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Strange blurring/loss of hard edges
I’m trying to merge a bunch of still images into a video using ffmpeg. The process has been fine and very fast (which is why I’d like to use ffmpeg over Final Cut), but the source files are hard-edged graphics and the resulting videos have a lot of blurring and compression-looking issues.
Here’s my current command (I’ve experimented changing the bitrate with no difference noted):
ffmpeg -r 24 -i %04d.png test.movHere is the original image file:
… and here is the resulting video frame:
… and finally a detail of the weird compression issues:
Can any ffmpeg ninjas suggest some settings to try?
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3 Replies
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First off, most video codecs do not designed for hard-edged graphics. Second, you haven’t specified what codecs to use, so it will just use the default. (which has changed over time, so that depends on the verion you are using) So it may default to a crappy compression format. You need to give direction as to what codec and codec options to use. Just upping the bitrate doesn’t mean much if you don’t know what codec you are using. Bitrates vary quite a bit between different codecs.
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Thanks Rueben, fantastic suggestion – should have been obvious to look into codecs. I’ve had great success in the past in Final Cut using PhotoJPEG (not supported by my installation of ffmpeg) and PNG (which is, and is the format for the source images so that helps a lot too).
For others, the following command seems to do great with little to no artifacting or blurring on flat areas of color:
ffmpeg -y -r 24 -i %04d.png -c:v png test.mov -
[Jeff Thompson] “I’ve had great success in the past in Final Cut using PhotoJPEG (not supported by my installation of ffmpeg)”
This is supported by the mjpeg codec which is the same as Photojpeg for all intents and purposes.
Check out this post from a while ago:
https://forums.creativecow.net/readpost/291/143Michael
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