Peter Weissgerber | 8 Feb 21:05 2005
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TT USB Budget cc discontinuity / lost sync.

Hello,

I bought the TT USB DVB-s Budget box and use it as
second device for the VDR software (with LinVDR,
Kernel 2.6.9, DVB drivers from CVS as of Dec 03 2004).

Short recording work without problems. But in longer
records (films etc.) I have artifacts at some places.
When I type "dmesg" I see the following:
ttusb_init_controller: dsp-version: 0.0
DVB: registering new adapter (Technotrend/Hauppauge
Nova-USB).
DVB: registering frontend 0 (Philips TDA8083 DVB-S)...
usbcore: registered new driver Technotrend/Hauppauge
USB-Nova
[...] and then
ttusb_process_muxpack: muxpack with incorrect
checksum, ignoring
ttusb_process_frame: lost sync.
ttusb_process_muxpack: cc discontinuity (2 frames
missing)

What does this mean? Can it be related to the
artifacts I see? (I guess so...)

Reception should be OK, femon plugin tells a STR about
62 and SNR about 81. BER and UNC are 0.

Thanks in advance,
Peter
(Continue reading)

Peter Weissgerber | 9 Feb 12:13 2005
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Re: TT USB Budget cc discontinuity / lost sync.

Hello,

I have made some tests and thus some additional
information.

 --- Peter Weissgerber <peterw2k <at> yahoo.de> schrieb: 
> [TT USB Budget-artifacts and the following error
msg]
> ttusb_process_muxpack: muxpack with incorrect
> checksum, ignoring
> ttusb_process_frame: lost sync.
> ttusb_process_muxpack: cc discontinuity (2 frames
> missing)

The problem seems to occur only with channels that
send with a high bit rate (> about 5 MBit/s). For
example EuroNews (from ZDF transponder) works
flowlessly; RTL, Kabel1 work most of the time but have
occasional artifacts; ZDF, WDR (from WDR transponder)
work never (only artifacts). 

Seems that the transmission over USB is too lame. Can
this be a hardware issue or a driver issue. How can I
tune-up it so that it works (it should work,
shouldn't?)? My board is an VIA EPIA V5000 with USB
1.1 onboard (uhci_hcd). USB is on IRQ 5. This IRQ is
only used by USB.

Some ideas?

(Continue reading)

Johannes Stezenbach | 9 Feb 21:02 2005

Re: TT USB Budget cc discontinuity / lost sync.

Peter Weissgerber wrote:
>  --- Peter Weissgerber <peterw2k <at> yahoo.de> schrieb: 
> > [TT USB Budget-artifacts and the following error
> msg]
> > ttusb_process_muxpack: muxpack with incorrect
> > checksum, ignoring
> > ttusb_process_frame: lost sync.
> > ttusb_process_muxpack: cc discontinuity (2 frames
> > missing)
> 
> The problem seems to occur only with channels that
> send with a high bit rate (> about 5 MBit/s). For
> example EuroNews (from ZDF transponder) works
> flowlessly; RTL, Kabel1 work most of the time but have
> occasional artifacts; ZDF, WDR (from WDR transponder)
> work never (only artifacts). 
> 
> Seems that the transmission over USB is too lame. Can
> this be a hardware issue or a driver issue. How can I
> tune-up it so that it works (it should work,
> shouldn't?)? My board is an VIA EPIA V5000 with USB
> 1.1 onboard (uhci_hcd). USB is on IRQ 5. This IRQ is
> only used by USB.

I know nothing about the TT USB Budget. Anyway:
Did you try to raise ISO_BUF_COUNT? I don't know
how to detect missed iso usb packets, but I guess
that is what happens.

Johannes
(Continue reading)

Peter Weissgerber | 10 Feb 20:00 2005
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Re: TT USB Budget cc discontinuity / lost sync.

Hello Johannes,

 --- Johannes Stezenbach <js <at> linuxtv.org> schrieb: 
[...]
> I know nothing about the TT USB Budget. Anyway:
> Did you try to raise ISO_BUF_COUNT? I don't know
> how to detect missed iso usb packets, but I guess
> that is what happens.

I did not know of this variable until yet. Where can I
change it (I guess somewhere in the source) and what
does this var mean?

Thanks,
Peter

	
		
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Peter Weissgerber | 22 Feb 20:14 2005
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Re: Re: TT USB Budget cc discontinuity / lost sync.

[Sorry, Johannes, for writing you a PM. Accidently,
your mail address was in the "To"-line]

Hi Johannes,

I have tried the box now on another PC (VIA KT266
based mainboard) and have the same problem [only
artifacts when bitrate of channel is > about 5MBit/s,
e.g. for ZDF or WDR Aachen; error messages about "lost
sync"]....

 --- Johannes Stezenbach <js <at> linuxtv.org> schrieb: 
> Did you try to raise ISO_BUF_COUNT? I don't know
> how to detect missed iso usb packets, but I guess
> that is what happens.

... I did try this but it does not help. Maybe the
hardware is simply defective?? Or has anybody a better
idea what is going wrong?

Cheers,
Peter

	
		
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Johannes Stezenbach | 22 Feb 21:04 2005

Re: Re: TT USB Budget cc discontinuity / lost sync.

Peter Weissgerber wrote:
> I have tried the box now on another PC (VIA KT266
> based mainboard) and have the same problem [only
> artifacts when bitrate of channel is > about 5MBit/s,
> e.g. for ZDF or WDR Aachen; error messages about "lost
> sync"]....
> 
>  --- Johannes Stezenbach <js <at> linuxtv.org> schrieb: 
> > Did you try to raise ISO_BUF_COUNT? I don't know
> > how to detect missed iso usb packets, but I guess
> > that is what happens.
> 
> ... I did try this but it does not help. Maybe the
> hardware is simply defective?? Or has anybody a better
> idea what is going wrong?

I know nothing about the TT USB boxes, you could ask
TT support if this is a limitation of the box; or
you could try if it works better with Windoze.
Could also be a problem with USB isoc xfers, AFAIK
some newer boxes use bulk xfers -- maybe there's a
reason...

Johannes

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http://www.linuxtv.org/cgi-bin/mailman/listinfo/linux-dvb

(Continue reading)

Felix Domke | 22 Feb 21:22 2005
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Re: Re: TT USB Budget cc discontinuity / lost sync.

Hi,

>>... I did try this but it does not help. Maybe the
>>hardware is simply defective?? Or has anybody a better
>>idea what is going wrong?
> I know nothing about the TT USB boxes, you could ask
> TT support if this is a limitation of the box; or
> you could try if it works better with Windoze.
> Could also be a problem with USB isoc xfers, AFAIK
> some newer boxes use bulk xfers -- maybe there's a
> reason...
Back in the days when I continued Holger's work, I implemented that
muxpack stuff. It worked very fine, and i was even able to stream two
video services at once (as long as they are below
90%*11Mbit-muxpack_overhead).

This was back on kernel 2.4. I didn't touched the driver since then, but
 started using it some time ago with 2.6, and had these problems as
well, using same hardware.

ISO transfers are fine (in my eyes). (The only problem is that the
bandwidth is totally static, so the muxstream will be stuffed when
there's less.)

I'm not sure what changed since then, maybe something with the ISO urb
scheduling goes wrong, i'm not that familiar with the linux usb stuff
(anymore).

Another thing i could think of would be the DSP's firmware. Iirc it was
uploaded when the driver is loaded, is that still the case?
(Continue reading)

Johannes Stezenbach | 22 Feb 22:30 2005

Re: Re: TT USB Budget cc discontinuity / lost sync.

Felix Domke wrote:
> ISO transfers are fine (in my eyes). (The only problem is that the
> bandwidth is totally static, so the muxstream will be stuffed when
> there's less.)

How does the device/usb-controller know how much bandwidth to allocate?
Or does it always use the maximum (90% of 11Mbit/s)?

Johannes

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Peter Weissgerber | 23 Feb 11:30 2005
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Re: Re: TT USB Budget cc discontinuity / lost sync.

Hi,

 --- Felix Domke <tmbinc <at> elitedvb.net> schrieb: 
> Back in the days when I continued Holger's 
> work, I implemented that muxpack stuff. It 
> worked very fine, and i was even able to
> stream twovideo services at once (as long as 
> they are below 90%*11Mbit-muxpack_overhead).

This means stream until about 9,5 MBit/s should work.
I doubt if any German TV station sends streams larger
than that. The largest I know of are the WDR regional
streams (WDR Dortmund/Aachen/etc) with about 6-8
MBit/s.

> This was back on kernel 2.4. I didn't touched 
> the driver since then, but started using it 
> some time ago with 2.6, and had these problems
> as well, using same hardware.

So this does mean, when I switch to Kernel 2.4 on my
VDR machine, this problem will go away. Ok, I will try
it, but I'm not sure if it is simple because LinVDR
comes without compiler and I don't know how easy it is
to let it run with a 2.4 kernel...

> I'm not sure what changed since then, maybe
> something with the ISO urb scheduling goes
> wrong, i'm not that familiar with the linux
> usb stuff (anymore).
(Continue reading)

Peter Weissgerber | 24 Feb 01:28 2005
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Re: Re: TT USB Budget cc discontinuity / lost sync.

Hi,

I have run some tests...
 --- Peter Weissgerber <peterw2k <at> yahoo.de> schrieb: 
> Hi,
> 
>  --- Felix Domke <tmbinc <at> elitedvb.net> schrieb: 
> > Back in the days when I continued Holger's 
> > work, I implemented that muxpack stuff. It 
> > worked very fine, and i was even able to
> > stream twovideo services at once (as long as 
> > they are below 90%*11Mbit-muxpack_overhead).
[...]
> > This was back on kernel 2.4. I didn't touched 
> > the driver since then, but started using it 
> > some time ago with 2.6, and had these problems
> > as well, using same hardware.

I have installed kernel 2.4.29 now. I tried dvb-kernel
CVS (kernel_2_4 branch) as well as linuxtv release
1.1.1. With all of these has had the same problem.
Seems that the kernel version is not the problem.

Now, I try if it makes a difference if I use
CONFIG_USB_UHCI or CONFIG_USB_UHCI_ALT. The tests
until now have been made with the _ALT version.

Cheers,
Peter

(Continue reading)

Peter Weissgerber | 24 Feb 02:54 2005
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Re: Re: TT USB Budget cc discontinuity / lost sync.

 --- Peter Weissgerber <peterw2k <at> yahoo.de> schrieb: 
> Hi,
> 
> I have run some tests...
>  --- Peter Weissgerber <peterw2k <at> yahoo.de> schrieb: 
> > Hi,
> > 
> >  --- Felix Domke <tmbinc <at> elitedvb.net> schrieb: 
> > > Back in the days when I continued Holger's 
> > > work, I implemented that muxpack stuff. It 
> > > worked very fine, and i was even able to
> > > stream twovideo services at once (as long as 
> > > they are below 90%*11Mbit-muxpack_overhead).
> [...]
> > > This was back on kernel 2.4. I didn't touched 
> > > the driver since then, but started using it 
> > > some time ago with 2.6, and had these problems
> > > as well, using same hardware.
> 
> I have installed kernel 2.4.29 now. I tried
> dvb-kernel
> CVS (kernel_2_4 branch) as well as linuxtv release
> 1.1.1. With all of these has had the same problem.
> Seems that the kernel version is not the problem.
> 
> Now, I try if it makes a difference if I use
> CONFIG_USB_UHCI or CONFIG_USB_UHCI_ALT. The tests
> until now have been made with the _ALT version.

It does not matter if I use UHCI or UHCI_ALT (usb-uhci
(Continue reading)

Peter Weissgerber | 2 Mar 19:19 2005
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Re: Re: TT USB Budget cc discontinuity / lost sync.

Hi,

 --- Felix Domke <tmbinc <at> elitedvb.net> schrieb: 
> Back in the days when I continued Holger's work, I
> implemented that muxpack stuff. It worked very fine,

> and i was even able to stream two
> video services at once (as long as they are below
> 90%*11Mbit-muxpack_overhead).
> 
> This was back on kernel 2.4. I didn't touched the
> driver since then, but started using it some time
> ago with 2.6, and had these problems as
> well, using same hardware.

I have browsed the linuxtv CVS again and think now
that the versions I have tested in the meantime
(linuxtv-dvb-1.1.0 and -1.1.1 with Kernel 2.4.29) may
still be too new. Can you please advice me, how I can
pull an older version that should have worked from
CVS. What kernel version should I use with it, then?

Thanks.

Peter

	

	
		
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