On 6/28/15, qw <[email protected]> wrote: > At 2015-06-28 17:11:03, "Paul B Mahol" <[email protected]> wrote: >>Dana 28. 6. 2015. 09:31 osoba "qw" <[email protected]> napisala je: >>> >>> Hi, >>> >>> >>> PNG format supports alpha channel, but some png images don't have alpha >>channel. How to add alpha channel to those png images and set alpha value? >>> >>> >> >>See colorkey filter documentation. >> > I use the below command to run colorkey filter, and ffmpeg report there is > no colorkey filter: > ffmpeg -i ./image.png -vf colorkey=green ./output.png > > > ffmpeg version 2.7.1 Copyright (c) 2000-2015 the FFmpeg developers > built with gcc 4.4.7 (GCC) 20120313 (Red Hat 4.4.7-11) > configuration: --enable-gpl --enable-libx264 > libavutil 54. 27.100 / 54. 27.100 > libavcodec 56. 41.100 / 56. 41.100 > libavformat 56. 36.100 / 56. 36.100 > libavdevice 56. 4.100 / 56. 4.100 > libavfilter 5. 16.101 / 5. 16.101 > libswscale 3. 1.101 / 3. 1.101 > libswresample 1. 2.100 / 1. 2.100 > libpostproc 53. 3.100 / 53. 3.100 > Input #0, png_pipe, from './transparent_3.png': > Duration: N/A, bitrate: N/A > Stream #0:0: Video: png, rgba(pc), 256x256, 25 tbr, 25 tbn, 25 tbc > [AVFilterGraph @ 0x1d1e900] No such filter: 'colorkey' > Error opening filters! > > > which version of ffmpeg has colorkey filter? >
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