Win a Pentax Limited Lens: Raffle Now Live!

oriweissman · 03-28-2012, 07:44 AM

Hi all!
I shot a short film on my KX and now I need to edit it.
I use my PC (i7) with adobe premiere cs4 and have installed an mjpeg codec.
I heard Jasper Gray on youtube saying it is best to convert the mjpeg compressed format to an uncompressed one, before editing it. he claims it will work better.

1 - is there realy a difference?
2 - by uncompressed he meens uncompressed AVI? don't I lose quality by pre-converting?
3 - does it metters (the quality) which mjpeg codec I use?

Thank you very much!

photoleet · 03-28-2012, 08:03 AM

I don't think you need to. It is already contained in AVI container. I'm on Windows 7, and loaded up one of my K-x movies into Sony Vegas, and I was able to edit just fine. I don't have any special codec, just latest version of ffdshow-tryouts. But I think I didn't even need that, I think Windows 7 can decode MJPEG codec on it's own.

Anvh · 03-28-2012, 09:09 AM

What's the reason he says you need to do that?

For quality it doesn't matter as far as i know, premiere applies the edits on the files in a "layer" like fashion like photoshop but different though, so you won't gain any quality that isn't there since it doesn't bake in the edits only after you decode the video.

oriweissman · 03-28-2012, 09:50 AM

Thanks

He says that with uncompressed format there are less problems on the way.. he says that the rendering is faster and that the uncompressed format is much more editing-software-friendly.

Anvh · 03-28-2012, 10:39 AM

Uncompressing could indeed make the rendering faster and also make the software faster so there are some merrits that way but you're getting serious large files and it also takes time to uncompress them so in the end i doubt it's really worth it.
And with Premiere there shouldn't be a differnce in quality.

oriweissman · 03-28-2012, 10:47 AM

Perfect thanks!

Anvh · 03-28-2012, 12:16 PM

What kind of video card do you've.
If you have a new Nividia card and a pretty high end one you mught be able to use CUDA in CS5, that would speed things up a lot!

oriweissman · 03-28-2012, 11:48 PM

Hi,
I am using a 32bit windows XP so I have the CS4

lordofthestrings · 03-29-2012, 01:56 AM

Allright. It depends on the codec and what kind of editing you want to do. If you're going to work hard on colors or do several encodings (chroma key, color correction, more than one rendering...) it's always better to transcode before to a lossless codec. A kind of "upsampling". Yes, you could lose a little bit at first but than you'll have a strong codec to work with that could stand several "treatments".
But........ If you're doing a light editing there is non need to transcode MJPEG, because (even if it's an old, surpassed codec) it's a video codec based on single jpeg pictures and it allows a FRAME-BY-FRAME accurate editing just the way it is. If you're working with HDV or "better/worse" AVCHD you'll have more compressed (Long GOP - "group" - "of" - "frames" - codecs, because there are about 12-15 frames compressed in one group) and heavy codecs and you cannot do "frame by frame" editing if you don't transcode first. That's all.

Anvh · 03-29-2012, 10:01 AM

Is cs5 64bit only?

@lordofthestrings are you sure about that in regards to Premiere CS4?
I thought that premiere placed the edits "on top" of the video file on not in it.
So it works somewhat you tell premiere what kind of edits you want to do and only at the end when you encode it it applies them to the files.
When you encode the video the original files gets uncompressed, premiere aplies the edits to that and then premiere decode the file to your selected output.

If it works like i wrote down then there is no quality difference if you uncompress the file or not first.

lordofthestrings · 03-29-2012, 10:54 AM

My speech was generic. That was the theory behind, regardless the software used. I don't know how Premiere works, what you told me sounds a lot like "proxy editing". Again, regardless the software you're using, everything I told you remains true. You have to be very careful editing this kind of video codecs because they generally are compressed and don't have a high dinamic range like raw ".pef" pictures (chroma subsampling 4:2:2 - 12-bit), they have a lot less color depht, (4:2:2 - 8-bit). I told you what is the main purpose of transcoding first. If you don't do that kind of "hard color work" and, since MJPEG is already a low-compression codec which you can edit frame-by-frame, you can work like you wish, you won't lose that much, pay attention to the output codec and settings instead ;-)

Anvh · 03-29-2012, 11:18 AM

But you're now talking about the format it's captured in, something else then actual editing.
No dslr actually film in 4:2:2 so not much to gain there...

Yeah something like proxy editing but a bit different.

Most of not all video software work with an actually "preview" not many actually show the real file at full resolution. it would take too much power.
Besides with premiere filters are applied a bit like layers in photoshop, they even look somewhat the same and you can turn them on and off so that shows that the edits aren't baked in the video when editing, they are just a layer over the video to show the effect. Only when you encode them the effect is actually put into the file.

Maybe it's easier to explain it with photos.
JPG file can sometimes best be edited as a 16bit TIFF file with a larger colour space because you can move the data in the pixels around and they will keep the data better because you've more room.
However if we look at Lightroom and Layers with Photoshop then those edits aren't actually moving the data in the file around they more or less put a filter over the image to show you the effect so you can have thousands of layers in photoshop or edits in lightroom but because they don't actually edit the file there is no need to use the bigger file for more movement.
With layers you actually have one edit from the original file to the edited file, that's when you decide to safe it while with the first example you have a step every time you do an edit.

lordofthestrings · 03-29-2012, 11:31 PM

I understand. And I'm not saying you're wrong. I'm saying something different and it seems to me that you already have enough knowledge. Yes, the transcoding/upsampling I was referring to is exactly like what you said (converting a 12-bit .pef file to a 16-bit tiff file for example). You don't do this to increase quality (obviously you can't) but to minimize the loss of quality throughout a particular/long editing process (multi-render, chroma key, color correction).
I don't use myself commercial software but a photographic example could be: I edit a raw 12-bit .PEF in lightroom, export a 16-bit .TIFF file and then open it with Photoshop to do more advanced/creative editing. You do this upsampling process because you have to stress that file and edit a second time with another program and you want to minimize the loss of quality, right?
That's all I'm saying. Just "theory". You can put the mjpeg into Premiere, do all your editing stuff and render the way you want and you'll be fine.
Nobody here is wrong, I just wanted to point out one or two things

.

Wheatfield · 03-29-2012, 11:41 PM

Originally posted by oriweissman

Should I decompress before editing?

I find it more relaxing is I do....

lordofthestrings · 03-29-2012, 11:52 PM

Sometimes I do.

03-28-2012, 07:44 AM	#1
oriweissman New Member Join Date: Mar 2011 Location: Bologna, Italy Posts: 7	Should I decompress before editing? Hi all! I shot a short film on my KX and now I need to edit it. I use my PC (i7) with adobe premiere cs4 and have installed an mjpeg codec. I heard Jasper Gray on youtube saying it is best to convert the mjpeg compressed format to an uncompressed one, before editing it. he claims it will work better. 1 - is there realy a difference? 2 - by uncompressed he meens uncompressed AVI? don't I lose quality by pre-converting? 3 - does it metters (the quality) which mjpeg codec I use? Thank you very much!

03-29-2012, 11:18 AM	#12
Anvh Veteran Member Join Date: Sep 2011 Posts: 4,616	But you're now talking about the format it's captured in, something else then actual editing. No dslr actually film in 4:2:2 so not much to gain there... Yeah something like proxy editing but a bit different. Most of not all video software work with an actually "preview" not many actually show the real file at full resolution. it would take too much power. Besides with premiere filters are applied a bit like layers in photoshop, they even look somewhat the same and you can turn them on and off so that shows that the edits aren't baked in the video when editing, they are just a layer over the video to show the effect. Only when you encode them the effect is actually put into the file. Maybe it's easier to explain it with photos. JPG file can sometimes best be edited as a 16bit TIFF file with a larger colour space because you can move the data in the pixels around and they will keep the data better because you've more room. However if we look at Lightroom and Layers with Photoshop then those edits aren't actually moving the data in the file around they more or less put a filter over the image to show you the effect so you can have thousands of layers in photoshop or edits in lightroom but because they don't actually edit the file there is no need to use the bigger file for more movement. With layers you actually have one edit from the original file to the edited file, that's when you decide to safe it while with the first example you have a step every time you do an edit. Last edited by Anvh; 03-29-2012 at 11:26 AM.

Similar Threads
Thread	Thread Starter	Forum	Replies	Last Post
Photo editing help	derelict	Digital Processing, Software, and Printing	5	08-12-2011 05:50 AM
in camera editing	Rusky40	Pentax DSLR Discussion	2	11-29-2010 07:02 AM
Best editing software?	clim920	Video Recording and Processing	9	07-31-2010 12:30 PM
Editing K-X pics (several ?'s)	subeeds	Troubleshooting and Beginner Help	5	05-30-2010 07:44 PM

03-28-2012, 08:03 AM	#2
photoleet Veteran Member Join Date: Jul 2011 Location: DMV Photos: Albums Posts: 431	I don't think you need to. It is already contained in AVI container. I'm on Windows 7, and loaded up one of my K-x movies into Sony Vegas, and I was able to edit just fine. I don't have any special codec, just latest version of ffdshow-tryouts. But I think I didn't even need that, I think Windows 7 can decode MJPEG codec on it's own.

03-28-2012, 09:09 AM	#3
Anvh Veteran Member Join Date: Sep 2011 Posts: 4,616	What's the reason he says you need to do that? For quality it doesn't matter as far as i know, premiere applies the edits on the files in a "layer" like fashion like photoshop but different though, so you won't gain any quality that isn't there since it doesn't bake in the edits only after you decode the video.

03-28-2012, 09:50 AM	#4
oriweissman New Member Join Date: Mar 2011 Location: Bologna, Italy Posts: 7 Original Poster	Thanks He says that with uncompressed format there are less problems on the way.. he says that the rendering is faster and that the uncompressed format is much more editing-software-friendly.

03-28-2012, 10:39 AM	#5
Anvh Veteran Member Join Date: Sep 2011 Posts: 4,616	Uncompressing could indeed make the rendering faster and also make the software faster so there are some merrits that way but you're getting serious large files and it also takes time to uncompress them so in the end i doubt it's really worth it. And with Premiere there shouldn't be a differnce in quality.

03-28-2012, 10:47 AM	#6
oriweissman New Member Join Date: Mar 2011 Location: Bologna, Italy Posts: 7 Original Poster	Perfect thanks!

03-28-2012, 12:16 PM	#7
Anvh Veteran Member Join Date: Sep 2011 Posts: 4,616	What kind of video card do you've. If you have a new Nividia card and a pretty high end one you mught be able to use CUDA in CS5, that would speed things up a lot!

03-28-2012, 11:48 PM	#8
oriweissman New Member Join Date: Mar 2011 Location: Bologna, Italy Posts: 7 Original Poster	Hi, I am using a 32bit windows XP so I have the CS4

03-29-2012, 01:56 AM	#9
lordofthestrings Junior Member Join Date: Jan 2012 Posts: 39	Allright. It depends on the codec and what kind of editing you want to do. If you're going to work hard on colors or do several encodings (chroma key, color correction, more than one rendering...) it's always better to transcode before to a lossless codec. A kind of "upsampling". Yes, you could lose a little bit at first but than you'll have a strong codec to work with that could stand several "treatments". But........ If you're doing a light editing there is non need to transcode MJPEG, because (even if it's an old, surpassed codec) it's a video codec based on single jpeg pictures and it allows a FRAME-BY-FRAME accurate editing just the way it is. If you're working with HDV or "better/worse" AVCHD you'll have more compressed (Long GOP - "group" - "of" - "frames" - codecs, because there are about 12-15 frames compressed in one group) and heavy codecs and you cannot do "frame by frame" editing if you don't transcode first. That's all.

03-29-2012, 10:01 AM	#10
Anvh Veteran Member Join Date: Sep 2011 Posts: 4,616	Is cs5 64bit only? @lordofthestrings are you sure about that in regards to Premiere CS4? I thought that premiere placed the edits "on top" of the video file on not in it. So it works somewhat you tell premiere what kind of edits you want to do and only at the end when you encode it it applies them to the files. When you encode the video the original files gets uncompressed, premiere aplies the edits to that and then premiere decode the file to your selected output. If it works like i wrote down then there is no quality difference if you uncompress the file or not first.

03-29-2012, 10:54 AM	#11
lordofthestrings Junior Member Join Date: Jan 2012 Posts: 39	My speech was generic. That was the theory behind, regardless the software used. I don't know how Premiere works, what you told me sounds a lot like "proxy editing". Again, regardless the software you're using, everything I told you remains true. You have to be very careful editing this kind of video codecs because they generally are compressed and don't have a high dinamic range like raw ".pef" pictures (chroma subsampling 4:2:2 - 12-bit), they have a lot less color depht, (4:2:2 - 8-bit). I told you what is the main purpose of transcoding first. If you don't do that kind of "hard color work" and, since MJPEG is already a low-compression codec which you can edit frame-by-frame, you can work like you wish, you won't lose that much, pay attention to the output codec and settings instead ;-)

03-29-2012, 11:31 PM	#13
lordofthestrings Junior Member Join Date: Jan 2012 Posts: 39	I understand. And I'm not saying you're wrong. I'm saying something different and it seems to me that you already have enough knowledge. Yes, the transcoding/upsampling I was referring to is exactly like what you said (converting a 12-bit .pef file to a 16-bit tiff file for example). You don't do this to increase quality (obviously you can't) but to minimize the loss of quality throughout a particular/long editing process (multi-render, chroma key, color correction). I don't use myself commercial software but a photographic example could be: I edit a raw 12-bit .PEF in lightroom, export a 16-bit .TIFF file and then open it with Photoshop to do more advanced/creative editing. You do this upsampling process because you have to stress that file and edit a second time with another program and you want to minimize the loss of quality, right? That's all I'm saying. Just "theory". You can put the mjpeg into Premiere, do all your editing stuff and render the way you want and you'll be fine. Nobody here is wrong, I just wanted to point out one or two things .

03-29-2012, 11:41 PM	#14
Wheatfield Moderator Join Date: Apr 2008 Location: The wheatfields of Canada Posts: 15,987	Originally posted by oriweissman Should I decompress before editing? I find it more relaxing is I do....

03-29-2012, 11:52 PM	#15
lordofthestrings Junior Member Join Date: Jan 2012 Posts: 39	Sometimes I do.