Help with H264 related artifact

[xAlienxx]

Hello, newbie here trying to learn about a certain artifact that shows up on a streamed video versus my DVD version. (it's a grainy episode from a 90s show.)

Whenever there's too much going on, the video will show blocks, what I think are 8x8 blocks, when I encode my DVD, even with low settings these blocks never show. What can I do to create a similar effect? I just want to know what causes it, how can it be avoided, and does avoiding it decrease decoding performance(if using software decoding)



Zoomed and highlighted one of the blocks.


This is during a slight pan, after a few seconds the blocks simply vanish but usually if the scene continues to be too detailed, grainy, or whatever, they will form again.
All I know about the streamed video is that it's 640x480, h264 baseline, 29.97, 1300 kbps, and that their 24 fps videos don't share this problem... from what I can tell anyway.

Might as well mention that the reason why I think it's related to h264 is because there are other quality levels on the streaming site that show the artifact differently, so I think this at least proves that it wasn't present in the source.

Any help is greatly appreciated, this has bothered me for quite some time now, heh.

[KarMa]

Whenever there's too much going on, the video will show blocks, what I think are 8x8 blocks, when I encode my DVD, even with low settings these blocks never show. What can I do to create a similar effect? I just want to know what causes it, how can it be avoided, and does avoiding it decrease decoding performance(if using software decoding)

If you want to create these artifacts, use a low bitrate, single pass, with low complexity settings (ultra fast preset in x264 e.g.). Using a higher bitrate and more complex settings will decrease decoding performance.