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conversion from VHS to DVD, why is some of the image quality so much worse than in the intermediate DV file?

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David Paine
conversion from VHS to DVD, why is some of the image quality so much worse than in the intermediate DV file?
on Jan 11, 2015 at 11:08:45 pm

I haven't noticed anyone mentioning the precise problem I am experiencing, but I would like to understand what I am observing.

Here is my setup:
20-year old VHS tape played on S-VHS player
S-VHS player attached via S-video cable to Canopus ADVC 100
ADVC 100 attached via 1394 cable to Windows 8.1 PC
DV captured through Vegas Pro v12

Capturing for about 10 minutes yielded an avi file with the properties listed in block 1 below, but summarizing--> file size 2.87 GB, format DV, 720 x 480, interlaced (bottom field first), NTSC, 29.97 fps, 24 mbps video bit rate.

Playing back the captured DV file on my computer, I was pleasantly surprised at the video quality I was observing.

In trying to produce a DVD from this DV file using Vegas Pro and DVD Architect with appropriate NTSC profiles, I was very dissatisfied with the video quality that was output from a DVD player. Specifically, landscapes and peoples' faces were smudged (that blurry, plastic, watercolor look). Other than those types of scenes the image quality was fine.

The media information for the DVD VOB is in block 2 below.
Summarizing it --> file size 771 MB, format MPEG-PS V2, 7270 x 480, interlaced (bottom field first), NTSC, 29.97 fps, 8 mbps video bit rate.

Clearly, the video file on the DVD is far smaller than the DV file captured from the VHS tape, so it is reasonable that the DVD quality would be reduced...
A. but a typical DVD can deliver a pretty high quality image at 8 mbps, and
B. my computer can generate a pretty good picture from the captured DV file prior to rendering for DVD

So, my questions are:
why the disparity for certain image types?
How can I improve the image quality when building the files for a DVD?

Thanks for your insights,

- David P


************ block 1 *******************************************************
General
Complete name : H:\TTS video\TTS2 - Clip 001.avi
Format : AVI
Format/Info : Audio Video Interleave
Commercial name : DV
Format profile : OpenDML
File size : 2.87 GiB
Duration : 13mn 30s
Overall bit rate mode : Constant
Overall bit rate : 30.4 Mbps
TAPE : TTS2
TCOD : 3537534000
TCDO : 11641630000
VMAJ : 4
VMIN : 0
STAT : 24288 0 3.120727 1
DTIM : 0 0

Video
ID : 0
Format : DV
Codec ID : dvsd
Codec ID/Hint : Sony
Duration : 13mn 30s
Bit rate mode : Constant
Bit rate : 24.4 Mbps
Encoded bit rate : 28.8 Mbps
Width : 720 pixels
Height : 480 pixels
Display aspect ratio : 4:3
Frame rate mode : Constant
Frame rate : 29.970 fps
Standard : NTSC
Color space : YUV
Chroma subsampling : 4:1:1
Bit depth : 8 bits
Scan type : Interlaced
Scan order : Bottom Field First
Compression mode : Lossy
Bits/(Pixel*Frame) : 2.357
Time code of first frame : 00:05:53;22
Time code source : Subcode time code
Stream size : 2.71 GiB (95%)

Audio
ID : 1
Format : PCM
Format settings, Endianness : Little
Format settings, Sign : Signed
Codec ID : 1
Duration : 13mn 30s
Bit rate mode : Constant
Bit rate : 1 536 Kbps
Channel(s) : 2 channels
Sampling rate : 48.0 KHz
Bit depth : 16 bits
Stream size : 148 MiB (5%)
Alignment : Aligned on interleaves
Interleave, duration : 267 ms (8.00 video frames)
Interleave, preload duration : 266 ms




************ block 2 *******************************************************
General
Complete name : D:\transitory\DVD Architect image\TTS\VIDEO_TS\VTS_01_1.VOB
Format : MPEG-PS
File size : 771 MiB
Duration : 10mn 59s
Overall bit rate mode : Variable
Overall bit rate : 9 797 Kbps

Video
ID : 224 (0xE0)
Format : MPEG Video
Format version : Version 2
Format profile : Main@Main
Format settings, BVOP : Yes
Format settings, Matrix : Default
Format settings, GOP : M=3, N=15
Duration : 10mn 59s
Bit rate mode : Variable
Bit rate : 8 066 Kbps
Maximum bit rate : 9 500 Kbps
Width : 720 pixels
Height : 480 pixels
Display aspect ratio : 4:3
Frame rate : 29.970 fps
Standard : NTSC
Color space : YUV
Chroma subsampling : 4:2:0
Bit depth : 8 bits
Scan type : Interlaced
Scan order : Bottom Field First
Compression mode : Lossy
Bits/(Pixel*Frame) : 0.779
Time code of first frame : 00:00:00:00
Time code source : Group of pictures header
Stream size : 635 MiB (82%)

Audio
ID : 189 (0xBD)-160 (0xA0)
Format : PCM
Format settings, Endianness : Big
Format settings, Sign : Signed
Muxing mode : DVD-Video
Duration : 10mn 59s
Bit rate mode : Constant
Bit rate : 1 536 Kbps
Channel(s) : 2 channels
Sampling rate : 48.0 KHz
Bit depth : 16 bits
Delay relative to video : -67ms
Stream size : 121 MiB (16%)


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Sorin Nicu
Re: conversion from VHS to DVD, why is some of the image quality so much worse than in the intermediate DV file?
on Jan 12, 2015 at 6:02:48 pm

Try to use the two-pass encoding.


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John Rofrano
Re: conversion from VHS to DVD, why is some of the image quality so much worse than in the intermediate DV file?
on Jan 12, 2015 at 10:15:02 pm

[Sorin Nicu] "Try to use the two-pass encoding."
Definitely try Two-Pass under Customize Template. You also have to realize that DV uses 4:1:1 color sampling and DVD MPEG2 uses 4:2:0 which means your final video uses 4:1:0 color sampling. That's pretty poor so don't expect much.

~jr

http://www.johnrofrano.com
http://www.vasst.com



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Sorin Nicu
Re: conversion from VHS to DVD, why is some of the image quality so much worse than in the intermediate DV file?
on Jan 12, 2015 at 10:47:58 pm
Last Edited By Sorin Nicu on Jan 12, 2015 at 10:50:20 pm

[John Rofrano] "DV uses 4:1:1 color sampling and DVD MPEG2 uses 4:2:0"
That's what's sad.
I thought that because DV uses 4:1:1 subsampling in NTSC/60 Hz variant and 4:2:0 subsampling in PAL/50 Hz variant, DVD MPEG2 will do the same.
But no, they know better :)


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John Rofrano
Re: conversion from VHS to DVD, why is some of the image quality so much worse than in the intermediate DV file?
on Jan 13, 2015 at 12:49:15 pm

You're correct. I should have said NTSC DV uses 4:1:1 because PAL DV does use 4:2:0 which maintains better color when printing to DVD. I was commenting based on the specs that were posted which clearly said, "Chroma subsampling : 4:1:1" and therefore I assumed NTSC.

~jr

http://www.johnrofrano.com
http://www.vasst.com



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Nigel O'Neill
Re: conversion from VHS to DVD, why is some of the image quality so much worse than in the intermediate DV file?
on Jan 12, 2015 at 11:55:36 pm

[John Rofrano] "That's pretty poor so don't expect much."

John, does that mean that using the default DVD template of Vegas and 2 pass encoding is the optimal way to preserve quality when trying to preserve VHS recordings? In my case, I used DV pass through from an old DV camera into firewire to capture. I did notice that there was a softening of the overall image, but put that down to conversion/compression. Are there any tricks of the trade to preserve quality when working with VHS?

My system specs: Intel i7 970, 12GB RAM, ASUS P6T, Vegas Pro 12 (x64), Windows 7 x64 Ultimate, Vegas Production Assistant 1.0, VASST Ultimate S Pro 4.1, Neat Video Pro 2.6


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Sorin Nicu
Re: conversion from VHS to DVD, why is some of the image quality so much worse than in the intermediate DV file?
on Jan 13, 2015 at 12:05:57 am

Maybe a dedicated MPEG2 converter will work better in preserving the VHS quality? Similar with:

http://www.newegg.com/Product/Product.aspx?Item=N82E16815116029


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John Rofrano
Re: conversion from VHS to DVD, why is some of the image quality so much worse than in the intermediate DV file?
on Jan 13, 2015 at 12:52:46 pm

[Sorin Nicu] "Maybe a dedicated MPEG2 converter will work better in preserving the VHS quality?"
Yea, that's what I was going to say. I purchased an MPEG2 capture device a long time ago specifically for capturing VHS tapes that I just wanted to send directly to DVD. I concluded that it was better to just buy a VHS to DVD player/recorder that cut the computer out completely (much quicker).

~jr

http://www.johnrofrano.com
http://www.vasst.com



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David Paine
Re: conversion from VHS to DVD, why is some of the image quality so much worse than in the intermediate DV file?
on Jan 15, 2015 at 6:01:46 am

A ten minute capture lets you try lots of experiments without big effort and time penalties. The suggestions in this thread have led to some improvements in VHS-to-DVD conversion quality, but after lots of A-B comparisons, and after learning a bit about video format conversion (and color sampling), I am realizing that there are fundamental barriers imposed by the source material and the technology available to me.

All things considered, I am satisfied with the modest quality improvements that I have obtained.

Thanks to the responders to my original question.


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John Rofrano
Re: conversion from VHS to DVD, why is some of the image quality so much worse than in the intermediate DV file?
on Jan 15, 2015 at 1:37:48 pm

Glad we could help.

~jr

http://www.johnrofrano.com
http://www.vasst.com



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