[pvrusb2] hauppage hvr-1900 on raspberry pi

[Felix Lighter]

Saving to a network share (e.g. NFS with intermediate block size)
might perform better.
The Ethernet port is likely to be much better served by the CPU's DMA
facilities than its SD interface is.

Cheers, FL

On 6 June 2012 14:45, Emmanuel Touzery <etouzery at gmail.com> wrote:
> 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
>>
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