Re: [CinCVS] DVD render: output quality not so good
-BEGIN PGP SIGNED MESSAGE- Hash: SHA1 Hi, I thanks everybody for his answer, and especially you for the time you took to explain me this MPEG stuff. I followed your recommandations and choosed a more static part of the movie, and did the same operation. Then, the image qualitity was good enough for my will. But I did the same thing on my full movie, encoding the same small extract embeded in my completely edited sequence, and again the quality was very poor. So the problem is not purely mpeg encoding; there is likely some parameter or effect I badly tuned in Cinelerra while editing. I'll spend some time on this problem, hoping to find out what it is. Else, I'll come again for help, when I'll have more details. Thanks again, Yannick PS: The texture is a Povray "marble" texture with a quite simple normal texture that creates some small horizontal bumps. [EMAIL PROTECTED] a écrit : > On Mon, 11 Jun 2007, Yannick Patois wrote: >> Most of the texture is lost in all rendered images... >> Thanks for any suggestion, > I also wonder if your requirement that the texture be preserved is really > reasonable. You've got a complicated pseudorandom texture (looks like > Perlin noise, for instance from POV-Ray), which won't compress well at the > best of times, and you're trying to change it pretty much completely every > single frame. Information theoretic considerations mean that it's just > not possible to really do that well, no matter what algorithm or settings > you use. You are trying to fit far more than 8600kbps of entropy through > an 8600kbps pipe. - -- _/ Yannick Patois _ Address (home) __ | irc(undernet): Garp on #france25+ | 7, rue de Brumath| | http://garp.feelingsurfer.net/| 67170 Rottelsheim| | Tel-home: +(33)(0)3 88 68 89 58 | FRANCE | | Le Portail des Copains : http://rezo.net | -BEGIN PGP SIGNATURE- Version: GnuPG v1.4.6 (GNU/Linux) Comment: Using GnuPG with Mozilla - http://enigmail.mozdev.org iD8DBQFGbi1uZY3s/IVpRFIRArhFAKC6vZd463/7SaVs/AzIVxrPzCbQyQCfY/85 uHX3wQs0DqSg12RRcKd4F6E= =IP77 -END PGP SIGNATURE- ___ Cinelerra mailing list Cinelerra@skolelinux.no https://init.linpro.no/mailman/skolelinux.no/listinfo/cinelerra
Re: [CinCVS] DVD render: output quality not so good
On Sunday 10 June 2007 15:38, Yannick Patois wrote: > To render, I did exactly what's in the doc: > created a small script containg: > #!/bin/bash > mpeg2enc -v 0 -K tmpgenc -r 16 -4 1 -2 1 -D 10 -E 10 -g 15 -G 15 -q 6 -b > 8600 -f 8 -o $1 If what the docs suggest, doesn't work, then understand what you are doing. RTFM of mpeg2enc. -K tmpgenc reduces bitrate, but also texture detail. -g 15 -G 15 says that there's an I frame at exactly every 15 frames, no optimization allowed. Try mpeg2enc -v 0 -f 8 -o $1 -- Hannes ___ Cinelerra mailing list Cinelerra@skolelinux.no https://init.linpro.no/mailman/skolelinux.no/listinfo/cinelerra
Re: [CinCVS] DVD render: output quality not so good
On Mon, 11 Jun 2007, Yannick Patois wrote: > Most of the texture is lost in all rendered images... > > Thanks for any suggestion, You seem to be forcing a large GOP size with -g 15 -G 15. That means it's only allowed to emit an I-frame (complete description of a frame) twice per second, and everything else has to be compressed by referring to changes from the I-frames. Since this video contains rapid full-screen motion, the image is totally different from one I-frame to the next, and so you can't compactly describe most of the frames in between in terms of differences from the I-frames; the compressor has to re-describe each frame almost completely anyway. I'd suggest setting a much smaller minimum GOP size, like "-g 5", with a maximum bigger than the minimum, so that the compressor can choose GOP sizes instead of being forced to have an I-frame exactly once every 15 frames. Then it can make a better attempt at conserving frame-to-frame information. Two-pass encoding would probably also help, if you're not already doing it. I also wonder if your requirement that the texture be preserved is really reasonable. You've got a complicated pseudorandom texture (looks like Perlin noise, for instance from POV-Ray), which won't compress well at the best of times, and you're trying to change it pretty much completely every single frame. Information theoretic considerations mean that it's just not possible to really do that well, no matter what algorithm or settings you use. You are trying to fit far more than 8600kbps of entropy through an 8600kbps pipe. That's an impossible feat. MPEG compression is dependant on faking it, with a psychovisual model of what human beings can actually see. It preserves the information that is really visible, throws away the rest, and the quality of the output is determined by how well the encoder guesses as to what's visible. It seems like the model is predicting that under these conditions the viewer won't really be able to see your texture, and the thing is, I think the model may actually be *right*. Maybe it would be more clear in a longer sample, but in your one-second clip, I can't focus on the white part firmly enough to be able to see a texture if one were there - it's moving so fast as to be a blur anyway. Can you really see the difference in quality between the compressed and uncompressed versions under actual viewing conditions at full speed? It's easy to spot the difference in still frame grabs, but MPEG cannot, and doesn't attempt to, preserve all details that might be visible with frame grabs. It's meant for moving video. -- Matthew Skala [EMAIL PROTECTED]Embrace and defend. http://ansuz.sooke.bc.ca/ ___ Cinelerra mailing list Cinelerra@skolelinux.no https://init.linpro.no/mailman/skolelinux.no/listinfo/cinelerra
Re: [CinCVS] DVD render: output quality not so good
-BEGIN PGP SIGNED MESSAGE- Hash: SHA1 Hi, Thanks for your help. Joe Friedrichsen a écrit : > On 6/10/07, Yannick Patois <[EMAIL PROTECTED]> wrote: >> To render, I did exactly what's in the doc: >> created a small script containg: >> #!/bin/bash >> mpeg2enc -v 0 -K tmpgenc -r 16 -4 1 -2 1 -D 10 -E 10 -g 15 -G 15 -q 6 -b >> 8600 -f 8 -o $1 > Well, you could increase the quality by reducing the quantization and > allowing for higher bitrate: > -q 3 -b 9600 Which bitracte can handle a DVD player to the maximum? Is 9600 still ok? I tried whith the setting you suggested; the result is not that impressive. I posted just the last image, at: http://animation.altespace.org/tmp/demonstration/extracted-2/0024.png I also realized that tga is not a very convenient format for browerj, I converted to png. http://animation.altespace.org/tmp/demonstration/images-png/ Here direct links to last frame, first orginal, the with my original render, last with your options: http://animation.altespace.org/tmp/demonstration/images-png/sequence-0105.png http://animation.altespace.org/tmp/demonstration/extracted/0024.png http://animation.altespace.org/tmp/demonstration/extracted-2/0024.png Most of the texture is lost in all rendered images... Thanks for any suggestion, Yannick - -- _/ Yannick Patois _ Address (home) __ | irc(undernet): Garp on #france25+ | 7, rue de Brumath| | http://garp.feelingsurfer.net/| 67170 Rottelsheim| | Tel-home: +(33)(0)3 88 68 89 58 | FRANCE | | Le Portail des Copains : http://rezo.net | -BEGIN PGP SIGNATURE- Version: GnuPG v1.4.6 (GNU/Linux) Comment: Using GnuPG with Mozilla - http://enigmail.mozdev.org iD8DBQFGbZYQZY3s/IVpRFIRAoI2AJ0YiYA+4TfvVmT0guTyjz1jrwSQjACgxIsk Vu+fZNumBq4eRU9A0Pa1Pb4= =M9h/ -END PGP SIGNATURE- ___ Cinelerra mailing list Cinelerra@skolelinux.no https://init.linpro.no/mailman/skolelinux.no/listinfo/cinelerra
Re: [CinCVS] DVD render: output quality not so good
On 6/10/07, Yannick Patois <[EMAIL PROTECTED]> wrote: -BEGIN PGP SIGNED MESSAGE- To render, I did exactly what's in the doc: created a small script containg: #!/bin/bash mpeg2enc -v 0 -K tmpgenc -r 16 -4 1 -2 1 -D 10 -E 10 -g 15 -G 15 -q 6 -b 8600 -f 8 -o $1 Well, you could increase the quality by reducing the quantization and allowing for higher bitrate: -q 3 -b 9600 Joe ___ Cinelerra mailing list Cinelerra@skolelinux.no https://init.linpro.no/mailman/skolelinux.no/listinfo/cinelerra
[CinCVS] DVD render: output quality not so good
-BEGIN PGP SIGNED MESSAGE- Hash: SHA1 Hi, I'm trying for quite some time to get a decent output on DVD for my small movie. Until now, I've not been very successful. So, I'm now asking you for help, hoping for some solution. I posted a test for you to see my problem. In http://animation.altespace.org/tmp/demonstration/images/ is the set of 25 images I started from to generate a 1s movie with cinelerra. The cinelerra code is http://animation.altespace.org/tmp/demonstration/simpletest.xml To render, I did exactly what's in the doc: created a small script containg: #!/bin/bash mpeg2enc -v 0 -K tmpgenc -r 16 -4 1 -2 1 -D 10 -E 10 -g 15 -G 15 -q 6 -b 8600 -f 8 -o $1 And calling it as suggested. This created a movie: http://animation.altespace.org/tmp/demonstration/atest.m2v I used mplayer to extract frames from it (mplayer -frames 25 -vo png atest.m2v). I put the output in http://animation.altespace.org/tmp/demonstration/extracted/. I'm pretty annoyed by the almost complete disapearance of texture in the encoded video. The quality is incredibly lower. I know DVD is not that good, but I'm sure I saw better! For example, compare top left corner textures for http://animation.altespace.org/tmp/demonstration/extracted/0024.png and http://animation.altespace.org/tmp/demonstration/images/sequence-0105.tga In the original image, one can see a light but obvious shade of grey texturing the white surface. Once rendered, it's almost completly white, no texture is visible. This is of course only a small example of what I could see in my whole movie. Can it been done better? Even when leaving DVD formats (avi or whatever) I couldnt got anything significantly better... Should I accept that DVD quality is unable to restitute such a shading? Is there something I missed? Is there a better encoder? Thanks for any help. Yannick - -- _/ Yannick Patois _ Address (home) __ | irc(undernet): Garp on #france25+ | 7, rue de Brumath| | http://garp.feelingsurfer.net/| 67170 Rottelsheim| | Tel-home: +(33)(0)3 88 68 89 58 | FRANCE | | Le Portail des Copains : http://rezo.net | -BEGIN PGP SIGNATURE- Version: GnuPG v1.4.6 (GNU/Linux) Comment: Using GnuPG with Mozilla - http://enigmail.mozdev.org iD8DBQFGa/7PZY3s/IVpRFIRAoC7AJwIjPRIL7P/PMmI8C9jwinUQLrd/gCeIhtw FWDJXmPTh6Z8U8eeXNZ0T3Y= =olfC -END PGP SIGNATURE- ___ Cinelerra mailing list Cinelerra@skolelinux.no https://init.linpro.no/mailman/skolelinux.no/listinfo/cinelerra
[CinCVS] DVD render: output quality not so good
-BEGIN PGP SIGNED MESSAGE- Hash: SHA1 Hi, I'm trying for quite some time to get a decent output on DVD for my small movie. Until now, I've not been very successful. So, I'm now asking you for help, hoping for some solution. I posted a test for you to see my problem. In http://animation.altespace.org/tmp/demonstration/images/ is the set of 25 images I started from to generate a 1s movie with cinelerra. The cinelerra code is http://animation.altespace.org/tmp/demonstration/simpletest.xml To render, I did exactly what's in the doc: created a small script containg: #!/bin/bash mpeg2enc -v 0 -K tmpgenc -r 16 -4 1 -2 1 -D 10 -E 10 -g 15 -G 15 -q 6 -b 8600 -f 8 -o $1 And calling it as suggested. This created a movie: http://animation.altespace.org/tmp/demonstration/atest.m2v I used mplayer to extract frames from it (mplayer -frames 25 -vo png atest.m2v). I put the output in http://animation.altespace.org/tmp/demonstration/extracted/. I'm pretty annoyed by the almost complete disapearance of texture in the encoded video. The quality is incredibly lower. I know DVD is not that good, but I'm sure I saw better! For example, compare top left corner textures for http://animation.altespace.org/tmp/demonstration/extracted/0024.png and http://animation.altespace.org/tmp/demonstration/images/sequence-0105.tga In the original image, one can see a light but obvious shade of grey texturing the white surface. Once rendered, it's almost completly white, no texture is visible. This is of course only a small example of what I could see in my whole movie. Can it been done better? Even when leaving DVD formats (avi or whatever) I couldnt got anything significantly better... Should I accept that DVD quality is unable to restitute such a shading? Is there something I missed? Is there a better encoder? Thanks for any help. Yannick - -- _/ Yannick Patois _ Address (home) __ | irc(undernet): Garp on #france25+ | 7, rue de Brumath| | http://garp.feelingsurfer.net/| 67170 Rottelsheim| | Tel-home: +(33)(0)3 88 68 89 58 | FRANCE | | Le Portail des Copains : http://rezo.net | -BEGIN PGP SIGNATURE- Version: GnuPG v1.4.6 (GNU/Linux) Comment: Using GnuPG with Mozilla - http://enigmail.mozdev.org iD8DBQFGa/7PZY3s/IVpRFIRAoC7AJwIjPRIL7P/PMmI8C9jwinUQLrd/gCeIhtw FWDJXmPTh6Z8U8eeXNZ0T3Y= =olfC -END PGP SIGNATURE- ___ Cinelerra mailing list Cinelerra@skolelinux.no https://init.linpro.no/mailman/skolelinux.no/listinfo/cinelerra
