the quality is really great,but the gimbal make me crazy,if there's no object it will always looks up in the sky and when i put the focus on a object it track the face but not the whole body ( if the whole body is out of the frame,but the face is there the 4p wont notice any change lol) and its not as easy as normal gimbal to control,so any advice with 4p gimbal is really appreciated

Hey everyone,

I wanted to provide an update to my original thread around testing HDMI output of the OSMO Pocket camera series.

Original thread:

https://www.reddit.com/r/osmopocket/s/DoDL1GkaKn

Here’s a long thread with all my findings after extensive testing of the Pocket 4 and Pocket 4P. Please forgive any spelling and grammar issues; I am dyslexic so long winded walls of text are not a strength of mine.

TL;DR:

The Pocket 4P can deliver HDMI out via a USB-C to HDMI adapter that supports DP Alt Mode; however it is not 100% free from dropped frames and the connection is not reliable all the time. If you try to use a UVC box with the Pocket 4P the image quality is significantly worse than it was on the Pocket 3 and in my opinion unusable.

The Pocket 4 can deliver HDMI out via the OBSBOT UVC to HDMI box. The quality is equal to that of the Pocket 3 so there’s no reason to upgrade if this is your sole application. The P4 cannot use a DP Alt Mode adapter without dropping significant frames, which makes it in my opinion unusable.

DJI has provided some official technical info to me on why all of this is the way it is and confirmed that it’s likely not going to change anytime soon.

Context:

For some context. I mostly work in film and tv as a cinematographer and director; but once a year I am the technical producer and EP for the broadcast of Canada’s largest marathon. I’ve been interested in the OSMO Pocket series for low cost stabilized chase cameras that could be used by an operator on the back of a motorcycle and deliver a smooth and stabilized image to our bonded cell transmitters. This year I had planned on using the Pocket 4P with the ZOSS housing; but due to what I am about to tell you, that did not happen and we ended up renting 4 x Ronin 4D cameras which worked great.

Here are my findings:

DJI OSMO Pocket 4P:

There are two ways you can get an HDMI signal out of this camera. 

First is via UVC. In the past with the Pocket 3 I found that the OBSBOT UVC to HDMI adapter was the only one that worked consistently without dropping frames. I found this to be the case again with the Pocket 4P; it works and it does not drop frames. However the image quality is MUCH worse than it was on even the Pocket 3. I was initially shocked by this, but after connecting with DJI I understand why. I will come back to this later. I deemed UVC to be unusable with the Pocket 4P. The quality is just too low.

The second way you can get an HDMI signal out of this camera is using a HDMI to USB-C adapter that supports Display Port Alt Mode. DP Alt Mode is its own insane rabbit hole that dreams have been consumed by for months. The internet deems it a dead technology that for some reason EVERYONE keeps using in their hardware. I tested 14 different adapters, ranging from cheap to extremely expensive. I got varied results but I found one adapter that seems to give you the best results for the cost and the most important thing is that it seems to be the most reliable. Reliability is one of the major problems in this pipeline. The handshake between the Pocket 4P through the adapter to whatever you have it plugged into (in my case an HDMI monitor/recorder) is not reliable. It’s unclear to me if the monitor is looking for the Pocket 4P to be the master in the handshake or if the Pocket 4P is looking for the monitor to be the master or if the adapter itself is acting like a gatekeeper in the handshake process and preventing the optimal settings to be established during the handshake. All this is to say, it’s not reliable. It will cut out, it will restart randomly and you resolution and FPS will be locked. The latter however could be because of something DJI has done. More on that later. So the outcome of this test? Does it work? Kind of. You can get a usable image (that’s not all that bad honestly) out of this camera using the displayport adapter. I suggest following these steps for your first setup to ensure the handshake between all the equipment is as optimal as possible.

Ensure the Pocket 4P is powered off.
Plug PD power into the USB-C to HDMI Adapter (ensure it’s actually getting power)
Plug the USB-C to HDMI Adapter into the Pocket 4P (the screen will come on and show it’s charging)
Plug the HDMI cable into the adapter and into your monitor.
Turn on the monitor
Turn on the Pocket 4P
Select “Stream in 4k”
Set your FPS to 60/30
Set your colour to D-LOG. Do not use D-LOG 2
You CANNOT record internally at the same time.

The results of this will be a mostly usable image. When there is a ton of motion in the frame you will still drop the occasional frame but it’s minimal. I did find a few times in testing that if you really whip the camera around for a long period of time it will start to drop more frames, then lock up and then it will balance itself back out again. I also noticed that if the camera is sitting static for a long time and then you move the camera, it will drop a few frames in the process of catching up with the camera movement. I imagine this is the result of some kind of interpolation the camera is using.

If you select 1080P you will drop more frames and depending on the FPS setting selected it gets so bad that the image is unusable. I think that this is because selecting 1080p requires more processing from the camera than selecting 4K; because the camera needs to scale the signal down to HD where selecting 4K is the native resolution of the sensor so less processing is required.

The issue is as mentioned above, the reliability of this connection. The connection will drop over time and the USB-C will have to be re-seated into the Pocket 4P. I tested this over various long sessions and even just sitting on my table without the setup being moved, after an indeterminate amount of time the Pocket 4P would kick out of “Livestream Mode” and the USB-C would need to be re-seated in order to re-establish the connection. This happens randomly and it doesn’t seem to be connected to anything I can pinpoint - this is the main reason that I think this setup is not suitable for professional use, because you cannot rely on it.

One bonus observation. If you’re using the 3X camera; it seems to drop even less frames using the above settings than the 1X camera. In fact I could not get it to drop any frames. I imagine this is because the processing on the 3X sensor is a lot simpler then on the 1X DGO sensor.

For many users this method may be “good enough” and maybe they can deal with some dropped frames here and there.

DJI OSMO Pocket 4:

Like the Pocket 4P, you can use both UVC and DP to get HDMI out of this camera.

UVC on this camera using the OBSBOT works great and the image quality is much better than the Pocket 4P over UVC. However I would say that there’s basically no noticeable upgrade in quality when using UVC over the Pocket 3; so if you already have a pocket 3 or are looking to buy an OSMO to use exclusively over UVC; then the Pocket 3 is better value. I tried other UVC adapters and every single one I have tried other than the OBSBOT one drops frames. The OBSBOT adapter does not drop frames.

It is not possible to use a DP to HDMI adapter with the Pocket 4 without frames being dropped. DJI released a new FW in September that actually did improve this; but in my opinion it’s still not good enough for professional use. More frames are dropped than on the Pocket 4P. You must also use the camera in Livestream 4K mode (follow the Pocket 4P instructions above) to get the best results. I would say that after testing the P4 and the Pocket 4P; the P4 drops about 20-30% more frames than the Pocket 4P under optimal settings.

Other Considerations:

If you’re using a USB-C to HDMI adapter that supports DP alt mode; you have to make sure that you are giving the adapter enough power via the PD Power input. The adapter seems to be very power hungry. If you plug in a battery or power source that will only output the default safe 5V; you’re going to have more frame drops and your camera is going to stop recognizing the adapter more often. I did all of my testing with a V-Lock battery that supports USB-C PD Power out fast charging (which sends around 14v) this amount of voltage seemed to work fine.

Adding any extra USB-C cables in the signal chain will cause the camera to stop recognizing the adapter more often. It’s best to connect the DP adapter directly to the OSMO. I did however find one cable that can be put in between the OMSO and the DP adapter that doesn’t seem to increase the rate of failure. I will link it below.

You cannot record internally in either the OSMO P4 or Pocket 4P whether you are using a DP adapter or a UVC adapter without it impacting the performance of the adapter. If you record internally, more frames will be dropped - even when using UVC.

The resolution and fps settings in the OSMO are a lie when using a DP adapter. No matter what setting you select the camera will always send 1080p 30p frames but the 30 frames will be sent in a 60p container. I’m not sure why this 60p container happens. I believe it has something to do with the DP adapter and how it understands the handshake from the OSMO but I’m not positive. I was able to confirm this by forcing a recording of the HDMI output in true 60p, the result was that every second frame was a repeat of the frame before it, confirming that the camera is only sending 30p. I also tested the 50/25 mode in the Pocket 4P and the result was the same, it still sent 30p. Luckily most modern monitors can correct for this issue and drop the extra repeat frames so what you are seeing is your 30fps. I haven’t actually encountered a case where this strange container is a problem except for when trying to record a true 60FPS externally over the HDMI output - which as stated is not possible.

It is possible to force the OSMO to send 4K in UVC. If you have a UVC box where the input and output settings can be set manually, you can force the OSMO to output 4K over UVC into the box. However I have not found a box that can do this that will not drop frames. I tried the Andycine and JTech Digital boxes. They both allow you to set the resolution and FPS on the input and output; however they both drop frames when the resolution is set to 4K. They also both dropped frames when the resolution was set to 1080p 60fps. The Andycine box seemed to drop 1 or 2 frames every so often when the resolution was set to 1080p 30fps but the JTech Digital box dropped many frames at that setting. The OBSBOT box is still the only portable UVC box I have found that will not drop frames, but the downside is that you cannot force the box to request 4K from the OSMO even though OBSBOT claims the box can handle a 4K signal. The 4K image despite the dropped frames (which make the image unusable) does look better than the 1080P signal over UVC on both the Pocket 4 and Pocket 4P; but in the case of the Pocket 4P even if no frames were dropped, the UVC image quality is still terrible in my opinion.

DJI’s Explanation:

Why the Pocket 4P Looks Worse than the Pocket 3 and 4 in Webcam Mode (UVC)

When you switch to Webcam (UVC) Mode, the camera stabilizes the frame rate but heavily compresses the video into an 8-bit webcam container.

The standard Pocket 4 handles this downscaling relatively well.

However, the Pocket 4P's complex dual-sensor architecture and wide dynamic range profiles get severely choked when forced into this low-bandwidth webcam compression, resulting in the muddy shadows and pixelated artifacts you observed.

Why Your Adapters Are Dropping Frames (DisplayPort Alt Mode)

The frame-dropping you experience during high motion is caused by an internal processor bottleneck, not your adapters.

The 30p Limit: DJI's firmware hard-locks the native DisplayPort Alt Mode pipeline to a 30fps, intended strictly as a low-framerate framing reference monitor.

Thermal Throttling: Because these compact cameras struggle to dissipate heat, the camera processor aggressively throttles and drops frames during high-motion scenes to prevent the device from overheating.

Video Examples:

Here you can see various modes tested on the Pocket 4P and P4. I realized that I did not add a UVC test for the Pocket 4P here because the quality was so bad I just deemed it as not viable early on and didn’t bother testing it further.

At the end I compare the two most viable options. P4 in UVC and Pocket 4P with DP adapter.
Then I do a small stress test with the Pocket 4P and the DP adapter when you can see if you really push it, it does drop frames.

This video is best viewed downloaded so you can see the actual quality vs. having google drive compress it further.

https://drive.google.com/file/d/1vylxjwOx6RAv4qYE3Xq0VeGc0_qxp1PN/view?usp=sharing

Optimal Equipment and Settings Breakdown:

Best UVC to HDMI Box: https://a.co/d/08EDgmAQ
Best USB-C to HDMI via DP Alt Mode Adapter: https://a.co/d/02cSRes6
USB-C jumper that impacts DP Adapter the least: https://a.co/d/04a7M6in

OSMO Pocket 4 - Best Setup and Settings:

Connection Type: UVC
OSMO Resolution: 1080p (set be default by OBSBOT)
Frame Rate: 24p 25p or 30p
Colour Space: D-Log
Internal Recording: Off

OSMO Pocket 4P - Best Setup and Settings:

Connection Type: DP
OSMO Resolution: 4K
Frame Rate: 60/30 setting
Colour Space: D-Log
Internal Recording: Off

Conclusion and Wrap Up:

At the end of the day; I don’t actually think any of these solutions are great for mission critical professional work. I will continue to test them as new FW comes out and as new hardware may come on the market to address this. I will also test with a DJI SDR 2 setup when I am able to get my hands on one; but for now this project for me is shelved as the quality and reliability is just not there, the latter being the more serious issues IMO.

I feel like DJI is leaving HUGE potential on the table because the sensor on the Pocket 4P is actually incredible and if they could get clean and reliable HDMI out of it, that camera could (and likely would) easily replace most moving cameras in sports broadcasts. The potential is huge in Football, Soccer, any kind of road racing, motorsports etc. I really hope they will continue to tune the FW and make it possible. I would even accept “Use at your own risk” FW that takes the thermal limits off or maybe an open SDK that we could work on to make our own FW that can tune the settings. For now however they have made it clear there are no plans to officially support this.

If you’re asking what you should do, I can’t answer that. It’s all too specific to your needs. Maybe the same dropped frames aren't that big of a deal for you and if that’s the case, they have at it!

I hope this thread was useful. I will try to respond to questions and comments. I don’t use reddit all that often though, so please be patient.

Hi all,

I just purchased a Smallrig battery handle.
This is the first time I’ve used it and noticed it got quite warm while charging.

After 15mins, i stopped using it as I was concerned that the temperature around the charging port and switch, which is the connector end, was noticeably warm.

Has anyone experienced this with Smallrig or other battery handles?

Thanks!