GH1 - Frame Rate Conversion Tests - 720 60p & 30p to 24p vs. HPX 170 1080 24p

[Jack Daniel Stanley]

GH1 720 60p & 30p to 24p vs. HPX 170 24p
Rate Conversion Tests
Mad Props to Luis Caffese for running out last minute in the dwindling sunlight and shooting this with me on his HPX-170.
And many thanks to Ninja HD Guru Barry Green for his help in figuring out how to set up the test.


5 min vid.

• 4 conversion methods using Cinema Tools, Compressor, and FCP
• GH1 shoe mounted to the top of an HPX 170 for a similar frame
• Shot cars crossing the frame since they move at a fairly similar rate and any cadence jumps, stuttering should be apparent.
• All 20-faux p referenced against HPX 170's 1080 24p

Click Image to go to Vimeo.
Orig file available for download there.
Tip: don't be afraid to turn HD off to eleminate possibility for streaming induced stutter vs. cadence issues.

I won't comment on the efficacy of each conversion method at this point (though I do have my opinions), but will point out some non frame rate stuff I found interesting:

GH1 handily wins for lattitude (HPX was a little over exposed in some shots, but you can see the latitude edge in all of the shots)

Even with the HPX 170 in 1080 mode and the GH1 in 720, it wins for resolution as well. Note the trees. But also note the murky gray pavement in the GH1 AVCHD shots. In 720 MJPEG shots everything is sharper than the 170's 1080 with no murkiness including the gravel. This is really interesting since in the AVCHD mods which are Long GOP, the still pavement should be where the codec excells and the blowing dancing tree leaves should challenge it, and yet the opposite seems to be true. I would suspect I had a big smear of sweat on my ND filter in the pavement if it weren't for the fact that the MJPEG (Intra frame shots) are smearless.

WHY NOT JUST SHOOT 108024p all the time? What's the point of these tests?
In 1080 24p because of the lack of B frames the camera is trying to predict frames as you shoot, and if you get a ahead of the prediction with your camera movement - you can get some macro blocking or "mud".
This problem is significantly reduced in 60p AVCHD making it suitable for most applications where 1080 24 might fail, and non existent in 720 30p MJPEG an intra frame codec. The good news is that 60p goes to 24p perfectly or near perfectly. 30p is a bit more of a challenge and should be avoided though it can still be used when mud is unavoidable. The good news here is that if you have a smooth moving subject or shot which would really reveal the stutteryness of 30p to 24p, you won't need to use 30p.

[Jack Daniel Stanley]

Reserved for Raw Files for you to play with.

[Jack Daniel Stanley]

METHOD 1: 60p & 30p to 24p

******RECOMMENDED******
This method, METHOD 1, using COMPRESSOR only, is the best for quality and number of steps.

• Under the "BEST - MOTION COMPENSATED" setting it is the absolute best rate conversion / motion you can get but it's slow.
• Under the "BETTER - MOTION COMPENSATED" setting it's much faster and still uses advanced motion interpolation, and looks good.
• Under the "GOOD - FRAME BLENDING" setting it will be very fast and 60p will be very smooth (though not so much with 30p), but the moving object or frame might look weird especially when frame by framing.
  
• This method is all one step, where METHOD's 2 and 3 require several painstaking multi-part steps.

"Better - Motion Compensated" vs. "Best - Motion Compensated" setting. Either method takes advantage of Optical Flow Analysis found in Shake and Motion. On my computer "Best" took exactly 2.5 times longer to render the same clip then "Better" did. "Better" looks really good, if not identical to "Best" to me. If you are having trouble with 30 to 24p (harder than 60 to 24) try "Best" but otherwise stick with "Better" unless the footage seems jerky or its rendering weird. (you'll see these settings below)

Recommending this method over METHOD 2 which involves using Cinema tools and Compressor AND keeping track of the original duration of every clip you convert AND replacing the new audio with the old audio. So given all the manual stuff you have to do in METHOD 2, I'm recommending this Method, the Compressor Only Method, again, for the following reasons:

• with the "Better" setting this might be the faster method
• This method allows for easier batch processing in one step
• you don't have to manually record the duration of each clip
• you don't have to replace the audio for each converted clip with audio from the original clip.
  
• The results are really good
• If you run into trouble or aren't satisfied for one or two clips, use the "Best" setting.

For the absolute fastes process I'm ALSO gonna recommend this method over METHOD 3, conforming in Cinema Tools and speeding back up in FCP - which is pretty fast - but every single step is manual. If you choose "Good - Frame Blending" in Compressor in this method, METHOD 1, you are speeding up exactl the same way FCP will do it. Only doing it in Compressor and selecting the duration as "100% of Source" saves you from having to manually determine, note and enter the duration of each and every clip by hand. So given the fact that Compressor will do the speed up in the same manner as FCP and that all of the duration will be determined and entered automatically, this method is the way to go for all your conversion needs.

60 & 30p to 24 conformed & retimed in COMPRESSOR only



OK here we go.

This is a variation on method 2 which first appeared on MKII forum ____, but will get to that. Method 2 conforms in Cinema Tools and retimes in Compressor. This method does it all in Compressor.

SPEED RATING: FASTEST with "GOOD - FRAME BLENDING", MEDIUM with "BETTER" SETTING and FEWEST STEPS. PRETTY SLOW on "BEST" setting even though this method has the fewest steps. Just Export, Compressor, Import, and all is automated, even the duration of the final clip. Depending on the speed of your computer this may be faster than "Method 2" below, since it has fewer steps.
60p to 24p QUALITY: VERY HIGH EVEN IN "BETTER" SETTING, SMOOTH MOTION but perhaps some weird frames in "GOOD - FRAME BLENDING"
30p to 24p QUALITY: SOMEWHAT CHOPPY, but much better than just dropping 30p in a 24p timeline. "BEST" probably won't make 30p smoother than "BETTER" but might help if the render looks weird (overlapping images). "GOOD - FRAME BLENDING" will be choppy for 30p conversions.

A: Start with a 60p or 30p clip. Either out of FCP or the raw file. You may want to consider trimming the file to just the part you want. You know how to do this in FCP. In QuickTime you can open the file, set new in and outpoints as well, and SAVE AS a new trimmed file. If you go out of FCP you musty export the clip from a 60p or 30p timeline based on whatever the clip actually is, or from the browser (click on it in the browser, export from the viewer). If you export from a 24p timeline, or click on a clip in a 24p timeline and export from the viewer, you will be exporting 24p and nothing else will work. So use the original clips in whatever folder you stored them in, or if going out of FCP export from a 60 or 30p timeline, or from the browser. Never from a 24p timeline.

B. Open COMPRESSOR. Drag your clip in. Set your settings as follows or make a preset as follows:

* Leave audio setting at "PASS-THROUGH", this means that the frame rate of the video will change but the audio will not be altered in anyway, and remain in sync since, while the frame rate of the video will change the duration of the clip will be set to 100% of it's original duration.




Ignore the Resizing Controls unless you want to experiment with taking your footage from 720 to 1080 here. But the resize filter in FCP is pretty good and it will save you time to not do it here.

The example shows "Best - Motion Compensated" but "Better Motion Compensated" is more than twice as fast as "Best" and the results are very good. Both take advantage of the Optical Flow technology found in Shake and Motion, but "Best" will take more time.

For Fastest speed choose "Good - Frame Blending" that's the same method that FCP uses in METHOD 3 "Conform in Cinema Tools & Retime in FCP". Here though, again, everything is automated. Using METHOD 3, will be the same as "Good - Frame Blending" but you will have to manually note the duration of each and every original clip and enter each duration manaully for each and every converted clip, which is not so fun even for 1 clip - and it's aobut as opposite from Batch Processing as you can get.

C. Bring the new clip back into FCP and drop it n your 24p timeline. For 60p to 24 conversions, marvel at the smoothness. For 30p to 24, sigh and know this is better than just dragging and dropping on a 24 timeline.

NOTE: For Slowmotion change step 7 above from "100% of source" to "so source plays at 23.98" as below:

This will get you slow mo, BUT Cinema Tools is much, much faster for slow mo - instantaneous. So really there's no reason to do just slow mo this way, unless you wanted to preserve the real time audio which this method leave untouched. Cinema Tools will give you that slow mo audio effect that never gets old. ;)

[Jack Daniel Stanley]

I read this basic method in a tutorial and wondered why you would go through Cinema Tools when you could do everthying in compressor, and automate half the steps outlined here with less chance for human error. I'm still wondering.

60 & 30 p to 24 conformed in CINEMA TOOLS & then retimed in COMPRESSOR



This is very much like Method 1, but starts with Cinema Tools which does very fast conforming to 23.98.
SPEED RATING: SLOW to MEDIUM SPEED but more steps than step 1 with less automation. If your computer is not super fast, this may be faster than "Method 1" above, even though it has more steps.
60p to 24p QUALITY: VERY HIGH
30p to 24p QUALITY: SOMEWHAT CHOPPY, but much better than just dropping 30p in a 24p timeline.

A: Start with a 60p or 30p clip. Either out of FCP or the raw file. You may want to consider trimming the file to just the part you want. You know how to do this in FCP. In QuickTime you can open the file, set new in and outpoints as well, and SAVE AS a new trimmed file. If you go out of FCP you musty export the clip from a 60p or 30p timeline based on whatever the clip actually is, or from the browser (click on it in the browser, export from the viewer). If you export from a 24p timeline, or click on a clip in a 24p timeline and export from the viewer, you will be exporting 24p and nothing else will work. So use the original clips in whatever folder you stored them in, or if going out of FCP export from a 60 or 30p timeline, or from the browser. Never from a 24p timeline.

So far everything so far has been identical to step "A" in the all Compressor Method, "Method 1" above. Here's where things get different for step "A". If you have started with a an original clip from the folder where you're storing them - MAKE A DUPLICATE OF THAT CLIP. Unlike Compressor, Cinema Tools will alter the original clip. "But I don't want that 30p clip anymore, I want to convert it, why do I need it?" you ask. You will need it as a reference for the duration of the clip a few steps later. If you forget to dulpicate the clip fro 60p AVCHD you can just convert the original MTS file again. If you forget to do this for a 30p MJPEG clip you will have to reconform it back to 30p in Cinema tools.

Now, IF you are coming out of FCP in the manner explained in step "A" you will be OK because your original clip will be sitting on your 30p or 60p timeline in FCP or in your browser in FCP. Just make sure you leave the in and out points set to where they were when you exported the clip.

B. Open Cinema tools, open the clip, and do like this:




NOTE: IF YOU STOP HERE. YOU'VE JUST INSTANTANEOUSLY MADE GLORIOUS SLOW MO. IF THAT'S WHAT YOU WANTED, BRING YOUR CLIP BACK INTO FCP AND ENJOY. (Remember when shooting that 1/60th is the recommended typical shutter speed to be converted to 24p - you can go over but NEVER under. For Slow Motion 1/120th (or perhaps above) is the recommended shutter speed for 60p to be converted to slow motion.)

Anyway ... never mind slow mo. On to the next step for real time 24p.

C. Open COMPRESSOR. Drag your newly slowmowed clip in. Set your settings as follows or make a preset as follows:

* You might as well use the "Disable Audio" setting. Your audio is all slow motiony sounding now. You'd think Compressor would speed it back up with the rest of the footage if you selected "Enable Audio" as opposed to "Audio - Pass Through" or "Disable Audio". Well it does. Sort of. It maintains sync but it won't change the PITCH back to normal! So if you export an actor talking, slow mowed that clip in Cinema Tools so the voice is all deep and evil sounding, Compressor will speed it back up and keep sync, but it will stay deep and evil sounding. So unless you want this effect, might as well disable the audio. This is one of the reasons you need to maintain a source clip with the same in and out as the one you're converting - so you can replace the converted audio with audio from the source clip. "PASS THROUGH" will leave it deep and out of sync. "ENABLE" will make it deep and in sync, but won't change the pitch back to normal.


For step 8 you need to know the duration of your source clip if it were dropped into a 24p timeline. So go into FCP and paste your original 30p or 60p clip with the same in / out points on your 24 time line.

Again, RATE CONVERSION shows the "BEST" setting, but this will take 2.5 times as long to render than "BETTER". Use "BETTER" until you see a reason not to. Both "BETTER" and "BEST" use Optical Flow interpolation found in SHAKE and MOTION.

Right click (control click) the clip and it will show you it's duration:


Now go back to compressor and enter that duration in step 8.


D. When the clip is done exporting bring it back into FCP, drop it on your 24p timeline. Delete the audio from the converted clip if you stil have it and replace that audio with the audio from the non converted clip in the 24p timeline.

[Jack Daniel Stanley]

* FASTEST WITH GOOD SMOOTHNESS. THE FRAME BLENDING DONE HERE LOOKS LIKE 1/48th MOTION BLUR TO ME MOST OF THE TIME. BUT IT's NOT A VERY SOPHISTICATED METHOD COMPARED TO THE MOTION INTERPOLATION DONE IN COMPRESSOR. IT's MORE LIKELY TO MAKE DOUBLE IMAGES, FOR EXAMPLE, AND MY NOT WORK AS WELL FOR 30p to 24p.

Ultimately though you can do frame blending in METHOD 1, the one step all in Compressor method. Here you will have to determine and noteall the durations and manually enter them. With Method 1 you can get the same type fast conversion - FRAME BLENDING - and batch process all your clips with the correct durations auto determined. So - use METHOD 1 unless it's for 1 or two clips and you just want to do it this way.

60 & 30 p to 24 conformed in CINEMA TOOLS & retimed in FCP Timeline



SPEED RATING: MEDIUM to FASTER. Has some manual steps.
60p to 24p QUALITY: GOOD. The smoothness will be comparable to METHODS 1 & 2 but you may notice some weirdness from the frame blending.
30p to 24p QUALITY: Choppy.

A: Starts identical to the previous two methods: Start with a 60p or 30p clip. Either out of FCP or the raw file. You may want to consider trimming the file to just the part you want. You know how to do this in FCP. In QuickTime you can open the file, set new in and outpoints as well, and SAVE AS a new trimmed file. If you go out of FCP you musty export the clip from a 60p or 30p timeline based on whatever the clip actually is, or from the browser (click on it in the browser, export from the viewer). If you export from a 24p timeline, or click on a clip in a 24p timeline and export from the viewer, you will be exporting 24p and nothing else will work. So use the original clips in whatever folder you stored them in, or if going out of FCP export from a 60 or 30p timeline, or from the browser. Never from a 24p timeline.

As in the 2nd method above you need to save a source clip for duration refernce later: If you have started with a an original clip from the folder where you're storing them - MAKE A DUPLICATE OF THAT CLIP. Unlike Compressor, Cinema Tools will alter the original clip. "But I don't want that 30p clip anymore, I want to convert it, why do I need it?" you ask. You will need it as a reference for the duration of the clip a few steps later. If you forget to dulpicate the clip fro 60p AVCHD you can just convert the original MTS file again. If you forget to do this for a 30p MJPEG clip you will have to reconform it back to 30p in Cinema tools.

Now, IF you are coming out of FCP in the manner explained in step "A" you will be OK because your original clip will be sitting on your 30p or 60p timeline in FCP or in your browser in FCP. Just make sure you leave the in and out points set to where they were when you exported the clip.

B. Same as Method 2 above: Open Cinema tools, open the clip, and do like this:




C. Bring the clip back into FCP. Drop both the originacl clip and the newly slow mowed clip on a 23.98 timeline. Control+click the origincal clip to get it's duration:


Control click the new clip, select SPEED, set it to the duration of the original clip.


Finally, replace the audio of the new clip with the audio of the old clip.

[Jack Daniel Stanley]

60 & 30 p to 24 conformed in CINEMA TOOLS & retimed in FCP Timeline



SPEED RATING: Fastest.
60p to 24p QUALITY: Acceptable to some.
30p to 24p QUALITY: Very bad.

A. Drag your 60 or 30p footage onto a 24p timeline.
B. Consider another method for 60p footage.
C. Choose another method for 30p footage.

[Ben_B]

Amazing thank you so much!

I was planning to use reverse telecine for doing my Gh1 stuff to 24p, aside from the stutter effect are there any problems with it? I was going to use it for most shots and only go through compressor/cinema tools for shots where it would be more obvious (like a car driving from one side of a frame to another...hmmmm where have I seen that?)

[SonicStates]

Thanks Jack. Nice to have a set of tests like this!! Cheers.
Sam.

[Jack Daniel Stanley]

You're welcome Sam

Ben - for 1080 24p - yes, use reverse telecine. You wind up with real 24p same as if you started out there natively.

For 60p or 30p to 24 you might as well save your time and just drop the footage in your NLE 24p timeline rather than rev telecine it because that will basically be the same thing. Advanced Reverse Telecine is for following breadcrumbs intentionally left in an interlaced stream which lead to 24p. When you go from 60p or 30p to 24 via rev telecine you're just deleting a sequence of frames that leave you with 24p. Dropping in your timeline will do the same.

For my workflow I'm going to do the following:
1080 24p - reverse telecine
60p - conform in Cinema Tools then retime in FCP or Compressor
30p - (if I just HAD to shoot 30p*) conform & retime in Compressor, or conform in Cinema Tools and Retime in Compressor.

*Reasons to shoot 30p MJPEG. A static shot where detail is being problematic in AVCHD. You are going nuts whipping the camera all over the place and need the one sure fire mud Rx - the intraframe MJPEG codec.

[John Caballero]

Excellent test. Thank you very much.

[Dalton Boettcher]

As others have said, thanks Jack! The hard work and time you've put into guides like this will make things easy on me, whenever I get my hands on a camera. Cheers

[Nighthawk]

Like the others I can't thank you enough. Looking forward to the workflow tutorials. Your work here exemplifies why this forum's the best.

[Ben_B]

60p - conform in Cinema Tools then retime in FCP or Compressor

You mean conform to 24p (making slow motion) and then changing the speed (command-J?) in Final Cut? Or reexporting it with compressor or what? How do you do that? Are there any advantages to this over just dropping the stuff in a 24p timeline in FCP? I know it does sort of a stutter-step thing but I don't think there's any way around that.

[Jack Daniel Stanley]

You mean conform to 24p (making slow motion) and then changing the speed (command-J?) in Final Cut? Or reexporting it with compressor or what? How do you do that? Are there any advantages to this over just dropping the stuff in a 24p timeline in FCP? I know it does sort of a stutter-step thing but I don't think there's any way around that.

Yeah the way around it is through method 1. Compressor alone, or 2. Cinema tools and then compressor or 3. Cinema tools and FCP. You get glass smooth 60p to 24p any of those three separate ways. Only dropping right into the timeline with 60p give you stutter.

Dropping 30p into a timeline is the worst, but method 1. or 2. help some. 3. and 4 (dropping in a timeline). are really bad.

For 60p, 1,2, and 3 are all really good. 4 may be fine for somethings of if you are not crazy picky.

For 60p to 24p with no stutter I'll be using one of the Cinema Tools combo methods (method 2, or 3):
In Cinema tools you "conform" to 23.98. That makes it slow mo.
Then you can
A. Set the duration of the newly slowed down clip back to the duration of the original in compressor (method 2)
OR
B. Set the duration of the newly slowed down clip back to the duration of the original in FCP. (method 3)
A or B gives you 24p.
B (FCP) uses frame blending. A (compressor) I think uses some more advanced interpolation where it's trying to render new frames. To my eye, the quicker method B yielded a result that looked a little more like 1/48th shutter motion blur, but it is frame blending, i.e., more of a fudge and not as good as whatever compressor does - in theory. Like I said, for the type of motion I was doing from 60 - 24p it looks more like 1/48th motion blur, but both the methods A and B looked smooth.

But this way you don't drop any frames, you kind of over (or would it be under?) crank the footage

THE TRICK: The trick is that you want to retime your duration to the duration of the original clip AS IF the original clip had been reverse telecined. Not the time of the original clip at it's original Frame Rate. For example. An almost 2 second clip will be 1.59 in 60 fps and 1.23 in 24 frames per second. When I get the tutorial up I can show you how to determine the target duration.

[sdhurley]

Thanks for the thorough work on this, much appreciated.

on the results... is anyone else seeing some bad color rendition in the clouds/sky on the GH1 footage near the begining of the clips?