native footage AVCHD and Premiere Pro CC 2015

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offbeatbryce

Well-known member
I have always had issues editing in native footage with the AVCHD format using Adobe Premiere Pro CC. First here is the specs of my computer.


Model Name: iMac

Model Identifier: iMac13,2

Processor Name: Intel Core i7

Processor Speed: 3.4 GHz

Number of Processors: 1

Total Number of Cores: 4

L2 Cache (per Core): 256 KB

L3 Cache: 8 MB

Memory: 8 GB


External 2TB SSD for footage 256GB SSD for Scratch Disk and my built in imac drive is a fusion drive of 1TB.



As I understand it my computer should efficiently edit naitive footage. It does not. After I import my AVCHD .mts file using the browser in Premiere. I can only edit exactly 3 layers of video. Wheather that be with effects on or off. Sometimes it freezes if I try to add text to the timeline. Even when editing anything 2 video layers or 1 and render heavy effects which works fine with less layers the quality goes to crap. It's like all fuzzy. I have the playback set to the maximum quality. Is there a reason why my computer can't handle native footage? I've always had to transcode to prores but sometimes I'm really on a deadline and would prefer to edit natively if I can.

 
I think part of it depends on the effects you are using and part of it is just the fact most machines would not be able to play-back, in real-time, three video layers with heavy effects applied to them.

I know a lot of effects just have a hard time being played back by themselves in real time without rendering or other effects applied.

Does the footage have any problems playing back by itself with no effects applied to it?
 
What display card do you have? Being able to take advantage of the Mercury Hardware GPU Playback feature can make a very big difference on any computer and would be my best guess as to why playback is poor. Not that this would necessarily help with your issue, 8GB of RAM is light for Premiere, 16GB is better.

PS - how is SSD connected - Thunderbolt?

Thanks

Jeff Pulera
Safe Harbor Computers
 
DigitalVision said:
What display card do you have? Being able to take advantage of the Mercury Hardware GPU Playback feature can make a very big difference on any computer and would be my best guess as to why playback is poor. Not that this would necessarily help with your issue, 8GB of RAM is light for Premiere, 16GB is better.

PS - how is SSD connected - Thunderbolt?

Thanks

Jeff Pulera
Safe Harbor Computers
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I just listed my graphics card in the first post. I'm on CUDA GPU. Switched to Open CL to test and get no difference. even with no effects the computer freezes with three layers at the lowest quality playback. If I transcode to prores HQ I can have up to 10 layers with over 10 effects and nothing crashes. It's confusing to me why that is. SSD is Thunderbolt and USB 3. Tried thunderbolt and USB 3 modes same result. native footage just doesn't work.
 
Long GOP codecs like AVCHD require considerably more processing overhead to decode in an NLE than a proper i-frame mezzanine codec like Prores that is designed for editing. NLE's can only edit fully decompressed i-frames, so with AVC, the entire group of pictures between i-frames has to be decoded on the fly and buffered to ram first. The usual bottleneck is nowhere near enough ram to do this efficiently. On a Mac you can use Prores. On a PC I have switched to Cineform. This is a short sample I made to illustrate the performance difference between 1080p H.264 from my iPad and the same clip transcoded to Cineform HQ on a Lightworks timeline. I'm running a 4GHz overclocked i7 4770K with 16GB ram and a 2GB Nvidia 760 GPU. I never edit long GOP codecs directly anymore. 4:2:2 10 bit i-frame like Prores or Cineform HQ is not only much more efficient for editing, it makes a better quality master for exporting to streaming delivery codecs with less loss of quality on recompression.
 
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Razz16mm said:
Long GOP codecs like AVCHD require considerably more processing overhead to decode in an NLE than a proper i-frame mezzanine codec like Prores that is designed for editing. NLE's can only edit fully decompressed i-frames, so with AVC, the entire group of pictures between i-frames has to be decoded on the fly and buffered to ram first. The usual bottleneck is nowhere near enough ram to do this efficiently. On a Mac you can use Prores. On a PC I have switched to Cineform. This is a short sample I made to illustrate the performance difference between 1080p H.264 from my iPad and the same clip transcoded to Cineform HQ on a Lightworks timeline. I'm running a 4GHz overclocked i7 4770K with 16GB ram and a 2GB Nvidia 760 GPU. I never edit long GOP codecs directly anymore. 4:2:2 10 bit i-frame like Prores or Cineform HQ is not only much more efficient for editing, it makes a better quality master for exporting to streaming delivery codecs with less loss of quality on recompression.
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is i-frame interlaced or is this another term?
 
offbeatbryce said:
is i-frame interlaced or is this another term?
Click to expand...

I-frame means intra-frame. An intra-frame is a complete image that is only compressed within itself. In long GOP INTER-frame compressed video, there are B and P frames between I-frames. These only store the pixels that changed between the last and next i-frames. They have to be decompressed and reconstructed into a complete image frame by the decoder. On that iPad video above, only one frame out of 15 is a complete image on its own. Mezzanine codecs like Prores and Cineform are all i-frames, each one stands on its own. The trade off is the file sizes are much larger. A player like VLC only has to decode and play frames sequentially one at a time. An NLE decodes the entire GOP, 15 frames in the iPad example, and stores it in ram. If you do a 3 second dissolve between two 15 frame GOP clips for example, that is a total of 90 frames that have to be decompressed and stored in ram to perform the effect. This is mostly done by the CPU, not the GPU. 4:2:0 long GOP AVC codecs are lousy editing material.
 
I also read something odd about every time you have to render an effect using sequence menu>Render that it degrades the AVCHD files. I have seen others edit AVCHD and when they render no quality is degraded. I don't know why that is for some people
 
offbeatbryce said:
so should I transcode or is there a way to use native AVCHD without needing to?
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Sure you can edit AVC. Your computer is going to take a heavy performance hit to do it. You need to at least double your ram to 16GB for more buffer space.
If your camera can shoot an intra-frame AVC codec, the performance hit will be much less and FX quality will be better.
 
I still can't see the GPU you're using listed anywhere? This will make a big difference with particular effects. Not all GPU's are created equal and simply stating you have a CUDA GPU does not tell us much. The number of CUDA cores is particlarly important when it comes to GPU-accelerated effects.

8GB RAM is not enough - 16GB is better and 32GB is good More than that won't hurt! You say that trying to add a title causes the program to freeze - this sort of behaviour is indicative of a RAM shortage, though this is probably only one of your problems.

You can also try lowering the playback quality. This will greatly improve performance particularly as your timeline becomes more and more complicated. There's a reason Premiere introduced the lower-quality playback options at the same time as they ramped up native support for AVCHD - quite simply, these codec's are processor intensive and playing back multiple streams at once is extremely taxing on the CPU.

Rendering effects will not cause any degradation to the original files or to the final exported file, unless you've ticked the "use rendered effects" checkbox in the export settings, which is off by default. It may, however, result in a lower quality preview image depending on what render settings you have selected.
 
The easiest way I can think to cut AVCHD is to not. Try transcoding to an intermediate codec such as DNXHD, cineform or ProRes. ProRes is pretty much the industry standard.
 
alan665 said:
The easiest way I can think to cut AVCHD is to not. Try transcoding to an intermediate codec such as DNXHD, cineform or ProRes. ProRes is pretty much the industry standard.
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My take on it too. If you work on a Mac, Prores is a no brainer. You do not lose quality doing the transcode with a decent utility. Mezanine codecs were designed for efficient high quality editing and mastering.
 
Razz16mm said:
My take on it too. If you work on a Mac, Prores is a no brainer. You do not lose quality doing the transcode with a decent utility. Mezanine codecs were designed for efficient high quality editing and mastering.
Click to expand...

I've seen side by side comparisons of AVCHD vs ProRes 422 and there is quality loss. Although the video I saw didn't mention if they transcoded or if they had shot in prores 422.

Video below

AVCHD better than Prores?
 
I was finally able to get AVCHD .mts files to work in Premiere Pro without having to transcode. I do have a few questions though.


my cameras film in 4:2:0 color space. I'm guessing that's 8 bit. Is that correct? If so how come when I try color correcting AVCHD .mts file the picture becomes pixilated? If I do transcode which I did as a test where I transcoded the same .mts file to ProRes 422 the same color was applied to that ProRes file and it wasn't pixilated. Certainly there is no way the 4:2:0 color space is getting better when transcoding right? Why would color filters in ProRes look better than .mts when the color space is the same?


I also did a test and set up my sequence setting to render out to ProRes 422 using the .mts footage files. Is this a good way of doing this or should I actually still be transcoding? It's nice I can use AVCHD .mts natively now without importing problems but the color is what confuses me.
 
offbeatbryce said:
I was finally able to get AVCHD .mts files to work in Premiere Pro without having to transcode. I do have a few questions though.


my cameras film in 4:2:0 color space. I'm guessing that's 8 bit. Is that correct? If so how come when I try color correcting AVCHD .mts file the picture becomes pixilated? If I do transcode which I did as a test where I transcoded the same .mts file to ProRes 422 the same color was applied to that ProRes file and it wasn't pixilated. Certainly there is no way the 4:2:0 color space is getting better when transcoding right? Why would color filters in ProRes look better than .mts when the color space is the same?


I also did a test and set up my sequence setting to render out to ProRes 422 using the .mts footage files. Is this a good way of doing this or should I actually still be transcoding? It's nice I can use AVCHD .mts natively now without importing problems but the color is what confuses me.
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In 4:2:0 your R and B channels are half resolution horizontally and vertically. Transcoding doesn't improve the original quality , but grading adjustments in 4:2:2 10 bit are much less coarse than adjustments made in 8 bit 4:2:0. So yes it does improve the quality of your grades. Prores will produce far fewer artifacts if you are using complex effects too. You wind up with a better quality master that will stand up to recompression for delivery better.
If you want to save disc space, rough cut your originals, transcode the rough cuts to Prores and finish your post with that.
 
If you're working in PP 2015.3 (latest update), why don't you just use the new proxy feature? That's what I do with my AVCHD footage...
 
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scorsesefan said:
If you're working in PP 2015.3 (latest update), why don't you just use the new proxy feature? That's what I do with my AVCHD footage...
Click to expand...

wouldn't proxy not be in the 10 bit color space?

I've tried doing proxy before. If I rename a file that's a proxy and organize all my bins and link my footage back to their original media the files I've named revert back to their original names
 
Razz16mm said:
In 4:2:0 your R and B channels are half resolution horizontally and vertically. Transcoding doesn't improve the original quality , but grading adjustments in 4:2:2 10 bit are much less coarse than adjustments made in 8 bit 4:2:0. So yes it does improve the quality of your grades. Prores will produce far fewer artifacts if you are using complex effects too. You wind up with a better quality master that will stand up to recompression for delivery better.
If you want to save disc space, rough cut your originals, transcode the rough cuts to Prores and finish your post with that.
Click to expand...

how do you trasncode your rough cuts without losing all the crossfades and titles when you transcode to ProRes?
 
offbeatbryce said:
wouldn't proxy not be in the 10 bit color space?

I've tried doing proxy before. If I rename a file that's a proxy and organize all my bins and link my footage back to their original media the files I've named revert back to their original names
Click to expand...
PP is just referencing your files while you edit. There is a toggle to turn on/off proxy. When you're ready to export you just do so with the full res files...
 
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