On Sat, Jun 11, 2022 at 1:37 AM Аскар Сафин <safinas...@gmail.com> wrote:
> Hi. I use Debian Linux. I always capture my screen. I do this using my > own program, which takes rgb24 frames from X server and saves them > lossless in my own format. At fps 4 > (but duplicate frames are dropped). My codec is absolutely trivial > (and lossless), it is based on ideas from QOI ( > https://github.com/phoboslab/qoi ) and QOV ( > https://github.com/wide-video/qov ). > First I apply something like QOV encoding (with interframe coding) and > then compress every frame using zstd with level 8. Surprisingly such > trivial codec performs very well on my data. > It gives better compress ratio than all lossless ffmpeg codecs I tried > (x264, x265, vp9, av1, ffv1, ffvhuff, flv). > > I write this not because I want to brag. I write this because it is > possible that you will be interested in my ideas, that you will > incorporate my ideas into your code. > > ffv1 spec reads: "FFV1 is designed to support a wide range of lossless > video applications such as... screen recording..." Unfortunately, ffv1 > turned out to be bad compared to my codec > on screen recording data, so it is possible ffv1 could benefit from my > ideas. > > Now let me show you some data. I have a test video named > "test-video-2022-05-16-17.mkv" in lossless x264 fullhd, which was > captured from my screen. Uncompressed PAM size is > 208,268,339,335 bytes (208.2 G). Unfortunately I cannot share it, > because it contains a lot of my personal info. Now let me show you how > different codecs perform on this file. All data > was collected with this premises: pix_fmt is rgb24, everything is > lossless, gop is 32, everything is on aws ec2 c3.4xlarge with 16 > cores, everything on Debian sid with sid's version of ffmpeg. > > Codec: x264 > Command line: ffmpeg -loglevel warning -i /tmp/t.mkv -pix_fmt rgb24 > -c:v libx264rgb -preset veryslow -qp 0 -threads 16 -g 32 /tmp/out.mkv > Size: 2506211845 (~ 2.5 G) > Time: 1218.22 > > Codec: ffv1 > Command line: ffmpeg -loglevel warning -i /tmp/t.mkv -c:v ffv1 > -pix_fmt rgb24 -level 3 -threads 16 -g 32 -context 1 -slices 4 -coder > -2 /tmp/o.mkv > Size: 9431473324 (~9.4 G) > Time: 1125.15 > > Codec: my codec (single threaded!) > Command line: ffmpeg -loglevel warning -i /tmp/t.mkv -c:v pam -pix_fmt > rgb24 -f image2pipe pipe: < /dev/null | /tmp/nrdy encode 8 32 > Size: 1860479127 (~1.8 G) > Time: 470.88 > > So, as you can see my codec beats ffv1 and x264 both by compress ratio > and speed. Moreover, my single-threaded codec beats other > multi-threads codecs by time. Are you interested? > If yes, I can share my code. Of course, under some permissive license. > Again: there is no any magic here, just something like QOV + zstd. > Also, I can specially extract some sample > from my videos, which doesn't contain personal info, and perform tests > on this sample and publish sample > What about different samples? Not just single big one. > _______________________________________________ > ffmpeg-devel mailing list > ffmpeg-devel@ffmpeg.org > https://ffmpeg.org/mailman/listinfo/ffmpeg-devel > > To unsubscribe, visit link above, or email > ffmpeg-devel-requ...@ffmpeg.org with subject "unsubscribe". > _______________________________________________ ffmpeg-devel mailing list ffmpeg-devel@ffmpeg.org https://ffmpeg.org/mailman/listinfo/ffmpeg-devel To unsubscribe, visit link above, or email ffmpeg-devel-requ...@ffmpeg.org with subject "unsubscribe".
