Wikipedia:Reference desk/Archives/Computing/2020 May 20

= May 20 =

Converting several JPEGs to animated GIF
I have eight high-resolution JPEGs (24 megapixel DSLR, 6000x4000 pixels) that I want to put into an animated GIF. I used one of the recommended free online converters and the results were terrible. (1) The maximum resolution is only 500x333, (2) it is horribly pixilated, and (3) I wanted to show them at 3 second each, but the longest setting is 1 second each.

What is a good way to convert eight JPEGs into an animated GIF or a movie, show them at 3 or 4 seconds each, and keep decent resolution? Bubba73 You talkin' to me? 00:37, 20 May 2020 (UTC)
 * , if you can install The GIMP, it can create animated GIFs. Elizium23 (talk) 00:41, 20 May 2020 (UTC)
 * Thanks, I'll try that. Bubba73 You talkin' to me? 00:50, 20 May 2020 (UTC)

I tried to use these instructions, but I couldn't. In step 1 I did ctrl-A and Ctrl+, but nothing happened. Then I didn't see "selection" etc. The directions are written for someone who already knows how to use the program, and I don't. Bubba73 You talkin' to me? 01:25, 20 May 2020 (UTC)


 * How big do you want the animated GIF to be? I could be wrong, but I suspect a 6000x4000 gif is going to be unwieldy no matter what.
 * I have successfully used NetPBM to shrink and convert JPEG to GIF, and gifsicle to collate individual GIFs into an animated GIF, but these are admittedly all low-level command-line tools, which won't be to everyone's taste. I can give you steps if you want to give it a try. —Steve Summit (talk) 02:42, 20 May 2020 (UTC)

Be aware that animated gifs, like regular gifs, are limited to 256 colors. If you want to preserve true color, you'll have to use a video format. Try playing around with ffmpeg maybe. 93.136.148.29 (talk) 05:56, 20 May 2020 (UTC)


 * Lest we fall in to an XY problem trap, let us clarify an important point.
 * Does our original poster really wish to create a GIF (a very specific type of container-file using a very particular and limited form of image compression)? Or does the actual ask revolve around a more generic request to create a simple, highly-compatible, easy-to-view file that can contain a short, configurable animation, produced from an input sequence of images?
 * It is probable that the GIF file format is not the best choice for this latter task: it is not very modern; it has severe technical limitations compared to other animated-image and video file and compression standards; and the actual output that is displayed for an animation can appear very differently when viewed on diverse software-platforms, web-browsers, and hardware types that are commonly used by typical end-users. I would even venture so far as to say that in 2020, fewer users are able to view a GIF image than other video file formats, using the default software and tools that are in common usage in this decade - provided that our audience consists of all users of all types of system, across the entire world.  In other words, "GIF" isn't even the proverbial simple-enough-to-get-the-job-done, "lowest-common-denominator" file anymore.  For example, Microsoft Windows - a popular commercial operating system - stopped supporting the preview of animated GIF images in its file explorer more than a decade ago.
 * So - allow us to pose the question to Bubba73: What do you really want to do?
 * If you refer to ffmpeg documentation on video file format conversion, you will find that that tool - one of the mainstays of free-software tools for video and image processing - can ingest a sequence of input files (including JPEG files); and can output a video file, allowing the user to specify framerate, resolution, encoding, and so on. FFmpeg is available in binary distributions for Windows and other major platforms; and it can be built from source if you require that approach.
 * For example, just this moment, I have verified (...and I admit that I am a bit unusual, in that I happen to already have a copy of ffmpeg that I built from source, and I also happen to have available at all times a stack of sequentially numbered, very-large JFIF-file-format JPEG files - but, I am a commensurate professional, this is my day job, and it is how I pay for my extraordinarily expensive fuel bills),...
 * ffmpeg -framerate 1/3.0 -i /tmp/ffmpeg-test/051920_133415-%d.jpg /tmp/out.mov
 * ...which ingested my very large, nicely-timestamped JPEG files from source-directory /tmp/ffmpeg-test/; and output a .MOV file-format video file with 3-seconds-per-frame at location /tmp/; and because I specified no other non-default option, the video uses my FFmpeg system's favorite encoder algorithm (H.264, it happens, on this particular system) - which provides both better perceptual quality and a smaller output file than what I would get if I specified a GIF output file, using the extra command-line option -f gif and a corresponding appropriate file name.
 * For what it is worth - my system automatically previews the animation in the .MOV file when I open it; but in order to view the GIF file in motion on my system, I actually need a special tool - even though I can attest to you that this GIF file is a "standards-conforming file."
 * Nimur (talk) 16:04, 20 May 2020 (UTC)


 * I didn't know that GIFs were limited to 256 colors. That is probably too much of a limitation.  I'll probably make a movie - I've done that before.  Bubba73 You talkin' to me? 17:50, 20 May 2020 (UTC)


 * Just out of curiosity, because I don't make animations: is that limitation 256 colors for the entire animated GIF, or is it 256 colors in each frame? --76.71.5.208 (talk) 19:30, 20 May 2020 (UTC)
 * The animation can use a single global "color table" (palette), but each frame can optionally have its own local table - see GIF. AndrewWTaylor (talk) 20:10, 20 May 2020 (UTC)
 * The GIF89a specification is published at the official site of the W3. One problem with GIF files is that so many of the application softwares that you commonly find in the real world are not exactly conformant to the standard specifications - so the actual image that shows up on a user's screen is very difficult to predict.  But in broad brush-strokes, the specification requires a global color palette of not larger than 256 entries, indexing into an RGB color space of not larger than 8 bits per primary.  We might say that any color-space other than the so-to-speak "generic" linear 24-bit RGB space is "esoteric," irrespective of how it is palettized; but even that is actually permitted by the GIF89a file format.  And, the ability to use the GIF89a Graphic Control Extension to overlay arbitrarily many subsequent images, with arbitrary or zero delay, permits the GIF89a file format to encode images with arbitrary bit-depth per pixel.  So, the issue isn't so much "is it possible for a GIF to encode more than n colors in the image"... the issue is, "if we present a user with a valid but esoteric GIF file that is anything-other-than-exactly-identical to a normal GIF file produced by the most common software packages, how will that user's computer software display it - if at all?"  The answer, it turns out, is "quite poorly;" and as it turns out, there are hundreds of documented methods to damage a user's computer software by exploiting the standard, spec-compliant GIF file format - and even more by abusing the aforementioned standard.
 * Nimur (talk) 20:55, 20 May 2020 (UTC)
 * Thanks, folks. --76.71.5.208 (talk) 00:09, 21 May 2020 (UTC)
 * Since you want to show JPEGs at 3 or 4 seconds each, it might be easier to create a slideshow and convert to video. 107.15.157.44 (talk) 08:59, 22 May 2020 (UTC)

Not a fan of bringing up the XY problem here, the question is well defined and the user seems interested in understanding the formats. I can recommend the ImageMagick software[1]. It's open source and has good documentation[2], so if you are looking to understand the problem at hand instead of just solving it, you'll find answers. [1] https://imagemagick.org [2] https://imagemagick.org/Usage/anim_basics/ --TZubiri (talk) 10:12, 23 May 2020 (UTC)

Is it safe for pen drive if I play movies on it?
My HDD near to die, so I decide to play movies on 4 GB pen drive in my desktop computer. It's playing smoothly. I like it. But will it affects the pen drive longevity ? Ram nareshji (talk) 17:40, 20 May 2020 (UTC)
 * If the drive is only read and nothing is written on it while playing movies then there is no problem. Ruslik_ Zero 19:59, 20 May 2020 (UTC)


 * Playing the movie means reading from the pen drive, and it can do that indefinitely without harm. It's only when you write to the drive thousands of times that it eventually wears out. So if you plan on saving ten movies a day for the next 100 years, maybe you might wear out the pen drive -- and it would cost less than $10 for a new one.


 * BTW, here is a USB pencil drive... [ https://www.amazon.com/dp/B07N37XFF6/ ] :) --Guy Macon (talk) 20:00, 20 May 2020 (UTC)

I forget to add one thing, I am playing movies and editing txt file and zipping it(txt file in USB) in middle of watching movie. Is that safe? Ram nareshji (talk) 05:16, 21 May 2020 (UTC)


 * Yes. --Guy Macon (talk) 10:39, 21 May 2020 (UTC)


 * What about writing speed ? Will it decrease? Ram nareshji (talk) 17:08, 21 May 2020 (UTC)


 * If you are concerned about writing speeds, don't write to a pen drive. They are not built for speed. --Guy Macon (talk) 17:28, 21 May 2020 (UTC)
 * If your hard drive is dying then the short-term solution of movies on a pen drive will, by definition, not last you very long. You should replace your hard drive (probably with a decent SSD) or at least plug a real external drive into that USB port. Elizium23 (talk) 19:01, 22 May 2020 (UTC)

Pen drives are made with the cheapest, crappiest flash memory they can find. They are convenient but not very reliable. If you like watching movies from your pen drive, that's great, go ahead and keep doing it, just make sure the data is also backed up elsewhere. If the pen drive stops working, it is probably unrelated to anything you did with it. They just stop working at random. You can buy expensive ones that might be better, but it's not worth it. As Elizium23 says, your best bet is to replace the HDD in your computer with a good SSD. Don't get one with the letter Q in the model name (such as QVO) since those are likely made with cheap unreliable quad-level cell (QLC) memory. TLC (triple level) used to be suspicious for similar reasons, but it is considered ok now. Don't get the cheapest per GB drive you can find, but get the next level up, and you'll be ok. But always, back up your stuff ;). 2601:648:8202:96B0:3567:50D5:8BFF:4588 (talk) 01:34, 23 May 2020 (UTC)

Facebook Messenger Rooms
So Facebook have just rolled out their new Messenger Rooms feature to me. Trouble is I don't want it, because I can imagine it being more trouble than it's worth. Is there a way to hide/disable the feature in their settings? I'm using a Windows 10 PC, but can access it via IOS as well if necessary. Thanks in advance. This is Paul (talk) 23:52, 20 May 2020 (UTC)


 * Here is the official word from Facebook: "You can only deactivate Messenger if you previously deactivated your Facebook account."


 * Here is what Daily Dot says: "As convenient as Facebook Messenger can be for private messages and phone calls, sometimes we could all use a break from the constant pings and notifications... Here are two simple ways to turn off Facebook Messenger."


 * Related:
 * Facebook Users Beware: Here’s Why Messenger Rooms Is Not Actually That Private -- Forbes
 * Facebook's latest privacy scandal: What we know about the company's handling of user data -- USA Today
 * For years, Facebook gave some of the world’s largest technology companies more intrusive access to users’ personal data than it has disclosed, effectively exempting those business partners from its usual privacy rules -- New York Times
 * A timeline of Facebook's privacy issues — and its responses -- NBC News
 * --Guy Macon (talk) 10:59, 21 May 2020 (UTC)
 * Cheers Guy, thanks for these, I've been having a read through them this afternoon. It sounds like I need to hide my presence on there. To be fair, Messenger can be a very useful tool, especially for contacting friends, and local businesses and facilities, but the possibility of Messenger Rooms becoming a haunt for those who are bored and have nothing better to do than annoy people (as happens with Messenger) is something that fills me with trepidation. This is Paul (talk) 15:42, 22 May 2020 (UTC)