G'day I have recently switched to using CVS mjpegtools (from 1.6.2), the latest snapshot being one I took on 24 Dec 2004. I have noticed some interesting artifacts in the mpeg2enc output when viewed on a standalone DVD player when the scene contains rapid movement.
Before I go on, it seems that in general movement appears smoother with this CVS snapshot than with 1.6.2. It might just be me though. I have a scene rendered in blender. I did field interlaced PNG output (bottom field first, which I have verified by looking at the resulting frames) which went through a rather tortuous route to MPEG (mainly due to the need to get them into cinelerra for editting first): ls *.png | xargs -n 1 pngtopnm | encodedv --fps=25 raw.dv mencoder raw.dv -o raw.avi -ovc copy -nosound [ into cinelerra, exported to QT/DV foo.mov ] lav2yuv foo.mov | mpeg2enc -f 8 -q 5 -c -s -E -10 -N 0.5 -o foo.m2v mplex -f 8 -V foo.m2v sound.m2a -o foo.mpg [ on to DVD via dvdauthor, mkisofs, growisofs ] I think they are the correct command lines but I'm going from memory here. Note that DPME *isn't* enabled here (it's off by default in CVS). At one point in the scene there is rapid movement whereby something solid moves approximately 20% of the frame width within one frame. Playing at fullspeed on the DVD player, the edges look a little jumpy as the movement occurs. Freezeframing at this point (the player does internal deinterlacing) reveals blocky artifacts on either side of this solid object which roughtly trace the shape of the object's location in the previous frame. The artifacts are the same colour as the object but with much less intensity. There doesn't appear to be much texture within each block. I don't believe this is an interlacing issue - I think that part of things is fine. The result is generally very smooth which isn't the case if interlacing is wrong or isn't generated in blender. Using "-q 4" to mpeg2enc doesn't make any difference. As far as I can tell, mplayer doesn't show these artifacts; it looks like another "hardware player" decoding issue which I happen to hit (like DPME :( ). Speaking of DPME (which my player also doesn't like) I'm wondering whether the issues I saw with DPME were just another angle on the present issue. Removing DPME from the encoding certainly makes things watchable - with DPME things are very jumpy; however, one effect of DPME on my player are blocky artifact trails. With DPME they are *much* more intense than the ones I'm seeing now (and possibly kick in at lower speeds), but I don't like ruling anything out. Any ideas? Playing with the -E and -N flags doesn't appear to make any difference (-E 5 -N 0.25 tried with no visible change). Hardware for mpeg2enc and friends: 550 MHz Pentium 3. I have blocking in other places: if the scene is generally dark but with some movement in places, the moving fetures tend to get blocky. I'm wondering whether it's two issues - this I guess could be caused by the use of -E. Another place I've seen it is if you have a scene which is faded out over the course of 1-2 seconds. As it fades, blocky artifacts are seen. Again, might this be due to -E? Regards jonathan ------------------------------------------------------- This SF.Net email is sponsored by: IntelliVIEW -- Interactive Reporting Tool for open source databases. Create drag-&-drop reports. Save time by over 75%! Publish reports on the web. Export to DOC, XLS, RTF, etc. Download a FREE copy at http://www.intelliview.com/go/osdn_nl _______________________________________________ Mjpeg-users mailing list Mjpeg-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/mjpeg-users
