Peter B. <pb <at> das-werkstatt.com> writes: > $ ffmpeg -i input.avi -c copy -s 10 -t 5 output.avi
I wanted to suggest -vframes 3 which would produce a significantly smaller output file. Note that you can cut avi with dd (if you don't trust FFmpeg which makes sense if you want to test losslessness.) But please note that the reason why r210 -> ffv1 -> r210 was not lossless in the past was a bug (or missing feature) in the software scaler. This issue was fixed a year ago and it has also fixed the issue with r10k. The difference with r10k is that it is more difficult to show that the conversion is lossless, instead of: > r10k's format: rrrrrrrr rrgggggg ggggbbbb bbbbbbxx FFmpeg writes: r10k's format: rrrrrrrr rrgggggg ggggbbbb bbbbbbbb (blue is 12 instead of 10 bits.) The conversion is still lossless but the most significant blue bits will be repeated as an eleventh and 12th bit making the files not bit-identical (while the saved frames are bit-identical) assuming xx are 0 (if they aren't 0 you will never get identical output files). Two patches are currently discussed to fix this issue in the encoder (which does not affect that the output is lossless but does affect the easiness of testing) but you can probably test by either doing: r10k -> ffv1 -> r10k -> ffv1 ->r10k and comparing the two ffv1 and the last two r10k files. You could also reencode to r210 and compare. And you can of course use -pix_fmt gbrp10 -f framecrc to get identical output (but this means you trust my fix for the gbrp10 conversion). Carl Eugen _______________________________________________ ffmpeg-user mailing list [email protected] http://ffmpeg.org/mailman/listinfo/ffmpeg-user
