MM2 video quality and compression

[le_wib]

Hi everyone, forst of all, I don't own a MM2, I very happy with the 1.

After downloading from 2 drones youtube channel the video files they share for their audience, such as TechDroneMedia and a french blog HelicoMicro, I noticed some heavy artefact of compression on the videos produced with the MM2, more visible on 4K, in comparison with the MM1, which I found less noisy.

Have you noticed the same ?

If II remember correct, this was also the case for the MM1 and it was corrected quickly with the first updates.

here the link to download and see for yourself the videos :
helicomicro : 2.51 GB file on MEGA
tech drone media : DOWNLOAD | TECH DRONE MEDIA

 

[Lastrexking]

A few of the videos I’ve seen have mentioned the quality improved after an update.

 

[karlblessing]

I haven't seen the same but how were the videos provided by the youtube channels, were they straight unedited videos off the microSD card, or downloaded into the phone? Did the exposure look correct as well?

Note that the MM is at most a 40Mbps bit rate, the lower details will usually get blended up in compression (which can also cause banding in very smooth ranges). Whereas the M2 has 100Mbps (a much more significant number especially to someone like myself who does video editing).

Also if the videos were pretty much turn on and fly away with automatic mode set, it's possible to get some anomalies such as frame drops or tears from higher shutter speeds. Especially if it's not divisible down to the frame rate set for the video. Which is why a lot of people will use ND filters on their lens for video so that they can manually set the shutter consistently twice that of the frame rate , such as 1/50 for 24fps, 1/60 for 30fps, etc, as it looks much more natural without the drops.

 

[DanMan32]

I believe the 100Mbs is only in 4K mode.
The MM1 can only go as high as 2.7K so it doesn't need as fast a bit rate to maintain the same minimum compression as 4K on the MM2.

One would need to compare bit rate at the same 2.7K on both models to see if there really is an improvement in minimum compression.

 

[karlblessing]

I believe the 100Mbs is only in 4K mode.
The MM1 can only go as high as 2.7K so it doesn't need as fast a bit rate to maintain the same minimum compression as 4K on the MM2.

One would need to compare bit rate at the same 2.7K on both models to see if there really is an improvement in minimum compression.

2.7k isn't that much smaller than 4K (compared to 1080p).

Also 100Mbps is usually set as the maximum but doesn't always record at the maximum (usually 'overall' it can be between 50 to 80 depending on scene details).

All recording sizes are 'variable' bit rate, 4:2:0, 8-bit YUV
Tested with a scene of high level of detail with adequate lighting. Data from "MediaInfo" shown in Media Player Plus.

4K 24p
Variable Bit rate mode
94Mbps overall
100Mb/s "Maximum Bitrate"

2.7K 24p
Variable Bit Rate Mode
40.0Mb/s Overall
40.0Mb/s Bit rate (no 'maximum' designation)

1080p 24p
Variable Bit Rate Mode
32.1Mb/s Overall
35.0Mb/s Bit rate (no 'maximum' designation)

So I guess it would seem that for 2.7K it's capped for 40Mb/s, and 1080p capped for 35Mb/s, with 4K being the only one that's capped for 100Mb/s, in which case 4K for intention of scaling down to 2.7K would still yield more information than 2.7K @ 40Mb/s (like I said, 2.7k is only about 0.71x of 4K).

On my old Panasonic GH1, which had an original maximum bit rate of 17Mb/s , after the firmware was finally hacked it was able to be set to 100Mb/s (not without some buffer issues depending on configuration to where 75 was more realistic), it was possible to manually adjust each recording mode to a specific maximum bit rate, but the main time that was useful was hacking the Motion-Jpeg 720p mode into becoming 1536x960 (somewhere in between 720p and 1080p) setting it to 4:2:2 color, and using the increased bit rate for much better color retention purposes such as chroma keying off a green screen.

So would like to see more bit rate in 2.7K as it would still be useful, but would be far more useful if it could somehow be processed as 4:2:2 instead of 4:2:0.

Edit: in case it wasn't already known, but if you have 4K footage at 4:2:0 8-bit, and transcode it to DNxHD or ProRes 1080p (you cannot crop or edit at all in transcoding, just a straight transcode), you will end up with 1080p 4:4:4 , but not quite 10-bit (somewhere closer to 9-bit color) color wise, a good improvement to shooting in 1080p 4:2:0. Only really useful if you're a professional or colorist really trying to squeeze out fidelity/tone, especially since it takes additional time and computing to transcode.

 

[zeusfl]

Very good info.

 

[nn666]

There is no d-log mode for video with the mini 2 so you are still basically stuck editing what you can with a MOV or MP4 file... the quality will be a little better with 4k but for things like posting to social media you will hardly notice any difference if any.

 

[karlblessing]

There is no d-log mode for video with the mini 2 so you are still basically stuck editing what you can with a MOV or MP4 file... the quality will be a little better with 4k but for things like posting to social media you will hardly notice any difference if any.

Pretty much.

At least on the first Mini, using Litchi Beta you can adjust the saturation, contrast, and sharpness so that the video off the card isn't quite as processed as it would be by default. I understand that the in-camera processing is usually tuned to what they expect most consumers to find appealing straight off the card, but it's a bit destructive for later editing. I was just hoping they'd at least allow that on the Mini 2 (or both) in the Fly App at least under advanced camera options or something, or something similar to many P&S cameras of having "Natural", "Muted", "Vivid" etc.

But yea, it's not dLog or vLog (which isn't that largely advantageous on a system that only records 8-bit anyways), but you probably wouldn't be banking on their 'entry' level drone being the same configuration availability as their Inspire. But that's why I have my eye on the Mavic 2 Pro, for the 10-bit color.

 

[TDZHDTV]

I’ve been asking myself just this about the Mini 2, I feel a little disappointed, but I don’t know if I’m expecting too much. I’ve also downloaded some 4K footage from other users and when I zoom in I see the same noise/ artefacts or what ever it is exactly like my own footage.

 

[karlblessing]

I’ve been asking myself just this about the Mini 2, I feel a little disappointed, but I don’t know if I’m expecting too much. I’ve also downloaded some 4K footage from other users and when I zoom in I see the same noise/ artefacts or what ever it is exactly like my own footage.

I'll get some with mine later, including with the ND filter with manual exposure set to keep true to the 180-degree rule if that makes a difference on artifacts etc (As well as shooting 2.7k straight out of the camera for a MM1 compare-ish).

 

[nathankw]

Would love to know your results. I'm most interested in getting the best quality 1080 output. So I'm interested whether the MM2 4k downressed to 1080 is significantly better than the MM1 1080 (or 2,7k downressed.)

The bitrate on the MM2 should make it better but I haven't seen / heard any direct comparisons.

 

[le_wib]

4K 24p
Variable Bit rate mode
94Mbps overall
100Mb/s "Maximum Bitrate"

2.7K 24p
Variable Bit Rate Mode
40.0Mb/s Overall
40.0Mb/s Bit rate (no 'maximum' designation)

1080p 24p
Variable Bit Rate Mode
32.1Mb/s Overall
35.0Mb/s Bit rate (no 'maximum' designation)

very interesting.

when I zoom in I see the same noise/ artefacts or what ever it is exactly like my own footage.

Exactly what I felt.

Thank you everyone for you answers !

 

[DanMan32]

If going by raw pixels, 2.7 is indeed quite a bit smaller in number of pixels than 4K. Not sure though it would be a 100:40 ratio though. There may be more compression in 2.7K than 4K.

Note that 1080 specifies vertical resolution where 16x9 in 1080 would have more pixels than 4x3.
With 2.7k/4k however, that specifies horizontal resolution so 16x9 has lower pixels due to fewer rows than 4x3.