Timeline playback performance with MOV. DSLRs, phones, etc

With the recent kerfuffle about Quicktime on Windows, I'll pile on here with this post.

First, what I mean by DSLR, phones etc in MOV. Specifically I am referencing a MOV file which contains AVC (H.264) video and PCM or AAC audio.

The Quicktime AVC decoder seems to be fubar with respect to performance relative to the native AVC decoder built into Hitfilm. Now Quicktime forces apps like Hitfilm to jump through hoops just to be able to use it and that incurs an additional overhead but DNxHD done via Quicktime MOV and seems to be fine so that extra overhead appears to not be critical. So I fall back to the Qt AVC decoder being subpar.

On my machine I can take some Panasonic GH4 UHD MOV files and Hitfilm fails miserably trying to play those back. If I rename the files to MP4 to get Hitfilm to use its native AVC decoder the files playback fine. All else is equal. I can reproduce this with a Canon 7D2 1080p60 MOV file. My machine is pretty stout and most AVC plays fine but 60p in HD or 4K pushes it over the edge and thus my two referenced examples.

Even if your AVC file plays fine the rename will save you some CPU cycles which may help in system performance.

For those who wonder how the rename can work. MP4 files are 99.9% the same structure as Quicktime MOV files.

Back in the Hitfilm 3 days I suggested to FxHome that they bypass Quicktime for AVC+PCM/AAC type MOV files and decode those natively since they already have those decoders. This is not a unique idea. Sony Vegas does this and maybe/likely others as well. First, you can import common files without the need for Quicktime and all of its baggage. Second, apparently the Qt AVC decoder sucks performance wise.

 

Here is a Windows batch you can use to easily rename files since the Windows file explorer makes this process a bit tedious. You can save this in a file named "rename MOV to MP4.cmd". It has two modes of operation. You can select a number of files and drag and drop them onto the icon for this script and they will be renamed. Or you can drag and drop a single folder onto the script icon and all MOV files in the folder will be renamed.

EDIT: Here is a link to a ZIP file which contains two windows scripts. One to rename MOV to MP4 and the other to rename MP4 to MOV.

EDIT: Added M4V to MP4 and MP4 to M4V rename scripts.

https://drive.google.com/open?id=0B0Ns35ef10qNN25BOHBFZkx1OWM

Here is the text of a script to rename from MOV to MP4.

@echo off

if exist %1\ goto folder

:top
ren "%~dpn1.mov" "%~n1.mp4"
IF errorlevel 1 goto errorF

shift
if NOT %1$==$ goto top
REM pause
goto :EOF

:folder
REM switch to passed directory
cd %1
%~d1

for %%I in (*.mov) do (
    ren "%%I" "%%~nI.mp4"
    IF errorlevel 1 goto errorD
)

REM pause
goto :EOF

:errorF
echo !!! file rename error !!!
pause
exit 1

:errorD
echo !!! folder rename error !!!
pause
exit 1

 

Comments

  • I have a question. I'm assuming I already know the answer.

    It's better to convert my .mov files my DSLR creates to DNxHD, than renaming them to .mp4?

    If that's not true, then I don't see the point of waiting for the converting, when renaming just takes seconds.

  • @KevinTheFilmmaker "Better" is a relative term. If you can get acceptable edit performance from your DSLR file directly, then why not use that. If you like rapidly scrubbing the playhead then an Intra format (i-frame only) like DNxHD will always perform better than anything AVC.

    If you cannot get acceptable performance then you have to transcode to something else. Again, what is a better something else is a relative term. 

  • I forgot that these things start wars. =P

    Thanks for explaining this to me. 

  • edited April 2016

    @KevinTheFilmmaker Yes, there can always be format wars but more often there are other things not involving pissing matches.

    DNxHD is a fine format with a low CPU overhead but the result files will be 3-4x larger than a typical DSLR AVC source file. You may also keep the original file with the DNxHD. Is that disk space use acceptable? Only each individual can answer that.

    I have a GoPro I attached to my mountain bike and I can have 10-15 minute MP4 AVC clips which if converted to DNxHD can balloon to 15GB. To me unacceptable. GoPro knows people end up with long clips and the free GoPro studio tool has a good workflow to trim the good bits out the mass of boring and transcode to Cineform all at once. Other transcoders, not so much. Cineform is similar to DNxHD. There was logic in GoPro purchasing Cineform. GoPro MP4 AVC files are probably the worst editing performance AVC files I have come across.

    If you want small files and edit performance it can be done with a transcode to AVC with certain settings. Your comment about "waiting for the converting" comes into play here. Transcoding to an edit performance AVC format will take longer than a typical DNxHD or Cineform transcode.

  • CNKCNK
    edited April 2016

    Speaking of DNxHD. You've ruined me. I'm sitting here comparing the "raw" against the DNxHD 36 and 115. I notice the difference, because 36 looks worse than raw, but 115 looks better than 36, and better(?) than raw? The file sizes of 115 is roughly 3x of raw. I never thought I cared about quality this much, until today....

    Image below shows left: DNxHD 115    right: raw

    Why does the DNxHD 115 look better than the raw media with whatever specs my Canon 600D outputs at 1080/23.

    To me, it looks like the left one which is 3x the size of the right one, has more detail in it. Is it an illusion and the raw actually looks better, but I just prefer the brighter one?

     

  • Triem23Triem23 Moderator

    One thing here is RAW footage is designed to be "flat" in contrast and color for maximum latitude in grading. DNxHD is a lower colorspace than RAW--RAW being 12-14 bits/color channel (depending on camera) where DNxHD 36 and 115 are 8 bits/color channel. Transcoding is probably applying a colorspace of some sort, having the side effect of boosting contrast. 

    But this is speculation without knowing which tool you transcode with. 

  • CNKCNK
    edited April 2016

    MPEG Streamclip 1.2

    Quality 100%

    That's all I changed.

  • Triem23Triem23 Moderator

    Ok, MPEG Streamclip converts in a YUV colorspace, where the RAW is likely uncompressed RGB. So, I stand by the earlier guess. 

  • edited April 2016

    I believe Kevin is incorrectly using the word "raw". The Canon T3i/600D does not output RAW video. It outputs 8-bit AVC like nearly everything else.

    DNxHD 36 (aka proxy) probably should look worse than the source AVC file.

    Canon DSLRs output full range video levels. Depending on what did the transcode and options used you might have gone through one or more levels conversions on the transcode and import into Hitfilm. Hitfilm 4 Update 1 was updated to recognize the full range VUI flag and not do a studio to full range levels conversion on import.

    What you are likely seeing as Triem23 stated is a contrast difference due to a levels conversion that was done somewhere in the process.

  • Aladdin4dAladdin4d Moderator

    DNxHD 36 quality seems to be very shot dependent. 

    If the video in is full range and you go with the DNxHD default Rec 709 then you will see a levels shift. There is an option for RGB levels but it isn't commonly used.

    @KevinTheFilmmaker You can also try DNxHD 80. That option is farther down the list than 115 but it's there and won't make as large a file as 115. Whether or not the quality is there is entirely up to you.

  • CNKCNK
    edited April 2016

    @Aladdin4d, the only settings I change is use the DNxHD codec, make sure it's DNxHD 115, change the quality to 100%, set to 709, and I use the batch file output thing.

    I tried RGB, and DNxHD 115 was darker than the original footage. 

     @NormanPCN That's why I wrote  "raw". I do have MagicLantern, which I've had for years already. I'll try to use their flat profile and see if it's any different. It does bother me though, just knowing that one looks better than the other. 

    If it's just the contrast, and not any information missing then I can live with that. 

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