role
13th January 2002, 15:56
XSVCD feuture - Variable output resolution
A lot of standalone players can handle different resolutions besides te standard VCD, SVCD or DVD resolutions. For example my stand-alone Philips seems to handle allmost everything (n*16,m*16) between the VCD (320*240) and DVD (720*576), provided that the bitrate is below 2.8Mbit/s.
My interest in a different resolution is not so much that I think that the standard SVCD is to low, but rather that I believe that the quality can actually be improved by reducing the resolution and thereby reduce the amount of compression distortion.
For example I think that a 1h/per CD of 16:9 AR movie looks better using the resolution of 512*288 compared to the original SVCD (480*432 + black borders), despite the lower resolution.
Of course variable output resolution is allready (kind of) supported by DVD2SVCD by editing the AVS file manually. It would however be a great improvement if this could be set allready from the beginning of the project.
Playing around with variable output resolution, a more advanced feature would be a "GKnot style compressibility ceck", e.g. , based on 1-pass VBR (Q-based) encoding.
This could for example be done with the following algoritm:
1. Calculate the desired VBR bitrate.
2. Perform a Q-based encoding on part(s) of the movie with an apropriate Q-value (say about 3?) and adjust the resolution until the avarage BR corresponds to the desired.
OR (the GKnot metod):
Perform a Q-based encoding on part(s) of the movie with Q-value=1 and adjust the resolution until the desired BR corresponds to a specified percentage (say 75% to 100% ?) of the average Q=1 BR.
3. Create VAF file with Q-based encoding (faster according to some posts in the forum?)
4. Finalize with 1 aditional multipass VBR to end up at the desired
A lot of standalone players can handle different resolutions besides te standard VCD, SVCD or DVD resolutions. For example my stand-alone Philips seems to handle allmost everything (n*16,m*16) between the VCD (320*240) and DVD (720*576), provided that the bitrate is below 2.8Mbit/s.
My interest in a different resolution is not so much that I think that the standard SVCD is to low, but rather that I believe that the quality can actually be improved by reducing the resolution and thereby reduce the amount of compression distortion.
For example I think that a 1h/per CD of 16:9 AR movie looks better using the resolution of 512*288 compared to the original SVCD (480*432 + black borders), despite the lower resolution.
Of course variable output resolution is allready (kind of) supported by DVD2SVCD by editing the AVS file manually. It would however be a great improvement if this could be set allready from the beginning of the project.
Playing around with variable output resolution, a more advanced feature would be a "GKnot style compressibility ceck", e.g. , based on 1-pass VBR (Q-based) encoding.
This could for example be done with the following algoritm:
1. Calculate the desired VBR bitrate.
2. Perform a Q-based encoding on part(s) of the movie with an apropriate Q-value (say about 3?) and adjust the resolution until the avarage BR corresponds to the desired.
OR (the GKnot metod):
Perform a Q-based encoding on part(s) of the movie with Q-value=1 and adjust the resolution until the desired BR corresponds to a specified percentage (say 75% to 100% ?) of the average Q=1 BR.
3. Create VAF file with Q-based encoding (faster according to some posts in the forum?)
4. Finalize with 1 aditional multipass VBR to end up at the desired