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  1. Member
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    I'm new to working with video and probably just need to be pointed in the right direction for where to learn about the various options out there.

    I've recorded several videos, and if I look at the codec metadata I see the following:
    Codec: H264 - MPEG-4 AVC
    Video resolution: 3840x2160
    Frame rate: 29.97

    I want to convert this into a different format because I'm having trouble working directly with the H264 codec - so far I've tried Prores and DNx. These import just fine for me, but the resulting files are so massive that they completely fill my hard drive. I'm guessing that I'm going to have to sacrifice some quality somehow, but do I do so in the framerate or in the resolution? I had no idea when I set out to make a simple YouTube video how many video formats there are; are there comparisons out there that will tell me what I'm losing with one over the other or how the compression changes. I've got several 4.3 GB video files and can't afford to have them coming out at 25 GB after conversion. Can anyone point me in the right direction to learn about this stuff or otherwise offer some advice? Thanks!
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  2. Dinosaur Supervisor KarMa's Avatar
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    You are going to want to use a proxy, which you may or may not already be doing. I'd suggest a 1280x720 Prores or DNx proxy and go from there. Or make it even smaller. Don't mess with the framerate.
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    Thank you for your reply! I've started looking into proxy files for editing and that looks like a great system to use. I may end up using that, but it doesn't actually solve my immediate problem.

    To make everything much more specific, I'm trying to use DaVinci Resolve (free edition) on Linux Ubuntu, and the camera that I'm using outputs in the format that I posted below - H264 mp4 with AAC audio. Unfortunately, DaVinci Resolve on Linux doesn't support H264 or AAC, so I have to convert before I can even import into the program. From what I've learned of proxies so far, it looks like they have to be imported into the program in the first place to be properly linked, so that doesn't get me around this particular issue.

    It's worth noting that my initial question came from a faulty understanding of video file formats and encodings. I had assumed that there was a pretty continuous spectrum of trade-offs between file size, resolution, and other quality metrics and I would just look for something that resulted in a file size I could handle without too much loss in quality. However, I've been informed that apparently there are really two options - large, uncompressed files for editing or smaller, compressed files for playing.

    In case anyone else happens to be in my particular position and stumbles across this later, I'll document where this got me. It looks like the limitation here is specific to the combination of Linux and the free version of Resolve. Therefore, the options I see before me right now are to either switch to working on this project in Windows with that free version of Resolve, bu y a Studio version of Resolve for Linux, or to try doing this in Lightworks and deal with the 1280x720 limitation on output resolution. If anyone has any advice between those options, I'd appreciate it, but I think that the specific question this thread was created for has been answered.
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  4. Dinosaur Supervisor KarMa's Avatar
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    Yeah DaVinci Resolve can be a pain with supported formats. Potentially lucky for you, you have a H.264 which it supports in Linux. It's just that Linux DaVinci does not like AAC. https://documents.blackmagicdesign.com/SupportNotes/DaVinci_Resolve_15_Supported_Codec_List.pdf

    I would suggest you use something like FFMPEG to simply copy the video to a single .MP4 file (no audio). Convert the AAC audio to PCM uncompressed as a .WAV. I'm saying this as it seems like DaVinci want's the WAV as separate file.

    https://alecaddd.com/davinci-resolve-ffmpeg-cheatsheet-for-linux/

    So for copying the H.264 into a new file you can try.
    ffmpeg -i input.mp4 -c:v copy output.mp4

    And for making the audio track maybe try
    ffmpeg -i input.mp4 -c:a pcm_s16le output.wav
    I'm not the best with FFMPEG but this should get you started.
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    Thanks, KarMa! Unfortunately, it looks like H.264 support is only in the Studio version. I've been on the Blackmagic forums trying to figure this out, too, and someone linked this list of supported codecs that makes the distinction a little more clearly:

    https://documents.blackmagicdesign.com/SupportNotes/DaVinci_Resolve_16_Supported_Codec...=1587452410000

    Thank you for that ffmpeg cheat sheet, though - I've been looking for a good resource for figuring out the basic stuff.

    My plan right now is to try the Windows free version, which apparently does support H.264 and go from there. I'd like to say with Resolve if I can just because it's what my friends use, so if I have trouble I can go to them for help more easily.
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  6. Dinosaur Supervisor KarMa's Avatar
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    Originally Posted by teddybouch View Post
    Thanks, KarMa! Unfortunately, it looks like H.264 support is only in the Studio version. I've been on the Blackmagic forums trying to figure this out, too, and someone linked this list of supported codecs that makes the distinction a little more clearly:
    It's funny how it actually does support H.264, but only "XAVC, XAVC Intra, XF-AVC, XF-AVC Intra, XF-HEVC (H.265), AVCHD". Anytime you see AVC, that's H.264. So it supports AVC that comes out of certain professional cameras, just not MP4 and only specific standards. I don't understand that.

    Anywho, it does support VP9 on Linux but would need FFMPEG to convert it. And could be a long encode. VP9 is used by Youtube to provide quality better than their basic H.264 streams. It's basically a free format made by Google.

    Originally Posted by teddybouch View Post
    https://documents.blackmagicdesign.com/SupportNotes/DaVinci_Resolve_16_Supported_Codec...=1587452410000

    Thank you for that ffmpeg cheat sheet, though - I've been looking for a good resource for figuring out the basic stuff.

    My plan right now is to try the Windows free version, which apparently does support H.264 and go from there. I'd like to say with Resolve if I can just because it's what my friends use, so if I have trouble I can go to them for help more easily.
    Yeah I've personally gotten H.264 to work fine on Resolve. At least 1080p.
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