[mythtv-users] Questionable capture quality from a PVR-250

Tom Walsh tom at openhardware.net
Wed Feb 4 15:54:39 EST 2004

brentfisher at shaw.ca wrote:

>I know that this has been touched on before but I still don't have a sense of where the problem lies based on the inconclusive discussions to date.
>The video that I capture is on my PVR-250 is of questionably quality; slightly fuzzy and washed out.  My symptoms are similar to those that Cory described a few days ago, refer to:
>I have been chalking this up to the fact that MPEG-2 is a lossy compression - I'm taking an analog signal, sampling it into a compressed digital format - some degradation is expected.  But increasing the sampling rate should then impove it, right?  This doesn't seem to be the case.
>Then I read some of the conversations on this mailing list and there are those claiming that their systems are outputting video that is in some cases superior to what the tuner on their TV is producing.  Jarod says that it should at least be on par.
>The tuner in my TV produces a noticably crisper picture compared to what I get out of my MythTV box.

Okay, you just might have a tuner card that has a bad crystal oscillator 
and it is off-frequency.  As a last resort, I would put the card into a 
windoze box and load the included Hauppauge software.  That way, if you 
still have lousy video, then you can call Hauppauge to get support and 
they can't bark at you with "we don't support linux".

My PVR-250, PVR-350 setup produces high-quality video recordings and 
output to the TV set.


>I don't suspect that the problem lies with my TV-out as DVD output from xine is quite good.  I have also downloaded some TV show episodes from a newsgroup (which are presumably captured using similar means as I am using) and they seem considerably higher in quality (also played back using xine).
>I have played around with the dnr_* settings and the bitrates but have been unable to affect the capture in any noticable way.
>1. Is it actually possible to get captured video with a PVR-250 that rivals/exceeds the output from my TV's tuner?
>2. Can the location of the card on the motherboard actually make a difference?  I've read some claims to that effect.
>3. Is it possible that my card just isn't very good?
>4. Does anyone have any suggestions as to how I can improve my captures?
>odds & sods:
>PVR-250 w/ remote (not M179)
>I'm using:
>ivtv: 0.1.9
>Firmware: 1.8.22024
>lspci says:
>01:08.0 Multimedia video controller: Internext Compression Inc iTVC15 MPEG-2 Encoder (rev 01)
>        Subsystem: Hauppauge computer works Inc.: Unknown device 4001
>        Flags: bus master, medium devsel, latency 64, IRQ 5
>        Memory at f4000000 (32-bit, prefetchable) [size=64M]
>        Capabilities: [44] Power Management version 2
>tveeprom reports:
>tveeprom.c: starting probe for adapter ivtv i2c driver #0 (0x10005)
>tveeprom.c: detecting tveeprom client on address 0xa0
>  9 [04] 20 77 00 40 38 b7 27 00 
>  3 [05] 8c 00 
>  8 [06] 8c bb 00 00 50 34 9d 
>  2 [07] 70 
>Not sure what to do with tag [07]
>  3 [09] 13 5f 
>Not sure what to do with tag [09]
>  3 [0a] 08 0a 
>  2 [0b] 13 
>Not sure what to do with tag [0b]
>  2 [0f] 01 
>Not sure what to do with tag [0f]
>  2 [10] 01 
>Not sure what to do with tag [10]
>  2 [11] 00 
>Not sure what to do with tag [11]
>tvee: Hauppauge: model=48012, rev=G310, serial#=2602808
>tvee: tuner=Philips FI1236 MK2 (idx=10, type=2)
>tvee: tuner fmt=NTSC(M) (eeprom=0x08, v4l2=0x00001000)
>tvee: audio_processor=MSP3445 (type=12)
>mythtv-users mailing list
>mythtv-users at mythtv.org

Tom Walsh - WN3L - Embedded Systems Consultant
http://openhardware.net, http://cyberiansoftware.com
"Windows? No thanks, I have work to do..."

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