why exported video looks different from original import ?

Hello,

I am editing a music video clip. I only removed some scenes. I don't understand why the new video looks not like the original. It's subtle but noticeable ! Go to second 8 for example when the singer is shown the way he moves his head and the frames it looks not natural on the second video. The first one is the original..

First one:   

Edited:   

Please let me know

 

Comments

  • Edit: the original got blocked on my channel :) So here is the official original, exactly the same:

  • CleverTagline
    CleverTagline Posts: 3,327 Ambassador

    Aside from the slight quality degradation because you're uncompressing a video and then recompressing it, I don't see much of a difference. What exactly is the difference you're talking about? Can you take a screen grab of two matching frames and put them side by side to show the difference you see?

  • I guess it's the quality degradation then.. The edited scenes look more jumpy in that scene at second 9 for example. I also edited it with the free version of powerdirector and did not have that.

     

    How come the quality loss is so pronounced in hitfilm ?

  • CedricBonnier
    CedricBonnier Posts: 1,204 Staff

    @FROMNOW I only glanced at the video but it looks like there's framerate issues. Is your original media variable framerate? What is the framerate of the original file (you can use MediaInfo to see)? What is the framerate of your comp/sequence?

    Also regarding the quality, I would check what target and maximum bit rates you are exporting with.

  • Frame rate mode: variable

    Frame rate: 23.976 FPS

    The comp is 24 FPS

    Good to know that there is an issue and that this is not supposed to be like this :)

     

  • CleverTagline
    CleverTagline Posts: 3,327 Ambassador

    @FROMNOW Variable frame rate files are tricky for HitFilm to process. Constant frame rates are much easier. You can convert to constant by transcoding. 

    If you’re not familiar with transcoding, I strongly suggest watching this video by @Triem23 . It talks about why transcoding is important, and shows several ways to do it using various tools.

  • Triem23
    Triem23 Posts: 20,519 Ambassador

    @FROMNOW You do have a user error here. @CedricBonnier I'm going to tag you just in case I get this simplified explaination fundamentally incorrect.

    Hitfilm's video clock deals in "Absolute Frames." What this means is, if you create a 10 second comp at 30 fps you have created 300 frames. When you export, Hitfilm is going to export this many frames. Let's say you export this comp at 24 fps... Your exported video is going to be 12 seconds and 12 frames. Why? You created a 300 frame comp and 300 (frames) divided by 24 (frames per second) is 12.5 seconds.

    Hitfilm's audio clock deals in "absolute time." 5 seconds of audio in any timeline exports as 5 seconds of audio at any export framerate.

    So. If you're dealing with 23.97/24fps that IS a difference. It's one frame every 10 seconds. Certainly make certain you always export at the same frame rate you edit in.

    Otherwise, as @CleverTagline notes if you have Variable Frame Rate footage, that can cause issues. Unlike most NLE's Hitfilm attempts to correctly parse VFR footage, but it can get it wrong. A lot.

    To digress with a real world example, I loaded a lot of phone videos into Hitfilm as a test. All videos were "29.97 fps." Some videos Hitfilm called 30, some 29.97, some 25, some 24, some 23.97 and some 20! Why? Well, I looked at the files in Mediainfo and would see that some of the video files varied between 32(?) fps and 12(!)fps. That video that varied between 12 and 32 is the one Hitfilm finally decided was 20. Can't blame Hitfilm, that's a HUGE variance.

    So, certainly you want to transcode your footage first.

    Cedric asked about your Export settings - your target and max bitrates. Note these should be different values. "Max" bitrate should be 1.5 to 2x the "Target" bitrate. So if your Target is 20mbps you want the Max bitrate between 30 and 40mbps. If these numbers are the same it can cause issues.

    Basic Hardware questions that should always be checked: Are your GPU drivers current, and have you run all critical OS updates? The FXHOME devs do write to later versions of drivers. Last itereation of Hitfilm was November, 2018, so it's reasonable to assume that Hitfilm was tuned for an October or September driver. If you have a 2018 driver, probably not a big deal, but if you have a PC that's a couple of years old and hasn't had driver updates that can cause Hitfilm problems.

    I'm kind of scatter-shooting every possible issue I can think of. Think that's it.

    Last couple of notes: The video Clever Tagline linked above is mine and the discussion on codecs is worth a watch. The sections on transcoding are accurate, but need to be expanded - more tools need to be covered - and one Very Important Thing I didn't know at the time needs to be addressed.... Handbrake does not correctly parse 23.97 or 59.98 footage. Instead it creates a variable file alternating 23/24 or 59/60. For correcting VFR footage at 23.97 fps use MPEG Streamclip, or, look in these threads for other options:

    http://fxhome.com/forum/discussion/42415/transcoding-to-fast-decode-avc-for-timeline-performance

    http://fxhome.com/forum/discussion/6418/the-intermediate-codec-thread

    http://fxhome.com/forum/discussion/42349/transcoding-for-better-performance-and-easier-editing

  • CedricBonnier
    CedricBonnier Posts: 1,204 Staff

    @Triem23 What you mention about framerate is only true for export. Importing a 24 fps video and dropping it in a 30 fps timeline should work. Same goes for variable framerate, it should in theory map correctly so that the missing frames are duplicated and the playback is synched to the audio. Saying that, there may still be issues and transcoding your variable framerate video to a constant one using Handbrake or other is probably still advisable as variable framerate videos tend to not be editing-friendly video codecs (ie high GOP h.264), so you'll gain performance as well by transcoding.

    Exporting doesn't resample frames as you said so if you export a 25 fps timeline with a 50 fps export preset you are likely to wonder why your audio and video are not in sync anymore. We will add timeline resampling on export at some point, it is what makes most sense for users. It's been on our todo list for a while but it hasn't been done yet.

  • Triem23
    Triem23 Posts: 20,519 Ambassador

    @CedricBonnier Thanks for the correction. I should have mentioned that Hitfilm conforms footage when first dropped to a timeline. @FROMNOW I say first dropped to a timeline, because, well....

    OK, we've created a 10 sec comp at 30 fps. We drop a 23.97 clip on it. The 23.97 clip is retimed (frames added as needed) to conform the clip to the 30fps comp. AT THIS POINT it seems to become subject to the "absolute frame" clock mentioned above. Changing the fps of the comp (from, say, 30 to 23.97) at a later point will change the timing of the existing clip because it's been defined as 300 frames.

    It is still safest in Hitfilm to set the Edit Timeline to and Comp Shots to the same fps you intend for export unless you need a different speed for a specific reason.

  • Most of the videos I want to edit are at 23.976 FPS.

    If they have VFR then it's best to transcode them with MPEG Streamclip first ?

    But can I export them to youtube at 23.976 FPS ?

    If Hitfilm or Youtube can only be 24 FPS then I should transcode first to 24FPS ?

     

  • CleverTagline
    CleverTagline Posts: 3,327 Ambassador

    @FROMNOW "If they have VFR then it's best to transcode them with MPEG Streamclip first ?"

    Yes

    "But can I export them to youtube at 23.976 FPS ?"

    You can, but keep in mind that YouTube's recommendation re: frame rates reads as follows:

    "Common frame rates include: 24, 25, 30, 48, 50, 60 frames per second (other frame rates are also acceptable)."

    It's hard to know how to interpret "other frame rates are also acceptable," but it could imply that they'll take other frame rates and internally convert them to their nearest equivalent, so 23.976 would likely be encoded on their end as 24...maybe? Anyone know for sure?

    Long story short: HitFilm doesn't care what frame rate you use. If your target platform is YouTube, then perhaps you should edit at 24.

This discussion has been closed.