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interceptor121

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Posts posted by interceptor121

  1. As I started this mess I wanted to give an update some time later

     

    AVC-I at 400 Mbps beats the xxxx out of ProRes 422 and I could not see any difference to ProRes 422 HQ at naked eye and pixel peep

    Looking for explanations I believe is due to two things

    1. intraframe predictive coding on 16x16 blocks that achieves high level of compression than standard discrete cosine transform in ProRes

    2. CABAC entropy encoding squeezing additional bits without loss in the clips

    It is difficult to average what the benefits are compared to ProRes but is not difficult to see that they are at least 30% based on perceived quality

    As there are no fast enough SD cards this is limited to 30p on the GH5 but in terms of non RAW capture this appears to be very good

     

    And with this I think I have closed the case I opened myself

  2. 4 hours ago, thebrothersthre3 said:

    Log tends to be nosier in general. If you are not feeling the need I don't see a reason to upgrade. You get a bit more dynamic range. Though HLG has the same amount of DR as Vlog. What issues do you have grading it?

    Thanks for your reply with ambient light I have zero issues with cine like D. I underexpose underwater around -2/3 (camera metering at zero gives rubbish results) then lift exposure and stretch blacks and whites in post increase saturation and works wonder. I white balance in water.

    However for deeper dives color are just lost as absorbed in water and there is less light I am just concerned cinelike may not work well at higher ISO but maybe am just worrying unnecessarily!!!

    At the end there is not much dynamic range due to environmental conditions so I though I would work in a rec709 format are the colors are not there anyway

     

    Maybe am worrying for nothing and should stick to my guns as it seems to work well

  3. 1 hour ago, kye said:

    Cool videos!  Really nice colours and movement.

    Not sure about Cine-D vs Vlog but why not just shoot a test and try both modes, lit only by your LED light?  Pulling the footage into NLE should answer most of your questions?

    Thanks Kye they are shot in 24p if that matters!

    So far I do not have the VLOG key I have tried HLG but it does get difficult in edit. I try to prepare as much as possible my settings before hitting the water as I need to get on a trip in order to dive with the camera so I am after some theoretical points that helps maximise the camera. Generally in conditions like those in the video is very bright at the same time I need to keep aperture between f/5.6 an f/11 so this means ISO ranges between 100 and 200. With this settings Cine Like works very nice I do not need anything more.

    My issue is what happens when am in the ISO 400-1000 region? Will cinelike D still do well or am I better off trying Log. Which one of those will give me less noise and allow me to shoot with the range of apertures I need? In theory VLOG starting at 400 seems a better candidate but I do not have enough experience as I do not have the VLOG to evaluate. Right now I have not felt the need to shoot in VLOG at all!

     

    So in theory the fact that VLOG clips at 85% should help with low light??

  4. Hi Everyone

    I finally managed to get my first short underwater clips with the GH5

     

    And

    I am using Cine Like D and the results are pretty good. However those videos are with rich ambient light in other situation I need to go in deeper water and there will be less light

    I am wondering if VLOG is a better option. Dynamic range is not the issue there isn't a lot at depth but low noise is. I will be shooting with predominant artificial LED light

    Would love some theoritical pro and cons of Vlog vs Cine like D in this circumstances (optimise noise not range(

     

    Thank you

  5. 1 hour ago, Shirozina said:

    A senor has a color space in the sense that it's colour response can be measured and quantified and this information used to enable a RAW conversion to interpret the data to create the desired output. 

    As no camera on the market seems to be able to meet your requirements for 10bit colour then why are you complaining about this one in particular?

    Bit depth as most people use the definition is to do with how many times you can slice the cake rather than how big the cake is. 

    They are two different things.

    An image can contain 24 bit different colours but they do not necessarily fit into the  RGB 8 bits. You could have some in a gradation in between your level and some values completely missing hence it is important to capture higher bit colour sample 10 or 12 bits if you can even if you eventually you discard them later

    35 minutes ago, Dan Sherman said:

    Please explain/articulate what you mean by more!

     

    The believe that 8bit is better, is confirmation bias tricking your mind.

    The various color profiles (ignoring v-logl for a moment) by nature don't change the amount of color that ends up in the footage, they change how the the color captured by the sensor is transformed. A given color is made brighter or darker, shifted towards red or green etc.

     

    Your eyes can't even discern the difference between two similar shades of 8 bit color, let alone 10 bit. You can verify this your self, by going into any 8 bit editor, like paint, or photoshop, etc. Draw a big box on the screen, and fillet it with one color say pure red (255,0,0). Mask of half the box so it stays pure red, and then make the other un-masked side (254,0,0). You will not be able to tell the difference between the 2 shades. keep dropping down from 254, to 253, 252 etc until you are sure you can see the line where the color changes.

    If you can tell the difference between 245 and 255 then you need a 10 shade spread to see a color difference. Now you need to realize that in 10 bit that becomes a 40 shade spread. Your ability to discern the difference gets worse with age, and it can also be skewed for a given color if you have any kind of color blindness.

    Dynamic range is a similar affair, the gh5 sensor is capable of a little over 12 stops at base iso. Your eyes are only capable of 10 stops, and again it can get worse with age and various medical conditions.

     


    Your getting beat up because you analysis reads as someone who has a serious lack of understanding about bit depth, chroma sub sampling, and their benefits or lack of, when it comes to video production. it a similar thing when it comes to codecs.


    Right out of any camera 10 bit isn't inherently better than 8 bit, 4:2:2 isn't better than 4:2:0 either. Higher bit depths and higher chroma sub-sampling are only really beneficial if you are going to push the footage around in post. higher bit depth and chroma sub-sampling can be pushed farther before the footage falls apart. This is important when it comes to major motion pictures and the like, because what comes out of the camera is usually drastically different to what ends up on the screen. 

    Codecs are the same, Noe one codec is inherently better than another by default. Prores or dnxhr isn't better than h.264. or h.265, or any of the other million codecs out there. They each have their pros and cons, and what is best is very situation specific.



     

    It sounds like you are confusing dynamic range with bit depth.

    I think you have less understanding than you think you have I am not sure what a colour profile is maybe you are talking about a transfer matrix? The amount of information the sensor captures is nothing to do with what ends up after compression and if you squeeze information into a narrower colour space you have clipping. The GH5 uses BT709 and BT2020 and there is a difference between the two otherwise you would not have colours in HLG that clip in REC709.

    And your last comment on dynamic range out of the blue of a whole set of statements is rather interesting I rather have no further explanations if you don't mind thank you

  6. 2 hours ago, Shirozina said:

    RAW does have a colour space concept otherwise it would not be possible to convert RAW images into Tiff's or jpegs etc that can be used in a colour managed workflow.The camera can do Adobe RGB in stills and REC 2020 in Video so it's safe to assume it has a large enough colour space to fit in the REC709 (sRGB) colour space.  The Panasonic specs and DXO describe the GH5 having 12 bit sensor - are you disputing this? 

     

    The sensor is 12 bit and raw does not have a colour space the camera saves files with sensor data and metadata the processing is then done by a program that works in an intermediate color space for editing and correction and then outputs in RGB format on JPEG

    The fact that the camera can work in a colour space as wide as adobe rgb or rec.2020 does not mean it can resolve 10 bit colours

    a pixel may have 8 bit resolution with colours coming from a wider colour space but still not able to resolve 12 bits on a single image

    even a DSLR with a 14 bit sensor stops at 26 bits which is 8 and 1/2 bits and in most cases there is no additional info between 12 and 14 bits RAW in terms of colour or resolution 

     

  7. 19 minutes ago, Shirozina said:

    If you are not shooting LOG or HLG or don't want to grade there is little point in 10bit and 8bit is plenty 

    My own tests of 150mbps vs 400mbps show the only advantage ( I only shoot LOG or HLG) is during the grading where the 400mbps codec is easier on the hardware. Visually I can't tell the difference and also can't 'break' the footage when applying even hefty tonal changes in terms of revealing artefacts. One reason you may want an ext recorder is that of you are recording a lot of footage it may be cheaper than V60/90 cards. 

    I can see 10bit vs 8bit differences when I grade as its visible in the scopes.

    You have not understood the bit depth data that DXO state - more research needed ;)

     

    I record underwater video the housing for the atomos costs $3000 plus the recorder cost so I am not planning to buy it

    V90 cards are much more affordable in that context

    Am not planning to shoot LOG either as underwater there may be quite a bit of noise and everyone who has tried even prores HQ has had poor results

    So my plan is currently cinelike D I need to decide between 8 and 10 bits and if I go all intra

    Generally All Intra should save me some time as my workstation is not strong enough to process h264 real time so I would need to convert to ProRes 422

    for what concerns your comment on dxomark enlightened me please raw images do not have a colour space concept so those are tonalities that may or not fit in a video colour space but it is unlikely they will all fit into REC709

    if you were shooting HLG you coild have deep colours

    I don’t know what transfer matrix LOG footage uses but am not planning to shoot LOG regardless best case I would shoot HLG on land but that eould require monitors etc

     

  8. I am not unhappy with the camera I was just expecting more out of the 422 10 bit mode as I am not planning to buy a recorder and I was hoping not to need V90 cards

    From what I can see with my naked eye footage straight out the camera without LOG looks better in 8 bit mode than it does in 10 bit I play it straight out of my Tv that has a 10 bit panel. I cannot see any benefit of 422 or additional colour using cinelike in the rec709 colour space compared to 420 8 bit. I white balance all my clips on a grey card so they are generally not off and look good at the outset.

    I do not use log at all and this is another form of compression that uses metadata and what comes out depend on many other factors.

    the considerations I have made are purely technical and generally are useless to compare different cameras but hold pretty well when you compare codecs offered by that same camera. 

    The considerations are objective and not subjective and when looking at interframe codecs (100-150) all of those are subject to the same motion interpolation errors therefore size of I frame is the measure for image quality.

    My impression based on combination of codec analysys and playing the clips straight out of camera on a 10 bit panel is that the camera is not capable of resolving 10 bits anyway and that you can’t see any difference between 422 and 420 so for majority of cases 100 or 150 mbps look the same and I do not see any banding on my screen dark scenes or blue skies

    In terms of editing I have done not tests but you cant edit h264 decently so you need to convert to prores 422 (I use a mac) or skip h264 altogether and use all intra

    based on my previous experience I would always work without conversion as any operation degrades the clip. However I find it puzzling that you can’t tell the diffference between prores HQ footage acquired with an external recorder and all intra if that is really the case the only conclusion wouls be that the camera actually does not manage to resolve 10 bits at all and thereforw the spare 300 bits go to waste

    this theory that I cannot verify is corroborated by dxomark raw image of the GH5 that says the camera can only resolve 23.9 bits within an image which is 8 bits

    Using the resources as your disposal as good as you can and knowing how things work is a good thing not a bad thing so am a  bit surprised that people keep going on beating up my quantitative analysis and comparing it with subjective statements

    quantitative and qualitative evaluations are two different things if you are happy with what you see you won’t know 8 10 bits colour spaces etc etc

  9. 1 hour ago, Dan Sherman said:

     

    1.  If a device can keep up or not, depends on what preset you use. Even a camera could keep up with the lower end presets as they are not that intensive, but a camera for sure isn't going to be able to handle veryslow or placebo.
    2. who said compress it over and over again? I said take clip A and trans code it to clip B using CRF mode.  Then take clip A again, and run NR on it before transcoding it to clip C. Then compare clip B & C. C will be smaller, because less noise means the codec can generate the same image quality with a lower bit-rate. In other words noise has a direct effect on how good a codec like  h.264  works.

     

     

    Picture profiles effect hdmi output, if it didn't v-log wouldn't work. The question is how much of the picture profile is applied to the hdmi output.


    As I said before, converting the internal data to be hdmi compliant has an effect on image quality. The wiki has a good overview of the actual spec. Keep in mind when you are doing transforms like this, rounding issues can cause problems as your camera isn't running at 64 or even 32 bit.
    https://en.wikipedia.org/wiki/HDMI

     


    The gh5 is most likely working in YUV/YCbCr internally, as that's what its internally recorded files are. HDMI out is most likely 10bit sRGB to maintain maximum compatibility. Prores will support  sRGB and Y’CbCr, but I don't know what color space recorders like the atomos line are using.

    Thus you have at-least one color space transom and if you are unlucky maybe 2. You will have rounding errors, and thus image quality degradation.

     

    Saying internal or external recording is better than the other based on a handful of non scientific tests is idiotic. Even if you had full transparency (Intellectual property level knowledge ) of what Panasonic and Atomos was doing, something as simple as cable interference could heavily skew the results. 

     





     

     

     

     

     

    HDMI outputs sensor signal that is affected by debayering and aliasing but nothing to do with coding errors

    The GH5 outputs REC709 and REC.2020 colour spaces otherwise would not support HDR so obvously it does not just output sRGB which is synonymous of rec709 8 bits

    also colour spaces and bit depth are totally different things

    in terms of colour depth the GH5 outputs 8 bits and 10 bits colour 

    When you record output signal from the 150 mbps modes the camera sends YCB 422 10 bit colour signal to an external recorder colour space will be rec.2020 for HLG REC709 for the rest

    if the camera was sending only srgb it would not record 10 bits at all 

    In terms of saying if internal or external recording is better is then down to codecs which come after the uncompressed data clearly we need to assume panasonic is not producing faulty HDMI ports and you use decent cables

    now I agree that this conclusion is not something I can make so I have taken it out from the post

     

    now going back to wolfcrow point if you take the all intra out a static capture of 10 bit 422 should be 1.67 the size of 8 bit 420 but here is the opposite the 420 I frames are bigger than 422 because the 422 format spends data for motion interpolation in a less efficient manner

    now can you see it or not and how will the footage withstand grading is a different story most people report similar performance between all intra and 150 422 If you believe panasonic claim that cabac makes compression 20-30% more efficient and precise this would make total sense and the gap between the two smaller

    however not many compare 8 bit and 10 bit straight out of camera those who do say 8 bit is better and my calculations are aligned 

  10. 23 minutes ago, Dan Sherman said:

     

    Run this simple test with any noisy footage from any camera. 

    1. Run the footage through ffmeg and encode it to h264 or h265 in crf mode
    2. Run a de-noiser on the footage and then encode it with the exact same settings as you used above.

    You will find the de-noised clip is smaller.

    This is important imo, because I don't believe the GH series applies the same processing to hdmi out as it does to its internal recording. Also keep in mind NR isn't the only thing the camera is doing internally. The video linked above even shows signs of this.

     

     

     

    The camera does not apply any codec to HDMI out it simply passes the buffer before encoding for the recorder to acquire code and save

    The test you mention is not appropriate as the size of the file depends on many other things not just bitrate H264 as a bunch of flags that squeeze the file but when encoding real time most of those are not active as otherwise the processing cannot keep up. Furthermore the codec is lossy so compressing it over and over again makes it smaller

    Noise reduction sharpening and all that comes in the picture profiles and the rest are applied before encoding which generally only makes things worst as it can transform sharpening and noise artefacts into other errors when compressing

    I think the improvements that you see over the 422 10 bit are not due to the 10 bits but to 422 vs 420 sub-sampling very well explained here

    http://www.red.com/learn/red-101/video-chroma-subsampling

  11. 1 hour ago, Dan Sherman said:

    It's better than 99% of the "technical" and "mathematical" reviews I've seen by people who are using pseudoscience. It seems like about 1 in 1000 understand their is more than bit rate, bit depth, chrome sampling, and codec involved in getting a good image.  

    It hilarious how many individuals think they more more than a large huge company.
     

     

     

    No there isn’t really

    you have optical image translated into digital signal and then compressed

    at equal optical quality the compression determines the perceived quality 

    Atomos are in the business of producing recorders but don’t own any of the codec logic I don’t know if they have a problem themselves with the hardware or software implementation 

    for what concerns that video a guy with a black shirt on a black background with a tiny part of the frame moving doesn’t really prove much about internal vs external but it does prove the point that for simple shots the camera works just fine which is in fact the idea behind heavily compressed IPB acquisition 

    You need a few more colours and movement to make the case although again there are many people (with a 8 bit monitor) that can take apart the 150 and 400 10 bit codec on such camera but the this could be due to the colors or detail not being there in the first place

    if you look on color depth measured off the GH5 it doesn’t reach 24 bits or 8 bits rgb for raw...

    So maybe the point is although the internal codecs will not allow for real 10 bits 422 uhd the camera doesn’t capture that detail anyway and therefore external recorders are a waste

    still a bigger screen than the gh5 lcd would be nice!

     

  12. 2 hours ago, deezid said:

    yep, that's exactly how it is.
    The 10 bit 150mbit/s implementation is way more effective but also more CPU excessive than the other H264 implementations. And in terms of artifacting it surpasses every 8 bit H264 choice on this camera quite easily in basically every situation (Talking about V-log L here).

    It isn’t mor

     

    2 hours ago, deezid said:

    Just shoot a clear sky in V-log using the 8 bit codecs.

     

    And you'll never do it again. Try using the codec instead and do colorgrading in Resove.

     

    In terms of actual visible quality the GH5 codecs behave like this:
    400Mbit/s Intra and 150Mbit/s IPB 10bit both look visually the same in most situations and grade extremely well, even in extreme low light with lot's of noise and usually don't show any banding artifacts. I actually managed to create banding using these codecs only once since I've bought the camera (gray wall underexposed).

    200 Mbit/s 10bit 4:2:0 H265 codec for 6K anamorphic has some slight banding issues and shows some macro blocking.

    150Mbit/s 8bit codec doesn't like gradients at all. Workaround is to use CineLike D and the Cinelike D to V-log conversion by @Sage

    72Mbit/s 10bit H265 codec shows some slight banding, macro blocking and even some blur.

    100Mbit/s 8bit codec doesn't work with gradients nor noise. Comparable to the GH4 H264 implemenation. Don't ever use it.

     

    Some showcase of the terrible 150mbit/s 10 bit codec:

     

    There isn’t an IPB 150 mbps 10 bit codec, the codec is IP only like Sony xavc. The level of compression is actually less than IPB 100 mbps or IPB 150 mbit 8 bits as you can see from the stream analysis there is less information packed in there 

    the reason you can’t decode it easily is because at 10 bit uncompressed your graphic card probably overflows

    The all intra has no cabac entropy encoding it just has intra frame interpolation pretty much like prores. Cabac introduces 20-30% efficiency so the codec once you shoot a static scene like yours are not much apart

    in terms of the prores comparison the avc intra does not have any technical benefits over prores so maybe the atomos implementation has problems on its own

     

     

  13. 1 hour ago, Shirozina said:

    Yes that's true (The HDMI out on my Sony A7s and A7r2  is very robust ) but it still doesn't change the fact that you don't need a 10 bit screen to benefit from a 10bit codec. I have argued many times previously that 10bit is not a cure-all. The advantage in video of 10bit is that in a YCBCR codec most of the data is stored in the Luma channel so higher rates of compression can be applied without running into some of the more obvious tonal artefacts. This I assume is why the 'theoreticaly inferior' 150mbps 10 bit codec can comfortably be used to shoot V-LOG, be subject to lots of tonal correction and still come out looking very good where as most internal 8 bit codecs fall apart.

    At the end of the day most users are not choosing their  codecs after doing theoretical data analysis exercises as it's not hard to see the artefacts of a poor codec once you start grading esp if you shoot LOG profiles.

     

    LOG is another form of compression overlayed on all the rest. I don’t use it but I would think this is too much to take for the 100/150 IPB codecs maybe the 150 mbps IP only works better with it assuming you don’t get motion artefacts

    For what concerns Luma my understanding is that it is linked to RGB coefficients it does not exist in isolation so your greys come fromntbeyae source so if you cant display 10 bit red you won’t see it either for me banding etc are more due to compression. I had a sony camera and the codec was the same at avchd and xavc despite different container I would get banding with 24 mbps but not with 50 and it was still 8 bits

    LOG should work better with All-Intra as there is more headroom

    just for clarity am not saying this camera is crap what am saying is that some of the features are not fully implemented at least for in camera recording

    Maybe I should have put a question mark in the title...

  14. 1 hour ago, KnightsFan said:

    I think you misunderstand me. We all know from experience that the quality of interframe compression varies based on the amount of motion in the frame. You even showed that as an example with the water fountain. I think it is faulty logic to assume that you can come up with a generic file size for an I frame, out of a long GOP file. I'll try to explain myself more clearly:

     

    "With an average video bit-rate of 94 Mbps each GOP has 45.3 Mbps"

    So far so good. We have 94 Mbits to describe a second of footage.

    "which means an I Frame has around 13.1 Mbits or 1.57 MB per frame"

    Ok, that's true. I can see from your chart that the I frame is 1648326 bytes, so that I-frame is indeed ~1.6 MB.

    "and an equivalent All-Intra bit-rate of approximately 328 Mbps."

    This is where I disagree. You are apparently multiplying the 13.1 Mb/frame by 25 frames/sec to get the "equivalent" data rate of 327.5 Mbps. You are assuming that the amount of data in a B frame (247334 bytes for example) is the SAME amount of data needed to retain the fidelity of that frame that is required by the I frame in total. That is, you assume that:

    1648326 absolute bytes = 247334 delta bytes

    Where "equivalence" means that they will retain the same amount of information relative to the original, real world scene that is being encoded.

    And we know, based on your example of the water fountain, that interframe compression quality depends heavily on what is being shot. Therefore, the idea of "equivalent" data rates being used as a measure of actual information retention is faulty, unless you specify what type of data is encoded.

     

    I actually think you are right about Prores retaining more information, but like I said you don't have evidence for it. And beyond that, the GH5 could have such poor image processing that uncompressed HDMI actually has no benefit over the internal recording either so even if Prores is theoretically better, concluding that people need an external recorder to get 10 bit quality does not seem justified.

    I have looked into Panasonic avc intra documentation

    In terms of all intra as implemented in the GH5 Cabac entropy encoding is not used only DCT is used so the assumption that this implementation of avc intra is similar to prores holds 

    For what concerns the equivalent bit rate calculation that assumes no error of motion interpolation. This of course can be true or not depending on the situation however on a static scene the calculations hold and the considerations are valid furthermore IPB codec use cabac encoding so provided that the motion interpolation works it is likely that the quality of the image is pretty much the same in the 420 8 bit implementation (Panasonic claims 20-30% increased efficiency with cabac)

    It is obvious that the choice between an intra codec and long gop depends on the amount of motion in the scene and what this proves is that the 100 mbps and 400 mbps produce very similar results in certain circumstances. 

    The post only aims at ranking the various options and to show that one of the implementations the 150 mbps 422 10 bit long gop is inferior to the others as the h264 codec is the same and the settings for that one are worst than the others

    prores conclusions need testing and it is possible that the camera is not good enough to push the boundaries of Prores 422 HQ anyway and therefore we see no difference from all intra

     

    2 hours ago, Shirozina said:

    You don't need a 10bit screen to see the benefits of using a 10bit codec - the lack of banding, posterization and macro blocking artefacts after applying tonal adjustments especially with LOG footage are it's big advantages. 

    Am not sure I follow fully some of those issue depend on the quality of the codec not just 8 to 10 bits

    8 bit colour should not give banding anyway and the fact you can apply corrections without breaking the codec has to do with the compression headroom more than anything else?

  15. 7 minutes ago, KnightsFan said:

    Thank you for the clarification. I am fairly certain now that I've been following your argument correctly. I do understand interframe compression, by the way.

    However, you can't simply compare bitrates, even adjusted for motion artifacts. There are different algorithms being used. You need to show, with image analysis or an analysis of the algorithm itself, that your method of comparison is valid.

     

    Again, for your conclusion, you have not shown that Prores is better. You are still just comparing the size of I frames from codecs that use different algorithms. That's why I suggest doing an actual analysis on real images.

    Chroma subsampling is for static images, and jpegs do use chroma subsampling. "[Chroma subsampling] is used in many video encoding schemes – both analog and digital – and also in JPEG encoding." (https://en.wikipedia.org/wiki/Chroma_subsampling)

    There is no need to analyse the frames for a relative comparison as the AVC family of Panasonic codec use the same algorithm only the GOP structure changes this is well explained in panasonic documentation of the codec so the assumption holds true

    in terma of avc intra being a proxy for prores I take the point but I have no information to conclude that the image processing of avc intra is better

     

  16. 3 minutes ago, KnightsFan said:

    You conclude with "If you want to produce genuine 10 bit colour high dynamic range footage you need to buy an external recorded capable of supporting ProRes 422 HQ or there is not game."

    That's why I'm suggesting an actual comparison with Prores that uses real world examples. If you just want to compare between internal codecs, that's a misleading conclusion.

    Not all Jpegs are the same, you can actually specify the quality amount and chroma subsampling of a Jpeg when you encode it. Could you specify which type of jpeg you are referring to? Also--what does jpeg have to do with any of this? I'll admit I'm having a hard time understanding why you use it as an example.

    Is that a valid assumption to make, though? My understanding is that motion artifacts is one of the main reasons people use All Intra codecs.

     

    To summarize my skepticism: It seems to me that you are judging codec quality purely in terms of adjusted bitrate. If I am misunderstanding, my apologies.

    No you dont understand the logic of motion compression. First in order to compare static image quality you need to assume the codec is correct otherwise of course there are artefacts. The camera buffers a certain amount of frames before encoding so you are reasonably sure that the performance will be good except radical scene changes 

    once you go last this point the image quality is only given by the full frames the others alone don’t even produce an image but just Delta signal to recreate one

    the analysis I have done on the GOP allows me to calculate the relative size of the frames with a certain degree of accuracy although not 100% once you have  done that you can normalise your GOP to an equivalent number of full frames and desume an average for your I frames across your footage. Those values don’t change a great deal. 

    Now in terms of the GH5 there are 4 codecs

    all intra : no motion interpolation just saving full I framea

    IPB GOP size 12 (used by all single frame rate codecs)

    IPB GOP size 24 (user by 50/60p)

    IP only used by 150 mbps 422 10 bit

    the latter is leas efficient than the IPB so the so the size of the full frames that determines image quality drops

    In terms of the conclusion that you need to use a recorder for full 422 10 bit colour this is based on the size of the I frames

    of course you can’t save a jpeg with subsampling it is a static image but the impact of quality as you increase compression is similar as it is relative to itself if youn notice it or not depends on how rich is the image 

     

    2 minutes ago, Deadcode said:

    Im grading in Davinci Resolve, and im using an old Dell U2711 (which is 8 bit), and working in REC709. 

    Used to grade 5D Raw and Sony SLOG2. 

    In the last couple of month i started grading in ACES, and this is where i can feel the 100Mbps 8bit  from Sony is not enough.

    Ok so the screen you use is not 10 bit how can you see the benefits?

    sony 100 mbps codec is IP only and is poor compared to panasonic IPB roughly is equivalent to 170-180 mbps and is less than half the all I of the GH5

    The GH5 422 10 bit 150 mbps uses IP too but has higher bitrate equivalent to 260 all I 

    So as per post all-I is the best option for 10 bit and it will take some reasonable grading but shooting at 700+ will be even better assuming you can see the benefits in your setup 

     

  17. 15 minutes ago, jonpais said:

    That’s why I switched to Sony’s 8-bit 100Mbps: the GH5’s 10-bit was shiite. ? Do you have actual footage to share shot with the GH5, @interceptor121 ? 

    That is not what I said the footage is not the point this is an analysis of the in camera codecs relative to each other 

    if you can’t understand it is fine too

    1 minute ago, Deadcode said:

    i have tried to grade 400Mbps 10 bit GH5 VLOG footage and i was impressed how well the codec holds even with extreme grading. I could not see any difference even in 400% magnification. 

    That is great news as I am wondering if I should buy a v90 memory card as mine fails after 30 seconds. What equipment do you use to grade? Do you have a 10 bit screen? 

    when i say the codec is weak I refer to the 150 mbps. If this codec was IBP it would have been roughly equivalent to 500 mbps

     

  18. 1 hour ago, Deadcode said:

    You mathematically proved that internal codec is sh1t.

    Rent an external recorder and show us the difference in real world situation please. 

    After seeing this awesome video from Andyax, i think the difference is negligible for most of the users.

     

    The internal codecs are pretty good at FHD they are excellent and at 4K only the 422 is poor 

    This is mathematical demonstration am not suggesting what you should use or not or if you want to buy a recorder or not that is your choice but I would not trust youtube as a tool for comparison amongs recorder and internal

    there many other benefits in using a recorder other than bitrates a larger screen helps to expose and focus and HDR

    10 minutes ago, KnightsFan said:

    You could be right. Do you have a source on that, though? Or a test showing that it is the case that hasn't gone through YouTube compression? In your post, you mainly seem to just compare the bitrates.

    I don't expect them to be exciting! However, it would give you more credibility if you could show that the numbers do translate to real world differences.

    Read the post carefully the comparison is between the codecs of the GH5 themselves and therefore relative and factual it has nothing to do with perceived image quality

    take a jpeg of an 8 mp shot compress it to thise sizes and see by yourself if you notice a difference 

    Assuming no artefacts from motion interpolation the size of the I frames determines the quality my calculations just extract the information 

    it makes me smile that some can post comparison between codecs not even understanding how they work and get away with it so I wanted to provide some back up info

    download ffprobe shou few clips of your choice at different settings and the averages won’t change

    relative image quality will change but if you can see it or not depends on many factors that are also subjective 

    It does not matter what you shoot the codec processes everything exactly the same the GOP structure is fixed and the ratio between the various frame pretty much too with minimal variations so you dont actually need to see what you shoot to test if it is correct or not it is a fact you see from the data

  19. 3 minutes ago, KnightsFan said:

    Nice analysis. I'm glad you actually delve into the numbers and explain the different types of encoding!

    However, it would be better if you included files straight out of camera and ran analysis on them, both qualitative and quantitative. Since Prores and AVC intra use different algorithms, simply comparing data rates is not an accurate representation of their fidelity. I  suggest encoding an uncompressed video into Prores, and also into AVC intra, and then running a script to compare the compressed images to the original and get an exact number on how much scene data is lost.

    Also, your title is meaningless unless you specify what the 10 bit internal is not good enough for. Is the 10 bit theoretically as good as Prores? Maybe--let's run some tests and see. Is the GH5's specific implementation inferior to external recording to Prores HQ? We need real world tests again. Are the GH5's 10 bit codecs better than any other photo/video hybrid's codecs? Almost certainly. Is it good enough for anything that we used to use GH3 and GH4's for? Of course!

    There isn’t a lot of difference between any of the intra codecs as in terms of image compression there hasn’t been great progress over the last 10 years. Prores avid avc intra xavc intra are pretty much the same. The difference comes from spatial compressions in the specific the 10 bit codecs of the GH5 at 4K are weak

    if you look at FHD the implementation is better

    with regards to the files they are the same scene and nothing exciting there won’t be much difference in the averages regardless of what you shoot quality will drop ad the bitrate is capped

     

  20. To say that the inferno has to be avoided compared to all intra has no foundation

    the only reason for prores 422 HQ to look similar to all intra was if the camera is not actually able to produce 10 bits

    both prores and avc-intra have no interpolation so there are no possible artifafts as frames are captured individually 

    maybe he has a cheap SSD skipping frames on the inferno lol!

  21. 39 minutes ago, jonpais said:

    Most of the articles and videos I’ve seen have tended to confirm your findings that 10-bit 150Mbps is to be avoided. 

    According to an article written by wolfcrow before the GH5 firmware update, 10-bit 4:2:2 150Mbps only contains 10% more data than 8-bit 4:2:0 100Mbps, not nearly enough to realize a difference in quality.

    He further calculated that 10-bit 4:2:2 would require 560Mbps just to be better than 8-bit 4:2:0 100Mbps. 

    Yet when he made a video about the GH5 after firmware update v2.1, he recommended shooting 400Mbps internally and not using the Inferno (I think he claimed to see artifacts when recording externally). 

    At the same time (I’m relying on my memory here) I seem to recall some people saying that 10-bit 150Mbps did offer a real advantage over 8-bit in that V-log footage was no longer plagued with banding artifacts.

    I never shoot 8-bit or V-log, so I can’t say - and that technical stuff is way over my head - but in my limited experience, HLG 10-bit 400Mbps can be manipulated in post quite nicely.

     

    I have read that blog and the assumptions are totally incorrect the guys does not understand the difference between all intra and motion interpolation it is just a coincidence he is correct.

    if Panasonic had implemented IPB on the 422 10 bit this would have been roughly equivalent to Prores 422 net of motion artefacts but it has not probably because the processing is limited 

     

    12 minutes ago, Shirozina said:

    Despite the poor specs of the 150mbps LongGOP codec it does hold up very well in grading. Mainly I think due to it's 10bits which make the luma channel near immune to banding unless you apply insane curves or tonal shifts and bends. The main reason to avoid it is the stress it places on most editing rigs trying to decode it on teh fly for smooth playback. The 400mbps codec is better in this respect but still harder on the CPU and GPU than ProRes or DNxHD. Given that most people will expose and color balance near optimally and not treat it as RAW the inadequacies you describe are purely academic and do not translate into real world problems. Until other mainstream manufacturers adopt 10bit 4.2.2 internal codecs the GH5 is well ahead of the game at the moment and a joy to work with compared to ubiquitous 8 bit 4.2.0 codecs with often even more compression.

    I don’t see any more strain with this codec than prores the only difference is that you need a program that supports it and not all of them do ir do well

    In terms of real life if you don’t beat it this codec performs ok but a 150 MBPS IPB would have been better

  22. I am not suggesting anything however the FHD formats are all almost equivalent in terms of image quality and 200 mbps is higher than Prores HQ so if you wanted to shoot LOG and do serious grading this codec will hold a lot of beating before breaking down

    I am just disappointed the FHD 422 10 bit 100 mbps is genuine IBP while the 4K has a poor codec probably the onboard processor can’t manage all that info but then I would have not even created that option. Having said that Sony codecs are the same with only I and P frames I was expecting more from Panasonic

     

  23. I have spent some time decomposing the codecs and I have had a real bad surprise with the 150 Mbps 422 10 bit codec.

    I was hoping this to be an equivalent to Prores 422 but it is really a poor codec implementation and I am not sure the 400 mbps all intra is good enough 

    full read of the findings here

    https://interceptor121.com/2018/08/13/panasonic-gh5-demystifying-movie-recording-settings/

    looks like no 10 bit recording really possible without an external recorder

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