The Pocket 2 has options for mono or stereo, and for "front only", "front and back", and "all". Cleverly, although the four mics are mounted in the handle of the camera, the references to "front" and "back" etc are in relation to the rotating gimbal head of the device. So if the handle is pointing to the front but the gimbal head (with the lens) is pointing 90 degrees to the left, the soundfield is rotated to match the picture. The result of all the processing is stored as a stereo file in AAC format as part of the mp4 video file, (you can't get at the individual channels) and is specified as follows -
Format : AAC LC
Format/Info : Advanced Audio Codec Low Complexity
Codec ID : mp4a-40-2
Bit rate mode : Constant
Bit rate : 192 kb/s
Channel(s) : 2 channels
Channel layout : L R
Sampling rate : 48.0 kHz
Frame rate : 46.875 FPS (1024 SPF)
Compression mode : Lossy
This of course is well below the expectation of recordists here, but for the target audience for the device, it's probably par for the course. I have put in a feature request for an option to save the audio in wave format, but I don't know whether that's feasible as a firmware update. It would increase the file sizes of course, but from this 90 minute gig I came home with 54GB of files as it is - uncompressed audio wouldn't make a big percentage difference I would have thought.
The compression or limiting is not an option in the menus. To be honest it wasn't until I compared it with the other recordings that I spotted its operation, but looking at the waveform, it's obvious. My mistake was to have the level set too high so the signal was driven into the limiter more than it should have been. But it was a totally run and gun thing, and next time I'll know. Compression is better than distortion imho, but of course having neither is best!
Other mistakes were to use the device inside a 3rd party protective case, which is supposed to be transparent to the audio, but I should test that before assuming it's true. And, in preparing the comparison samples, the AAC file from the Pocket 2 was put through an mp3 encoding stage, and I should know better!!
Generally though I think DJI have put a remarkable amount of thought into the audio side of this device - I'm unaware of anything that competes. How they achieve the sound when the mics are closely spaced and peek out of pinholes I have no idea. It's a bit like those modern warplanes which in theory can't fly, but due to fly-by-wire processing, they do. Normally.
The Ambeo headset I rather like in terms of simplicty of use, and end result. Getting the files off the iPhone is a bit of a pain, but that's the nature of the beast. Compared with the Roland in-ears that I have, it's less susceptible to handling and cable noise, which is relevant when wearing such a device. If I had the black version it would be a bit more low profile in appearance to the very white one I've got, but I think white is the only colour now readily and cheaply available. Chief problem with any in-ear binaural mic is the need to keep your head still throughout the performance to avoid the stereo image swinging about.
The Sony A10 internals don't seem to have gained much good press here, but I've heard worse. Personally I much prefer their stereo image compared with the M10 which I hated in that respect. Closely spaced omni mics just don't work for stereo. As a very compact run and gun device, it has a lot to recommend it.
For more info on the camera, 'Illconditioned', just search for "DJI Pocket 2" on YouTube - there's loads of stuff explaining its features, and showing samples of its use, though more or less nothing involving live acoustic (or semi acoustic) music, surprisingly. I'm awaiting feedback from the duo I recorded and I may be able to post the finished video for public access, in which case I'll mention it here, for those who love bass and trombone duos. (Actually I thought it worked rather well - and some of the items were acoustic guitar and trombone, with both players singing too - Something Completely Different!)