Maybe Im just too picky? Anyone want to take some screenshots to compare?

This doesnt really look too bad in this shot but its not what I really want my TV to look like.

Myth TV Picture

I guess my myth settings could be all screwed up but Ive changed just about everything I can think of.

That is not snowy. Snowy is no picture or picture with like snow artifacts. To me looks like digital distortion or distortion caused by another device like wireless LAN or a bus or power supply frequency is using spread spectrum. I suggest the following.

1) Set video quality to DVD. Play with no sound if your computer can not handle it.
2) Fine tune the reception of each channel
3) Adjust some settings for your CX2X88 chip
4) Use RG-6 quad sheilded cable
5) Buy a Video Isolation Transformer and a FM filter.
6) Test it in Windows. If it gives the same quality, probably the splitter is bad. I had a few splitters went bad on me in my cable TV setup because of weather conditions.

ok you just went right over my head.. If you dont mind, lets take it one step at a time.
where/how do you set video quality to DVD?

Anthing issue is I cannot watch LiveTV at all without the frontend crashing.

In the meantime I will do my best to on the rest of your answers

With my PVR-250, I use ivtvctl -c bitrate=8000000,bitrate_peak=9600000,stream_type=14,audio=0xc9 -d /dev/video1. The device node /dev/video1 is my PVR-250 and device node /dev/video0 is for my saa7133 video capture card. I have ivtv version 0.6.3 because the kernel version that I am using is 2.6.16. I should upgrade to 0.6.6, but the version that I have now works just fine. I normally have to use cat /dev/video1 > video.mpg and then use mplayer to play it. Probably it is fixed if I do upgrade the version to 0.6.6.

Skipping down to number four. Normal cable TV wiring is RG-59. The next grade is RG-6 and it actually better to upgrade to when thinking of using satellite TV or get better performance with cable modems. Quad shielded just means it uses four types of shielding to block all most all signals induced in the line.

5) Buying a video isolation transformer can fix a lot of problems. One is 60 hertz hum caused by ground loops and block a DC supply for an RF amplifier. Buying an FM filter will help block even more frequencies. Probably with an FM filter, it will block the lower channels.

6) Sometimes testing in Windows is the only to really test a device because the software is written by the manufacture instead reversed engineered. Splitters in cable setups are used to create two or more outputs from one line with out putting stress on the transmitter or in this case transmission line. A two-way splitter reduces the signal to -3 dB. A three-way splitter reduces the signal to -6 (I think). You can always add an RF amplifier, but not all cable TV equipment can handle high power like digital cable boxes.

ya, that's not snow... that's a crappy picture.

i agree that there are many causes for this kind of picture... oddly enough, one channel on my cable tv (Fox) always comes in this way while the others look great (even on the regular tv's themselves). Usually it's a reception / cabling / interference issue.

it could also be 'dvd quality' issue as the previous poster stated... if you are recording at say 320 x 240 at a frame rate of 600, then it might look like that too. (dvd quality for ntsc is 720 x 576 at 1798 frames per minute - with deinterlace enabled).

i use mencoder (mplayer) to record, and other than some audio / video sync issues i had, the quality of my video was never a problem.

NTSC is 720x480 not 720x576. 720x576 is for PAL.

Deinterlacing is not needed if you are going to output to a DVD disc.

assuming Im looking at the same settings as you are..
For video compression Im using 720x480
Stream type is set for MPEG-2 PS
Aspect ratio 4:3
Bitrate is 4500
Max bitrate is 6000
Deinterlacing isnt being used since I didnt see a difference in any of the settings (kernel vs bob etc).
Im not using this to output to a DVD disk

Cabeling I have attempted to run the cable from the outside box to the card with as few splitters as possible. I did attempt to get a signal booster but it didnt seem to help. Im not certain what a video isolation transformer is, can one be purchased at a Radio Shack?

I really would like to test the card in windows but other than my server I only have laptops. I guess I could set it up for a dual boot... but would really like to avoid that if possible.

Hauppauge PVR-250
CODEC: MPEG2-PS
Max Bitrate: 9600000 bps (9.6 Mbps)
Bitrate: 8000000 bps (8 Mbps)
Aspect: 1.333 or aspect number 2
FPS: 29.97 (aka 30)
Width: 720
Height: 480

For a video transformer or RF transformer, go to http://www.partsexpress.com/pe/showd...number=180-075.

For a FM filter, go to http://www.partsexpress.com/pe/showd...number=180-375.

I forgot to mention that Conexant MPEG encoders are sensitive to heat, so place them far away from the processor and/or graphic card if possible and make sure there is cool air pulling in the computer case.

... Video Transformer that was posted is actually a filter, not a transformer. The idea is sound though. Filter above common power transmission frequency, passively, and match it to both the characteristic impedance of the line and the input impedance of the average device. 9 bucks, and its in a nice little connector pre-fabbed -- that's fair.

... actually you're half right, PAL is x576, but NTSC is x525. 480 visible, but 525 broadcast (recorded, played, whatever). The proper way to record this, if you want to be real picky about quality, is to image all 525 lines and then crop the top and bottom to crop down to the middle 480. This gets rid of the "junk" lines (the signal lines that contain info about closed captioning and other stuff). To image at only 480 means that you are taking a picture of 525 lines and representing those lines by only 480 other lines. Craps up resolution. This isn't a big deal -- I mean, mine can't even keep up to that rate due to a slow CPU... I'm around half that.

... Deinterlacing is used primarily for transcoding to MPEG-4. I don't know why you're recording in MPEG-2 if you're not outputting it to a DVD. If you're saving it for viewing off the computer, then you're best recording it in MPEG-4 format (Divx / Xvid, etc... I prefer the lavc codec in the ffdshow codec), and it looks pretty darn good! I commonly rip live tv at MPEG-4 with audio as MP3: 900 frames per minute at 500 x 400 something resolution or a little less, and 128kbit mp3 audio.

With those settings, I'm getting about 750 MB per hour.

Not to get stupid here, but have you tried recording with just straight up Mencoder ? Bypass Mythtv and just record on your own and see what happens.

Here's a sample command line... (this requires you to have lame installed from source, mplayer installed [with mencoder obviously], and ffdshow codecs [lavc])

sudo nice --5 /usr/local/bin/mencoder -tv driver=v4l2:width=${WIDTH}:height=${HEIGHT}:immediatemode=0:norm=${REGION}:chanlist=${CHANNELS}:fps= ${FPS}utfmt=yv12:forceaudio:alsa=yes:amode=1:audiorate=${SAMPLEIN}:contrast=${CONTRAST}:brightness =${BRIGHTNESS}:buffersize=${BUFFER} -ovc lavc -lavcopts vcodec=${VCODEC}:vbitrate=${VBITRATE}:mbd=0:v4mv=no:trell=no -oac mp3lame -lameopts cbr:br=${ABITRATE} -endpos ${RECORD_TIME} -o "/opt/tv/out/${NAME}_on_${DATE}.avi" tv://${CHANNEL} -vf ${VFILTER} -af ${AFILTER} > /dev/null

all one line obviously ... change the above variables as follows
# REGION
REGION=NTSC
CHANNELS=us-cable
FPS=29.97
# VIDEO
WIDTH=512
HEIGHT=384
VBITRATE=1800 (start at 900 and work your way up until it tops out... 1798 is "1 for 1")
VCODEC=mpeg4
BUFFER=128
BRIGHTNESS=10
CONTRAST=0
VFILTER=lavcdeint,harddup
# AUDIO
SAMPLEIN=32000 (my card only samples at 32000 consistently... most cards sample at 44100 or 44800 -- find out what yorus does and enter that value)
ABITRATE=128
AFILTER=lavcresample=44100

give it a shot - can't hurt. it it works out, i can send you a more 'put together' script that i ripped that line out of.

A high quality low loss RF transformer costs a lot. Audio or RF Transformers are used to minimize ground loops. It can also block DC if it is not oscillating.

Video lines are not the same as pixels. If you want the highest quality, use 720x480 for NTSC and 720x576 for PAL. Though the highest setting for saa713x chips is 704x480 or 704x576, so you will have to add 16 pixels of black on the right edge of the picture to get 720 for MPEG codecs that can only accept certain resolutions.

PVR cards are only MPEG-1 or MPEG-2 encoders. They are not true capture cards that the user can record raw images. If a user uses mencoder to capture from a PVR card, it will first have to decode the video into raw or whatever colorspace it handles and then encode it with a different codec. On my Pentium 4 2.0 GHz (Northwood core) with 1 GB of RAMBUS memory, it can not encode any faster than 15 frames a second which will lose most of the frames.

You are using a video capture card that you can capture video in raw or whatever colorspace you want. A yv12 colorspace is ok for MPEG codecs, but I suggest using 422p for higher quality although you may have to provide swapuv as a video filter. By specifying 422p as the colorspace or outfmt in mencoder, you will get double the quality in color. mencoder does not capture from saa713x based cards correctly because saa713x based cards process the frames differently than BT878 based cards that the mencoder developers uses for testing (I think). tvtime correctly captures frames from saa713x based cards, but the developer has not yet included a basic video capture that outputs to a file.

hmm... that explains a lot.

i had thought that 'lines' and 'pixels' were interchangeable terms when dealing with television. the fact that you have pointed out (that they are actually different terms) clears up a good deal of confusion for me -- i had noticed some weird stuff when torture testing my home theatre box, and now it is starting to make sense.

i also had no idea that PVR cards were that different than TV-Capture cards. basically, with a PVR the CPU would have to decode to raw, then encode to whatever codec you were using. that's double the amount of work, and definately explains why you can only process 15 frames a second with a machine that is quick enough to do more (if it was dealing with raw video).

as far as 422p ... i tried various other colorspaces, with the apprpriate video filter to compensate, but it used up another 15% CPU while recording. so it pegged at 100%, and when the buffer was full, it dropped lots of frames. that is a limitation of my slow CPU though.

you seem to know a lot about the characteristics of tv card chipsets. would you reccomend a more suitable tv-card for my app? it would have to fit in a regular PCI slot (no PCI-express on the board). thanks!

Ok I guess I was lucky when installing everything I did put the PVR as far away as possible from the others.

Since its regular non-digital cable, Im just using regular coax and yes I do have a cable modem. But I do have one question, I believe a chain is as strong as its weakest link, so if the Cable guy ran RG-59 into my house and I then switch it to RG-6. Will this actually help or will the 5 foot of RG-59 already have ruined the signal?

I'll make the changes to my bitrate, maxbitrate and aspect to mirror yours and let you know if that helps. Im really not worried about space (for now) so I'll try just about anything.

I just ordered the FM Filter and Video Isolation Transformer and should get it around Monday.

I have done 'cat /dev/video1 > video.mpg' and the picture looks really really bad but mplayer doesnt want to play the video so I usually use VideoLAN to view the video or just transfer it to my windows box. I can post the video if you want to see that.

Also can I assume that I dont need any transcoding or deinterlacing?

P.S. I think it should be noted that I live in Rural area and the Cable provider here is very poor.

Thank you for your help.

I got both filters and hooked them up, same picture. I guess my next step is to test the card in a windows box?

Sorry that the filters did not help and you have to test the card in Windows. Though the filter and the transformer can be used in future setups.