Op zo, 26-11-2006 te 20:01 +0100, schreef Nicolas: > On Fri, Nov 24, 2006 at 11:08:20AM +0100, Linetec wrote: > > ... > > > > Example of the render pipe command: > > > > yuvcorrect -v 0 -T INTERLACED_BOTTOM_FIRST | mpeg2enc -M 2 -v 0 -r 32 -4 > > > > 1 -2 1 -D 10 -g 15 -G 15 -q 5 -b 9600 -f 8 -o % > > > > > > For one thing you could speed up the coding by deleting the "-r 32". > > > That is past the point of diminishing returns - i.e. you gain almost > > > nothing over the default "-r 16" but the encoding time is longer. > > > > > > I'm curious why 'yuvcorrect' is being used. DV is always bottom > > > field first - is something earlier in the pipeline mangling the > > > field order tag? > > > > Well, as I'm not too experienced yet (did I mention that already? :-), I > > started out by simply copying the pipe command from someone else who > > claimed that this would yield the best results. And indeed I did find a > > noticeable improvement when compared to the basic mpeg2enc -f 8 command. > > However, I *did* look up the man pages to see what each of these > > commands and options does. > > I'm probably the guy who advised you to use that syntax.
Well, sort of - I grabbed it from one of your postings in the Cinelerra mailing list archives. > On the Cinelerra mailing-list, there're often people who even don't know > how to export to mpeg2 while being able to specify the mpeg2enc options. > Anyway, -r 32 is for sure really high. However, users want in 99.99% of > cases the *BEST* quality. Hence the -r 32, even if -r 16 is sufficient > IMO. I've done some tests, and indeed the quality difference between -r 16 -b 8800 on one side and -r 32 -b 9600 on the other is minute at best, and invisible in most scenes. > As regards to the "yuvcorrect -v 0 -T INTERLACED_BOTTOM_FIRST", I added > it because of a bug in Cinelerra, where the field order wasn't properly > set when using the batch rendering feature of Cinelerra. In "normal > rendering", it's not necessary. Ah, good you mention it - I already noticed that it didn't seem to make any difference, and wondered why the command was there at all. I'll try and do some more testing with "difficult" material (sprinkling fountain, boiling water, flames); I guess that any quality issues should be visible here first. Anyway, it's quite an education - and although it involves a bit of a learning curve, I very much like the fact that I'm completely in control of just about every aspect. But then again, I'm quite spoilt in that respect, having used Linux for the past ten years :-) Thanks again, regards Richard Rasker ------------------------------------------------------------------------- Take Surveys. Earn Cash. Influence the Future of IT Join SourceForge.net's Techsay panel and you'll get the chance to share your opinions on IT & business topics through brief surveys - and earn cash http://www.techsay.com/default.php?page=join.php&p=sourceforge&CID=DEVDEV _______________________________________________ Mjpeg-users mailing list Mjpeg-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/mjpeg-users
