I am looking for a way to "find" animated GIFs so I can remove them from a folder.
This must work on Windows 7 or Windows XP.
Edit: I am looking to distinguish between animated and regular GIFs. If I could select all GIFs that might be ok as then I could sort by size, but some GIFs are saved with the extension .jpg! That is why I think I probably need a special Image viewer program.
You can use ImageMagick to get the number of frames in a GIF like this:
identify -format "%[scene]\n" YourImage.gif[-1]
identify -format "%[scene]\n" YourImage.jpeg[-1]
It actually gets the frame number of the last frame, so if the image has 37 frames, it will tell you that frame 36 (starting at zero) is the last. So, an animated GIF will give an output of 1 or more since it has multiple frames.
This also works, if the image is mis-named by using a different name suffix. ImageMagick isn't fooled by this, it will still discover that in reality it is a GIF. If it is a standard JPEG, or a GIF with only 1 frame it will return 0.
ImageMagick is free and available for OSX, Linux and Windows - here.
Related
I dont understand the explanation about why GIF files always has image resolution 72ppi.
I have tried using ImageMagick converting PNG to GIF specifying -density to be 300ppi, but the resulting GIF is still 72ppi.
The GIF format does not store any value for "ppi" or "dpi" or pixel density/resolution - see Wikipedia.
I think software assumes 72 dpi, and then loads your image, updating that assumption if it finds anything better... which it never will in the case of GIF.
In any case, the dpi/ppi is irrelevant until such time as you want to print your image, and I don't know of anyone ever using GIF as a method of submission of images to any reputable printers or publications - TIFF is probably the preferred or most common method.
Edit July 7, 2017: Downgrading to ImageMagick 6.9.5 solved this problem, which may be Cygwin-specific. I still don't know the underlying cause.
I need to extract data via OCR from images in PDF reports published by Chicago Public Schools. An example PDF is here (NB: this link downloads the file automatically rather than opening it in the browser). Here's a sample image (from PDF page 11, print page 8), extracted with pdfimages -png version 0.52.0 on Cygwin:
I'd like to crop each bar into its own file and extract the text with OCR. But when I try this with ImageMagick (version 7.0.4-5 Q16 x86_64 2017-01-25 according to convert -version), using the command convert chart.png -crop 320x600+0+0 bar.png, I get this image, with horizontal lines that interfere with OCR:
Running pdfimages to extract to PPM format first and then converting to PNG while cropping gives the same result, as does round-trip converting the extracted images to SVG format with ImageMagick's rsvg delegate, and fiddling with the PNG alpha channel changes the line's colors from gray to white or black but doesn't eliminate them. I've found a workaround of round-trip converting extracted images through JPG (introducing ringing artifacts, which I hope are irrelevant). But I don't see why I should have to do this. Incidentally, ImageMagick introduces the lines to PNGs even if I run a null conversion convert chart.png chart.png, which ought to leave the image unchanged:
I have found other complaints that PDF software adds horizontal lines to images, but none of them exactly matches this problem. A discussion thread mentions that versions of the PDF standard somehow differ in their treatment of alpha channels, but my knowledge of graphics is too poor understand the discussion fully; besides, my images get horizontal lines added after they're extracted from the PDF, because of something internal to ImageMagick. Can anyone shed some light on the causes of the grey lines?
Using the latest ImageMagick 7.0.6.0 Q16 Mac OS X, I get a good result. As mentioned above by Bonzo, the correct syntax for IM 7 is magick rather than convert. The use of convert reverts to IM 6. Also do not use magick convert either.
magick chart.png -crop 320x600+0+0 +repage bar.png
If this does not work for you, then there must have been a bug in your older version of IM 7. So you should then upgrade.
Note also the +repage is needed to remove the virtual canvas
I have a series of png's that have an alpha channel as a background. Each file is named like file_name.0001.png and so on, in subsequent order. I'd like to join these png's into a video with ffmpeg and maintain the transparency.
I've tried a couple of things but I suspect I'm running into a codec issue. When I run ffmpeg, the video is created but the background is black.
If it makes a difference, I'm wanting to use the video in Microsoft Powerpoint. Thanks!
Edit
The suggested duplicate is very close to what I was looking for, thank you! The only reason it's not a complete solution is none of the options presented in the other thread work well with Microsoft Powerpoint. None of the codecs used in the suggested solution play well with Powerpoint. This is not the fault of ffmpeg, but of Powerpoint.
Though ffmpeg doesn't seem to be able to do what I need, I found that imagemagick did the trick. I was able to create a gif from the images and the alpha channel was preserved. I used the following:
convert -dispose 3 -coalesce images.*.png gif_file_name.gif
The -dispose 3 is critical as it tells imagemagick to clear the image prior to overlay, otherwise, you can see each image overlaid on each other (since they have the transparent background).
I couldn't get ffmpeg to create a video that preserved the alpha channel and was Powerpoint friendly (not the fault of ffmpeg). Though ffmpeg doesn't seem to be able to do what I need, I found that imagemagick did the trick. I was able to create a gif from the images and the alpha channel was preserved. I used the following:
convert -dispose 3 -coalesce images.*.png gif_file_name.gif
The -dispose 3 is critical as it tells imagemagick to clear the image prior to overlay, otherwise, you can see each image overlaid on each other (since they have the transparent background).
I have a small problem, I have a set of animated gif images. I want to pick individual gif image files, and create multiple tiff images capturing individual frames.
I am looking to do it in Python/Java.
Help would be appreciated!
You can do this easily from the command-line using ImageMagick. It is available for free from here. It has bindings for Perl, C/C++, Python and lots of others. It is ready installed in many Linux distros.
Your command looks like this:
convert -coalesce input.gif %02d.tif
which will produce TIFF format output files, numbered 01.tif, 02.tif etc. according to the frame number.
You can also extract an individual frame, say frame 7, like this:
convert -coalesce input.gif[7] my_favourite.tif
or a sequence of frames, say 3-7 like this:
convert -coalesce input.gif[3-7] frames%02d.tif
Note however, that when you extract individual frames, you may get artefacts depending on how well compressed your original GIF files are - since they sometimes only store DIFFERENCES between frames, so you may be best advised to extract all frames then discard any you don't want.
I'm working on a Sidebar Gadget and cannot get my JPEGs to show up (PNGs work). When I try to open the file by itself in IE8 it doesn't work. Firefox, of course, can open it fine.
JPEG Details:
Dimensions: 1080X900
180 dpi
Bit depth 24
Color representation: uncalibrated
I've found some things talking about the images being compressed incorrectly (?) but I haven't been able to get it working...
Any clues?
IE8 drops support for CMYK JPEG and renders them as the infamous red X without so much as a warning.
If you have ImageMagick:
identify -verbose image.jpg
will show you the image colorspace. If it's CMYK, you can convert to RGB with:
convert broken.jpg -colorspace RGB fixed.jpg
If you need to do CMYK to RGB conversion on a whole batch of JPEG-images, this command may be helpful to you:
for i in *.jpg; do convert "$i" -colorspace RGB "$i"; done
PS: If you'd like to see what is going on, just add -verbose:
for i in *.jpg; do convert "$i" -colorspace RGB -verbose "$i"; done
I had a similar issue with IE8 not displaying two JPEG images. FF, Safari, Chrome all displayed them without complaint but IE acted as if the files were not there. I have no idea what was going on, but a quick image conversion to gif or png fixed the problem. Just another in a long line of confirmations that IE sucks.
Had similar problems with existing images, which will not show up in IE8.
Problem is, as converter42 says: CMYK-Images
Convert them to RGB colorspace and all is good
The Solution with the PNG is not the best, because PNG files can be MUUUCH larger than JPGS.
If you are using photoshop for creating the jpgs. Try the below.
Open the file and go to 'Image' menu
Go to Mode
Select RGB
Save and upload to server.
This should work.
Why are you dealing with the image at 180 dpi and not the 72dpi screen resolution? At screen resolution the image will be roughly double that size. Still, the size is manageable for any browser.
When creating a gadget, you should be using PNGs for all the elements of the gadgets. Are you having issues displaying JPEG photos?
Have you looked for the yellow bar at the top of IE that blocks certain suspicious content from being loaded (popups, activex, javascript, etc.)? If it appears, try telling it to "allow".
Lastly, what are you using to compress your images to JPEG?
EDIT: If you want to do batch conversion use the batch converter in photoshop or use the Actions panel to record the conversion process for a single image, then replay the action on an entire folder. Additionally, you can save this action to a "droplet" which is a small application containing the action that you can drop an image or folder on top to.
Alternatively, if you don't fell like learning Actions, XNView is an excellent image viewer and converter that supports something like 160 different image formats and can batch convert and batch rename huge lists of files.
I fixed this issue by opening the CMYK JPEG file in Windows Paint and then saving as a JPEG, which Paint encodes as RGB by default. Not a great solution because I'm sure that Paint's converter is not as robust as Photoshop's, but this can be a quick fix if the job needs to be done now and there's no access to the tools above.