I would like to use Tesseract OCR with a video.
With ffmpeg I can export some (.jpeg) images from a video. Can I convert a .jpeg into a valid .tiff or export directly .tiff images from the video with ffmpeg?
1 Answer 1
Converting to TIFF
You can convert a JPEG to TIFF:
ffmpeg -i input.jpeg -pix_fmt rgba output.tiff
Or from a video:
ffmpeg -i input.mp4 -pix_fmt rgba out%05d.tiff
What's important is specifying the RGBA colorspace via -pix_fmt rgba. Keeping the YUV 4:2:0 colorspace from video (-pix_fmt yuv420p) would produce TIFF files that cannot be opened in most programs (even though the YCbCr* colorspace is allowed).
How to compress output
By default this produces uncompressed TIFF images. You can choose a different compression algorithm using the -compression_algo option:
ffmpeg -i input.jpeg -pix_fmt rgb24 -compression_algo lzw output.tiff
Valid options are packbits, raw, lzw and deflate (see ffmpeg -h encoder=tiff).
* YCbCr refers to what in video compression is usually known as YUV
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Wow, amazing! That solve my problem! :) Thank you very much!Tenaciousd93– Tenaciousd932014年10月20日 06:57:19 +00:00Commented Oct 20, 2014 at 6:57
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Using this method, I end up with TIFFs that are huge compared to outputting (say) PNG and then converting to TIFF using ImageMagick; something that 0.5MB vs 3MB. Do you know why that is? Presumably something to do with compression. How do I enable lossless compression on the TIFFs?\Ray– Ray2018年03月06日 10:50:46 +00:00Commented Mar 6, 2018 at 10:50
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1@Ray See updated answer, there are some options for specifying compression algorithms.slhck– slhck2018年03月06日 11:08:12 +00:00Commented Mar 6, 2018 at 11:08
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what is
-pix_fmt? can you please tell what command I need to run inorder to compress the image without change the file extension?Mahesh Jamdade– Mahesh Jamdade2021年04月06日 09:04:39 +00:00Commented Apr 6, 2021 at 9:04 -
@MaheshJamdade It's the color space/color format of the input. If you simply want to compress an image without changing extension, have a look at stackoverflow.com/questions/7261855/… or similar.slhck– slhck2021年04月06日 10:58:50 +00:00Commented Apr 6, 2021 at 10:58
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