## Dealing with a picture frame that freezes.

I recently bought myself a (1920×1080 pixel) digital picture frame, that had rave reviews among other customers, but that began the habit of freezing after about 12 hours of continuous operation, with my JPEG Images on its SD Card.

This could signal that there is some sort of hardware error, including in the internal logic, or of the SD Card itself. And one of the steps which I took to troubleshoot this problem was, to try saving the ‘.jpg’ Files to different SD Cards, and once even, to save those pictures to a USB Key, since the picture frame in question accepts a USB Memory Stick. All these efforts resulted in the same behaviour. This brought me back to the problem, that there could be some sort of data-error, i.e., of the JPEG Files in question already being corrupted, as they were stored on my hard drives. I had known of this possibility, and so I already tried the following:


find . -type f -name '*.jpg' | jpeginfo -c -f - | grep -v 'OK'



Note: To run this command requires that the Debian package ‘jpeginfo’ be installed, which was not installed out-of-the-box on my computer.

This is the Linux way to find JPEG Files that Linux deems to be corrupted. But, aside from some trivial issues which this command found, and which I was easily able to correct, Linux deemed all the relevant JPEG Files to be clean.

And this is where my thinking became more difficult. I was not looking for a quick reimbursement for the picture frame, and continued to operate on the assumption that mine was working as well, as the frames that other users had given such good reviews for. And so, another type of problem came to my attention, which I had run in to previously, in a way that I could be sure of. Sometimes Linux will find media files to be ‘OK’, that non-Linux software (or embedded firmware) deems to be unacceptable. And with my collection of 253 photos, all it would take is one such photo, which, as soon as the frame selected it to be viewed, could still have caused the frame to crash.

(Updated 1/16/2020, 17h15 … )

## About a minor (Home-Screen) nuisance I’ve experienced on Android deviceS.

I have owned several Android-based devices, and some of those were purchased from Samsung, those being:

• A Galaxy Tab S, First Generation,
• (An earlier Smart-Phone),
• A Galaxy S6 Smart-Phone,
• A Galaxy S9 Smart-Phone.

A feature which all these devices have, is the Touchwiz Home-Screen (program). This is the default of what the devices display, when not displaying a specific app, when not displaying the app drawer, and when not displaying ‘Bixby’ (most recently). An unfortunate behaviour of the devices is, that Touchwiz will sometimes crash. In my experience, when it does, this is no big deal, because it restarts automatically, and after a few minutes, even my Notification-Bar Entries will reappear. If certain apps fail to make their notifications reappear by themselves, then launching those apps from the application groups will make their notifications reappear.

I tend to rate each Android device, according to how rarely its Home-Screen will crash in this way. According to that, my Google Pixel C Tablet fared better because its home-screen has never crashed on me. My S9 Phone fared almost as well, in that Touchwiz seldom crashed. But now I think I’ve identified a situation which will frequently cause Touchwiz to crash on the S9 Phone.

Firstly, as I’m writing this, the firmware on that phone is at its latest version, that being the October 1 patch, of 2019, of Android 9.

I discovered that I can trigger this situation, as I was experimenting with the Super-Slow-Mo camera recording mode, in which the camera can record up to 0.4 seconds of video at 960FPS, at a resolution of 1280×720. When the camera does this, it generates a 20MB video, after that has been compressed via a standard H.264 CODEC into an .MP4 container-file. I have the default set, to record all camera footage to the external Micro SD Card. Having recorded the super-slow-mo video once, triggered this behaviour.

There is a simple way to interpret what has caused this, that does not seem to lay any blame on Samsung: When the camera is recording video that fast, it’s generating data faster than the external SD Card can store it. Therefore, the data takes up RAM, until some later point in time, when the O/S has transferred the data to the SD Card, by writing it out. This moment was reached several seconds later.

Here’s where the news gets a bit worse. I can download This 3rd-party app, that’s designed to test what speed of external SD Card I have. The reason I need to do this is the fact that I never seem to remember exactly what type of SD Card I purchased, for use with one specific device.

According to this app, my external SD Card can be written to sequentially at ~12MBytes/Sec. That makes it a Class 10 card. Yet, 20MB of data are to be stored in 0.4 seconds. In fact, simply running the benchmarking app caused a second Touchwiz crash, which was just as inconsequential as the first, that I was trying to investigate. What this seems to suggest is, that virtually no SD Card that I can buy, can really be fast enough to be written to at the speed with which the camera app can generate its data. The camera app will need to cache its footage in RAM, before that footage has been written to the SD Card.

Further, the footage is certainly being stored in RAM in an uncompressed form of data (384 raw frames), while what’s to be written to the SD Card is finally compressed. (:1)

And yet, either of these two apps will cause the Touchwiz crash. Hmm… I think that for the moment, I’ll just hold my horses, and record a maximum of 0.2 seconds of Super-Slow-Mo. Thankfully, this is a parameter that I can choose, with the little icon in the upper-right-hand corner of the view, before shooting.

(Updated 11/17/2019, 12h10 … )