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Eduardo Granadsztejn

Prores Proxy

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Hi guys!

I was thinking with all this madness with the bmppc 4k about the prores proxy of it (or every other Blackmagic camera)

Is it really usable?

how bad or good is it against the h264 from Canon and Sony? (and against the XAVC-S)

How much weigth per minute?

 

Thanks!!

 

Regards from Uruguay!

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EOSHD Pro Color for Sony cameras EOSHD Pro LOG for Sony CamerasEOSHD C-LOG and Film Profiles for All Canon DSLRs

In my experience the image is much worse than h264 variants, including AVCHD and Canon dSLR codecs, but the performance is excellent.

It's a proxy codec, meant for offline edits. I wouldn't use it for anything else. It's not as efficient as h264 and the image quality is much worse, it's only built for speed for offline edits. 

Still, it's usually good enough to judge if footage is in focus or something so if you shoot with a built in LUT and nail exposure and don't expect to grade or otherwise manipulate the footage you could get away with it for certain content. 

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2 hours ago, HockeyFan12 said:

In my experience the image is much worse than h264 variants, including AVCHD and Canon dSLR codecs, but the performance is excellent.

It's a proxy codec, meant for offline edits. I wouldn't use it for anything else. It's not as efficient as h264 and the image quality is much worse, it's only built for speed for offline edits. 

Still, it's usually good enough to judge if footage is in focus or something so if you shoot with a built in LUT and nail exposure and don't expect to grade or otherwise manipulate the footage you could get away with it for certain content. 

I hope your experience is not built from Final Cut Pro X Proxy editing.

ProRes Proxy is fine if you dont want to grade the footage. For 4K 25p it's 151 Mbps which is a little low for ALL-I codec.

If your plan is to record in BMD Film LOG with any of the Blackmagic Camera's ProRes LT is the best choice with good balance between image quality performance and storage space (about 302Mbps for 4K 25p)

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37 minutes ago, Deadcode said:

I hope your experience is not built from Final Cut Pro X Proxy editing.

ProRes Proxy is fine if you dont want to grade the footage. For 4K 25p it's 151 Mbps which is a little low for ALL-I codec.

If your plan is to record in BMD Film LOG with any of the Blackmagic Camera's ProRes LT is the best choice with good balance between image quality performance and storage space (about 302Mbps for 4K 25p)

I've never used FCPX so I couldn't speak to that.

It's been my experience working in the offline edit (generally in Premiere; I assume the transcodes were done in Resolve by the DIT, though) that ProRes 422 Proxy footage is unusable for anything except preview. Fwiw, it's always been Alexa footage, sometimes with a rec709 LUT applied, sometimes in log. Perhaps the Alexa, because it's fairly noisy and flat, is particularly unsuited for that codec, but generally I find it to have excellent image quality.

I can't speak as well to LT, but I don't remember it looking particularly good, either. (I forget sometimes if the proxies were 422 Proxy or 422 LT since I think it varies by post house.)

This is more anecdotal because I think Atomos' early recorders may have had a poor ProRes implementation, but generally I found the image quality from external recorders as compared with AVCHD out of a camera to be:

422 HQ > AVCHD > 422 > 422 LT 

That's with the caveat that while AVCHD edged out 422 overall, when there was a lot of camera motion or a lot of moving foliage, AVCHD was significantly more susceptible to macro blocking. So for many people 422 would have been better than AVCHD depending on what they shoot. Below that, LT was clearly worse.

I was very surprised by this result since 422 is considered good enough for broadcast (some network shows used to and still might shoot 422 instead of 422 HQ to save space) and AVCHD isn't. To be fair, the difference was very small, whereas 422 HQ was a lot better than either.

I don't know if that's due to Atomos having a poor implementation of the codec–I suspect it is–but generally I find the thinner flavors of ProRes to be quite poor and Proxy to be unusable for anything but... proxies.

Also, you can't tell much by bitrate alone. ProRes is a DCT (discrete cosine transform) codec and less efficient than ALL-I h264, which is a wavelet codec, and that's only touching on the very basics of both codecs. ProRes is built for speed more than it's built for image quality.

Again, just my experience. 

Of course it is all up to the client, I agree with you. A while back I worked on a few shows for cable (tier one cable, but still lower budget shows) that seem to work with thinner ProRes or DNXHD variants than most people on this board would consider acceptable, and the raw footage had substantial macro blocking, whereas prime time network tv seems to mostly be 422 HQ but again standard 422 also seems to get use, or used to. (Most people on this board have wildly higher technical standards than prime time network tv and indie film, closer to Netflix or major studios, which is ironic since for a while streaming had the lowest quality delivery codecs and it still might.) Still, I would put Proxy and LT both below even the tier one cable threshold and to my eye they are far worse than AVCHD, but I think AVCHD is pretty good. I don't know whether or not the BBC accepts LT, but imo they should not. I don't know if their standards are based purely on bitrate or also on subjective impressions, since 50mbps MPEG2 is much better than LT as it's interframe and I believe that's the lowest they'll accept (they won't accept AVCHD).

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Nothing beats the original, and if the worst acquisition codec - AVCHD - was used, then transcoding that to ProRes, no matter the flavor, it won't get any better.

There's a useful rule of thumb:

ProRes Proxy: for proxy editing, but never for export!

ProRes LT: for editing of everything, for export of material up to 1080. Some report it as good upload codec for Youtube :expressionless: No recompression!

ProRes422: for editing of everything, for acquisition of HD, for crucial quality check, for export of UHD.

ProRes HQ: for acquisition of UHD, allows recompression.

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7 hours ago, Axel said:

Nothing beats the original, and if the worst acquisition codec - AVCHD - was used, then transcoding that to ProRes, no matter the flavor, it won't get any better.

I agree with your list, but everyone should do their own tests with LT. The image quality there is pretty dreadful even compared with XDCAM and AVCHD, but for some content that's fine and it's much better than standard definition or something.

While it's true that transcoding can't improve an image, I was comparing AVCHD vs ProRes variants from a clean (uncompressed) HDMI output. 

In my experience, AVCHD was still better overall than any ProRes codec below 422 HQ. Except with foliage. Here's a test that closely mirrors my findings, but theirs is much better!

 

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Just one minor error in your video: ProRes422 is 10-bit, not 8-bit.

I must admit I was shocked by your excellent test, thank you for that. I use ProRes a lot. So what I did is taking some XAVC clips I currently deal with and their ProRes422 copies, zooming in 400% to critical areas and making screenshots to compare the artifacts.

I was - again - shocked to see that there were indeed small differences. And then I was relieved to see that they were *very* small. Unlike in your comparison.

That leads me to two conclusions/statements, please comment:

1. be aware that even the highly praised ProRes degrades your images - to some extend!

2. there obviously is a difference if you record PR in camera, over HDMI with an Atomos or if you transcode it as intermediate. There is a logic to that. If those external PR recorders helped so much to avoid compression artifacts (without adding others, like the atrocious macroblocking on the meadow) , no one in their right minds used anything else.

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It seems to me those artifacts are only visible to the naked eye when hovering over a single frame and enlarging the image; that they would not be visible when viewed on a normal television; but that the extra color information of Prores HQ is immediately apparent to even the casual observer. 

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11 hours ago, Axel said:

Just one minor error in your video: ProRes422 is 10-bit, not 8-bit.

I must admit I was shocked by your excellent test, thank you for that. I use ProRes a lot. So what I did is taking some XAVC clips I currently deal with and their ProRes422 copies, zooming in 400% to critical areas and making screenshots to compare the artifacts.

I was - again - shocked to see that there were indeed small differences. And then I was relieved to see that they were *very* small. Unlike in your comparison.

That leads me to two conclusions/statements, please comment:

1. be aware that even the highly praised ProRes degrades your images - to some extend!

2. there obviously is a difference if you record PR in camera, over HDMI with an Atomos or if you transcode it as intermediate. There is a logic to that. If those external PR recorders helped so much to avoid compression artifacts (without adding others, like the atrocious macroblocking on the meadow) , no one in their right minds used anything else.

Not my test (what I shot was nowhere near as scientific!), but I agree with your conclusions. 

I suspect that the Atomos recorders have a poor implementation of ProRes, and that it really matters at lower data rates. PCs that can compress ProRes have a bit of a different look to it than Macs do, a codec can have different implementations. AVCHD is technically better on the C100 than XDCAM on the F3, even though the F3 has the technically better image AND a higher bitrate codec, for instance. (With external recorders, the equation flips.) 

Still, I've long considered 422 and especially anything below below compromises in quality, just from my experiences with them.

7 hours ago, jonpais said:

It seems to me those artifacts are only visible to the naked eye when hovering over a single frame and enlarging the image; that they would not be visible when viewed on a normal television; but that the extra color information of Prores HQ is immediately apparent to even the casual observer. 

This is why we do tests! The softness and DCT noise in the luma information in the grass, for instance, in 422 is immediate apparent to me, but the loss of color information in AVCHD is only visible to me in fast-moving clips (which would be invisible in motion) or in reduced color fringing (visible in motion, but not undesirable). To me the superiority of AVHCD vs 422 in the grass is blatantly obvious. It's not even close, and is only somewhat difficult to see at 100% in that clip because of heavy YouTube compression, hence the need to zoom in. Whereas the reduced fringing artifacts (probably from the offset pixels on the sensor, that camera has a weird sensor design) are the only big difference I see in color, but I think it's clear 422 HQ is best at everything! Everyone's concentration of rods vs cones is different so I suppose we probably see entirely different things, sensitivity to color or to contrast. But the loss of luma information at 422 in the grass would be unacceptable to me in almost any circumstance, whereas the loss of color information in AVCHD would only matter at all if I were doing heavy post work.

As I mentioned above, I suspect the Alexa has a better ProRes compressor than Atomos products do, and I would be happier with 422 standard from an Alexa than anything from a a C100's clean HMDI out. ;) 

I haven't tried flavors of ProRes other than HQ or 444 from Black Magic products, but I suspect their ProRes implementation is better than Atomos.

 

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So, this is my thought on the topic... why buy a camera and not use the best settings? If you want to shoot Raw, shoot the best Raw. If you want to use ProRes, shoot the best ProRes. 

If you really want to save storage space or use cheaper cards, shoot 1080p. Or honestly, maybe this camera isn’t for you? There are plenty of great cameras on the market.

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1 hour ago, mercer said:

So, this is my thought on the topic... why buy a camera and not use the best settings? If you want to shoot Raw, shoot the best Raw. If you want to use ProRes, shoot the best ProRes. 

If you really want to save storage space or use cheaper cards, shoot 1080p. Or honestly, maybe this camera isn’t for you? There are plenty of great cameras on the market.

Corporate events, storage space, etc. 

Makes sense to know what the smallest/cheapest codec you can get away with for a given client is. For personal work, I understand the impulse to just use what's best, though.

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1 minute ago, HockeyFan12 said:

Corporate events, storage space, etc. 

Makes sense to know what the smallest/cheapest codec you can get away with for a given client is. For personal work, I understand the impulse to just use what's best, though.

Yeah I get the idea, I just don’t think this camera will be as good for events as people hope it will be... I mean cinema is part of the product’s name. So, I get why somebody may choose ProRes over Raw... but...

Of course I could see this being popular with weddings and I guess that is a subset of event work?

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32 minutes ago, mercer said:

Yeah I get the idea, I just don’t think this camera will be as good for events as people hope it will be... I mean cinema is part of the product’s name. So, I get why somebody may choose ProRes over Raw... but...

Of course I could see this being popular with weddings and I guess that is a subset of event work?

If the past black magic cameras are any indication, I agree. Even for weddings I think dSLRs with autofocus make more sense unless you can afford a focus puller.

But I suppose some people are 95% hobbyists and occasionally want to shoot events. 

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