[Mjpeg-users] Mplex modification
Hi all, I have now modified mplex to remove a problem that occured when very small (less than one sector payload) frames appeared in video sequences that: a) Occasionally cause mis-aligned I-frames in SVCD streams. b) Rarely cause sequence end markers to be missed in SVCD streams. Unfortunately, to implement the fix I had to first tidy up some other bits of code so the changes in mplex are fairly wide-spread. I also (probably) fixed timestamp generation for 3:2 pulldown material. As always it'd be great if folk who were encountering these problems could see if they're now fixed! There is still a known bug relating to over-eager despatch of low-rate audio material that is next on my list. cheers, Andrew PS Once mplex bugs are done, I'll get back to mergeing the development branch of mpeg2enc (which *almost* has back-off-and-retry for better rate control implemented!) in the the main branch. --- This SF.Net email is sponsored by: IBM Linux Tutorials Free Linux tutorial presented by Daniel Robbins, President and CEO of GenToo technologies. Learn everything from fundamentals to system administration.http://ads.osdn.com/?ad_id=1470&alloc_id=3638&op=click ___ Mjpeg-users mailing list [EMAIL PROTECTED] https://lists.sourceforge.net/lists/listinfo/mjpeg-users
[Mjpeg-users] Does the mpeg2enc option "-R" influence quality?
Hello. Does the option "-R" used with mpeg2enc have any influence in the quality of the transcoded video stream? If I am not wrong, in old versions of mjpegtools the default is "-R 2" and in the latest one it is "-R 0", which speeds up processing. Regards. Romildo --- This SF.Net email is sponsored by: IBM Linux Tutorials Free Linux tutorial presented by Daniel Robbins, President and CEO of GenToo technologies. Learn everything from fundamentals to system administration.http://ads.osdn.com/?ad_id=1470&alloc_id=3638&op=click ___ Mjpeg-users mailing list [EMAIL PROTECTED] https://lists.sourceforge.net/lists/listinfo/mjpeg-users
Re: [Mjpeg-users] Does the mpeg2enc option "-R" influence quality?
On Mon, 15 Mar 2004 [EMAIL PROTECTED] wrote: > Does the option "-R" used with mpeg2enc have > any influence in the quality of the transcoded > video stream? If I am not wrong, in old versions > of mjpegtools the default is "-R 2" and in the > latest one it is "-R 0", which speeds up processing. -R simply specifies the number of B frames to place between I/P frames. The special case of -R 0 means to disable B frames completely _and_ by default use DPME (Dual Prime Motion Estimation). NOTE: At least 1 hardware player and a couple software players do not implement DP in their MPEG-2 decoders. There is now an option to mpeg2enc called --no-dualprime-mpeg2 which can be used when generating output for broken decoders. Now for the real answer ;) For very clean (miniDV/Digital8) sources B frames are ok, but if the sources are analog (and thus likely to have noise) the B frames take bits away from the P frames which effectively reduces the quality of the encoded video. Even for high quality sources NOT using B frames helps with high motion scenes. In general I have found that not using B frames at all gives a lower bitrate and better looking (to the eyeballs - I haven't run any objective tests) output. The other benefit is that without having to compute B frames the encoding runs faster ;) Cheers, Steven Schultz p.s. For even better quality use -D 10. That also helps to reduce the moving grey blocks effect. --- This SF.Net email is sponsored by: IBM Linux Tutorials Free Linux tutorial presented by Daniel Robbins, President and CEO of GenToo technologies. Learn everything from fundamentals to system administration.http://ads.osdn.com/?ad_id=1470&alloc_id=3638&op=click ___ Mjpeg-users mailing list [EMAIL PROTECTED] https://lists.sourceforge.net/lists/listinfo/mjpeg-users
Re: [Mjpeg-users] Mplex modification
Speaking of timestamp issues... :-) I'd reported such a problem and had believed it had to do with pulldown, but I've since switched away from using pulldown to encoding interlaced. The counter on my set-top DVD player does really weird things - counts very, very eradically - sometimes even going backwards a second, then 'catching up' a few seconds later. -- Ray On Mon, 15 Mar 2004 20:05:09 +0100 Andrew Stevens <[EMAIL PROTECTED]> wrote: > Hi all, > > I have now modified mplex to remove a problem that occured when very small > (less than one sector payload) frames appeared in video sequences that: > > a)Occasionally cause mis-aligned I-frames in SVCD streams. > b)Rarely cause sequence end markers to be missed in SVCD streams. > > Unfortunately, to implement the fix I had to first tidy up some other bits of > code so the changes in mplex are fairly wide-spread. I also (probably) > fixed timestamp generation for 3:2 pulldown material. > > As always it'd be great if folk who were encountering these problems could see > if they're now fixed! > > There is still a known bug relating to over-eager despatch of low-rate audio > material that is next on my list. > > cheers, > > Andrew > PS > Once mplex bugs are done, I'll get back to mergeing the development branch of > mpeg2enc (which *almost* has back-off-and-retry for better rate control > implemented!) in the the main branch. > > > > --- > This SF.Net email is sponsored by: IBM Linux Tutorials > Free Linux tutorial presented by Daniel Robbins, President and CEO of > GenToo technologies. Learn everything from fundamentals to system > administration.http://ads.osdn.com/?ad_id=1470&alloc_id=3638&op=click > ___ > Mjpeg-users mailing list > [EMAIL PROTECTED] > https://lists.sourceforge.net/lists/listinfo/mjpeg-users --- This SF.Net email is sponsored by: IBM Linux Tutorials Free Linux tutorial presented by Daniel Robbins, President and CEO of GenToo technologies. Learn everything from fundamentals to system administration.http://ads.osdn.com/?ad_id=1470&alloc_id=3638&op=click ___ Mjpeg-users mailing list [EMAIL PROTECTED] https://lists.sourceforge.net/lists/listinfo/mjpeg-users
Re: [Mjpeg-users] Mplex modification
On Mon, 15 Mar 2004, Ray Cole wrote: > Speaking of timestamp issues... :-) I'd reported such a problem and had > believed it had to do with pulldown, but I've since switched away from > using pulldown to encoding interlaced. The counter on my set-top DVD > player does really weird things - counts very, very eradically - sometimes > even going backwards a second, then 'catching up' a few seconds later. The video picture itself plays fine, right? (Hope so). Idle question - is it possible that the DVD authoring process is adjusting the timestamps as it converts/packs .mpg files into the .vob files? What happens if you put a simple PS file into an ISO filesystem? Does the time still jump around? Or is the "play a file" an uncommon capability? Cheers, Steven Schultz --- This SF.Net email is sponsored by: IBM Linux Tutorials Free Linux tutorial presented by Daniel Robbins, President and CEO of GenToo technologies. Learn everything from fundamentals to system administration.http://ads.osdn.com/?ad_id=1470&alloc_id=3638&op=click ___ Mjpeg-users mailing list [EMAIL PROTECTED] https://lists.sourceforge.net/lists/listinfo/mjpeg-users
Re: [Mjpeg-users] Mplex modification
Picture plays fine. Could be the DVD authoring process. I use mplex piped into dvdauthor. I'm not sure what you mean by placing a PS file into an ISO filesystem. I understand what an ISO filesystem is, not sure I know the term PS :-) If it means anything non-standard then I'm betting my player won't handle it :-) I have 3 players, but only one has a timestamp display on it (hmm...perhaps one of the others has a way of displayin it and I haven't noticed...will check). -- Ray On Mon, 15 Mar 2004 16:00:28 -0800 (PST) "Steven M. Schultz" <[EMAIL PROTECTED]> wrote: > > On Mon, 15 Mar 2004, Ray Cole wrote: > > > Speaking of timestamp issues... :-) I'd reported such a problem and had > > believed it had to do with pulldown, but I've since switched away from > > using pulldown to encoding interlaced. The counter on my set-top DVD > > player does really weird things - counts very, very eradically - sometimes > > even going backwards a second, then 'catching up' a few seconds later. > > The video picture itself plays fine, right? (Hope so). > > Idle question - is it possible that the DVD authoring process is > adjusting the timestamps as it converts/packs .mpg files into the > .vob files? > > What happens if you put a simple PS file into an ISO filesystem? Does > the time still jump around? Or is the "play a file" an uncommon > capability? > > Cheers, > Steven Schultz > > > > --- > This SF.Net email is sponsored by: IBM Linux Tutorials > Free Linux tutorial presented by Daniel Robbins, President and CEO of > GenToo technologies. Learn everything from fundamentals to system > administration.http://ads.osdn.com/?ad_id=1470&alloc_id=3638&op=click > ___ > Mjpeg-users mailing list > [EMAIL PROTECTED] > https://lists.sourceforge.net/lists/listinfo/mjpeg-users --- This SF.Net email is sponsored by: IBM Linux Tutorials Free Linux tutorial presented by Daniel Robbins, President and CEO of GenToo technologies. Learn everything from fundamentals to system administration.http://ads.osdn.com/?ad_id=1470&alloc_id=3638&op=click ___ Mjpeg-users mailing list [EMAIL PROTECTED] https://lists.sourceforge.net/lists/listinfo/mjpeg-users
Re: [Mjpeg-users] Mplex modification
On Mon, 15 Mar 2004, Ray Cole wrote: > Picture plays fine. Could be the DVD authoring process. I use mplex piped > into dvdauthor. I'm not sure what you mean by placing a PS file into an ISO > filesystem. I understand what an ISO filesystem is, not sure I know the > term PS :-) Program Stream. It's what mplex creates from the .m2v file (which is an ES or Elementary Stream) and the audio file.Use mkisofs and to place the .mpg files on a ISO filesystem (the files do have to be less than 2GB though). Try creating a file instead of running thru a pipe - doubt that will make a difference but it's something to eliminate from the list of suspects. My Philips player pops up a file browsing menu if the disc isn't one of the VCD/SVCD/DVD formats. Useful for generic .mpg files downloaded from the net. But you should be watching the movie and not the player's display :) Cheers, Steven Schultz --- This SF.Net email is sponsored by: IBM Linux Tutorials Free Linux tutorial presented by Daniel Robbins, President and CEO of GenToo technologies. Learn everything from fundamentals to system administration.http://ads.osdn.com/?ad_id=1470&alloc_id=3638&op=click ___ Mjpeg-users mailing list [EMAIL PROTECTED] https://lists.sourceforge.net/lists/listinfo/mjpeg-users
Re: [Mjpeg-users] Mplex modification
> But you should be watching the movie and not the player's display :) My wife agrees... :-) --- This SF.Net email is sponsored by: IBM Linux Tutorials Free Linux tutorial presented by Daniel Robbins, President and CEO of GenToo technologies. Learn everything from fundamentals to system administration.http://ads.osdn.com/?ad_id=1470&alloc_id=3638&op=click ___ Mjpeg-users mailing list [EMAIL PROTECTED] https://lists.sourceforge.net/lists/listinfo/mjpeg-users
