DVD quality captures...I'm almost there, help!

[roshrin]

Okay, I've been using my Sony HC42 to capture from VCR. Using the DV format it creates a 24 gig file for 1hr 52min of capture. The quality is AWESOME, as perfect a picture as you can get.

Now I import this into DVDit and try and create a DVD. I basically have to to the transcode to find the best bite rate for the size. It seems it has to drop down from the awesome 8000 (which say it will need 7.8 gig disc space) to probably somewhere around 4800-5000. So i do this and the quality SUFFERS!!! ugh. Actually this will occur whether i am xfering from my DV tape.

What gets my goat is that I have actual DVD's by the same company as my VHS and they fit the same length, 2 hours onto one 4.7 DVD (i know cuase i can copy the whole disk onto another 4.7)

So HOW do they get that perfect DVD quality onto 4.7 disc???

I've been working with vhs capturing for years (though it was through a capture card and not my new firewire sony)

What am I missing???

thanks

[jagabo]

They don't start with noisy telecined VHS tapes.

[edDV]

I'm surprise that your VHS tape playback looks good to you vs. the DVD version.

VHS is a low quality format and very noisy. That noise will defeat motion detection in the MPeg2 encoder forcing it to use more in frame compression. That requires higher bitrate to compensate.

Two strategies come to mind. First is to use dual layer media or split the tape over two DVD-5 discs. Second is the traditional compromise of heavy noise filtering. This will remove some detail but give the encoder something to work with.

[jagabo]

Encode at 352x480. You'll lose a tiny bit of resolution but the low bitrate will be sufficient.

[tug_hill2]

Hello, You might want to try using a variable bitrate to do the encoding. I like using Vegas video version 5 to transcode my uncompressed DV to mpeg-2. And the quality is GREAT.



Doc_B

[roshrin]

I'm surprise that your VHS tape playback looks good to you vs. the DVD version.

VHS is a low quality format and very noisy. That noise will defeat motion detection in the MPeg2 encoder forcing it to use more in frame compression. That requires higher bitrate to compensate.

it may very well be the motion detection, i hadnt thought of that. THANK YOU for bringing that up!! It's just that the picture was very very clear in my 24 gig capture but if it cant combine frames (which i think it does) it will have to use more space.


SO...if i take 2 hours of video that i took WITH my DV cam it SHOULD fit nicely onto one 4.7 disc with a higher compression?

[jagabo]

if i take 2 hours of video that i took WITH my DV cam it SHOULD fit nicely onto one 4.7 disc with a higher compression?

Most DV camcorders are pretty noisy -- especially in low light conditions. Most people don't use a tripod when filming so the camera shakes and rotates a lot. Most DV camcorders shoot 60 fields per second rather than 23.976 progressive frames per second. All these things will make it harder for the MPEG compressor.

[edDV]

if i take 2 hours of video that i took WITH my DV cam it SHOULD fit nicely onto one 4.7 disc with a higher compression?

Most DV camcorders are pretty noisy -- especially in low light conditions. Most people don't use a tripod when filming so the camera shakes and rotates a lot. Most DV camcorders shoot 60 fields per second rather than 23.976 progressive frames per second. All these things will make it harder for the MPEG compressor.

Agreed. Handheld camcorder material with constant X, Y and rotational motion not to mention overuse of zoom is as much a worse case as VHS. Even a high quality low noise camcorder will still overwhelm MPeg encoder motion detection forcing the encoder to turn to higher intraframe compression to meet average VBR and thus lowering quality.

Camcorder material should use high bitrates* unless shot "film style" with tripod, lighting plus controlled focus, pans and zooms. A tripod is the single most important factor to getting two hours on a DVD with adequate quality.

Most of what you record off TV has been professionally shot and thus is a candidate for higher compression.


* I use 8000-9100 Kb/s CBR (60-75min.) for DV material. DV is 25Mb/s with all intraframe compression. In order to compress that 3x more to 8300Kb/s, one hopes the encoder can use a maximum amount of interframe (motion) compression. The MPeg encoder will try motion compression first and then turn to more intraframe compression to meet the specified average bitrate. There is a huge difference between asking for 8000Kb/s vs. 4500Kb/s average bitrate assuming you maintain 720x480/576 frame size.

[geowharton]

I've been doinging what you are going through for about two years now. Every small defect in a video is amplified when encoding to MPG. If you have more hard drive (and a seporate one), use a lossless codec like Huffyuv instead of DV. The capture file of 2 hours of video will be anywhere from 45 to 65 GB depending on action, color change, etc. I can definately see the difference of this when compressing 2 hrs to fit on a 4.7. The lossless codec is better than DV.

Cheers.