[pvrusb2] hauppage hvr-1900 on raspberry pi

[Emmanuel Touzery]

and btw when saving to SD the CPU is at 15% maximum.

On Wed, Jun 6, 2012 at 8:41 PM, Emmanuel Touzery <etouzery at gmail.com> wrote:

> Hello,
>
>  I have a Hauppage hvr-1900 that I use with an old PC, but that PC has the
> usual downsides: it's big, loud and power-hungry. So I bought a raspberry
> pi, hoping to use it to control the USB hauppage and use it for TV
> recording.
>
>  The driver works beautifully even though the pi is an ARMv6 device. All I
> had to do was compile the kernel with the driver enabled and copy the
> firmware and then it literally worked out of the box.
>
>  But then of course there is a but ;-)
>
>  It cuts when saving the video. There are drop-outs in the video.
>
>  I googled the topic and found this:
> http://comments.gmane.org/gmane.linux.drivers.pvrusb2/2006
>
>  And this helped. Well with chrt it freezes the pi after a while, but with
> nice -20 I think it doesn't cut anymore for AV IN mpeg2 videos. I'm not
> 100% sure but I watched 15 minutes of video and there was no cut. I'll need
> more thorough testing to be 100% sure though. However for DVB-T recording
> the cuts are still there, and I just can't manage to get rid of them.
> Besides that flywheel app, and using a fifo, I've tried overclocking the
> pi, building a non-preempt kernel (just in case), stopping as many daemons
> as I could on the linux userspace, but nothing helps. I have measured the
> SD card on which I write to write at 3Mb/s and more (up to 4). The mpeg2
> stream is ~1Mb/s. And in fact here we have SD h264 dvb-t so the stream that
> gets written to the SD card has a much lower bitrate when recording dvb-t
> (and that cuts) than from av-in (which let's say doesn't cut). So in theory
> it's not the SD card writing speed which is the bottleneck.
>
>  Of course it's possible that the AV in mpeg2 stream still gets cut but
> that thanks to the error resilience in mpeg2 it's not that seen, while in
> h264 at the cuts, the video gets corrupted for a short time and you can't
> miss it.
>
>  Anyway, I'm a bit of a loss on this one. Is the CPU or the I/O (from
> hauppage or to SD) on the pi just too slow, or does anybody have an idea
> how to make it work? Specifically for DVB-T, I was told that the kernel
> does PID filtering in software. Maybe it slows things down, or is it that
> fast that even on a lowly CPU like that pi's, it could for sure be done
> realtime? I guess I can't turn it off and save the full unfiltered stream?
> Though then my SD card bandwidth could start being a problem I guess.
>
>  Anyway, any advice is welcome. I'm not giving up, but I'm definitely
> running out of ideas...
>
> emmanuel
>