Petition for Samsung NX1 hack

[kidzrevil]

Has anyone noticed macroblocking at high iso's take on a "wavy" texture in darker areas ? It almost looks as if the background is swimming ! I wonder if its a bitrate or NR thing or something that can be solved with mjpeg. 

[iamoui]

Quick question. Seeing as how you have to remove the battery for a short time then re-insert it, how would the vertical battery grip affect this? Should I be able to remove the grip to load the bitrate hack, then re-attach it? Thanks in advance.

[vasile]

1 hour ago, iamoui said:

Quick question. Seeing as how you have to remove the battery for a short time then re-insert it, how would the vertical battery grip affect this? Should I be able to remove the grip to load the bitrate hack, then re-attach it? Thanks in advance.

Battery pull means no battery whatsoever, the camera should have no power source. Turning off is not enough. If you have two batteries you need to pull both.

Will add this clarification to the next mod version.

[kinoseed]

1 hour ago, Marco Tecno said:

Pavel, very interesting. I still can't understand the reason for the reduced framerate when a higher bitrate is chosen. The higher the bitrate, the less work cpu has to do.

 

Btw, is there a way to create a shortcuts for video like this? :

Ev+fn= 4k, pro, pal, 25fps, 1x, dis

Ev+mobile= 1080, high, ntsc, 30, 0.25x, no dis

 

you can try this: http://***URL removed***/forums/post/57581215

[lucabutera]

1 hour ago, vasile said:

Battery pull means no battery whatsoever, the camera should have no power source. Turning off is not enough. If you have two batteries you need to pull both.

Will add this clarification to the next mod version.

Hi Vasile, thank you for your hack! Just a question: It possible internal 4.2.2 color subsampling or better clean raw file? Best

[vasile]

1 hour ago, lucabutera said:

Hi Vasile, thank you for your hack! Just a question: It possible internal 4.2.2 color subsampling or better clean raw file? Best

No idea but I doubt it w/o replacing the codec. Chant might eventually be able to do something about it but don't hold your breath. At the moment I see a slight chance to get:

• more resolutions (i.e. 2.5K on NX1)
• the high rate 2.5K on NX500 (subject to dangerous manipulations on burner cam)
• maybe higher res and rate MJPEG out of NX1 (although TBH I do not think it would reach the quality of 150-160 Mbps hevc)
• with a lot of luck disable or reduce video NR (I might take a look at this at some point in the future but this will definitely involve weeks of work so not too keen to start).

Basically Chant is looking into adding true new stuff.

I have been looking more on the side of tweaking what's already in there - easier than Chant's ambitions but I already picked the low and medium hanging fruits.

[pressland]

5 hours ago, vasile said:

 

• with a lot of luck disable or reduce video NR

and sharpening.

I also dream of having Gamma DR on the NX500, but all the effort so far is very much appreciated

[vasile]

4 hours ago, pressland said:

and sharpening.

I also dream of having Gamma DR on the NX500, but all the effort so far is very much appreciated

I talk about reasonable possibilities that I see based on my current knowledge of NX innards.

You talk about dreams/expectations.

Two entirely different beasts.

[Pavel Mašek]

12 hours ago, Marco Tecno said:

I still can't understand the reason for the reduced framerate when a higher bitrate is chosen. The higher the bitrate, the less work cpu has to do.

Yes, I do not understand that too - it behaves in exactly opposite way.

12 hours ago, Marco Tecno said:

Btw, is there a way to create a shortcuts for video

Yes, that would be very useful.

[vasile]

20 minutes ago, Pavel Mašek said:

Yes, I do not understand that too - it behaves in exactly opposite way.

Yes, that would be very useful.

Overall top fps depends on multiple pipelines: sensor=>CPU, CPU=> memory, memory=>card, as well as on codec intrinsic speed. Hard to say which one impacts in this instance but my guess is that it's the codec (and by codec I mean the software and hardware together).

You might think that the encoding CPU is less taxed with higher output rates but IMO that is not completely/always true.

[/Chop N Shoot Films/]

Since 120fps doesn't play nice with the bitrate hack has anyone tried PAL 100fps?  I feel like that should work without issue since the hack brings the 120fps recordings down to 106fps.

[vasile]

8 minutes ago, /Chop N Shoot Films/ said:

Since 120fps doesn't play nice with the bitrate hack has anyone tried PAL 100fps?  I feel like that should work without issue since the hack brings the 120fps recordings down to 106fps.

As I wrote earlier, you should gradually decrease the mod bitrate for that video mode and check what this does to overall fps.

At some point you will reach the point where the fps gets back to 120, at some max bitrate that will also depend on your card. Do not assume that max video bitrate for the camera is the same regardless of video size and fps combination because this is not true.

The encoder workload is different between these even if the target bitrate is the same.

Whilst we may start to play with the CPU speed/power profiles, and might be able to overclock it, I am not sure this is advisable - I think Samsung chose their power profiles based on engineering constraints and target environment factors (e.g. extreme usage like in the Nevada desert) with some margin too, but this does not mean that we should start playing with the fire.

Unless you are willing to risk your camera's reliability and lifetime.

[Pavel Mašek]

4 minutes ago, vasile said:

you should gradually decrease the mod bitrate for that video mode and check what this does to overall fps.

120 fps works fine with 110Mbit as max bitrate. 100fps should be completely fine even with 160Mbits...

[Marco Tecno]

110 is already a nice jump from the standard 80. Almost 40% more, actually.

[vasile]

2 minutes ago, Pavel Mašek said:

120 fps works fine with 110Mbit as max bitrate. 100fps should be completely fine even with 160Mbits...

Which means that the encoder block cannot deal with more than this bitrate at that size/fps. No other possible explanation so do not expect more from the camera as far as 1080p/120fps is concerned, unless you are willing to overclock.

[/Chop N Shoot Films/]

I didn't mean overclocking. I just meant getting 100fps at 160 bitrate instead of scaling back for 120fps. Seems like fair compromise to maintain the highest quality. 

[Syme]

While in theory having a higher data rate means compressing less and compressing less requires less work that's definitely not the case in practice. I think it might be the case with software implementations of some codecs, but it is usually not true with dedicated hardware. I think it probably has to do with the fact that the codec in a camera has to guarantee a certain resolution and framerate regardless of how "difficult" the input is to compress. In other words, the codec isn't allowed to slow down if it has to compress more so the opposite is also true: the codec isn't allowed to speed up if it gets to compress less. The designers had to pick an algorithm to implement HEVC that was stable (w.r.t. changing input) at the cost of flexibility (and also an algorithm that is easy to implement in hardware).

This may or may not be the main reason why the NX1 is behaving like it is, but it's important to understand.

p.s. I hope that makes sense. I'm not a hardware codec designer, so correct/clarify if I'm wrong.

[RieGo]

so there is a little misconception: the higher the bitrate/quality the encoder has to output the more work he has to do. so it's usual (at least in my experience) for encoders to get slower while bitrate increases. you can try a simple x264 crf 18 vs x264 crf 30 to see what i'm talking about.

also don't forget: a major quality decrease at 120p compared to 30p/60p comes from no full sensor readout, which also makes it harder to compress because of more noise.

[vasile]

eoshd is the "other" board mentioned here :-)

http://***URL removed***/forums/post/57589144

[tugela]

16 hours ago, pressland said:

and sharpening.

I also dream of having Gamma DR on the NX500, but all the effort so far is very much appreciated

I don't believe that the NX1 has much sharpening applied (which IMO is just a debeyering parameter when done in camera anyway - not sharpening in the post-processing sense). The footage looks sharp most likely as a result of downsampling of the native image.