For me, I'm shooting in a rec709-ish profile that is "pre-graded" with fairly high contrast and color saturatiuon, than 60Mbp/s concerns me less. And make no mistake, the fact that all (I think) Sony cameras have it along with 100Mbp/s is great. (60mbp/s needs to be there)

However, if shooting in flat de-saturated colors to help protect RGB channels form clipping and grading is necessary? I really feel strongly that Sony is doing the right thing in trying to support higher PXW-X70 bit rates.

As a general rule of thumb for almost all compression schemes...higher bit rates provide less and less quality loss. We know that many compression types allocate bandwidth to the most vital and visible areas if an image...mid tones. Shadows and the darkest areas often get less bits because of this. If you want to lift the shadows of an image, you will typically find more macro blocking, large block rounding and banding in those tones.

So for me to declare that less compression is a good thing for image quality and grading in post. (in general). I don't see how anybody can say that is nutts.

Yes,..if Sony succeeds in getting the X70 100Mbp/s....YES!,..I will still use 60Mbp/s on occasion for certain applications!

I just got the new RX10-II and I'm loving the SLOG-2 on it so far. This little monster has 100mbp/s and I NEVER would want to try and grade/normalize SLOG-2 from a 60Mbp/s codec. That is too much bending and stretching for 8bit 60Mbp/s. Can we at least all agree with that? H.264 is great but it DOES have it's limitations.

Is the slog2 from the rx10II also not 4:2:0 8bit?

The RX10-II is 8 bit, 4:2:0. Like all Sony 4k/UHD cameras today, it can shoot in 60mbp/s and 100mbp/s. (Whoops,...with the only exception being the PXW-X70)

Almost forgot there.

CT :-)

Yes, but you said you never would grade/normalize SLOG-2 from a 60Mbp/s codec, do you think 100mbs would make such an enourmous difference?

I'll let you know when I try on the RX10-II. My SLOG-2 experience so far only comes from the A7s and ProRes from the Shogun. I typically use the 600Mbp/s flavor of Prores. (is that right?...yeah, it's somewhere around the 600Mbp/s area)

That is only 8bit as well. I have to admit though, ProRes is tough as nails, even in 8bit.

I have only done a few minutes of SLOG-2 footage and that was just to see how much dynamic range I could see in the RX10-II's sensor

Will let you know!

60Mbp/s average bit rate = 7.5 megaBYTEs ber second.

100Mbp/s average bit rate = 12.5 megaBYTES per second.

That's an average of 5 additional megaBYTES per second across 30 frames using this higher bit rate.

Can anybody actually say with a straight face that all that extra image data (40Mbp/s additional information) is "useless"...or "worthless"??

The Sony XAVC engineers and marketing departments certainly wont say that!!! ;-)

Can anybody actually say with a straight face that all that extra image data (40Mbp/s additional information) is "useless"...or "worthless"??

If you can show what that 40mbs means in the real world, like showing actual footage that would support your statement, then it would not be necessary to talk numbers again. Also If that slog2 from the rx10 would be 10bit 4:2:2 this would help a lot more when you want to grade your footage then a higher bitrate only.

OK. So to clear all this up for everybody, I'll setup a nasty stress test for both 60Mbp/s and 100Mbp/s. I guess we can all inspect the results. (whatever that may be)

I can only do this with the h.264 XAVC-S .MP4 wrapper. (AX100 or RX10-II) I'd love to try it with the .MXF wrapper but the X70 wont do 100Mbp/s and I dont have any other .mxf 4k camera.

Will post something this weekend. I think it will be a nice test to possibly put this all to rest. One way or the other.

Who knows? Maybe the "60Mbp/s is already the best in 4:2:0, 8bit long GOP and no more is needed" crowd is right!

Let's break them and see what happens!

CT ;-)

Can anybody actually say with a straight face that all that extra image data (40Mbp/s additional information) is "useless"...or "worthless"??
But is it extra information - or just extra bitrate?

Think of a word document and using a zip file to compress it. You'd expect the file size to decrease substantially wouldn't you?

So does that mean that it's therefore losing a lot of information in the zip process? The answer's no. In this case none at all. The file size is smaller but no information has been lost. Unzip the file and reopen and the document will be identical to the original.

It's the difference between lossless and lossy compression that's significant, and as I've been trying to say all along, don't draw too many conclusions from headline numbers.

For the record, my bet on such as this is that the 100Mbs sample is likely to be better - but not such a night and day difference as might be first expected. The question then is whether any difference is worth the extra overhead.

Well, ZIP works totally different. If you zip a book of text, you will get huge gains. What is rebuilt on the unZip is identical to the original text. 0% loss. Text and other types of data compress very well.

Try to Zip a .jpg or an .mp4 file. What happens? Almost nothing. The only way to compress "video" is to throw away image data to make it smaller. When it's uncompressed, it doesn't equal the same as the source. Very very different than zip.

Yup,..numbers alone don't tell all the story. 60Mbp/s on the X70 is not bad, I know this.

I'm actually curious to see a real world stress test between the two. Let's see how far we can push each one in a really complex moving scene.

I'm doing a side by side test between the PXW-X70 "XDCAM" at 60Mbp/s .MXF against the AX100 "HandyCam" at 100Mbp/s .MP4.

I have no evidence of this but I strongly believe they use the exact same encoder chip. It's the same h.264 codec inside two different wrappers.

It will be a good fight. Let's see how they fair this weekend.

Try to Zip a .jpg or an .mp4 file. What happens? Almost nothing.
Yes, true - a .jpg or an .mp4 file is already compressed.
The only way to compress "video" is to throw away image data to make it smaller. When it's uncompressed, it doesn't equal the same as the source. Very very different than zip.
Not true. Not if you start with the uncompressed original.

You'll be able to compress *to a certain extent* without any loss at all (same as zipping) and then the uncompressed signal will be exactly the same as source. You're taking advantages of redundancies in the signal. Preserving all the information, but in a smaller file size. And if you take advantage of similarities between frames it works even better - which is why interframe compression will give better results than intra for a given bitrate.

Practically, it's still likely to end up too large a file to be practical. So to compress further then yes, you have to discard information. The trick of a good coder is to lose bits which are least important, and it's quite surprising how far you can go before it becomes noticeable.

But it's an exponential graph. No loss at all initially, then very little, even for quite big bitrate reductions, then eventually even a small decrease in bitrate will make a big difference. The trick is to choose the most sensible point on the curve. It'd be lovely to do as zip files do - as much as possible but remain lossless - but impractical.

OK,..just did a super quick...VERY quick stress test. Both files are the exact same zoom/crop.

These are two frame grabs. One set is 60Mbps and the other set is 100Mbps. Each set has 1 color and 1 Luma channel view only.

Let's see how good our eyes are. Can you tell which set comes from the 60Mbps frame grab and which set comes from the 100Mbps?

Let's all toss it around and speculate. In a while, I will reveal the answer.

Yes, yes, yes...I know that is quick and unscientific. A more accurate test will happen this Saturday. This one wont be frame grabs, it will be motion video, side by side. Cheap consumer Handycam 100Mbp/s vs. Professional XDCAM, 60Mbp/s.

For now with have this to toss around....

Hmmm...who has the best eyes here? This one is not easy. Jody, Noah, David, Ron, Craig and anybody else, what do y'all think?

CT ;-)

My guess is one on the left is AX100.

Ron Evans

I don't see any difference, imagined or otherwise. Pretty much what I found with my AX100 60vs100Mbps testing.

Mark

Fair enough. I can understand that....

Did you inspect the color removed images?

JPEG compressed files not the best way to compare. PNG or TIFF might have been better.

Notice the lower right palm fron. Compare at the edges.

Fair enough. I can understand that....

Did you inspect the color removed images?

I hadn't, (too disturbed by the rule of thirds violation.)

Having done so now, I would say the one on the left makes a better black and white image due to the obvious pixelating of the one on the right. So, I'd guess the one on the left is higher bit rate?

Mark
Note to self: next time I do an A/B test, try to find scantily clad women to film.

Notice the lower right palm fron. Compare at the edges.

Do you watch all of your films in this way? Take a screen grab and blow up the image? :) Ofcourse there should be a difference between a lower and a higher bitrate where the lower one will display more pixelation due to codec break up in a scene with lots of movement and fine details but no-one will ever see the difference if you playback both side by side without magnifying it and that was just the point of this whole discussion. You are only trying to prove a point we all know but what we never will notice when you watch your footage like it was intended to.

Low bitrate only becomes an issue if you start seeing the difference on moving images like I have seen on the olympus omd-em5 mark 1 which was clearly visible once you moved the camera and it could look very bad in some cases. But if you have an efficient codec and if the hardware behind it fills any gaps then a lower bitrate will only have benefits in terms of storage space.

No silly,..hehe...I don't watch all my films that way. This is not for fun, it all just in the interest of science! ;-)

Will do a live video side by side this weekend. I think that will be a better indicator of the two modes.

It's funny, my wife is like "HD, 4k, 8k, who cares-K..." She is perfectly happy to grab her old standard def DVD's and play them on our 70 UHD TV. She just doesn't care about resolution, it doesn't "wow" her. Because of people like her, 4k might always have a limited future.To her that is "geek talk" and it more about the "story" than anything.. And actually, she could be right to a certain extent.

I'm saving up for an FS7. She thinks this is a total waste of money and that even my EX1r was too expensive and not necessary several years back. "Why do you want that FS7 thing?...your EX-whatever looks OK and there is nothing wrong with it..." Oddly enough, we went form a 50inch 1080 TV to a 70inch UHD TV last month and shes DOES think that is nice. (The viewing size increase is nice bit not the resolution increase...go figure?)

So yeah, there are BILLIONS of people just like her. I'm not one of them.

Yes, this is a just a "science experiment". The "artist" in me doesn't care at all but the "nerd" in me is having a blast with it. ;-)

Cliff, as Noa says we all know the difference but like your wife we are more concerned about how the video looks. My wife is much the same. Playing back SD DVD's from my Bluray player to our 240Hz Sony TV she sees no difference to the Bluray of the same show. I can point out the detail in the coloured areas etc all I want but she says there is no difference as far as she is concerned. I may point out to you that if you shot the same scene at 30P 100Mbps and 60P at 150Mbps you would see a difference too as I do. Halving the frame rate when things move has more of an effect to my eyes than bit rate. However you may need to watch the video moving in this case not a still though that too may show an improvement.

Ron Evans

I'm certainly not suggesting that the difference between 60 and 100mbp/s SHOULD matter to everybody. That is a question for each individual. You as the content creator are the only one that can make that call. There is a HUGE population that of shooters that say "4k is a total waste of time. I'm never going to 4k...why?...what for?" Non of these 4k "haters" would care anything about my little 4k 60/100Mbp/s bit rate debate. To them, pointing out these differences is all a waste of time.

Does XDCAM 4:2:2 look better than HDV? Many say: "nope,..they dont see it" Does YouTube or Netflix 4k look great? Some swear it's awesome while others say it's terrible!

This stuff matters at all different levels with different consumers. If 100% of the population on the planet were like my wife, Hollywood would never have a need to shoot anything in 24p raw 4k. They could just take an FS100 and shoot in common AVCHD and save a ton of cash. It's the people that are ridiculously passionate about visual science that drive it forward and improve it constantly.

I'm not expecting my little X70 to have the same quality as an FS7. I just want it to match the codec of its Handycam and Alpha siblings.

GEEK ALLERT!!...motion testing between the two Camara on Saturday...no screen shots this time. A real world test for any that find this interesting. I know,..I know...it's iust a bunch of nerdy hot air for all the others! (Like my wife)

If anybody finds inspecting compression artifacts to be disturbing or emotionally upsetting, I certainly don't recommended that you watch. It will prolly make your stomach turn.

CT :-)

I shot a little test footage with the AX100 before and after the firmware update (from 60 to 100), and I saw a little bit of difference in the two... was it huge? Nope... was it significant to ME? Well, the 100 looked better, so I guess... yup...

In the end, while you can obsess over specs and such, in the end it's what you're shooting (content), and how well your tool does the job.

The simple fact is that most people don't "see" what those of us here do - unless the bride is a sickly color of green, or 21:9 from a 4:3 original, or the screen is blank, or the audio is all noise... it'll probably "pass". What for us might be an audio/visual atrocity is prolly "good enough" for the "average" viewer!

Yes, it's painful to feel like somehow you COULD be getting better quality because "this" or "that" spec looks better on paper, in the end if the results look GOOD, then they are. There are a lot of nice 4K capture devices that really do look amazing, and some that are pretty 'blah' - the Sony 1" class sensor output is definitely in the former, whatever the bitrate.


The other aspect here is that the "untrained" eye may not see the differences, but after a little training, it's hard to "unsee" many of the "little things"... IF it happens to matter to the viewer (in most cases they really don't CARE!).

Can you tell which set comes from the 60Mbps frame grab and which set comes from the 100Mbps? ..........

This one is not easy. Jody, Noah, David, Ron, Craig and anybody else, what do y'all think?
Image 1 looks less compressed, image 2 more so. So I'd assume image 1 is 100Mbs, image 2 60Mbs?

I previously said "For the record, my bet on such as this is that the 100Mbs sample is likely to be better - but not such a night and day difference as might be first expected. The question then is whether any difference is worth the extra overhead."

What you show seems to bear that out - but the last sentence still stands...... :-)

Dave and David, I could not agree more with your last posts.

I'm already shooting in BOTH 60Mbp/s and 100Mb/s on my AX100 and RX10-II. When the A7sII hits the streets, I'm sure I'll do the same with that as well.

With h.264 compression, the "law of diminishing returns" kicks in at some point. In 1080, 29.97p, 8bit 4:2:2 CABAC on, image quality improves significantly as you go up. But once you hit the 20Mbp/s mark, the higher you go, the less you get back. I have done tests between 20 and 30Mbp/s and the results are very minor.

Bit rates are very much a bell curve in quality return.

I'm looking forward to this test to put an end to the debate. I'm not thinking it will change anybody's mind but it may give us a good example of just how much is really gained or lost. This way you can choose the bit rate that really works best for you.

Again, I have met MANY people that have told me: "HDV looks fine to me, I don't see why anybody needs XDCAM 4:2:2" or "It's not like to need to chroma key everyday." Call me crazy but I'll take XDCAM 4:2:2 over HDV any day.I know...more weird talk from me again.

Personally I LOVE 4k...even when all my customers only want 1080. And for my friends that say 4K is just a waste of space?...what can I say to that?

As far as Sony goes? Cheap cameras should NEVER have better 4K bit rate options than upper "pro" cameras. I believe this on principle alone. I think Sony agrees too.

I would not assume the x70 encoder is the same as the AX100.
Looking at the AX100 at 60mbps and 100mbps may not be relevant to the x70 at 60mbps.

I'd really like to see an x70 and AX100 comparison in MediaInfo in addition to seeing moving video. Seeing single frames doesn't tell the story either because the encoders may handle temporal compression differently.

I would not assume the x70 encoder is the same as the AX100.
Looking at the AX100 at 60mbps and 100mbps may not be relevant to the x70 at 60mbps.


An extremely valid point, Craig!

Piotr

I would not assume the x70 encoder is the same as the AX100.
Looking at the AX100 at 60mbps and 100mbps may not be relevant to the x70 at 60mbps.

I'd really like to see an x70 and AX100 comparison in MediaInfo in addition to seeing moving video. Seeing single frames doesn't tell the story either because the encoders may handle temporal compression differently.

Hi Craig, Cliff already posted the mediainfo results in post 138. They do indeed appear to be different codecs.

An extremely valid point, Craig!

Piotr

It's certainly easy to see that the "container" is radically different. The meta data is spread out differently as well. However, the H.264 CODEC inside could easily be the same. The long GOP structure, 8bit, 4:2:0 with high profile, CABC could easily be 100% identical.

Remember, XAVC-x is not a "CODEC" in itself. XAVC-x is a "container format" and it's "CODEC" is 100% H.264 MPEG library compliant. I expect that Sony has all the MPEG h.264 available tool sets turned "on". (something that other manufactures don't always do)

I think we often tend to think of XAVC as a "special" CODEC. It's really not. It's a "special container" format that employs MPEG's generic h.264 CODEC library.

Hi Craig, Cliff already posted the mediainfo results in post 138. They do indeed appear to be different codecs.

Thanks. Had a look. Seems there's some info I'm not seeing that I'd expect to be there. The AX100 is CABAC and High Profile. No M and N number. That info isn't there at all in the x70 file.

The codecs would be the same but the encoding parameters (libraries?) may be different. They're certainly not visible in the x70 and the GOP is not expressed in either.

It's certainly easy to see that the "container" is radically different. The meta data is spread out differently as well. However, the H.264 CODEC inside could easily be the same. The long GOP structure, 8bit, 4:2:0 with high profile, CABC could easily be 100% identical.

Remember, XAVC-x is not a "CODEC" in itself. XAVC-x is a "container format" and it's "CODEC" is 100% H.264 MPEG library compliant. I expect that Sony has all the MPEG h.264 available tool sets turned "on". (something that other manufactures don't always do)

I think we often tend to think of XAVC as a "special" CODEC. It's really not. It's a "special container" format that employs MPEG's generic h.264 CODEC library.

Some may know that I did some tests comparing/contrasting the AX100 4K 100 mbps XAVC-S and the X70 4K 60 mbps XAVC-L. These tests were of virtually the same footage shot at the same time and projected in 4K onto a 15-foot screen in a high-end 4K color grading suite here in Los Angeles. In the opinion of two cameramen and two colorists present (one of them the senior colorist), while both cameras looked excellent, the X70 images looked slightly superior. They definitely graded better.

There have been various discussions about why Sony didn't put 100 mbps in their professional camera but did so in the consumer version. Briefly, the two codecs are significantly different and the professional codec performs better.

I just received this word from Sony's X70 product manager regarding possible future 100 mbps in the X70: "We are working on that, but have not clarified whether or not whether it is technically feasible to incorporate 100Mbps. It is different from those of consumer FDR-AX100 and other models."

I think we often tend to think of XAVC as a "special" CODEC. It's really not. It's a "special container" format that employs MPEG's generic h.264 CODEC library.

Cliff, this has already been covered. There is no such thing as a single "generic h.264 CODEC library" - it's something that's constantly evolving. But in a way that ensures backwards compatibility. So that the latest DECODER will be able to decode H264 from an early encoder - but an early decoder may not be able to decode H264 from a modern coder.

And because XAVC is a new(ish) implementation of H264, expect it to able to employ the latest "tricks" - but on the flip side don't expect older decoders to be happy with it. That means much more than just a container difference.

And all this is quite apart from all coders of nominally the same codec performing equally. An implementation (such as XAVC) may imply all the "tricks" that MAY be used - it doesn't mean that all coders necessarily will use them all.

Yup, you are right. There are different decoders out there from all the years of H.264's existence.

For instance, if you have a 7 year old, fully H.264 AVC compliant decoder that can handle up to level 4.2 and you try to feed it H.264, UHD level 5.2 it probably wont be able to handle it.

Why? Although, this 7 year old dcecoder could easily have all the tools and calculations needed for decoding the newer file, it likely would crash on the bit rate, frame rate and/or frame size increases. That is the part that will freak out the decoder. It's not the "high profile" tools or CABAC or loop deblocking or any of the other 100 compression options.

A 7 year old "hardware" decoder is guaranteed to crash. A 7 year old "software" decoder probably too but who know's maybe not, if it's running with a modern CPU and is not inspecting that metadata too hard.

It's hard to believe but even the highest level 5.2 (XAVC) limitation is already 4+ years old!!

Remember, the MPEG Part 10 (AVC) tool sets and compression library is 10 years old now. The "compression" itself is the same,...what has changed over all the years is the "level" restrictions. The same 10 year old compression tools are allowed to operate in bigger and bigger parameters with every level increase. (yeah,..3d packing was added, color space changes...stuff like that has been increased over the years)

Remember, Sony cannot add a new awesome calculation of their own for entropy encoding to XAVC. Add one single thing that is "outside" the decoder library and a "new" codec is born. (it will no longer be H.264 AVC)

H.264 AVC is "evolving" as you say...because of level limitation increases. What is not "evolving" is the compression tool sets and decoding library. That was "locked-in" when h.264 AVC was ratified.

The H.264 compression tool sets and calculations have evolved in the form of the next new codec. H.265 HEVC. This new codec takes h.264 AVC and DOES add new calculations and tools into it. But this is why we must call it a new CODEC and not just H.264 "turbo" or H.264 "plus" or h.264 level 6....it breaks H.264's tool book!

Just bumping this thread up to say someone in our community is now using 60mbps 4K30p in ENG news gathering, full of police strobe lights and numerous things that will cause the codec to literally break up. Keep an eye on Paul Anderegg's ENG work to see how well 60mbps holds up for news.

Also, it's been a few months, where was the promised scientific test? The best test would be crashing waves, as even on the Panasonic TM700 back in the day, I could see the codec break up on the details of the waves.

I got an offer for my AX100 and sold it before I could do the side by side high motion codec test. :-(

Oh well. Maybe somebody has an AX100 that they could do this with? After months of working with bot the AX100 and the X70, (I use the x70 allot today in 4k) I can say that both 100Mbp/s and 60Mbp/s look pretty similar under light to medium complexity scenes. Only the heaviest random movement like a flock of birds taking flight or intense ocean waves will brake the 60Mbp/s codec. You CAN break 60 but it really needs allot of crazy motion to do it.

I really wish that Sony would add the 100Mbp/s option. It sucks when Sony's consumer division adds 100Mbp/s all over the place in their cheaper models and Sony Pro is being stingy with it on this XDCAM model.

Jack, here are a few test clips from a fire I shot this morning.

https://youtu.be/D418dKtLpI0

Wow Paul, that's some impressive footage there, well done - how high did you put the gain?

As high as necessary, probably no higher than 27 for the grainiest. In an action environment, the stupid 3 button one dial exposure controls are a huge disadvantage. I had to click in full auto a few times just to get the shots. I still think my X180 looks better in 720p60 than the X70 does in 4K. The X70 colors are just all wrong most of the time. Accurate colors can make standard def look amazing.

Since my 4K conversion, red LED fire truck lights are now ellow instead of orange...........ugh, 4:2:0.

Paul

Noting that the just announced Sony FS5 which lists for about $6000 with lens at B&H shoots 4k 8 bit 4:2:0 at 100mbps.