIT IC-7G motherboard with an AC7 compatible audio
chipset by Realtek which is connected to my AV amp via an S/PDIF
optical cable. I have all the latest drivers



but every time I try to play a file or Windows XP tries to play
a sound effect such as a mouse click there is a 0.5 second delay before
the sound comes out from the AV amp

If you look at the amplifier's display during this delay, do you see it
unlocking/relocking onto the digital signal at all?

No. The only time the display changes is if I mute the S/PDIF channel on
the

Actually, I just tested it again and there is a slight flicker which is so
short I didn't notice it the first time. The amp is behind the computer so I
have to twist round to look at it so its not easy to press play and look at
the amp and monitor at the same time.

What might be happening is that the computer is unlocking the PCM stream
when I press play with just one file playing. If I start to play another
file while the first is playing the unlock does not happen. Why is it doing
this. Can I instruct Windows XP not to unlock the PCM stream. Is there a
setting which tells it I'm using S/PDIF in PCM mode so that it doesn't try
to reset it all the time.

volume mixer control on the PC (because it switches the LED off) or when
it switches to Dolby Digital or 5/7.1 mode when I'm playing a DVD. When
I'm playing PCM audio the display remains locked and is always locked even
when the computer is idle. There is not even a flicker when I start to
play a audio file.