I have a High resolution DivX - is there an easy way to keep the quality but drop the resolution - so go from 720p to a lower resolution?
I have a High resolution DivX - is there an easy way to keep the quality but drop the resolution - so go from 720p to a lower resolution?
it wont take long on that quad core, the lucky so and so
Yes, You are basicaly looking at re-encoding the whole file. As you are reducing the picture size, you should get decent quality without any artifacts from the original comming through.
In theory it would be possible for the encoder to look at the original file for keyframes, motion vectors etc, and use it instead of doing a first pass (and do the second pass a bit faster), but I doubt XviD has that feature, (though no doubt it is on their roadmap)
You'll probably lose quite a bit of detail also as you're resizing the grid at which it was compressed last time and therefore compressing across the gridlines this time around. I guess it all depends how compressed it is in the first place.
Are you resizing it for filesize or some other reason?
What application would you recommend to maintain the highest quality
VirtualDub is very very good. I've been using it for a while now. It's free and very easy to use.
Install VirtualDub and XviD.
Open the original in VDub, go to the Video menu, and select Full Processing Mode (if you were doing the resize outside Vdub you could select Fast Recompress, but not in this case). Open Video menu again, select filters, click Add. Select resize, set your new width and height (make sure the ratio between them is the same as the original). Set filter mode to Lanczos3, click OK.
Open Video menu again, select Compression... Scroll down and click on the xvid codec, then click Configure. Click the arrow next to Profile@level and select Home Theatre PAL - this will enforce a coding that'll work on standalone Divx players. Set Encoding Type to Twopass - 1st pass, click OK.
Goto File->SaveAs... type in the output name and click the 'Don't run this job now' box. Click Save. File->SaveAs, use the same filename and make sure the Don't run now box is still ticked, then click Change next to the compression box and set the Encoding Type to Twopass - 2nd pass and click OK. Finally go to File->Job Control and click Start.
Last edited by charleski; 03-10-2006 at 07:04 PM.
What bitrate, resolution and framerate is the original DivX?
Also what is the reason for reducing the resolution?
Something to do with Hexus.TV me thinks.
er?
its a high-def kite video someone gave me and I wanted to upload it
ahhhh
Well if it's going to be uploaded, then you need as small a bitrate as you can get away with.
Resolution has nothing to do with filesize, which is totally dependent on playtime*bitrate.
A 640*480 10 minute video @ 1000knps will be exactly the same filesize as a 320*240 10 minute video @ 1000kbps. However, the smaller rez. video will look better with a lower bitrate than the higher rez one, same as looking at a bad quality movie on a 14" portable TV will look "better" than watching it on a 42" screen.
HD 1280*720 progressive video could be resized to 428*240 with a video bitrate of say, 500-1000kbps for not too bad quality Vs. filesize using VirtualDub with either the Xvid or DivX codec, and MP3 sound.
You could cut a 10 second segment out of the original video with VirtualDub, and experiment with different bitrates to see what bitrate Vs. quality you are happy with.
Whatever codec you use, the people downloading the file will need to have it installed also, before they can view the video.
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