On 10 Dec 2002, Florin Andrei wrote: > On Mon, 2002-12-09 at 08:00, Selva Nair wrote: > > > > On 8 Dec 2002, Florin Andrei wrote: > > > > > > [export_mpeg2enc.so] cmd=mpeg2enc -v 0 -q 3 -f 5 -4 2 -2 3 -b 2900 -F 4 > > > -n n -V 230 -o "casa".m2v -a 2 > > > [export_mp2enc.so] (44/4096) cmd=mp2enc -v 0 -r 44100 -b 128 -s -o > > > "casa".mpa > > > > Bit rate of 2900 is out of specs for SVCD and may not play well on many > > stand alone players. > > Hmmm... > I'm by no means an expert, but i've heard people saying that the > "non-standard" SVCDs will actually play just fine on most standalone > players. > I did a bit of testing myself, and indeed my SVCDs can be played almost > anywhere.
Well, if you are targetting a particular player it makes sense to use the maximum supported bit rate. My Pioneer HTD510 is quite linient when it comes to VCD/SVCD playback (it even plays 720x480 or 720x576 mpegs burned as an SVCD), but it can't handle more than 3000kb/s muxed rate. I have a philips 623 player that I am yet to stress test, but I know that 2000kb/s VCD is very jerky on it. With this and simpilar philips players this is not a concern as it can play almost all kinds of mpeg1/mpeg2 files simply burned on to a ISO data track on a CD-R -- I have tried peak bit rates up to 6000kb/s. > > > Also -q 3 is too low a value -- you will most > > certainly get a better output with -q 8 or so. > > But isn't "lower" supposed to be "better"? Yes low values of q mean higher quality, but specifying a lower q does not translate into a higher quality video. I am no expert either, but my understanding is that -q specifies a quantisation floor and allowing q to dip down to as low as 3 within the bit rate contsraint of 2900 would leave little room for rate control. The encoder first estimates the required q value using maximum allowed bit rate and then clamps it to be above the user specified quantisation floor, saving bits on simple scenes. Thus if the floor value is too low, one would end up with a virtually CBR stream. I am most probably wrong here, but I think if one is not concerned about the final size of the movie, but only constrained by the maximum bit rate the player can handle, a CBR stream with that maximum bit rate should be as good or even better than a VBR stream. Can someone correct me? Selva ------------------------------------------------------- This sf.net email is sponsored by: With Great Power, Comes Great Responsibility Learn to use your power at OSDN's High Performance Computing Channel http://hpc.devchannel.org/ _______________________________________________ Mjpeg-users mailing list [EMAIL PROTECTED] https://lists.sourceforge.net/lists/listinfo/mjpeg-users
