Small film festival submission - h264, sound, confusion

Hello,

We're submitting a short dance film we've made to a festival. It's one of the smaller independent ones, so they don't ask for DCPs but for mp4 files. They specified a maximum bitrate of 20Mbps (our material is at 1080p).

We tried that, and it looks like the grain is slightly more emphasised, compared to the ProRes, making it feel a little "flatter" in a way. We tried denoising it first in Resolve (we don't have Neat Video), touching the luma channel mostly. Granted it looks a bit better as the grain is toned down and not exaggerated, but we seem to have lost some sharpness.

I'm aware that it is a tradeoff, but the festival will be screening in a cinema with a big screen, and we have zero experience with that, so we can't tell which one will look less objectionable there. I should note that the ProRes version looks lovely and the grain is as much as we'd like, it's the compression that subtly brings it up and gives it a "digital" quality. Any thoughts? The film was shot with a BMCC in raw 2.5k, delivered in 1080p. I could post stills, but they look incredibly similar, it's in motion that the problem becomes annoying.

Second related question: Sound levels. Originally this film was done with the web in mind. We mastered the audio using the EBU broadcast standard, at -23LUFS integrated with plenty of range. This, on home equipment, sounds rather quiet, compared to other stuff. I don't have a Dolby-calibrated control room that I can access, but I did a very rough test in a theatre with a PA system, calibrating just pink noise at -20dBFS RMS to 85dBCSPL for each channel (stereo), and the sound was actually a touch louder than what I'd consider perfect for that space.

However, I guess that without knowing how all the other films are produced, it is impossible to know how it will sound in comparison, and thus how loud will the sound system be set on the day. I realise that there's little I can do about it, I was just looking for some conventional wisdom here. What do you guys do? How do you set your levels in such circumstances?

Thanks in advance!

If they want MP4 than you have no choice. Don't use Resolve h264 export. Make a ProRes file and than encode with 20Mbit with eg. Handbrake(eg slow preset, tune film or grain). This should look way better than Resolve MP4. 20Mbit Handbrake encode should give you quite decent grain preservation.

Based on this:

http://www.bbc.co.uk/academy/technology ... 7124204700

it shouldn't sound much different. It's more about dynamic range I assume than about average level or peak.

If they want MP4 than you have no choice. Don't use Resolve h264 export. Make a ProRes file and than encode with 20Mbit with eg. Handbrake(eg slow preset, tune film or grain). This should look way better than Resolve MP4. 20Mbit Handbrake encode should give you quite decent grain preservation.

Thanks for your response Andrew.

That's exactly what I did to begin with. I use medium on handbrake, as some feature of slow leads to a weird artefact every once in a while (medium is always fine). Tune grain never worked for me, film looks good. The grain is preserved alright, maybe a little too much... it becomes a touch "harsher" in quality.

That's why I tried the denoise... the grain becomes less prominent at source, and Handbrake has an easier time with it. Except I lose some sharpness, and I'm not sure which one will be better.

. It's more about dynamic range I assume than about average level or peak.

That's the gist of it, but it only works in a loudness normalised environment, like the bbc or any good broadcaster. If the festival technician decides to implement loudness normalisation, i.e. use a target LUFS value and let everyone know what it's gonna be (like the EBU did with -23LUFS and the broadcasters followed), then by making sure you deliver exactly to that means you retain the maximum dynamic range. In fact the BBC's current QC specifies only +/-0.5dB of tolerance from that target.

The whole thing sounds a bit un-cinematic, but in festival situations with a lot of different productions the system would be invaluable, yet at the discretion of the organiser. Since, however, no such provision is ever made at the moment, I was appealing to the conventional wisdom of the infinitely-more-experienced-than-me people in this group, as to what kind of level (or range, if you prefer) usually works in such situations. My experience is extensive with music production, decent with broadcasting, sadly zero with cinema...

What would really help noobs would be taking a few reference films of different genres and running some loudness metrics on them with the EBU tools. Not the same as a Dolby control room, sure, but if you're stuck in a smaller production suite with near field monitors, it could help give at least an indication of where one is in terms of range, integrated and short term loudness graphs, etc. I'd be happy to do some work on this, if anyone is interested. I'd just need the audio files (of the actual theatrical releases, not the DVD's though!)

Not sure what sort of artefact slow can introduce. There shouldn't be any. It should be better than medium. I tend to not use tune grain, as it sometimes has negative effect, so looks like you had the same experience.
You could always try to send higher bitrate encode- maybe they won't notice

Denison always help with encoding, but I don't like it. If you do it than keep it low, just to cut these high frequencies. I'm not sure how good is Resolve denoiser, but NeatVideo should be good.
If you know how than avisynth can do magic, but you need a PC and some knowledge.

Cinema mix is as far as I know quite different to R128 for broadcast, so don't expect this to sound the same.
I don't think you should take any broadcast spec as reference for cinema mix. Audio chain, including speakers is very different in cinemas than in broadcast/TVs

Not sure what sort of artefact slow can introduce. There shouldn't be any. It should be better than medium.

Well, we had a few instances where for a second or so, there was some colour shift towards red, which disappeared on the next B-frame. Very weird, but it was repeatable, and observable on all players. I can't explain it. On higher bitrates, I find that the benefits of slower encoding are much less than if you compress more. But medium does work fine at 20Mbps or more, other than that grainy texture that does not change at all, even in placebo.

Regarding the denoisers, the problem was that I had to do it quickly, and Resolve was the only one I had available. It does work up to a point before artefacts show up, texture gets lost quite easily, but I guess that's to be expected.

Cinema mix is as far as I know quite different to R128 for broadcast, so don't expect this to sound the same.
I don't think you should take any broadcast spec as reference for cinema mix. Audio chain, including speakers is very different in cinemas than in broadcast/TVs

Essentially, a mix is a mix. Not much different in any medium in its essence. What does change is your reference level, and what one deems an acceptable range. I respect the Dolby approach for what it is and how it can yield very accurate playback in properly calibrated theatres. But at least for stereo work there's no reason at all why what I propose shouldn't be possible. My only note is that it would be possible in an audio control room, with good, accurate monitoring and acoustics, in conjunction with a mastering lab, not in an edit suite.

Well, yes. As long as your mid point is not to high not to low than all should be fine- it may be just louder or quieter.
If bitrate is relatively high than as you said- slow or slower preset is just a waste of time- you don't gain any real/visible quality.

These festival people are morons. H. 264 is a very poor choice for projection in my opinion. I think they're just killing themselves to keep the bandwidth low so they don't have to invest in bigger drives and servers. The compression is going to stomp the crap out of pictures.

I really hate it when ignorant people are put in charge of making technical decisions. There's a dozen other formats that would have worked far better for projection.

Whatever you do, try to watch your film for at least a few minutes without an audience to make sure it's in the right color space and gamma space, and there are no unpleasant surprises.

I don't think that you always need DCP master, but it should be at least ProRes or other intermediate codec quality alike 10bit file, not h264.

ProRes would be ideal. It's easy to make, easy to review, light in terms of playback (given a moderately fast hard drive in 24-25fps). But it's out of my control...

I doubt that I'll get to see the film in the theatre before the event, and even if I do, it'll probably be too late to change it then. I do plan to have an "emergency" hard drive with a couple of alternate versions. Fingers crossed...

Thank you guys for the responses!

These festival people are morons. H. 264 is a very poor choice for projection in my opinion. I think they're just killing themselves to keep the bandwidth low so they don't have to invest in bigger drives and servers. The compression is going to stomp the crap out of pictures.

I really hate it when ignorant people are put in charge of making technical decisions. There's a dozen other formats that would have worked far better for projection.

Can't do much about it. Plenty of film festivals want DCP, Blu Ray as well as a h264 .mov file as a backup. Instead of blaming the festival authorities, we need to find out how to go about it. To begin with, any .mov file has an inherent problem, whether that is h264 or Prores. They will look quite different depending on the player you choose to play the file. Just play the file on QTplayer and VLC side by side and you would know. So, delivering in Prores also doesn't solve the problem. Since the festival authorities have asked for h264 mp4 files, I presume they'll be playing them either in VLC player or WM Player on a Windows platform. So, again you can't do much about it.

My suggestion would be to proceed like this, assuming you are on Mac platform.

1. Render out your movie from Resolve in Prores 4444 or Prores 4444 XQ using "data" instead of "auto" or "video" level.
2. Render out the audio tracks separately. If it's stereo, the upper track will be L and the lower R.
3. Come to Apple compressor.
4. Open "surround sound" option. Put the audio tracks in proper place.
5. Add your video to the files and check if everything is in sync.
6. If you are on Compressor 3.x, you have the option of encoding h264. Go ahead and make the master. You can adjust your bitrate in the options tab. The master will be okay, with very little artefacts and your sound will be automatically encoded in Dolby for a proper theater environment.
7. If you are on Compressor 4.x, there is no h264 option. Here, the "publish to vimeo" does the same thing. But before going ahead just check the file video sizing. Normally, it's set to 720p. Change that to 1080p by using the video option tab. Here you have the provision to adjust to bitrate also. The higher the bitrate, better is the final product, but your file size also increases.

Check your final master. There won't be much of visual difference from your original Prores file. During projection, leave everything to the video player and God. You can't do much there.

At very small cost such a "cinema" with Premiere (or even MediaExpress)+Decklink card can have proper 10bit, properly synced pipe with multichannel audio to the projector. VLC or any other desktop player is a very dirty and bad way of doing this. Shame that "theses cinemas' are run in most case by people without much of technical knowledge.
Proper 10bit "pipe" from a machine to projector cost tiny money these days.

At very small cost such a "cinema" with Premiere (or even MediaExpress)+Decklink card can have proper 10bit, properly synced pipe with multichannel audio to the projector. VLC or any other desktop player is a very dirty and bad way of doing this. Shame that "theses cinemas' are run in most case by people without much of technical knowledge.
Proper 10bit "pipe" from a machine to projector cost tiny money these days.

I absolutely agree.

Dani,

I am a tech director for one of the larger festivals. Feel free to email me at Brandon@newfilmmakers.com to discuss delivery.

Brandon

Small advice- don't put emails in clear form on forums as in next weeks you will have tons of spam. Better to use private messages or links.