Capturing/Converting question

[curt1sw]

Hello,

I have a Haupage PVR150 video card. I am using GBPVR to capture TV shows. Each 30 minute show I capture is around 1 gig in mpg format.

I tried converting the mpg to divx with DivX Converter program afterwards. The resulting file was not much smaller at all and the quality was much worse.

For a 30 minute show what settings do I need to use when capturing with GBPVR? WHat program should I use to convert afterwards? I was thinking a 30 minute program should be no bigger than 175MB and in good quality.

Thanks!
Curtis

[Baldrick]

Use a program where you can set the output size / bitrate like AutoGK, Dr DivX, avi.net.

And try lower the video frame size / resolution also like 320x240.

And capture in highest possible quality (= higher bitrate = biggger file size) to get best quality when reconverting to divx or xvid.

[jagabo]

The size of the recording depends on the bitrate you use. I don't know GBPVR but if you have WinTV2000 installed use Pref -> Movies -> Advanced to see the bitrates used for the different preset recording modes. File size = bitrate * running time.

For creating Divx files you should make your original MPEG2 recording at a high bitrate setting then convert to Divx. Try starting with the 12 Mbit/sec CBR preset. A 30 minute recording at that setting will result in a ~3GB MPEG2 file.

Don't expect noisy analog recordings to compress as well as a typical DVD rip. All that picture noise makes the video less compressible. DVD rips usually start with 24 fps progressive video. You will be starting with 30 fps interlaced video. That means there are 25 percent more frames per second to encode, and hence a 25 percent higher bitrate to get the same quality. Add all the video noise and you'll probably need twice the bitrate. You'll probably also want to deinterlace or inverse telecine for Divx files.

For best results at a specific file size you should use a 2-pass encoding with Divx. Again, file size = bitrate * running time. You can use a bitrate calculator to deterime what bitrate to use for a given running time. If you want a 175 MB Divx AVI file from a 22 minute video (typical running time after removing commercials) you will want to use a variable bitrate around 900 kbps for the video, 128 kbps for the audio.

[curt1sw]

Hey thanks for the followup. Have you used GBPVR? I dont know if I am capturing in the highest quality, because I cant find that stuff in the config.

So programs like AutoGK/dr. divx are just for converting then?

Thanks!
Curtis

[mats.hogberg]

I think GBPVR has 3 presets (it was a while since I used it) High medium and low quality. As mentioned, WinTV2000 gives you better ways to control the capture quality/bitrate.
Analog captures are by nature noisy, which eats bitrate - they don't compress well. You may consider filtering your mpg using AviSynth before feeding the video to your XviD/DivX encoder.

/Mats

[curt1sw]

What are "analog" captures?

Thanks

[curt1sw]

>You'll probably also want to deinterlace or inverse telecine for Divx files.

How do I do this? When do I do this? What software? Sorry I am new

Curtis

[mats.hogberg]

What are "analog" captures?

"Analog" like in "from the aerial coax, or s-video". What the PVR150 captures.
In contrast to "digital captures" where you feed a digital data stream into the computer (which is more data transfer than capture), let's say from a DVB-T "tuner/capture" card.

/Mats

[curt1sw]

Ok just so I have this straight:

1. If capturing with GBPVR capture with "High Quality"
2. Run AviSynth on mpeg2 capture
3. deinterlace or inverse telecine for Divx files????
4. Use AutoGK/Dr DivX/avi.net to convert to DivX. try lower the video frame size / resolution also like 320x240

IS this all I need to do??? What do I need to do step 3??

Man this is confusing! lol

Thanks,
Curtis

[mats.hogberg]

Well, avi.net uses the degrain filter, and can interlace too - as you encode. A one step process. From captured mpg to XviD/divX one one go, denoised and deinterlaced (if you want to)

/Mats