Doom9's Forum - View Single Post - Pls help me understand B, I & P frames and psy-rd

J_Darnley · 5th April 2009, 01:50

1) An I-frame (or key frame) is one that does not depend on any other. A P-frame is one that involves prediction/compensation from other previous frames. A B-frame is one that that involves prediction/compensation from previous and future frames. B-frames are good because they are small. With a good encoder/format B-frames don't have to look bad.

2) Psy-rd is a psycho-visual adjustment in x264. It try to retain a similar frame complexity as in the original because this looks good.

3) x264 supports psy-rd. What is it? You just asked and I just answered. For more see: http://forum.doom9.org/showthread.php?t=138293

4) Yes but more makes x264 slower and there are level-related restrictions.

5) x264's verbose switch is --verbose (-v for short). In future check x264 --longhelp

Finally: H.264 is a video format, x264 is an encoder for that format.

5th April 2009, 01:50	#2 \| Link
J_Darnley Registered User Join Date: May 2006 Posts: 957	1) An I-frame (or key frame) is one that does not depend on any other. A P-frame is one that involves prediction/compensation from other previous frames. A B-frame is one that that involves prediction/compensation from previous and future frames. B-frames are good because they are small. With a good encoder/format B-frames don't have to look bad. 2) Psy-rd is a psycho-visual adjustment in x264. It try to retain a similar frame complexity as in the original because this looks good. 3) x264 supports psy-rd. What is it? You just asked and I just answered. For more see: http://forum.doom9.org/showthread.php?t=138293 4) Yes but more makes x264 slower and there are level-related restrictions. 5) x264's verbose switch is --verbose (-v for short). In future check x264 --longhelp Finally: H.264 is a video format, x264 is an encoder for that format. __________________ x264 log explained \|\| x264 deblocking how-to preset -> tune -> user set options -> fast first pass -> profile -> level Doom10 - Of course it's better, it's one more.