Hey all, I'm trying to produce JPEG thumbnails of movies and gifs. I am scaling them to a particular size, which requires letter boxing them, and I noticed that the black letterbox I use isn't always black. It works fine when converting to other formats.
I assume this has something to do with RBG/YUV or YUV Range conversion, but I'm not fluent in how FFmpeg handles color conversions and haven't found too much documentation. Here is an example command line I'm using: ffmpeg -i source.gif -frames 1 -pix_fmt yuvj420p -filter_complex '[0:v]scale=360:360,pad=width=640:height=360:x=640-trunc(iw*min(360/iw\,360/ih)/4)*2:y=360-trunc(ih*min(640/iw\,360/ih)/4)*2:color=black' -sws_flags lanczos -y -f singlejpeg out.jpg I also tried yuv420p which works for mp4. Thanks for any help! bjorn -- Bjorn Roche Sr. Video Pipeline Engineer bj...@giphy.com _______________________________________________ ffmpeg-user mailing list firstname.lastname@example.org http://ffmpeg.org/mailman/listinfo/ffmpeg-user To unsubscribe, visit link above, or email ffmpeg-user-requ...@ffmpeg.org with subject "unsubscribe".