Did I just hear elimination of B frames: 1) lowers bitrate, ie file size 2) improves output 3) faster encoding (ok so i'm reaching)
so, basically, unless you're editing, B frames are a 3 strike out, IMO. ----- Original Message ----- From: "Steven M. Schultz" <[EMAIL PROTECTED]> To: <[EMAIL PROTECTED]> Sent: Tuesday, November 11, 2003 6:55 PM Subject: Re: [Mjpeg-users] MPEG2 encoding performance > > On 11 Nov 2003, Florin Andrei wrote: > > > What is _your_ source? > > Which one? ;) > > The author of mpeg2enc is one. Another can be found in one of > the links from http://www.mir.com/DMG/, go to the MPEG FAQ > and read http://tns-www.lcs.mit.edu/manuals/mpeg2/FAQ > > Question/answers #16, #19, #20 and #24.5 > > In particular #16 which gives the definitions of the MPEG profiles, > note that the "Simple" profile is I and P frame only. One could > look up the formal definitions in one of Charles Poynton's books > but for now the FAQ will suffice ;) > > The discussion in #19 and #20 is quite interesting - in essence > at higher (relative to MPEG-1 SIF size) bitrates B frames are > considered by some to be 'wasted bits'. > > Then in #24.5 there's the Dual Prime prediction discussed. That's > the part that Ogle doesn't implement but it is most certainly > a part of the standard. > > > Mine is a recent el-cheapo Sony digital camcorder (DCR TRV240); kinda > > good in full daylight, but rather noisy in indoors scenes. Is that less > > than perfect enough to warrant dropping the B-frames? > > Same here - actually mine's the TRV140 (or was it the 120) - D8 so it's > not analog but nothing fancy (that's for sure :)). Thinking of > getting one of those 3CCD units (Panasonic has one that can be had > for under $1k) one of these days. > > Anyhow I shot some footage of the fires that were going on in > Southern California a short time ago (just a couple miles from > the house) and got somewhere around 10% or so reduction in the > bitrate by dropping B frames. I've some tapes made earlier > that I could re-capture and experiment with. > > It's also possible to split the difference - instead of dropping > B frames completely you can specify that just 1 is to be used between > P frames. The "-R 1" will reduce but not eliminate the B frames. > > It's been mentioned to me that high motion scenes can also benefit > from reducing or eliminating the B frames. Something to consider > when going for maximum quality with live footage. > > Cheers, > Steven Schultz > > > > ------------------------------------------------------- > This SF.Net email sponsored by: ApacheCon 2003, > 16-19 November in Las Vegas. Learn firsthand the latest > developments in Apache, PHP, Perl, XML, Java, MySQL, > WebDAV, and more! http://www.apachecon.com/ > _______________________________________________ > Mjpeg-users mailing list > [EMAIL PROTECTED] > https://lists.sourceforge.net/lists/listinfo/mjpeg-users > ------------------------------------------------------- This SF.Net email sponsored by: ApacheCon 2003, 16-19 November in Las Vegas. Learn firsthand the latest developments in Apache, PHP, Perl, XML, Java, MySQL, WebDAV, and more! http://www.apachecon.com/ _______________________________________________ Mjpeg-users mailing list [EMAIL PROTECTED] https://lists.sourceforge.net/lists/listinfo/mjpeg-users
