-----BEGIN PGP SIGNED MESSAGE----- Hash: SHA1 On Tuesday 24 Aug 2004 04:16, Selva Nair wrote: > Hi Anne, > Hi, Selva
> At last I managed to reproduce your stuttering audio on another machine > with the latest xine (xine-lib-1-rc5, xine-ui-0.99.2). The older > version of xine plays it fine, though. > Interesting. > After some experimentation this is what I have concluded. The audio > stutters when the average bitrate is much below the dvd rate (see below) > but is mplexed at the dvd rate (with -f 8). This could be something > peculiar about this version of xine, may be not. xine-0.9.20, mplayer and > vlc play the clip fine. > > I suggest you to do a few more tests before burning to a dvd. Although you > made this video with -b 4500, the average rate is kess than 2000 kbps, > possibly because this is made from still images. So remake it with -f 8 > and low value of quantization, say -q 4 or even lower. The idea is to get > a decent bitrate of 5000 kbps or so which amounts to a total size of 70 MB > for your 116 second stream instead of the current 24 MB or so. If you have > to lower the q value to get to that size, do it. Lower the q better is > your quality as long as the average rate does not not get too close to the > peak rate (a 20% room is recommended). Although for normal full size > video such low values of q are not recommended, in this special case > of still images you can go pretty low. By the way, the default peak > bitrate for "mpeg2enc -f 8" is 7500kbps; aim for an average of > 5000 or so - it may be hard to get more than that with stills. > You can make a quick estimate of the average bitrate from the file size > as > > average video bit rate = m2v size in bytes * 8 / duration in seconds > > Multiplex as dvd and test it with xine again. > > $ lav2yuv coda.eli | mpeg2enc -f 8 -q 4 -4 2 -2 1 -o coda.m2v > > (add scaler if the source is not 720x576) > > $ lav2wav coda.eli | mp2enc -r 48000 -o coda.mp2 > > $ mplex -f 8 coda.mp2 coda.m2v -o coda.mpg > > Let's see how this goes. > I've left the whole quoted, because it will be useful in the archives, I think. This is definitely the right track. Encoding at -q 4 brought fewer stutters, -q 3 didn't seem much better - the file size was not much bigger, and there were still quite a few stutters. At -q the file size shot up to around 56 MB, and the only stutters were one at the beginning, where there was a fault in the input file, so unavoidable, and in the last 2-3 seconds. Although it's not perfect I could live with that. > > disk performance is usually a non-issue for dvd rate mpeg2 > playback. OK - fine. Tutorial time again, though ;-) First, what do these parameters mean (it's not obvious from the man page)? - -4 2 -2 1 Then, the problems I've had appear to be caused by the way I have created the avi. This was done by grabbing a series of single frames, creating 25fps avis from them, creating transition avis, then writing an eli that could bring them together into one. Is there any way I could have lessened the chances of the problems I've had? Could they, for instance, be made interlaced in some way? And would it have helped? Or is it maybe that I didn't get a good quality sound grab in the first place? If so, again, recommendations would help. Finally, the main recording is in the form of a series of avis (filename02%.avi), interlaced. The coda is formed from a series of non-interlaced avis. I know I can't create a transition between the, but will I encounter problems when I try to stitch them together into one long production? I guess it's time to start reading up on dvdAuthor, too. Anne - -- Registered Linux User No.293302 Have you visited http://twiki.mdklinuxfaq.org yet? -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.2.4 (GNU/Linux) iD8DBQFBK0HZkFAvMr/nNX8RAqpAAJ9+x36yKKetLdVhmAfXwlvNWP/9SgCfYg80 Tq7KSxsHhPBioNVCzmCRFxU= =SCUg -----END PGP SIGNATURE----- ------------------------------------------------------- SF.Net email is sponsored by Shop4tech.com-Lowest price on Blank Media 100pk Sonic DVD-R 4x for only $29 -100pk Sonic DVD+R for only $33 Save 50% off Retail on Ink & Toner - Free Shipping and Free Gift. http://www.shop4tech.com/z/Inkjet_Cartridges/9_108_r285 _______________________________________________ Mjpeg-users mailing list [EMAIL PROTECTED] https://lists.sourceforge.net/lists/listinfo/mjpeg-users
