low bitrate artifacts on TV, not on computer [Solved]

Message

csab · Post by **csab** » Fri Jul 28, 2006 1:25 am

Hi,

I've tried to encode some AVI to DVD with transcode. Everything worked, except the final result is not satisfactory on TV. When I use xine or mplayer to watch the DVD on the computer, it is perfect, but on the TV, ugly artifacts show up.

I encoded the material in VCD resolution and 1800 kbps.

I have a Philips DVD 622 player that is usually praised in the reviews. Maybe it doesn't like low bitrates and/or low resolution?

repolho · Post by **repolho** » Fri Jul 28, 2006 3:41 am

Maybe the brightness of your monitor is hiding some of the artifacts.
Are you sure they are artifacts from a low quality encode?
Does the video have the same framerate as your TV expects (30000/1001 for NTSC, 24000/1001 for PAL)?

csab · Post by **csab** » Sat Jul 29, 2006 6:13 pm

repolho wrote:Maybe the brightness of your monitor is hiding some of the artifacts.

No, that's not what is happening, for sure. My TV is probably brighter than my monitor and the artifact are pretty serious, I would certainly see them on the monitor if they were there.

Are you sure they are artifacts from a low quality encode?

I can't imagine anything else. They are those tipical "blocking" artifacts at motion that you see in digital media files that are encoded with very low bitrate.

Does the video have the same framerate as your TV expects (30000/1001 for NTSC, 24000/1001 for PAL)?

Yes. In fact I made two DVDs, one PAL and one NTSC, with the same result. My DVD player supposed to be able to play both (and it does). My TV is NTSC.

chunderbunny · Post by **chunderbunny** » Sun Jul 30, 2006 7:25 am

Mplayer and Xine both do video post-processing to remove blocking and other video artifacts. Try turning off the post processing to see if the artifacts show up on your PC.

csab · Post by **csab** » Thu Aug 03, 2006 1:02 am

OK, maybe a stupid question but exactly how do I tun it off. E.g. for mplayer I tried a few things but I still didn't see any artifacts. So my simple question is what would be a command line for mplayer that turns off all the postprocessing? Thx,

repolho · Post by **repolho** » Mon Aug 14, 2006 3:00 am

I think it would be something like

Code: Select all

mplayer -vf pp=-default

csab · Post by **csab** » Tue Aug 15, 2006 12:14 am

Thanks. Still no artifacts on computer. This is unbeleivable. I can only assume that the DVD player's firmware uses a poor decoding algorithm that works poorly with low bitrate.

csab · Post by **csab** » Sat Dec 02, 2006 7:44 pm

I sort of solved it.

I'm still not sure why, but it appears that my DVD player (Philips DVD 622) doesn't like the VCD resolution. If I encode the video using the normal DVD resolution, it is fine on the TV, even if I lower the bitrate to 2700 kbit/s. Probably the DVD player uses a very poor decoding algorithms for low resolutions.

And yes, I'm sure, the blocking artifacts are indeed artifacts, and not just low resolution. I know it, because it is perfect on the computer without any filters, and because it displays still images on TV perfectly - the artifacts only appear for moving images.