Jump to content

Mac AVCHD gamma issues - the fix


Andrew Reid
 Share

Recommended Posts

Thanks for the info!

I use GH2 and edit with FCX. Like the workflow so much, not going for Premiere.

Does the same clipping problem occur there? If yes, does it make any difference if I import (inside FCX) the AVCHD files from card > to ProRes ... or use some other conversion before importing to FCX?

The other way around I have done before in "the old days" with FCP7 is I converted my AVCHD files in Elgato Turbo 264.HD to H.264 > and from that via MPGstreamclip to ProRes. Yes, that was time consuming and I´m glad those days are over man...

Anyone?

Best,
Jaskair
Link to comment
Share on other sites

[quote name='Jaskair' timestamp='1343371169' post='14597']
I use GH2 and edit with FCX. Like the workflow so much, not going for Premiere.

Does the same clipping problem occur there? If yes, does it make any difference if I import (inside FCX) the AVCHD files from card > to ProRes ... or use some other conversion before importing to FCX?
[/quote]

I recommend the optimize media option during import (don't know if it is actually called so, I translate from german). You get ProRes then. This ProRes is identical in every respect (also in the exact bitrate and file size) to the ProRes 5D2RGB produces with the "709 Broadcast Range" activated. No wonder, since 5D2RGB doesn't provide a new encoder, it is primarily a new GUI for QT, with some options added. So in a way the suspicion that QT harms the footage is right.

And wrong at the same time. You color correct anyway, don't you? And the finally exported clips look the same however you proceeded before.
Link to comment
Share on other sites

[b]I think it's better to convert using 5DtoRGB. [/b]

Our goal is to keep as much of the information your camera captured. Let's look at the process.

When you bring in an .mts file from your GH2, it has data from 0-255. Your NLE assumes the .mts file should be broadcast safe, so it limits the values to 16-235.

The data from 0-15 and 236-255 are G-O-N-E. Not hidden. Discarded by the NLE.

When you use a color corrector to expand the color space back to 0-255, you're just stretching the 16-235 values across the full range. That makes gaps in the transitions, which makes for banding and abrupt tranistions when you color correct the footage.

[img]http://i48.tinypic.com/6ynrz4.jpg[/img]

With 8-bit footage, every bit of quality and latitude counts. The 5DtoRGB process results in the full 0-255 data being imported, which gives you more flexibility in color correction.

Hard drives are getting cheaper. Buy a bigger one. ;-)

P.S. -- I think I've found a way to do the conversion in Apple Compressor. Haven't had any luck with Adobe Media Encoder. Eager for any suggestions. Thanks!
Link to comment
Share on other sites

Broadcast is 16-235 so thats one reason why the NLE is cuting it but it could just as well convert it with 32 bit floating point and make it loook right.... son no real excuse for Adobe here.

But [b]5DtoRGB is doing the higlights correctly but it makes milky blacks... read on why:[/b]

all of this i posted 2 months ago ... nobody except user : YELLOW red it. no one else reacted to it...

Hey Thats exactly what most people get wrong: The FS100 does NOT do 0-255 it does 16-255! and thats why every software threats it as 16-235 and not as the odd 16-255 it is.

U can test it ur self keep the lens cap on an record a few seconds with lowest gain or iso... and u will see that u won´t get info at levels: 1,2,... 15. All will start at 16. So basicly Premiere takes the 16 and threats it right. and goes on up until 235 and cuts off everything else above. So basicly there is no crushing of the blacks but clipping of the whites. I know this sounds strange about the blacks but really what u are getting with the 5dto.... conversion tool ist that it will make ur whites
spot on! but it will make ur blacks "milky" because it will move them exactly 16 levels. and if your desire is a lil brighter blacks than you can have perfect controll in premiere pro with the "fast color corrector" too. I delt with this so so much and had a big discussion with Adobe too. For them its the easiest way to threat the blacks first and cut off the levels above 235... because this way they wont have to deal with each camera individually. And when u ask them they say : "well thats AVCHD superwhite levels" thats why we clip it ...
So for instance if u have a GH2 (16-235) then premiere threats the blacks perfectly fine and goes up till the brightest white the GH2 can output which is 235 instead of 255. So u wont get clipping or crushing with this one.


Back then I also commented on how to deal with native NEX footage in After Effects which opens up much bigger problems...!
Link to comment
Share on other sites

I personaly use Neoscene Cineform since GH1 was released and it works just fine. 5D to RGB does not bring any more latitude in highlights to my opinion. (I made many test using 5D2RBG rec 601/709 on a same footage)
My workflow : MTS > Neoscene > ProRes (SQ or HQ) > AE or FCP > ProRes HQ > MP4/H264 > Vimeo

Only drawback it's a bit pricy but it's reliable (trusted by Avid and the Industry) it supports batch and multi-cores processing

I am using Neoscene on GH2 hacked footage on a Mac Pro Workstation (still running Snow Leopard so far)
Link to comment
Share on other sites

[b] [url="http://www.eoshd.com/comments/user/20701-adr/"]AdR[/url] actually harddrives are much more expensive then in 2010...[/b]


NLE like Premiere works nativly in 32bit so u can bring all the data back! No need to convert with 5d to rgb... and as i said 5d to rgb might work well with canon eos footage but it does not with nex! It will fix the highlights but will make washed blacks... if u want to bring up some shadow detail in Premiere u can better do it the same way u can bring down the clipped highlights ... just need teh "fast colour corrector"
Link to comment
Share on other sites

@alexander, you can buy a 2Tb Array at Office Depot for $200. That's 8¢ per Gb. (That's like buying a 32 Gb SDHC for $2.56) Kind of hard to call that expensive.

Also, doing a 709 to 601 stretch in 32-bit float will help a little, but the underlying facts are the same. You're still missing 14% of your color data, and the discontinuities degrade your image.

The 5DtoRGB conversion is quick and easy, and it keeps the entire 0-255 color space. That's what I'll be doing.
Link to comment
Share on other sites

[quote name='alexander' timestamp='1343384534' post='14606']
Broadcast is 16-235 so thats one reason why the NLE is cuting it but it could just as well convert it with 32 bit floating point and make it loook right.... son no real excuse for Adobe here.

But [b]5DtoRGB is doing the higlights correctly but it makes milky blacks... read on why:[/b]

all of this i posted 2 months ago ... nobody except user : YELLOW red it. no one else reacted to it...



Back then I also commented on how to deal with native NEX footage in After Effects which opens up much bigger problems...!
[/quote]

Dear Alex, Could you please post a ling to your mentioned post? I'm having a hard time finding it.
thanks in Advance
Link to comment
Share on other sites

there u go
[url="http://www.eoshd.com/comments/topic/661-how-mac-osx-still-screws-your-gh2-fs100-nex-footage-a-must-read/page__st__60"]http://www.eoshd.com...ad/page__st__60[/url]
there are a few posts look at the second one

If u have questions about after effects workflow just ask here.
Link to comment
Share on other sites

[quote name='alexander' timestamp='1343413564' post='14636']
AdR i dont get it ... what do u think, that [color=#ff0000]5[/color]dtoRGB uses some extraterrestrial technology and converts better then Premiere Pro 32bit engine?
[/quote]

[color=#0000ff]@alexander[/color] Um, no. Let's try to keep this friendly and polite, 'k?

It's really simple. The problem comes from the Quicktime APIs. From the 5DtoRGB website:

[quote name='5DtoRGB website'] QuickTime adds noise to its H.264 output (and so does any program that uses QuickTime to decompress H.264)[/quote]

So 5DtoRGB gets better results by NOT using Quicktime for the conversion. They send the video one frame at a time to the GPU, and let the graphics card do the math.

As far as I can see, the difference is moderate until you start doing day-for-night and other radical color grading. For me, 5DtoRGB is also more convenient, because I just batch convert the clips and then I don't have to worry about it any more.

YMMV.
Link to comment
Share on other sites

I dont know if PPRO is using quicktime to nativly deal AVCHD 2.0 files from the NEX. I dont think it does. Only with encoding u could choose h.264 to encode the output files ...but i use quicktime photjpeg because it gives the best quality ...


Most people use 5d to rgb because of the clipping... never heard about noise issues... and also Premiere Pro uses CUDA for AVCHD

are u saing that PPro uses quicktime APIs in windows too? Because if what ur saing is true for just MAC systems then MAC users schould use 5dto RGB then... But in windows I have never ever heared of such problems with Noise because of Premiere using Quicktime API and also have never seen such a problem

The Problem discussed in this thread is clipping ... not Andrew, Yellow, me or other user talked about this "noise issue" ur talking about. If there really is som noise issue well then let us discuss it.

But when it comes to the conversion of rgb then I can assure u PPro is doing it nativly with 32bit percision, it does it LIVE when u pusch the sliders in the Fast Colour Corrector. 5dtoRGb is same conversion step but just fixed and also 32 bit
Link to comment
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.
Note: Your post will require moderator approval before it will be visible.

Guest
Reply to this topic...

×   Pasted as rich text.   Restore formatting

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

 Share

×
×
  • Create New...