I'm actually getting the same problem with videos long before they have been sent to YouTube or even gone through Kino or AVIDemux. So it isn't a YouTube conversion problem.
Here are some sample clips.
http://s4.photobucket.com/albums/y12...le-Clip-02.mp4 - Freshly Captured Unprocessed Clip
http://s4.photobucket.com/albums/y12...y-Sample-1.mp4 - A short sample that was made with Kino after being captured with WinDVR
http://s4.photobucket.com/albums/y12...y-Crockett.mp4 - A full length piece that was also put together via Kino
And running mediainfo on a couple of the files gave this:
For the Small World clip:
Format : MPEG-PS
File size : 41.1 MiB
Duration : 45s 0ms
Overall bit rate : 7 658 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 : 44s 845ms
Bit rate mode : Variable
Bit rate : 7 281 Kbps
Nominal bit rate : 11.1 Mbps
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 : Progressive
Bits/(Pixel*Frame) : 0.703
Stream size : 38.9 MiB (95%)
Audio
ID : 192 (0xC0)
Format : MPEG Audio
Format version : Version 1
Format profile : Layer 2
Duration : 45s 0ms
Bit rate mode : Constant
Bit rate : 224 Kbps
Channel(s) : 2 channels
Sampling rate : 48.0 KHz
Video delay : -9ms
Stream size : 1.20 MiB (3%)
For the Detroit Rock City clip:
Format : MPEG-PS
File size : 16.4 MiB
Duration : 35s 880ms
Overall bit rate : 3 827 Kbps
Video
ID : 224 (0xE0)
Format : MPEG Video
Format version : Version 2
Format profile : Main@Main
Format settings, BVOP : No
Format settings, Matrix : Default
Duration : 35s 836ms
Bit rate mode : Variable
Bit rate : 3 687 Kbps
Nominal bit rate : 4 000 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
Bits/(Pixel*Frame) : 0.356
Stream size : 15.8 MiB (96%)
Audio
ID : 192 (0xC0)
Format : MPEG Audio
Format version : Version 1
Format profile : Layer 2
Duration : 35s 880ms
Bit rate mode : Constant
Bit rate : 64.0 Kbps
Channel(s) : 2 channels
Sampling rate : 48.0 KHz
Stream size : 280 KiB (2%)