Pixelated video after export

Tornaut
Tornaut Website User Posts: 13 Just Starting Out
edited November 2020 in HitFilm

Hi,

I hope someone can help me with this little problem. I have been trying to find a solution but I have not been lucky with it and I finally though that maybe someone can give me a hand with this little issue.

I have been editing a 720p 29.97 fps video using Hitfilm Express but the final result looks a bit pixelated. The original footage does not have this problem so I assume that the problem comes from the preset configuration or the export process. The pixelated effect is easier to notice in scenes with poor light and contrast. For example, in the attached photos you can see how the original footage (second picture) has a soft and nice diffused light at the background of the scene while in the exported video (first picture), the light diffusion is dotted with pixels.

Does anybody know why this happens and how can I solve it?

Attached you can also find the preset conditions I used for exporting.


Thank you very much for your time and help.


Comments

  • EvilDaystar
    EvilDaystar Website User Posts: 300 Enthusiast
    edited November 2020

    You can see some compression banding on the streetlamp glow in the fog ... my instincs say bump up the Bitrate but it's already not exactly low ... there must be something else we can do other than throwing tons more data at the problem.

  • Triem23
    Triem23 Moderator Moderator, Website User, Ambassador, Imerge Beta Tester, HitFilm Beta Tester Posts: 18,953 Ambassador

    @EvilDaystar probably not much. The original footage is dark and low contrast. It's exactly the type of thing that MPEG type compression destroys.

    @Tornaut I should do that video I keep meaning to do about how digital video isn't pristine, Marvel and Lucasfilm (so, Disney) can't get a good looking YouTube stream, and every video you see looks as "bad" as what you're seeing, but you're only noticing it now because it's yours, but it always takes 45 minutes to type up.

    Hence the video I need to make.

    You can try upping the bitrate, you can try different export formats, but, the bottom line is, if you upload the final video to YouTube it's gonna get crunched more, no matter what.

  • Tornaut
    Tornaut Website User Posts: 13 Just Starting Out

    Hi! Thank you for your replies!

    But how is possible then that the original video does not have this banding compression even when is the same format and the original bitrate is lower (around 6.000 mbps)? I also see that other people have this problem with this kind of scenes but still the pixelation they suffer is minimal compared to the one I see in my video. And in my case, I see it even before updating the video in any social platform so I am worried that as @Triem23 says, its gonna be even worst once I upload it.

    I will play with the bitrate and format and lets see what happens...

  • Tornaut
    Tornaut Website User Posts: 13 Just Starting Out

    So, I have been playing a bit with the export settings but I have not been succesful at all. I have tried increasing the bitrate even to max, variating the level and profile, upscaling, changing the framerate and exporting in different formats. But nothing really worked. The only thing that seemed to improve a little bit the quality of these scenes was to export the video in uncompressed avi, but 4 min of video was already 23 gb, something not useful at all because I plan a video of around 1 h.

    Any idea on why the original footage (720p 29.97 fps; main profile; level 3.1; bitrate around 6.0 mbps) does not suffer from this problem and it only happens after exporting? If I export with exactly the same settings as the original video, should not then have the same quality because no modification in image quality was actually added? I am just cutting some sequences out and denoising audio but not changing the quality of the image... am I? 🤔

  • georgefilmltd
    georgefilmltd Website User Posts: 349 Enthusiast

    @Tornaut Maybe you have to many effects, and your computer can't handle it, so it decompresses the file?

  • [Deleted User]
    [Deleted User] Posts: 0 Enthusiast
    edited November 2020

    Since you're troubleshooting an issue with your video. Increase the bitrate to max mbit and see if the problem still exists, unless you have already? It doesn't matter if it's twice as high as the actual max judging by the video, but just to get that out the way to continue troubleshooting.

    Exporting compresses the image further. The lower the starting bitrate is, the worse the result gets, as a rule of thumb. This could change depending on codec, since it's not always visible, but dark pixel compression is pretty noticeable. 6 mbit is not very high, especially for a game recording, even at 720

  • Tornaut
    Tornaut Website User Posts: 13 Just Starting Out

    Hi , thank you for your replies.

    @GeorgefilmLtd : I do not have any effects on the video. I just cutted out scenes that I do not like and eliminated the noise of the audio. My computer should be able to handle it as I had videos with way more things on it and they did not have this problem.

    @kevin_n : I tried to bring the target and max bitrate up to 300.000 mbps which is the maximum that allowed me with this preset but the problem still persist. Attached you can see a pic of the same slide with the increased bitrate.


  • Triem23
    Triem23 Moderator Moderator, Website User, Ambassador, Imerge Beta Tester, HitFilm Beta Tester Posts: 18,953 Ambassador

    "If I export with exactly the same settings as the original video, should not then have the same quality because no modification in image quality was actually added?"

    Editors don't work that way.

    Mp4 is a LOSSY format. Your under 6mbps footage is already degraded, but you're not noticing it yet.

    The uncompressed data rate of 720p, 29.97 fps is about 949mbps. Your compression ratio is about 158:1. I guarantee you your source footage is already badly degraded.

    Mp4 is a DELIVERY codec. This means it was designed to hold a final output, compressed for distribution on web or Blu-Ray. Mp4 was NOT designed to be edited (same goes for h.265, btw). It is not your fault camera manufacturers and screencapnsoftware use a format not intended for editing, but there you are.

    Mp4 is a "Long Group of Pictures" (Long GOP) format. This means the chances are only 1 of every 60-to-120 frames is a complete image. Everything else is interpolated data.

    MPEG compression schemes are specifically designed to throw away details in dark, low contrast areas, and areas of similar color . Your footage is dark, low contrast and basically all blue. You're feeding the MPEG encoder exactly what it mangles the most.

    An NLE decompress a frame fully to put on the timeline and recompresses it again from scratch. It doesn't matter if you didn't "make any changes" to it. Your degraded, compressed footage is being compressed again. In fact, Hitfilm globally anti-aliases all renders. Period. You can not completely disable that, which means, no matter what you think, you have changed your footage.

    (Side note - software that decodes and encodes footage without alterations are "transcoders," and are used to convert files from one format to another. Transcoders are not editors.)

    Now, when you say you "turned the bitrate up to max," what did you actually do? If you opened an existing preset and turned the "target" bitrate up to match the "max" bitrate, then you didn't do what you thought you did.

    For mp4 output, create a new Preset. Set Level to 5, Profile to High, set Target Bitrate to, oh... 200 and the Max to 300. Setting Target and Max to the same value is another way to get a bad encode.

    If that doesn't work, try exporting Cineform (Windows) or ProRes (Mac).

    If that doesn't work, you can try image sequences, but you'll have to render audio separately and remux.

    Now, in my last comment I said, " digital video isn't pristine, Marvel and Lucasfilm (so, Disney) can't get a good looking YouTube stream, and every video you see looks as 'bad' as what you're seeing, but you're only noticing it now because it's yours, but it always takes 45 minutes to type up....You can try upping the bitrate, you can try different export formats, but, the bottom line is, if you upload the final video to YouTube it's gonna get crunched more, no matter what."

    Three frames from the Rogue 1 trailer on YouTube. Top left, Kemmler's shuttle. Top right the MPEG compression has removed the tail of the Shuttle for a frame. Bottom....just look at all the banding and pixelization of the Death Star.

    When I said Disney/Lucasfilm/ILM can't get a good YouTube stream I was being literal. Go watch some streaming media at 720p or 1080p pause at times. Really inspect the frame. It will look like crap. Thing about 4k? It's not actually compressed better, it's just that on a phone, tablet or Computer monitor - basically any screen under 50 inches - you literally cannot resolve the individual pixels. The noise is there, it's just too teeny to pick out.

    Sorry, I wish there was a magic "make it beautiful" filter, but there isn't. Your source footage started compressed and degraded, and there's very little that can be done about it.

  • Tornaut
    Tornaut Website User Posts: 13 Just Starting Out
    edited November 2020

    Hi!

    Thank you very much @Triem23 for the complete explanation and sorry for my ignorance in the topic. This kind of situations actually help me to learn more about video editing so I appreciate your explanation. :)

    So, I followed your advice @Triem23 and I have rendered it with target bitrate to 200 and the Max to 300. However, I do not see any improvement at all. Attached you can see the same scene with the new export settings.

    I understand that youtube normally compresses the video causing a loss of image quality. I have seen that in some of my other videos. However, it is the first time I see a loss of image quality before uploading the video in Youtube, just after exporting. Normally, after editing, the final product always had a very similar quality to the original video and if there was a loss in image quality, was always minimal. Is when I upload it to Youtube that I notice the compression effect of the website and the loss in image quality. This time however, with this video I notice this effect just after editing, before uploading it into Youtube. That is why I thought that maybe the export step could be optimized and I decided to look for help. What also kept my hopes in optimizing the render/export process is that I have other videos with dark scenes where I do not see a blocky effect as pronounced as in this one, and most of the times the blocky effect easier to notice in the uploaded youtube version due to youtube compression rather than in the exported file. My concern now is that if there is nothing I can do, once I upload it to Youtube it will lose even more image quality due to Youtube compression, so I can expect that the final result will look even worst... :(

    I think I will keep following your advice and try with Cineform or ProRes and see if I notice any difference. Also, does anybody you know of any add-on to Hitfilm or specific software to "repair" or clean this kind of images? Maybe a filter that minimize it?

    Thanks a lot! ;)




  • [Deleted User]
    [Deleted User] Posts: 0 Enthusiast

    A 6 mbit 720 recording is practially nothing. You should record your next recording at a much higher bitrate, especially if it's a lot of dark scenes, vivid scenes or fast moving scenes.

  • Tornaut
    Tornaut Website User Posts: 13 Just Starting Out

    Hi!

    It's me again. So, I have two news... A good one and a not so good one... :S

    I start with the good one: I have solved the problem... Which brings me to the not so good one: with another video editor. Attached you have the original scene (first pic), the scene rendered with hitfilm (second pic) and the scene rendered with a different editor (third pic). None of the edited ones look as good as the original one, but the third one has better quality than the second one; the third one has less loss of quality image. And this is how used to be also with other dark scenes that I did before in Hitfilm. There was always an slightly decrease in image quality but not so pronounced as with this particular video. The funny thing is that the bitrate used with this other editor is even lower than the one used in Hitfilm... Any theory on that? It might be interesting to know why.

    At the moment I think I will use both softwares. I have been using Hitfilm for long time and I like that is user-friendly, intuitive and fast. However, I will keep the other editor just in case I find any other video that becomes a challenge...

    I appreciate all your help and explanations! I learned a lot! Thank you! :)


  • [Deleted User]
    [Deleted User] Posts: 0 Enthusiast
    edited November 2020

    #2 and #3 look pretty much identical to me. I think that HitFilm is lower quality than most other editors, but not by much. It used to be worse. The softening used to be on the level of uneven pixel mapping, regardless if media and project matched.

    But again, 6 mbit/s is almost nothing. Like triem said earlier, youre compressing the image by a ratio of more than 150 times. Besides, a still image doesnt tell the full story. What codec? What do they look like when played back side by side, and how were they rendered, hardware encoding is softer than software on CPU at the same bitrate, in my experience the few times ive actually cared to test it.

    I think that were beating a dead horse here. But if you need help in the future, or if you find something thats not quite right when rendering in HitFilm, then feel welcome to start a new thread.

  • Tornaut
    Tornaut Website User Posts: 13 Just Starting Out

    Maybe depends on the screen you are looking it up @kevin_n. I have checked the picture in two different computers and in one I see the differences much easier than in the other one, but in both I have the feeling that the #3 is closer to 1# than #2 is.

    Regarding the bitrate, I followed the advices of @Triem23 and increased it to 200 with a 300 max bitrate so the final product had a bitrate around 130 Mbps but still the blocky effect was there and no sings of improvement. The codec was H264 for both softwares. When I play them side by side I see the blocky effect much visible in the Hitfilm video than in the video rendered with the other software (even when the bitrate of this last one was around 3 Mbps). As I said before, I edited before other dark videos in Hitfilm and I never had this problem. So maybe the new version of Hitfilm has some issues with dark scenes than previous versions did not have? I mention it because I updated the software before starting this project. Or maybe was this particular video the one that was difficult to handle for Hitfilm who knows why... Combination of colours? This specific kind of poor light and contrast? 🤔

    Anyway, I appreciate all your help and thank you very much for your time! It has been a pleasure to talk to you guys. 😁

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