AVCHD Workflow

Robert M Wright · January 2nd, 2010, 05:13 PM

On the subject of video compression, this is probably a good thread to pass along a tip for folks that want to use a good intermediate codec, without spending a dime to purchase something like Cineform (which is an excellent product, by the way).

XVID is an excellent implementation of an MPEG-4 ASP codec, and it's free. We usually think of (almost any) MPEG video compression as almost synonymous with interframe compression, but it doesn't have to be.

You can easily configure XVID for intraframe only compression (by setting the maximum I frame interval to 1). If you also configure the codec to for constant quality, using the highest quantizer setting (1), you wind up with very high quality intraframe only compression. I've done some testing, and as far as I can tell, this method appears to result in quality that edges out the quality of the Canopus HQ codec, which is pretty good, and very suitable for many purposes. I did a few tests, using the SSIM metric, and the results beat out Canopus HQ in my tests. My eyes tell me that it's safely in the realm of what most folks would consider a "visually lossless" codec.

XVID is limited to 8 bit color, and you won't get 4:2:2 either (like with Cineform), but can also be quite a bit more flexible than Canopus HQ, in that you are not confined only to the common video frame sizes and framerates. For example, you can do 960x540, at 15fps, just fine (can be quite useful for things like DIY web video projects). XVID will work with Virtual Dub nicely, as well as generally with other apps that allow the use of 3rd party codecs installed on your computer, in an AVI container.

XVID could also be used for archiving the results of projects, with visually lossless compression, yet with smaller file sizes than something like Cineform or Canopus HQ. It's slightly more involved, but you can configure the codec to take advantage of interframe compression also, and still maintain the same quality as with the intraframe only method (by also setting quantizer offsets to zero, for P and B frames), as outlined above, and achieve notably smaller file sizes (depending on the material being encoded). You don't even need to slow down the performance all that much, while still getting somewhat smaller file sizes, using short I frame intervals (like 3 or 4).

Perrone Ford · January 2nd, 2010, 05:31 PM

Quote:

Originally Posted by Robert M Wright

I've been studying video seriously for about 5 years now, and while I'm arguably quite an expert in some areas (like video compression, especially from a practical perspective, for example), there still a few common terms I don't really know the meaning of. What does color grading actually mean?

Color grading is the process by which we modify the look and feel of video by altering it's colors. Whether that is to get a very naturalistic tone, or to get an ultra-stylized one. Color affects our moods, and manipulating that with video is a part of the art.

Robert M Wright · January 2nd, 2010, 06:14 PM

Quote:

Originally Posted by Perrone Ford

Color grading is the process by which we modify the look and feel of video by altering it's colors. Whether that is to get a very naturalistic tone, or to get an ultra-stylized one. Color affects our moods, and manipulating that with video is a part of the art.

So color grading is just another term for color correction, right?

Perrone Ford · January 2nd, 2010, 06:27 PM

Quote:

Originally Posted by Robert M Wright

So color grading is just another term for color correction, right?

No.

Color correction attempts to get the color to a neutral state. Let's say for instance that we're shooting a scene for a movie. The cameraman puts the camera on tungsten balance when we are actually lit for daylight.

When I got in the editing suite, I'd first color correct, and get the color balance correct. THEN I would apply whatever artistic effect I wanted to.

Correction is generally used to match shots. To try and get all the exposure and colors to match from shot to shot, and day to day if the same scene was shot on multiple days. The grading comes after everything is matching and seamless.

Robert M Wright · January 2nd, 2010, 06:44 PM

Quote:

Originally Posted by Perrone Ford

No.

Color correction attempts to get the color to a neutral state. Let's say for instance that we're shooting a scene for a movie. The cameraman puts the camera on tungsten balance when we are actually lit for daylight.

When I got in the editing suite, I'd first color correct, and get the color balance correct. THEN I would apply whatever artistic effect I wanted to.

Correction is generally used to match shots. To try and get all the exposure and colors to match from shot to shot, and day to day if the same scene was shot on multiple days. The grading comes after everything is matching and seamless.

Gotcha. So, color correction is truly about correction and color grading speaks to artistic effect - a somewhat subtle difference, but significantly different meaning.

Robert M Wright · January 2nd, 2010, 07:27 PM

I've got another little tip, that might be useful for newbies (or even maybe for some folks that have been shooting for awhile).

I often lend out an inexpensive camcorder to friends who don't own a camcorder and rarely (if ever) shoot video, for shooting stuff that's important to them (like their kid's high school graduation ceremony or something). I even bought a cheap MiniDV camcorder on eBay a few years ago, for just that purpose.

When I hand them the camcorder, I usually try to give them a practical 5 minute lesson on shooting, so their video (hopefully) doesn't come out completely awful.

Basically, I set the cam to it's widest zoom, and first thing I tell them is to forget the zoom lever is even there (unless they REALLY need to use it - with genuine emphasis on REALLY). I've actually thought about crazy gluing it to wide (cause some folks just ignore that counsel, to really sad effect - sometimes almost makes me get motion sickness, when capturing the footage for them later - especially the stuff that's zoomed in to the max, and looks like it was shot during a major earthquake!).

The second thing I tell them is not to ever use the AWB, because if they use a preset, even the wrong one, I can at least do a somewhat reasonable color-correction pretty dang quickly, after capturing the footage. Then I tell them to think light source, not whether they are indoors or outdoors, to choose the preset. That really does help, because it's easy to wind up with a tungsten preset, shooting indoors when most the light is coming from the sun through windows, if you don't pay attention to what you are doing. (Occasionally, they even remember that!)

Ervin Farkas · January 4th, 2010, 10:19 AM

Color correction & grading are terms that need to be clarified by the specialists. While grading comes from film times, color adjustments are nowadays made on computers even by those shooting on film, then transferred back to film.

For getting colors to neutral, some use the term color correction, others prefer white balance... correction and grading are used interchangeably.

Perrone Ford · January 4th, 2010, 10:33 AM

Quote:

Originally Posted by Ervin Farkas

For getting colors to neutral, some use the term color correction, others prefer white balance... correction and grading are used interchangeably.

Very true Ervin,

I prefer NOT to use the term white balance because I find it ambiguous. When I "correct" a scene I am doing a white balance, black balance, and often adjusting mid-tones as well. It is only after doing that, that I will begin stylizing the colors if desired.

Robert M Wright · January 4th, 2010, 03:53 PM

I don't edit professionally. In my little world, I just color grade I guess. I set white balance manually on the camera, or use the closest preset for the conditions (often actually - and rarely miss by a whole lot that way anyway), and then in post I don't spend time trying to make color neutral, but rather go directly to getting the color the way it actually looks best to me, even if that isn't true to life (and if matching to other clips, doing it pretty much at the same time).

Robert M Wright · January 4th, 2010, 04:16 PM

I guess in a sense, shooting and editing to please myself, and nobody else, affords me the luxury of simple practicality. I'm pretty picky, but I don't need to satisfy anyone with any arbitrary standards. A lot of pros might say you should always manually white balance, but I get results that work just as well, as a practical matter, using presets often. I just don't need the color to be spot on out of the camera, to suit an editor, or anyone else's likings. I know I'm going to be adjusting color a tad anyway (always do), even if I do take the time to white balance properly, so it just doesn't really make any difference in the end. From getting to know a camera for awhile, I can pretty reliably tell, just by looking through the viewfinder, if a preset is off so much that it will matter, and then take the time to do the manual white balance if none of the presets is decent for the lighting circumstances.

Jason Woodbury · January 7th, 2010, 01:21 PM

Robert, what do you use as a target when setting a manual white balance? I have a Canon HG20. Should I use a white balance card like I would with my Canon 30D DSLR camera? Or are there camcorder-specific white balance targets I should look for?

Thanks!

Robert M Wright · January 7th, 2010, 02:36 PM

A piece of decent white copier paper usually works quite well for me - simple, cheap and practical.

Robert M Wright · January 7th, 2010, 03:14 PM

When you stop and carefully consider the practical realities of shooting video, in the vast majority of circumstances, the end result difference between balancing to a piece of good copy paper, as opposed to balancing to a "true white" (or gray) card is, most likely, utterly insignificant.

The nature of shooting motion pictures is that there is movement of some sort (if not, you are simply shooting a stream of stills that are duplicates of each other, in essence), whether it's camera movement, subject movement or movement in the background (often in combination). Almost invariably, movement of any sort (even outside of the framing) will result in a shift in the defacto color temperature of the lighting (even if it's incredibly minor). Way more often than not, I've got to think that the shift in defacto color temperature of lighting, while shooting video, will dwarf the difference in color between a piece of good copy paper, and "true" white.

January 2nd, 2010, 05:13 PM	#31
Robert M Wright Inner Circle Join Date: Jan 2006 Location: Minnesota (USA) Posts: 2,171	On the subject of video compression, this is probably a good thread to pass along a tip for folks that want to use a good intermediate codec, without spending a dime to purchase something like Cineform (which is an excellent product, by the way). XVID is an excellent implementation of an MPEG-4 ASP codec, and it's free. We usually think of (almost any) MPEG video compression as almost synonymous with interframe compression, but it doesn't have to be. You can easily configure XVID for intraframe only compression (by setting the maximum I frame interval to 1). If you also configure the codec to for constant quality, using the highest quantizer setting (1), you wind up with very high quality intraframe only compression. I've done some testing, and as far as I can tell, this method appears to result in quality that edges out the quality of the Canopus HQ codec, which is pretty good, and very suitable for many purposes. I did a few tests, using the SSIM metric, and the results beat out Canopus HQ in my tests. My eyes tell me that it's safely in the realm of what most folks would consider a "visually lossless" codec. XVID is limited to 8 bit color, and you won't get 4:2:2 either (like with Cineform), but can also be quite a bit more flexible than Canopus HQ, in that you are not confined only to the common video frame sizes and framerates. For example, you can do 960x540, at 15fps, just fine (can be quite useful for things like DIY web video projects). XVID will work with Virtual Dub nicely, as well as generally with other apps that allow the use of 3rd party codecs installed on your computer, in an AVI container. XVID could also be used for archiving the results of projects, with visually lossless compression, yet with smaller file sizes than something like Cineform or Canopus HQ. It's slightly more involved, but you can configure the codec to take advantage of interframe compression also, and still maintain the same quality as with the intraframe only method (by also setting quantizer offsets to zero, for P and B frames), as outlined above, and achieve notably smaller file sizes (depending on the material being encoded). You don't even need to slow down the performance all that much, while still getting somewhat smaller file sizes, using short I frame intervals (like 3 or 4). Last edited by Robert M Wright; January 2nd, 2010 at 06:10 PM.

January 4th, 2010, 10:19 AM	#37
Ervin Farkas Inner Circle Join Date: Aug 2005 Location: Atlanta/USA Posts: 2,515	Color correction & grading are terms that need to be clarified by the specialists. While grading comes from film times, color adjustments are nowadays made on computers even by those shooting on film, then transferred back to film. For getting colors to neutral, some use the term color correction, others prefer white balance... correction and grading are used interchangeably. __________________ Ervin Farkas www.AtlantaLegalVideo.com

January 2nd, 2010, 07:27 PM	#36
Robert M Wright Inner Circle Join Date: Jan 2006 Location: Minnesota (USA) Posts: 2,171	I've got another little tip, that might be useful for newbies (or even maybe for some folks that have been shooting for awhile). I often lend out an inexpensive camcorder to friends who don't own a camcorder and rarely (if ever) shoot video, for shooting stuff that's important to them (like their kid's high school graduation ceremony or something). I even bought a cheap MiniDV camcorder on eBay a few years ago, for just that purpose. When I hand them the camcorder, I usually try to give them a practical 5 minute lesson on shooting, so their video (hopefully) doesn't come out completely awful. Basically, I set the cam to it's widest zoom, and first thing I tell them is to forget the zoom lever is even there (unless they REALLY need to use it - with genuine emphasis on REALLY). I've actually thought about crazy gluing it to wide (cause some folks just ignore that counsel, to really sad effect - sometimes almost makes me get motion sickness, when capturing the footage for them later - especially the stuff that's zoomed in to the max, and looks like it was shot during a major earthquake!). The second thing I tell them is not to ever use the AWB, because if they use a preset, even the wrong one, I can at least do a somewhat reasonable color-correction pretty dang quickly, after capturing the footage. Then I tell them to think light source, not whether they are indoors or outdoors, to choose the preset. That really does help, because it's easy to wind up with a tungsten preset, shooting indoors when most the light is coming from the sun through windows, if you don't pay attention to what you are doing. (Occasionally, they even remember that!)

January 4th, 2010, 03:53 PM	#39
Robert M Wright Inner Circle Join Date: Jan 2006 Location: Minnesota (USA) Posts: 2,171	I don't edit professionally. In my little world, I just color grade I guess. I set white balance manually on the camera, or use the closest preset for the conditions (often actually - and rarely miss by a whole lot that way anyway), and then in post I don't spend time trying to make color neutral, but rather go directly to getting the color the way it actually looks best to me, even if that isn't true to life (and if matching to other clips, doing it pretty much at the same time).

January 4th, 2010, 04:16 PM	#40
Robert M Wright Inner Circle Join Date: Jan 2006 Location: Minnesota (USA) Posts: 2,171	I guess in a sense, shooting and editing to please myself, and nobody else, affords me the luxury of simple practicality. I'm pretty picky, but I don't need to satisfy anyone with any arbitrary standards. A lot of pros might say you should always manually white balance, but I get results that work just as well, as a practical matter, using presets often. I just don't need the color to be spot on out of the camera, to suit an editor, or anyone else's likings. I know I'm going to be adjusting color a tad anyway (always do), even if I do take the time to white balance properly, so it just doesn't really make any difference in the end. From getting to know a camera for awhile, I can pretty reliably tell, just by looking through the viewfinder, if a preset is off so much that it will matter, and then take the time to do the manual white balance if none of the presets is decent for the lighting circumstances.

January 7th, 2010, 01:21 PM	#41
Jason Woodbury New Boot Join Date: Nov 2008 Location: Houston, Texas USA Posts: 20	Robert, what do you use as a target when setting a manual white balance? I have a Canon HG20. Should I use a white balance card like I would with my Canon 30D DSLR camera? Or are there camcorder-specific white balance targets I should look for? Thanks!

January 7th, 2010, 02:36 PM	#42
Robert M Wright Inner Circle Join Date: Jan 2006 Location: Minnesota (USA) Posts: 2,171	A piece of decent white copier paper usually works quite well for me - simple, cheap and practical.

January 7th, 2010, 03:14 PM	#43
Robert M Wright Inner Circle Join Date: Jan 2006 Location: Minnesota (USA) Posts: 2,171	When you stop and carefully consider the practical realities of shooting video, in the vast majority of circumstances, the end result difference between balancing to a piece of good copy paper, as opposed to balancing to a "true white" (or gray) card is, most likely, utterly insignificant. The nature of shooting motion pictures is that there is movement of some sort (if not, you are simply shooting a stream of stills that are duplicates of each other, in essence), whether it's camera movement, subject movement or movement in the background (often in combination). Almost invariably, movement of any sort (even outside of the framing) will result in a shift in the defacto color temperature of the lighting (even if it's incredibly minor). Way more often than not, I've got to think that the shift in defacto color temperature of lighting, while shooting video, will dwarf the difference in color between a piece of good copy paper, and "true" white.