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That's the photos, we're talking of video here
All very true but.....the C100 doesn't pretend to be a 4k camera (which of course it isn't) and the frame rate tops out at 30fps/60i. If we start shooting interlaced we are going to lose 30% horizontal resolution due to the Kell factor and nobody wants that with aerial footage .
Like you, I want to see untouched files straight out of the X5 where I can examine them properly locked away in my man cave before I make any sort of credit card type decision.
I've provided the feedback on bitrate to Eric Cheng @ DJI and he acknowledged it and was thankful for the feedback.
He did suggest we should probably reserve judgement until we see the actual results of the production X5 units, as we've been here before with the X3 "shaky gimbal" issue prior to I1 launch etc.
I think that's fair to ask.
Hopefully the feedback will be heard and possibly result in a FW update to bitrate. I think the X5 / R can be real game changers.
X5 video write speed = 60Mbps, same as the current X3. Some folks have speculated that's due to current SD card limits. They're mixing bits and bytes. 60Mbps = only 7.5 MB/s. Current SD cards can sustain up to 90MB/s write speed.
I've said it before and I'll say it again, the bitrate on canon c100 is max 35 Mbps..
Only at 1080 resolution, and these days 35Mbps is pretty low with most cameras of that level now offering 50Mbps 422 at 1080 resolutions. Now of course 4K is here and needs even higher bitrates.
You're dead right. Their entire business model is hinged on the fact that they produce products that are first to market. If you say "**** the X5 is way to expensive", DJI can say "Yes but can you do the same for cheaper?", and the answer is generally no. This is why we bought the Inspire in the first place - you can't do the same for less money. They need to realize that RAW capture of 4K video alone is the X5R's selling point. I would buy the X5 right now if it did 100mbps. I will never buy the X5R. Unfortunately, I'm buying neither.
A 4K equivalent bitrate to the 1080P @ 35Mb that the C100 Mark II shoots is 140Mb. UHD is twice the horizontal AND vertical resolution of 1080P, so it's four times as much data as 1080P.
For what it's worth the C100 Mark II only gets 35Mb when it's doing 1080P at 60fps. For 24 or 30fps, it records at 28Mb in AVCHD... which looks great... but you'd need 112Mb to get the same compression level at UHD/4K.
Going the other direction, 60Mb @ 4K is the 1080P equivalent of 15Mb. My old FS100 could record 17Mb 1080P in "FH" mode and I can tell you from experience with stuff shot that way that it was SIGNIFICANTLY degraded vs. stuff that was shot at 28Mb.
It's the same reason ProTune GoPro footage is terrible to grade vs. ProRes 422 out of a Ninja Star. A LOT of data is thrown away (especially dynamic range data) when you compress things heavily.
There's a reason you're FAR better off shooting 2.7K on your GoPro unless you need the 4K pixels for some reason. 60Mb is just simply too low for great-quality UHD much less DCI 4K.
Well 1080p60 @ 35 mbps would be equivalent to 4k30 at 70 mbps, according to your logic.
Practically speaking, who cares on numbers that are that close... I mean we all want the least compressed image possible, but if for some miraculous reason DJI released another version that was smack dab in between (let's say ProRes 422 at 145 mbps), I doubt many pros would notice much of a difference when presented with the two files side by side. When we go to push them in colour grading, that's when we'll run into issues, but I would argue the lack of bit depth (8-bit) will provide more problems than the bitrate.
I'd pony up for the recorder if it used commercially available memory (i.e. SD cards) and recorded ProRes 422 a la Atoms Ninja Blade. 1.7 gbps on a 4/3 sensor is overkill and necessitates an expensive and of course, proprietary 512 GB SSD. Probably why I won't be purchasing the 'R', and instead hoping for a firmware update unlocking some better bitrates and bit-depth (it'll probably never happen)
Um...
1920x1080 = 2,073,600 pixels for each frame
3840x2160 = 8,294,400 pixels for each frame
8,294,400 / 2,073,600 = 4
A UHD frame is essentially FOUR 1080P frames in a 2x2 grid.
UHD video takes FOUR TIMES as much data space per frame as 1080p.
So, "according to my logic" (and math) my original numbers we correct.
There is also a framerate difference, 4K @ 30 fps vs 1080p @ 60 fps. Gruvpix's calculation took that into the consideration.
Absolutely, and yes I was taking frame rate into account.My original numbers are correct:
1920x1080 = 2,073,600 pixels for each frame
3840x2160 = 8,294,400 pixels for each frame
8,294,400 / 2,073,600 = 4
A UHD frame is essentially FOUR 1080P frames in a 2x2 grid.
UHD video takes FOUR TIMES as much data space per frame as 1080p so to get equivalent compression rates at UHD resolution, you need a bitrate four times higher than the equivalent at 1080P.
As for the rest... ProRes is a pretty poor acquisition codec all things considered. It's popular because the encoder chips are out there and it's quick to edit, but it's very inefficient when it comes to card space (ProRes 422 HQ @ UHD is 880Mb/s) compared to some of the more advanced inter-frame codecs like XAVC or higher-bitrate AVC/H.264 in an MP4 wrapper.
ProRes was (and is) intended as an EDITING codec. It's intraframe, so it plays nice in the NLE. I transcode pretty much all my H.264 stuff to ProRes as part of my ingest workflow because it makes the NLE run smoother.
The Ninja Blade doesn't use SD cards... it uses 2.5" laptop SSDs (I have one sitting on my desk right now). Recording 4K ProRes would require a guaranteed card write throughput in the 75MB/s range, which is do-able but only with the fastest SD available... and even then, that's getting pretty close to the 90MB/s max these cards are promising. That's why the high-end world is moving past SD to CFast and XQD (and SSD).
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