Low Quality Stills but Perfect 4k?

the best compromise is UHD (not full 4K) at 25 fps. It appears that the codec is optimized for that mode.

Thanks for the tip! I've been shooting 4K (4096 × 2160) but will run a test with UHD (3840 × 2160).

UHD has an additional advantage using 16:9 aspect ratio (I output HD 1920x1080). With 4K I often zoom in 107% to get rid of the letterbox in HD output.
 
I tested picture and video quality with different settings using my P3P (latest firmware). One of the major issues with the video quality (aside from the rolling shutter issues) is pixel noise (sharpness = 0 setting) due to a relatively low quality codec (limited by processing power and bitrate). There is no good or effective way to reduce/eliminate that kind of noise in post production. Consequently, reducing the sharpness to -2 is necessary. Post production sharpening can not return the lost details as a result of sharpness=-2, but it clarifies the recorded details well and clean with almost no perceptible noise.

The overall quality of the recorded video is a compromise between image resolution, frame rate and codec/bitrate. There is nothing we can do about the last (most critical) element. The goal is to record the most detail at best quality. Due to the codec limitations, it turns out the best compromise is UHD (not full 4K) at 25 fps. It appears that the codec is optimized for that mode. Testing UHD at 30 fps shows a very small reduction of recorded details. For all intents and purposes, no difference. The overall quality of UHD footage is substantially better than full 4K.

Bottom line settings for best quality video (P3P): UHD 25fps (or 30fps) with D-Log and fixed white balance along with Custom sharpness = -2, contrast = -3 and saturation = -2.
In post production (Adobe Premiere Pro) using the free LUT (DJI_Phantom_Inspire1_Osmo-LUT_fly4image.cube) I increase the saturation to 120% (offsetting saturation setting) and increase sharpness by 20% along with pushing down the blacks just a little and increasing the highlights just a little too. The resulting footage is quite stunning. An additional observation demonstrates that down converting UHD to 1080p results in significantly better quality 1080p than recorded in that mode directly with the P3P.

With stills it is a different. The JPG encoding quality of the codec is OK, but sharpness (even if set to 0 on capture) is quite low and for many situations, I like to add some sharpness to stills in post production.

Using Adobe Photoshop and processing the raw format significantly improves the resolution and clarity of the still. (The JPG version comes with artifacts that increase significantly when sharpening the still). Photoshop also recognizes the lens profile which helps a great deal for optical and chromatic corrections, let alone the ability to "massage" the image in post production.


Wow what an amazing and in depth tutorial for people. I deal with video everyday and I never knew about the UHD mode looking better than full 4k.? Do you have anything to back this up or is it based on the logic of 60mbps with less resolution to compress = better quality?

Amazing information for people to screen grab!
 
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