[libav-tools] pngenc compression level

Luca Barbato lu_zero at gentoo.org
Wed May 4 04:41:07 CEST 2011

On 5/3/11 8:55 PM, Uri Okrent wrote:
> Hey guys, based on this:
> http://webcache.googleusercontent.com/search?q=cache:uP_EPJI98igJ:lists.mplayerhq.hu/pipermail/ffmpeg-devel/2007-October/036474.html+ffmpeg+png+compression&cd=1&hl=en&ct=clnk&gl=us&source=www.google.com
> it seems there is some way to set the compression level when using
> pngenc (-vcodec png). I can't seem to figure out how to do it though. I
> tried -compression_level, but that doesn't seem to be doing what I
> expect. It has an effect on the result but its always far larger than
> the source.

compression_level should do what you expect.

> My source is 84 frames of uncompressed tiffs which are 222 MB in size
> altogether. With compression level 0 my mov file is 534 MB, and with
> level 9 it is 275 MB. In either case it's much larger than the
> uncompressed frames! Something not right...

Maybe the tiffs aren't uncompressed and maybe our zlib settings aren't 
exactly optimal. Please first make 100% sure the tiffs aren't deflated 
as well.


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