Canon XF-AVC from C300MKIII

I am on a iMacPro with a decent Raid (600mB/S) as a scratch drive. I am able to edit XAVC 4K25p/50p from Sony Cameras fluetly but recently switched to Canon and their XF-AVC codec, which has a slightly higher bitrate, but otherwise it‘s quite similar as far as I could find out. I can‘t edit this codec in FCP fluently in either 25p or 50p timelines. I need to render Proxies or Optimized Media, which is really annyoing. I‘m shooting the 400MBit all Intra variant of the Canon C300MKIII. Do you any of you edit this codec? if you can edit fluently, which machine do you have?

maschinsky wrote: I am on a iMacPro with a decent Raid (600mB/S) as a scratch drive. I am able to edit XAVC 4K25p/50p from Sony Cameras fluetly but recently switched to Canon and their XF-AVC codec, which has a slightly higher bitrate, but otherwise it‘s quite similar as far as I could find out. I can‘t edit this codec in FCP fluently in either 25p or 50p timelines. I need to render Proxies or Optimized Media, which is really annyoing. I‘m shooting the 400MBit all Intra variant of the Canon C300MKIII...

I have a 10-core Vega64 iMac Pro and my team has many cameras including the Sony A7SIII, FS5 and FX6, also the Panasonic DVX-200, S1, etc. The only Canon material I've edited is the XC15 4k 10-bit 300 mbps All-I. That was fast and smooth in FCP on an earlier iMac; I don't recollect trying it on the iMac Pro.

It's common that several newer 4k 10-bit 4:2:2 codecs are sluggish on an iMac Pro. Even older Sony 4k 8-bit 4:2:0 XAVC-S material is slow. That is because the Xeon CPU does not have Quick Sync, which forced Apple to add decode acceleration to the T2 chip, which was a 1st generation product. The decode acceleration on Apple Silicon CPUs is much better.

Terms like XF-AVC, XAVC, etc. are just wrappers. The internal codec and computational difficulty of decoding that varies. E.g, Sony XAVC can be 8-bit, 10-bit 4:2:0, 4:2:2, H264, HEVC or All-I. Various hardware accelerators and NLEs have widely differing performance across those. 

If you could post the codec specifics for the problematic XF-AVC that would help. I suggest using Invisor or MediaInfo for this. Invisor lets you compare various codec metadata in a side-by-side fashion:  apps.apple.com/us/app/invisor-media-file...or/id442947586?mt=12

However it's likely that your particular XF-AVC codec may have some attribute that impedes efficient use of the 1st-generation acceleration logic in the iMac Pro's T2 chip. If so the only solution is create proxies or get a machine which is faster on that codec.

It's good to first differentiate between a sluggish playback problem caused by effects vs just decoding. Make a snapshot copy of your timeline, open it, then select all clips with CMD+A and remove all Fx with Edit>Remove Effects. Then see if it plays smoother. 

If you could upload a short camera clip I can try it on several different Macs and various NLEs. 

Thanks for that thorough answer. I was suspecting the lack of Quick Synch having to do with the sluggishness of the codec, but I don't have a recent i-CPU Mac for testing. I uploaded a clip here: www.dropbox.com/s/ukoxxs6zfff1b4x/A015C3...619GX_CANON.MXF?dl=0 and would like to take you up on the offer to try it on different macs. As a sidenote: I have found that the codec performs a bit better when I switch off A/V output in FCP. That is kind of expected and is helpful for pure editing work. I am in desperate need for a M-CPU pro level Mac, because I don't want to buy an Intel CPU anymore.

Here is the Media Info data about the Codec:

GeneralComplete name                            : /Volumes/Attic/DROPBOX/Web Sharing/A015C335_210619GX_CANON.MXFFormat                                   : MXFFormat version                           : 1.3Format profile                           : OP-1aFormat settings                          : Closed / CompleteFile size                                : 2.06 GiBDuration                                 : 46 s 280 msOverall bit rate                         : 382 Mb/sEncoded date                             : 2021-06-19 10:50:09.000Writing application                      : CANON EOS C300 Mark III 1.00VideoID                                       : 2Format                                   : AVCFormat/Info                              : Advanced Video CodecFormat profile                           : High 4:2:2 Intra@L5.1Format settings, CABAC                   : NoFormat settings, GOP                     : N=1Format settings, wrapping mode           : FrameCodec ID                                 : 0D01030102106001-0401020201323001Duration                                 : 46 s 280 msBit rate                                 : 377 Mb/sMaximum bit rate                         : 400 Mb/sWidth                                    : 3 840 pixelsHeight                                   : 2 160 pixelsDisplay aspect ratio                     : 16:9Frame rate                               : 25.000 FPSColor space                              : YUVChroma subsampling                       : 4:2:2Bit depth                                : 10 bitsScan type                                : ProgressiveBits/(Pixel*Frame)                       : 1.819Stream size                              : 2.03 GiB (99%)Color range                              : Min: 0, Max: 1023, Chroma range: 1023colour_range_Original                    : FullMatrix coefficients                      : BT.709

maschinsky wrote: ...I uploaded a clip...and would like to take you up on the offer to try it on different macs. As a sidenote: I have found that the codec performs a bit better when I switch off A/V output in FCP. That is kind of expected and is helpful for pure editing work.

I tested your MXF clip on a 10-core Vega 64 iMac Pro running FCP 10.5.3 and MacOS 11.4, and it seemed smooth and responsive. I also tested that clip using Resolve Studio 17.2.1 and Premiere Pro 15.2.0 on the same machine. Resolve was a little slower, and Premiere a bit slower still, but all were usable. MacOS Big Sur 11.4 was used. In FCP I tried the viewer in Better Quality and Better Performance. The latter was a little faster but both were OK.

There are various criteria for editing smoothness and responsiveness: viewer update rate, playhead update rate, audio update rate, response lag to JKL input. For FCP the skimmer may have different performance for all those items. One NLE may be quicker at one area and slower at others. Historically Premiere has updated the playhead position fairly well but has poorer response to JKL input and slower viewer update rate than FCP or Resolve.

I also tested the MXF clip in FCP on a top-spec 2019 MacBook Pro 16. It was even smoother than the iMac Pro but the iMP wasn't bad. That is probably the difference in hardware accelerators: 1st-gen T2 vs a later-generation version of Quick Sync.

The codec data indicates (as expected) it's UHD 4k/25 10-bit 4:2:2 All-Intra at about 400 megabits/sec. Nothing unusual there.

It's not unknown that outboard A/V hardware and drivers such as breakout boxes or wireless audio may cause problems. Since it runs OK on my iMac Pro, I suggest you remove any items like that, make sure you're on the latest versions of FCP and MacOS, then re-evaluate.

Since certain effects can slow down any timeline on any machine, continue to inspect whether it's a decode performance problem on an Fx-free timeline, or was introduced by certain effects.

Thanks again for your answer, the time spent and investigation. I have sluggishness even on a completely empty timeline with a single C300 clip and no effects in a newly created project. That’s why I suspected something wrong in the first place. Sluggishness with effects is expected. DaVinci is a little more responsive than FCP which is odd in itself. FCP has always been snappier than DR. FCP even beachballs for a second at times when I interact with a more complex timeline using the Canon Codec. I’ll try it on another user account today and if that works clean-install the machine soon. I would not know what else to try. (OS and FCP are both the current versions.)

*** Update *** I created a new user on the same machine and lo and behold I can edit C300III XF-AVI BLAZINGLY FAST. Even 50p is buttery smooth. By the way, have you ever noticed that if you apply the same LUT via the inspector "Camera LUT function or the "Custom LUT" effect, that "Custom LUT" is a lot faster?
So there is something wrong with my main user. Just have to find what it is.

A user directory can get corrupted over time, mainly due to consecutive OS updates without doing a clean install (wipe the drive). A corrupt user account is one of the main causes why a computer can get sluggish over time. You will notice this particularly when performing tasks that require a lot of resources from your system, such as editing.

There is a way to rebuild an existing user account so you don't have to build a new one from scratch, which can be very time consuming.

Tom Wolsky has explained the procedure here: www.fcpxbook.com/tips/resetting-the-user.html

I haven't tried this with Big Sur yet, but it still worked in Catalina. So I think you should be good.

- Ronny

That sounds awesome. I'll give that a try. Thanks so much!