Intermediate Files for Editing

Thank you, @D_S. :slight_smile: This description reflects my experience with the HuffYUV lossless preset in Shotcut. Following the long loading after both dragging the file to Shotcut and bringing the file down to the timeline, playback is just fine unless I make edits to it in the timeline. None of that is the case with Ut Video which runs just about as smoothly as any file can in Shotcut no matter the size of the Ut file. Ut Video is really something. Have you experimented with the Ut lossless preset in Shotcut?

Honestly no, and I probably won’t since I use Tencoder or Hybrid to process the media files before editing since I can feed them a batch of files and off they go. I haven’t had a new project(yet) to try UT video but will give it a try later this week when I have an audio mixer review and new microphone to review.

That is incorrect. Nothing passes through un-transcoded. You cannot even download your original. How do I know? Because, I used to work for a video streaming company and knowledgable about things like adaptive bitrate streaming over HTTP (DASH, HLS, etc.) In order to ensure that these streaming formats work correctly, they need to have a strict GOP and keyframe alignment between each bitrate/resolution. It is fundamental to how they operate, and nothing that is uploaded can be considered trustworthy.

Did you account for the fact that waveform data (technically, it is audio RMS data and a graph of that and not truly a waveform) is cached in a database only when completed? Maybe the one file has its data cached and the other does not.

I did let the FLAC finish caching from what I could tell however it’s possible it was not(the gui did show it the entire timeline I’m not sure how else to tell if it’s done caching) I haven’t tested AC-3 or WAV to compare them to AAC and FLAC but I have a video I’m shooting tonight(a review for an audio mixer) that I will compare all 4 as best possible.

You are correct, my understanding was transcoding only applied to other file sizes since the uploaded size seems available first when using the youtube preset. Having had to setup HLS streaming myself I know how messy that can get. I do know other services (at least vimeo) let you download what they claim is the original still though i’ve never compared that to an uploaded file. Based on your experience is @chris319 really gaining anything uploading HuffYUV directly to youtube?

Yes, because it is the best quality possible, but FFV1 will give more compression if it does not break down under stress as he found.

I’m curious about this too. I’m surprised the HuffYUV upload even worked. It’s not on the list of supported formats, unless it’s bundled under AVI. Neither is FFV1. Is the list just out of date?

But my real question is how bad would the degradation be if we upload a high-bitrate H.264 file and YouTube transcodes it to VP9? Would this be significantly worse than uploading in ProRes format using a visually lossless profile and YouTube builds a VP9 from there? If so, I wonder if ProRes would get all the quality benefits without the enormous upload file size of the lossless codecs. We only care about what the human eye can see at this point anyway.

I think that YouTube help topic is there mainly to give people an answer to a frequent question. Also, it is very short on details as it is mainly about container formats and not codecs. For example, my HuffYUV and FFV1 presets are in Matroska format, which is not listed, but WebM is, which is the same container format. From the beginning, YouTube needed to support as many formats as possible to be simple and reliable in order to become popular as it did.

Probably not very bad if > 50 Mb/s with High profile since their necessary down-rating will be doing the most damage.

I wonder if ProRes would get all the quality benefits without the enormous upload file size of the lossless codecs.

I think so. I think lossless is overkill for streaming delivery even when you take into consideration future-proofing if they reprocess your title in the future for higher bitrates or a new codec such as AV1.

Also, some people have done experiments that show they get better quality by upscaling to UHD before uploading even if the source was not UHD. If you take that route, lossless is even less appealing.

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Very useful information. Thank you!

On a totally unrelated note that’s not worth starting a dedicated thread… I am totally digging the AppImage delivery of Shotcut builds for Linux. Chasing down package dependencies on Linux is a terrible use of my precious time alive. That’s all I have to say about that.

The list is either not comprehensive in the first place or has not been kept up to date.

If you’re really concerned about quality, open an account with a paid hosting service and upload your video to it. No transcoding. I’m convinced transcoding to a lower bit rate is a gambit by YouTube to save bandwidth, which is smart of them to do for a free hosting service geared toward the masses. The problem is, it will be hard to find your video on a private hosting service unless you give someone the URL. With YouTube you simply enter “minestrone” and you get several videos with wannabe Julia Childs showing you how to make minestrone soup.

I have an account with InMotion Hosting and they’ve been pretty good so far.

I tried it myself, the HuffYUV was accepted for upload but I didn’t have the patience to upload a 100Gb file when I only get a 15mbit uplink! I’ve also heard good things about vimeo but haven’t tried it myself.

I believe Vimeo and all the rest will downsample to economize on bandwidth.

As I said, if you’re going to upload HuffYUV, you start the upload and go to bed.

@shotcut, can you weight in on this?

Most of the lossless presets and the ProRes preset are at 60%. So are they not actually lossless unless they are at 100%?

I’ll weigh in that at least the HuffYUV preset isn’t chancing based on that quality percentage, ProRes certainly will however.

Here’s what I was looking for.

Vimeo Plus(which is actually the only experience I have with it) keeps the original source file while the free version won’t. That said “Plus” members can only upload 20gb worth of files a week so there’s a limit on how big your files can be based on how much you upload. I know they don’t stream the original but it’s at least still there to download.

The lossless codecs should not respond to the quality parameter, and ProRes is not lossless. The export UI is not very adaptive to the codec selected. This is part of the reason it is an Advanced section now. I will make the the ProRes presets change the quality to 100% in the next release, but it will not do that if you manually select that codec in the UI.

Should the preset for Quicktime Animation also be 100%?

This codec does not respond to the quality parameter. As I have said before, the Export > Advanced options do not completely adjust themselves based on the combination of format, codec, and rate control method. That would be a very large amount of logic to design, code, debug, and maintain. Thus, it is indicated as Advanced because here you are expected to analyze and understand things yourself. The ProRes presets were changed because we learned they do respond to the quality parameter and should default to 100% to achieve the ProRes profile.