The Definitive Answer, Once and For ALL! at DVinfo.net

Hugh DiMauro · January 26th, 2006, 08:09 AM

Does post letterboxing 4 X 3 video in PPro 1.5 degrade the picture? If so, how?

Tom Hardwick · January 26th, 2006, 09:15 AM

If you mean adding a black mask top and bottom to blank out 25% of the screen image then no, this won't alter the resolution, brightness, sharpness, contrast, gamma you name it. A face in the middle of the screen is as sharp whether it's masked or not.

If however you show this full screen on a 16:9 TV, then the 430 (PAL) lines you have left after masking will be interpolated to fill the 576 lines of the TV, and this does indeed make the image a lot softer.

tom.

Jean-Francois Robichaud · January 26th, 2006, 09:21 AM

If working with DV footage, then yes it will degrade the quality, in the sense that the DV stream needs to be recompressed. But one generation of DV recompression is nothing to be worried about. If you are already adding effects to you video (color correction or else), then a recompression was already required.

However, if you do this in 2 passes (color correction then render [export] to DV, then letterboxing and the final render [export] to DV), you'll have 2 generation losses. It would be better to do it all in one pass, or render [export] the color-corrected video to uncompressed video. But then again, DV can go through a few generations with very little artifacting.

Hugh DiMauro · January 26th, 2006, 09:47 AM

So then what you are saying is that on the timeline, have everything applied at once, i.e. lettrboxing, color correction, effects (no pre-rendering before the various effects) and render only once to then export to DVD?

Steven Gotz · January 26th, 2006, 10:03 AM

It is OK to render along the way. The program will rerender as needed from the original information, not from the preview files that already exist.

Just don't export to a new AVI and then letterbox that AVI. That would add another generation of loss.

Hugh DiMauro · January 26th, 2006, 12:06 PM

Thanks. Master Steve. By the way, is what J.F. Robichaud said true? (I'm not trying to start a skirmish, I'm only trying to know what's what! Thanks!)

Steven Gotz · January 26th, 2006, 01:46 PM

He is correct, except that I object the way he uses the word "render". He is correct, except that it is safer to use the word "export" instead of render. I had to read his comments again to agree with him. The first time they sounded wrong because to me, rendering is creating preview files. The way he used it, I believe, was to export to a new AVI and then work on that again.

Render is a difficult word to use with new editors since Premiere Pro uses it specifically to mean creating preview files. Yet older editors use render to mean export. Sometimes. Sigh.

Just leave it that he is correct, and understand exactly what he means by render.

Jean-Francois Robichaud · January 27th, 2006, 08:34 AM

Yeah, when I said render I meant exporting to a video file. I should have been clearer.

In other words, you can edit in one sequence, add colour-correcting effects, nest that first sequence in another one if you want and then do the letterboxing (either a crop or adding a "black bars" matte). When you export that, all the effects will be computed starting with the original source files, so it's only one generation of loss.

Hugh DiMauro · January 31st, 2006, 02:08 PM

Thank you. But you mention one generation loss. So that means by adding the black bars from the title designer I am degrading the image somewhat? Just by the use of the matte bars (as opposed to the pillar bars, LOL)

Steven Gotz · January 31st, 2006, 02:20 PM

When you add a title, or any effect, or anything except a simple straight cut, the video has to be recompressed. So yes, just adding bars reduces the quality ever so slightly.

Hugh DiMauro · February 1st, 2006, 09:19 AM

Thank you! I guess this even affects the big Hollywood boys when they shoot in HD.

Steven Gotz · February 1st, 2006, 09:45 AM

I suppose they suffer a bit, but they spend a lot more time manually compressing sections of their films or HD video to get it down to the SD that you see on a DVD. They don't just run it through some software a couple of passes on the entire video. It is much more complicated than that.

Besides, they start with a much higher quality and therefore can afford a bit of loss without detection.

Hugh DiMauro · February 1st, 2006, 11:25 AM

Yeah, the lucky bastards.

Jonathan Reynolds · February 6th, 2006, 08:18 AM

You could render out un-compressed, depending on the length of the project, the size of your hard drive, and your computer specs. I do this all the time at work. You can also use quick-time animation compression, it will bring down the file size a bit, and it is lossless. But, I think that once you do that you may have to render the footage before you can view it in the preview window. I am usually going to after effects after rendering from premier.

January 26th, 2006, 08:09 AM	#1
Hugh DiMauro Trustee Join Date: Jun 2003 Location: Central Florida Posts: 1,207	The Definitive Answer, Once and For ALL! Does post letterboxing 4 X 3 video in PPro 1.5 degrade the picture? If so, how? __________________ Interesting, if true. And interesting anyway.

January 26th, 2006, 09:21 AM	#3
Jean-Francois Robichaud Regular Crew Join Date: Sep 2005 Location: Montreal, Canada Posts: 142	If working with DV footage, then yes it will degrade the quality, in the sense that the DV stream needs to be recompressed. But one generation of DV recompression is nothing to be worried about. If you are already adding effects to you video (color correction or else), then a recompression was already required. However, if you do this in 2 passes (color correction then render [export] to DV, then letterboxing and the final render [export] to DV), you'll have 2 generation losses. It would be better to do it all in one pass, or render [export] the color-corrected video to uncompressed video. But then again, DV can go through a few generations with very little artifacting. __________________ JF Robichaud Last edited by Jean-Francois Robichaud; January 27th, 2006 at 08:34 AM.

January 26th, 2006, 09:47 AM	#4
Hugh DiMauro Trustee Join Date: Jun 2003 Location: Central Florida Posts: 1,207	So then what you are saying is that on the timeline, have everything applied at once, i.e. lettrboxing, color correction, effects (no pre-rendering before the various effects) and render only once to then export to DVD? __________________ Interesting, if true. And interesting anyway.

January 26th, 2006, 10:03 AM	#5
Steven Gotz Trustee Join Date: May 2002 Location: Clermont, FL Posts: 1,520	It is OK to render along the way. The program will rerender as needed from the original information, not from the preview files that already exist. Just don't export to a new AVI and then letterbox that AVI. That would add another generation of loss. __________________ Steven Gotz http://www.stevengotz.com

January 26th, 2006, 12:06 PM	#6
Hugh DiMauro Trustee Join Date: Jun 2003 Location: Central Florida Posts: 1,207	Thanks. Master Steve. By the way, is what J.F. Robichaud said true? (I'm not trying to start a skirmish, I'm only trying to know what's what! Thanks!) __________________ Interesting, if true. And interesting anyway.

January 26th, 2006, 09:15 AM	#2
Tom Hardwick Inner Circle Join Date: Mar 2003 Location: Billericay, England UK Posts: 4,711	If you mean adding a black mask top and bottom to blank out 25% of the screen image then no, this won't alter the resolution, brightness, sharpness, contrast, gamma you name it. A face in the middle of the screen is as sharp whether it's masked or not. If however you show this full screen on a 16:9 TV, then the 430 (PAL) lines you have left after masking will be interpolated to fill the 576 lines of the TV, and this does indeed make the image a lot softer. tom.

January 26th, 2006, 01:46 PM	#7
Steven Gotz Trustee Join Date: May 2002 Location: Clermont, FL Posts: 1,520	He is correct, except that I object the way he uses the word "render". He is correct, except that it is safer to use the word "export" instead of render. I had to read his comments again to agree with him. The first time they sounded wrong because to me, rendering is creating preview files. The way he used it, I believe, was to export to a new AVI and then work on that again. Render is a difficult word to use with new editors since Premiere Pro uses it specifically to mean creating preview files. Yet older editors use render to mean export. Sometimes. Sigh. Just leave it that he is correct, and understand exactly what he means by render. __________________ Steven Gotz http://www.stevengotz.com

January 27th, 2006, 08:34 AM	#8
Jean-Francois Robichaud Regular Crew Join Date: Sep 2005 Location: Montreal, Canada Posts: 142	Yeah, when I said render I meant exporting to a video file. I should have been clearer. In other words, you can edit in one sequence, add colour-correcting effects, nest that first sequence in another one if you want and then do the letterboxing (either a crop or adding a "black bars" matte). When you export that, all the effects will be computed starting with the original source files, so it's only one generation of loss. __________________ JF Robichaud

January 31st, 2006, 02:08 PM	#9
Hugh DiMauro Trustee Join Date: Jun 2003 Location: Central Florida Posts: 1,207	Thank you. But you mention one generation loss. So that means by adding the black bars from the title designer I am degrading the image somewhat? Just by the use of the matte bars (as opposed to the pillar bars, LOL) __________________ Interesting, if true. And interesting anyway.

January 31st, 2006, 02:20 PM	#10
Steven Gotz Trustee Join Date: May 2002 Location: Clermont, FL Posts: 1,520	When you add a title, or any effect, or anything except a simple straight cut, the video has to be recompressed. So yes, just adding bars reduces the quality ever so slightly. __________________ Steven Gotz http://www.stevengotz.com

February 1st, 2006, 09:19 AM	#11
Hugh DiMauro Trustee Join Date: Jun 2003 Location: Central Florida Posts: 1,207	Thank you! I guess this even affects the big Hollywood boys when they shoot in HD. __________________ Interesting, if true. And interesting anyway.

February 1st, 2006, 09:45 AM	#12
Steven Gotz Trustee Join Date: May 2002 Location: Clermont, FL Posts: 1,520	I suppose they suffer a bit, but they spend a lot more time manually compressing sections of their films or HD video to get it down to the SD that you see on a DVD. They don't just run it through some software a couple of passes on the entire video. It is much more complicated than that. Besides, they start with a much higher quality and therefore can afford a bit of loss without detection. __________________ Steven Gotz http://www.stevengotz.com

February 1st, 2006, 11:25 AM	#13
Hugh DiMauro Trustee Join Date: Jun 2003 Location: Central Florida Posts: 1,207	Yeah, the lucky bastards. __________________ Interesting, if true. And interesting anyway.

February 6th, 2006, 08:18 AM	#14
Jonathan Reynolds Tourist Join Date: Feb 2006 Posts: 4	You could render out un-compressed, depending on the length of the project, the size of your hard drive, and your computer specs. I do this all the time at work. You can also use quick-time animation compression, it will bring down the file size a bit, and it is lossless. But, I think that once you do that you may have to render the footage before you can view it in the preview window. I am usually going to after effects after rendering from premier.