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Am I going nuts? Inexplicable file size reduction!

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Alexander Wolf
Am I going nuts? Inexplicable file size reduction!
on Oct 19, 2015 at 9:02:56 am

I've been exporting UHD clips as photojpeg and the file sizes are usually between 1 and 1,5 gigs.
Now for the first time in a month I'm doing the same thing but the file sizes seem to have been reduced by 75% ??!

I'm looking at the properties of an 8 second clip (1,2 GB):

3840 x 2160, Linear PCM, Photo-jpeg, Color Profile: HD (1-1-1), 2 audio channels.

And comparing them to the properties of a 17 second clip I just exported (247 MB) and they are exactly the same?!! (I've exported several files and they're all way smaller than prior exports.)

The only thing I can think of is that I did a software update and photo-jpeg has become 4 times as efficient ;-)

But seriously- what am I overseeing?


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Robin S. Kurz
Re: Am I going nuts? Inexplicable file size reduction!
on Oct 19, 2015 at 1:02:31 pm

Compression is always relative to the actual image being compressed i.e. in video the delta. Therefore one can only assume the one clips simply has significantly higher overall delta than the other. At least there's no other reason I can think of for why that should/could be happening, if everything is in fact exactly as you describe.

- RK

____________________________________________________
Deutsch? Hier gibt es ein umfassendes FCP X Training für dich!


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Alexander Wolf
Re: Am I going nuts? Inexplicable file size reduction!
on Oct 19, 2015 at 3:19:21 pm

Thanks, Robin, but the difference is 90%!! And it's not just one file!

Something has changed but I can't pinpoint it. All the clips I have exported are incredibly small. As if they are HD as opposed to 4K...

Where else can I look?


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Walter Soyka
Re: Am I going nuts? Inexplicable file size reduction!
on Oct 19, 2015 at 6:51:42 pm

[Alexander Wolf] "Something has changed but I can't pinpoint it. All the clips I have exported are incredibly small. As if they are HD as opposed to 4K... Where else can I look?"

PhotoJPEG has a quality slider that governs the severity of compression. Have you tried adjusting this?

Walter Soyka
Designer & Mad Scientist at Keen Live [link]
Motion Graphics, Widescreen Events, Presentation Design, and Consulting
@keenlive [twitter]   |   RenderBreak [blog]   |   Profile [LinkedIn]


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Alexander Wolf
Re: Am I going nuts? Inexplicable file size reduction!
on Oct 19, 2015 at 7:02:21 pm

Thanks, Walter. I use a preset that I've been using for the last year! (Maybe I accidentally changed it?)


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Paul Neumann
Re: Am I going nuts? Inexplicable file size reduction!
on Oct 19, 2015 at 5:01:22 pm

First, I would embrace being nuts as it helps in our chosen profession and then I would re-output one the other big clips and see what you get.


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Noah Kadner
Re: Am I going nuts? Inexplicable file size reduction!
on Oct 19, 2015 at 5:39:42 pm

Why Photo-JPEG?

Noah

FCPWORKS - FCPX Workflow
FCP eXchange - FCPX Workshops


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Robin S. Kurz
Re: Am I going nuts? Inexplicable file size reduction!
on Oct 19, 2015 at 5:56:27 pm

[Noah Kadner] "Why Photo-JPEG?"

:D ... was gonna ask that, too, but figured he'd know why. :-P

- RK

____________________________________________________
Deutsch? Hier gibt es ein umfassendes FCP X Training für dich!


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Alexander Wolf
Re: Am I going nuts? Inexplicable file size reduction!
on Oct 19, 2015 at 6:24:22 pm

Why not?

It's what stock companies seem to like best.

And even though I'm all for a healthy dosis of madness, I'd rather have someone help me understand what's going on!


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Robin S. Kurz
Re: Am I going nuts? Inexplicable file size reduction!
on Oct 19, 2015 at 6:42:23 pm

[Alexander Wolf] "Why not? "

Because it's inferior to e.g. ProRes?

But bottom line: if the image looks acceptable, what's the problem? I wouldn't overthink it.

- RK

____________________________________________________
Deutsch? Hier gibt es ein umfassendes FCP X Training für dich!


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Walter Soyka
Re: Am I going nuts? Inexplicable file size reduction!
on Oct 19, 2015 at 6:54:04 pm

[Robin S. Kurz] "Because it's inferior to e.g. ProRes?"

MOV-wrapped PhotoJPEG is as common as it is because it can be decoded with good performance almost universally on all kinds of systems and hardware.

Walter Soyka
Designer & Mad Scientist at Keen Live [link]
Motion Graphics, Widescreen Events, Presentation Design, and Consulting
@keenlive [twitter]   |   RenderBreak [blog]   |   Profile [LinkedIn]


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Alexander Wolf
Re: Am I going nuts? Inexplicable file size reduction!
on Nov 3, 2015 at 11:05:20 am

So to answer my own question: I discovered that it is the data rate that causes the difference in file size. Data rate is not shown when you type Cmd+i on a file that's not opened in QT. When you open it in Quicktime and then click Cmd+i, it shows the data rate, I accidentally found out.

I have no idea why the data rate changed but I'm sure it's a user error ;-(

Now all I have to do is figure out how to get the data rate back to where it was...


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Alexander Wolf
Re: Am I going nuts? Inexplicable file size reduction!
on Nov 4, 2015 at 8:59:33 pm

Since there is no Apple Compressor forum (?) and the Compression Techniques forum seems like a very lonely place, I'd like to call out to some sharp souls out here and help me figure out how to change data rates in Apple Compressor, specifically in Photo-Jpeg.


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Tero Ahlfors
Re: Am I going nuts? Inexplicable file size reduction!
on Nov 5, 2015 at 5:08:15 am

The Photo-JPEG codec only has a quality slider. The data rate is set by the codec.


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Alexander Wolf
Re: Am I going nuts? Inexplicable file size reduction!
on Nov 5, 2015 at 8:45:32 am

But how come exporting photo-jpeg from my iMac 5K generates a 15MB file from a 6 second HD clip while the exact same clip generates a 200MB file on my MB Pro?

Has Apple reduced the base setting for data rate in the photo-jpeg setting by factor 14 in their Compressor upgrade from 4.2 to 4.2.1? (no mention in their release note) Weird!

I hope it's not too much to ask but could someone please export a 6 second HD clip from Compressor 4.2.1 in photo-jpeg and see how big the file turns out?

Would really appreciate it.


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Tero Ahlfors
Re: Am I going nuts? Inexplicable file size reduction!
on Nov 5, 2015 at 9:12:13 am

A six second clip of HD bars and tone is about 15 megs from AME with the QT Photo JPEG codec and AAC audio. Same clip is about 8 megs from Compressor 4.2.1 with the same settings. Data rate from AME is about 20 Mbit/s and Compressor about 10 Mbit/s.

Either this is some one off mystery bug or an user error.


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Alexander Wolf
Re: Am I going nuts? Inexplicable file size reduction!
on Nov 5, 2015 at 9:43:39 am

Thanks, Tero.

Isn't that an extremely low data rate? 10mbit/s?

I've been generating files at much higher data rates for the last year on my iMac and for some reason this has changed in the last month. The only thing I can think of is the Compressor upgrade. Why would I change the Compressor settings when it has worked for me for the last year?? (I never even use Compressor, except when I created a preset for FCP X a long time ago)


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Robin S. Kurz
Re: Am I going nuts? Inexplicable file size reduction!
on Nov 5, 2015 at 9:23:05 am

[Alexander Wolf] "But how come exporting photo-jpeg from my iMac 5K generates a 15MB file from a 6 second HD clip while the exact same clip generates a 200MB file on my MB Pro?"

Question is, which preset are you using?? Because there are no default P-JPEG presets in Compressor, so you must have made it yourself in both cases. But the 15MB file-size would be the one to expect, yes. The only explanation imho could be, that you in fact are not using the exact same preset and the the latter simply isn't even set to P-JPEG. Clips of all types here show a size roughly between 15 and 25MB. If this were H.264 I'd suspect you're using different entropy modes.

No offense, but I'd have to go with PEBKAC.

Otherwise simply post the preset file somewhere for others to look at or rather try out themselves.

- RK

____________________________________________________
Deutsch? Hier gibt es ein umfassendes FCP X Training für dich!


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Alexander Wolf
Re: Am I going nuts? Inexplicable file size reduction!
on Nov 5, 2015 at 10:31:57 am

I've been using a preset I created: New Setting-QT movie - in the inspector pane I changed the QT settings to photo-jpeg. That's all. I just created new settings in the exact same way on my MB Pro and iMac: 200 MB file vs an 18 MB file.

I've also checked on Pond5 to see what another contributor's file sizes are for photo-jpeg. They are much, much higher than 15MB for a 6 second file. They approximate what I've been producing in the last year- until something inexplicably changed...




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Walter Soyka
Re: Am I going nuts? Inexplicable file size reduction!
on Nov 12, 2015 at 8:28:41 pm

If you click on the "Change" button next to QuickTime settings, what is the Quality slider set to?

Walter Soyka
Designer & Mad Scientist at Keen Live [link]
Motion Graphics, Widescreen Events, Presentation Design, and Consulting
@keenlive [twitter]   |   RenderBreak [blog]   |   Profile [LinkedIn]


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Alexander Wolf
Re: Am I going nuts? Inexplicable file size reduction!
on Nov 12, 2015 at 8:58:34 pm

Best...


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Walter Soyka
Re: Am I going nuts? Inexplicable file size reduction!
on Nov 12, 2015 at 8:59:47 pm

On both machines?

Walter Soyka
Designer & Mad Scientist at Keen Live [link]
Motion Graphics, Widescreen Events, Presentation Design, and Consulting
@keenlive [twitter]   |   RenderBreak [blog]   |   Profile [LinkedIn]


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Robin S. Kurz
Re: Am I going nuts? Inexplicable file size reduction!
on Nov 13, 2015 at 9:20:09 am

[Walter Soyka] "On both machines?"

Yeah, you'll want to check that. Because that's the only thing I've been told could possibly affect the compression levels, since Compressor doesn't support profile changes other than Photo JPEG versus Motion JPEG, but rather just different quality/compression levels via the slider. So really that's the only thing it could be.

- RK

____________________________________________________
Deutsch? Hier gibt es ein umfassendes FCP X Training für dich!


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Alexander Wolf
Re: Am I going nuts? Inexplicable file size reduction!
on Nov 16, 2015 at 4:21:59 pm

I guess this will remain a mystery forever. I just created a new photo-jpeg setting again on both machines following the exact same procedure. Opened Compressor, new settings, change QT setting to photo-jpg, change slider to Best. That's it.

Then I exported a 6 second UHD clip from FCP X on both machines using this new preset.

On my MB Pro (running Compressor 4.2) I generated a 675 MB file with a data rate of 894 Mbit/s

On my iMac (running Compressor 4.2.1) I generated a 47 MB file with a data rate of 62 Mbit/s

Freakin' frustrating as hell...

(I think I figured it out: it's Apple's way of saying "Abandon photo-jpeg, embrace ProRes!")


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Robin S. Kurz
Re: Am I going nuts? Inexplicable file size reduction!
on Nov 18, 2015 at 6:20:58 pm

I'm told they're unable to reproduce and would need screenshots of e.g. the window with the slider settings to move forward. Basically any and all details of all the settings used that you can provide via screenshots.

- RK

____________________________________________________
Deutsch? Hier gibt es ein umfassendes FCP X Training für dich!


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Alexander Wolf
Re: Am I going nuts? Inexplicable file size reduction!
on Nov 9, 2015 at 5:51:47 pm

No takers? I posted some screenhots but I guess this will remain a mystery...


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Alexander Wolf
Re: Am I going nuts? Inexplicable file size reduction!
on Nov 11, 2015 at 12:02:34 pm

I thought Robin S. Kurz would have an opinion on my screenshots! Maybe you didn't notice but I shared the settings from Compressor 4.2 and 4.2.1.
I also included the 2 QT files showing their respective specifications. Can you figure it out, Robin?


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Robin S. Kurz
Re: Am I going nuts? Inexplicable file size reduction!
on Nov 12, 2015 at 5:15:28 pm

I've asked someone at Apple about it. I'll let you know if and when I hear back.

- RK

____________________________________________________
Deutsch? Hier gibt es ein umfassendes FCP X Training für dich!


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Alexander Wolf
Re: Am I going nuts? Inexplicable file size reduction!
on Nov 12, 2015 at 8:09:10 pm

Thanks for the effort, RK.


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Adriel Almirol
Re: Am I going nuts? Inexplicable file size reduction!
on Apr 2, 2016 at 9:01:17 pm

Seems like the data rate has been drastically reduced when using the latest version of Compressor. I also upload to stock sites and have noticed this change. Not sure if it's a bug but it's already April 2016, so has anyone figured out the cause of this or a workaround? I'd like to keep the data rates high to keep image quality up so until then we may have to settle with other software.


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Robin S. Kurz
Re: Am I going nuts? Inexplicable file size reduction!
on Apr 3, 2016 at 5:59:00 pm
Last Edited By Robin S. Kurz on Apr 4, 2016 at 5:16:40 am

So you're saying that the quality is factually worse, or you're simply assuming it is?

- RK

____________________________________________________
Deutsch? Hier gibt es ein umfassendes FCP X Training für dich!


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Adriel Almirol
Re: Am I going nuts? Inexplicable file size reduction!
on Apr 4, 2016 at 6:59:18 pm

If we're talking data rate being the measure of quality, then factually yes. The eye test is different though, the quality gap is not as discernible.

Here's a comparison of the data rate when compressing a file to Photo JPEG using Compressor 4 vs QT7 Pro.
http://imgur.com/wDGBWA6


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Alexander Wolf
Re: Am I going nuts? Inexplicable file size reduction!
on Apr 3, 2016 at 6:30:36 pm

I switched to ProRes...


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