![]() ![]() This is the framerate of the original (called MASTER) clip in RAW form. This is the encoded file which is being scored This launches an FFmpeg, which can be overloaded/changed with a variable FFMPEG_PATH, otherwise it will use the default FFmpeg in the $PATH To force the frame rate of the output file. This page discusses the Xilinx Video SDK command line flags used to optimize for objective quality (scores) and subjective quality (visual appeal) and provides additional details as to what is happening behind the scenes and why.įfmpeg -pix_fmt yuv420p -s:v 1920x1080 -r 60 -i $INPUT \ To set the video bitrate of the output file to 64 kbit/s: ffmpeg -i input.avi -b:v 64k -bufsize 64k output.avi. For example, common CPU encoders x264 and x265 have a tune parameter which optimizes to objective metrics. You can review the findings here.įurthermore, due to the industry standard of tracking encoder “performance” to quantitative metrics like the ones listed above, many encoders have “taught to the test” that is, they provide different command-line arguments that will give higher scores but may look worse to the human eye. ![]() Jan Ozer from the Streaming Media Center posted his experimental correlation of MOS vs the above metrics. ![]() Many people will argue which metric is best (although PSNR is commonly considered the least accurate). Mean Opinion Score (MOS) - Humans visually watching the screen and providing feedback Video Multimethod Assessment Fusion (VMAF) Structural Similarity Index Metric (SSIM) This has led to an evolution of algorithmic solutions, the most common of which are: There has been a longstanding goal for video engineers to quantitatively determine the output quality of an encoder without having to watch and inspect every individual frame. ![]()
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