Quality loss after rotating video at DVinfo.net

Prech Marton · June 28th, 2010, 11:20 AM

Hello!

I need to rotate very small my HDV video, about 1 degree. I do this with video event pan/crop.
The source video look sharp.
After rotated and rendered to HDV template (best quality video setting), the sharpness, details
disappear. It has a soft look. I thinked it is because in digital world, it has to be some degrading, nothing is for free. But then i test to render to uncompressed avi and that rotated avi look as sharp as the source.
What can i do? Why is this behavior?
Unfortunately I need the video in HDV format. It is just because the mpeg recompress?
When i change the opacity to 99%, and render it without rotating, there is also recompress but the sharpness remain good!

thx!
Marton

William Boehm · July 7th, 2010, 10:17 AM

this is a good question. anyone else have comments? i have some shot video of se alaska mountains and shoreline that is slight off, and needs to be rotated serveral degrees...process? quality loss if any with cineform int. codec?

Robin Davies-Rollinson · July 7th, 2010, 11:55 AM

Well, if you rotate an image, you're going to have to slightly enlarge it as well, to hide the black edges that you'll get, so there is bound to be a quality loss. It's the same as if you use a software image stabilizer...
Plus the fact that mpeg doesn't like a lot of tweaking in post. A transcode to something like Cineform might be the answer.

Mark Sudfeldt · July 7th, 2010, 02:47 PM

Does switching on Reduce Interlace Flicker for the rotated clip make any difference?

William Boehm · July 7th, 2010, 03:14 PM

i am using neoscene 5.04 intermediate codec, and wondering if i should rotate then in vegas 9 under pan, and save to what kind of file...i actually dont know if i can save to a cineform file codec still while in vegas using cineform files. .newbie..just started editing in the past month.

Bruce Phung · July 7th, 2010, 04:34 PM

Cineform is also a lossless codec, you would want to save it to Cineform to retain your high quality video.

William Boehm · July 8th, 2010, 09:06 AM

i havent checked yet..meaning that vegas 9 will let me edit the cineform file, and save back to a cineform file after editing instead of a .veg file?

Bruce Phung · July 8th, 2010, 10:31 AM

You got it all confused. The .veg file will always remain the same regardless of what codec is being used. The rendering and the codec that maintian the video is what you are after.

William Boehm · July 8th, 2010, 01:32 PM

bruce..please explain as i am pretty new at editing in vegas and cineform. my virutal dub download doesnt recognized veg files. so i probabl should deshake footage first, otherwise, edit in vegas, save the file in .veg, then render to a dvd hd in .veg? i need a little explanation if you have time. bill

Bruce Phung · July 8th, 2010, 02:26 PM

.Veg file will open by Vegas only. You can not use any other program to open .veg file. .Veg file is the Vegas project name itself. 1) Edit your footage, do what ever you want done to your video 2) when you are finished your edit and happy with it and then render it to AVI. 3) Click on custom and select your codec, in your case you would want to select cineform and click ok. 4) finish your rendering. From there you would import your video into Virtual Dub and deshake it or what ever filter you want to use. When you are finish and you would to render or export to AVI again and select your Cineform codec again. This way your video will always be lossless regardless how many times you have been rendering your video. It like a master video file. If you want to output to Blu ray then output to BD. If you want to output to DVD, then select your DV tempate for DVD. You follow me now?.
For example if you render in Vegas to WMV HD or what ever format. Now you have a video file. And you import that WMV HD file into Vegas, make changes or what ever, and then you render your video again, that will cause your video quality loss after many generations. With a lossless codecs, no matter what you do, your video will always be high quality. Cineform is your choice here. Hope this explaination make sense to you. Good luck

William Boehm · July 8th, 2010, 07:21 PM

thanks bruce that explains it. you would put virtual dub deshaker at the end then after rotating if needed on some not horizontal images, color correction, brightness contrast, the deshake? i will try this approach. bill

Bruce Phung · July 8th, 2010, 07:34 PM

I have spent more than 8 hrs playing with varies setting in deshaker and I never able to get good results. I have seen some impressive video that has been deshaked, but it ain't work for me. I use Virtual Dub mainly for HD to SD down conversion and the result is very impressive, very sharp pictures.

Prech Marton · July 9th, 2010, 12:26 PM

Robin, thanks for your post.
But my video was only rotated, but NOT upscaled!
I masked out the edges with black.
Now i try render to avi frameserver and encode to mpeg with different program.

June 28th, 2010, 11:20 AM	#1
Prech Marton Major Player Join Date: May 2004 Location: hungary Posts: 462	Quality loss after rotating video Hello! I need to rotate very small my HDV video, about 1 degree. I do this with video event pan/crop. The source video look sharp. After rotated and rendered to HDV template (best quality video setting), the sharpness, details disappear. It has a soft look. I thinked it is because in digital world, it has to be some degrading, nothing is for free. But then i test to render to uncompressed avi and that rotated avi look as sharp as the source. What can i do? Why is this behavior? Unfortunately I need the video in HDV format. It is just because the mpeg recompress? When i change the opacity to 99%, and render it without rotating, there is also recompress but the sharpness remain good! thx! Marton __________________ Relaxing clips with waterfalls and music, 3D photos, 3D videos: www.3d-video.hu

July 9th, 2010, 12:26 PM	#13
Prech Marton Major Player Join Date: May 2004 Location: hungary Posts: 462	Robin, thanks for your post. But my video was only rotated, but NOT upscaled! I masked out the edges with black. Now i try render to avi frameserver and encode to mpeg with different program. __________________ Relaxing clips with waterfalls and music, 3D photos, 3D videos: www.3d-video.hu

July 7th, 2010, 10:17 AM	#2
William Boehm Regular Crew Join Date: Feb 2007 Location: Bothell, Washington Posts: 195	this is a good question. anyone else have comments? i have some shot video of se alaska mountains and shoreline that is slight off, and needs to be rotated serveral degrees...process? quality loss if any with cineform int. codec?

July 7th, 2010, 11:55 AM	#3
Robin Davies-Rollinson Trustee Join Date: Dec 2002 Location: Gwaelod-y-garth, Cardiff, CYMRU/WALES Posts: 1,215	Well, if you rotate an image, you're going to have to slightly enlarge it as well, to hide the black edges that you'll get, so there is bound to be a quality loss. It's the same as if you use a software image stabilizer... Plus the fact that mpeg doesn't like a lot of tweaking in post. A transcode to something like Cineform might be the answer.

July 7th, 2010, 02:47 PM	#4
Mark Sudfeldt Regular Crew Join Date: Jun 2006 Location: New Zealand Posts: 63	Does switching on Reduce Interlace Flicker for the rotated clip make any difference?

July 7th, 2010, 03:14 PM	#5
William Boehm Regular Crew Join Date: Feb 2007 Location: Bothell, Washington Posts: 195	i am using neoscene 5.04 intermediate codec, and wondering if i should rotate then in vegas 9 under pan, and save to what kind of file...i actually dont know if i can save to a cineform file codec still while in vegas using cineform files. .newbie..just started editing in the past month.

July 7th, 2010, 04:34 PM	#6
Bruce Phung Major Player Join Date: Dec 2009 Location: Rochester,NY USA Posts: 285	Cineform is also a lossless codec, you would want to save it to Cineform to retain your high quality video.

July 8th, 2010, 09:06 AM	#7
William Boehm Regular Crew Join Date: Feb 2007 Location: Bothell, Washington Posts: 195	i havent checked yet..meaning that vegas 9 will let me edit the cineform file, and save back to a cineform file after editing instead of a .veg file?

July 8th, 2010, 10:31 AM	#8
Bruce Phung Major Player Join Date: Dec 2009 Location: Rochester,NY USA Posts: 285	You got it all confused. The .veg file will always remain the same regardless of what codec is being used. The rendering and the codec that maintian the video is what you are after.

July 8th, 2010, 01:32 PM	#9
William Boehm Regular Crew Join Date: Feb 2007 Location: Bothell, Washington Posts: 195	bruce..please explain as i am pretty new at editing in vegas and cineform. my virutal dub download doesnt recognized veg files. so i probabl should deshake footage first, otherwise, edit in vegas, save the file in .veg, then render to a dvd hd in .veg? i need a little explanation if you have time. bill

July 8th, 2010, 02:26 PM	#10
Bruce Phung Major Player Join Date: Dec 2009 Location: Rochester,NY USA Posts: 285	.Veg file will open by Vegas only. You can not use any other program to open .veg file. .Veg file is the Vegas project name itself. 1) Edit your footage, do what ever you want done to your video 2) when you are finished your edit and happy with it and then render it to AVI. 3) Click on custom and select your codec, in your case you would want to select cineform and click ok. 4) finish your rendering. From there you would import your video into Virtual Dub and deshake it or what ever filter you want to use. When you are finish and you would to render or export to AVI again and select your Cineform codec again. This way your video will always be lossless regardless how many times you have been rendering your video. It like a master video file. If you want to output to Blu ray then output to BD. If you want to output to DVD, then select your DV tempate for DVD. You follow me now?. For example if you render in Vegas to WMV HD or what ever format. Now you have a video file. And you import that WMV HD file into Vegas, make changes or what ever, and then you render your video again, that will cause your video quality loss after many generations. With a lossless codecs, no matter what you do, your video will always be high quality. Cineform is your choice here. Hope this explaination make sense to you. Good luck

July 8th, 2010, 07:21 PM	#11
William Boehm Regular Crew Join Date: Feb 2007 Location: Bothell, Washington Posts: 195	thanks bruce that explains it. you would put virtual dub deshaker at the end then after rotating if needed on some not horizontal images, color correction, brightness contrast, the deshake? i will try this approach. bill

July 8th, 2010, 07:34 PM	#12
Bruce Phung Major Player Join Date: Dec 2009 Location: Rochester,NY USA Posts: 285	I have spent more than 8 hrs playing with varies setting in deshaker and I never able to get good results. I have seen some impressive video that has been deshaked, but it ain't work for me. I use Virtual Dub mainly for HD to SD down conversion and the result is very impressive, very sharp pictures.