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So, you certainly could argue that a setting of 8 is reasonable for all encodes. Cost permitting, you’d certainly like to get to at least 4, if not 3 or 2.įor perspective, however, the total increase in harmonic mean from 94.90 to 96.31 is about 1.41 VMAF points, and it takes 6 VMAF points to produce a just noticeable difference that 75% of viewers would notice. As you can see, both metrics stay pretty flat through CPU Used 5, but jump noticeably at the 4 value, with another noticeable boost at 3 and 2 but flattening out thereafter. The first figure below presents the quality data graphically. The table presents the averages along with average encoding times, again for ten-second files. To identify the appropriate preset to use for my tests, I encoded seven of the files to all presets and measured the VMAF harmonic mean and low frame score, the latter a measure of the potential for transient quality issues. The default value is 1, which will be slow and high quality.” As with VP9, it’s OK to use the fastest preset (8) with the first pass it’s the setting used in the second pass that sets overall quality and encoding time. The valid range is from 0 to 8, higher numbers indicating greater speed and lower quality. If anyone sees any options that would improve encoding speed or quality, or if anything looks funky, please contact me at Question 3: Comments on the PresetĪccording to the FFmpeg documentation, the switch cpu-used “Set the quality/encoding speed tradeoff. I added the -row-mt switch upon the advice of Dirk Hildebrandt, CTO of Wavelet Beam. I created most of this with Google’s help when I wrote Good News: AV1 Encoding Times Drop to Near-Reasonable Levels for Streaming Media Magazine. For perspective, all files are 1080p at between 24 and 60 fps.įfmpeg -y -i input.mp4 -c:v libaom-av1 -strict -2 -b:v 3600K -g 48 -keyint_min 48 -sc_threshold 0 -row-mt 1 -tile-columns 1 -tile-rows 0 -threads 8 -cpu-used 8 -pass 1 -f matroska NUL & \įfmpeg -y -i input.mp4 -c:v libaom-av1 -strict -2 -b:v 3600K -maxrate 7200K -bufsize 7200k -g 48 -keyint_min 48 -sc_threshold 0 -row-mt 1 -tile-columns 1 -an -tile-rows 0 -threads 8 -cpu-used 8 -pass 2 output.mkv Here’s the encoding string that I’m using. If anyone knows which version of AV1 is included in FFmpeg 4.3, please let me know at Question 2: Comments on this Command String

Encoding is much faster than with previous FFmpeg versions but the version-related information looks the same in MediaInfo, so I can’t tell.

Question 1: What version of AV1 is in FFmpeg version 4.3?ĪV1 version 2.0 shipped on May 18 according to the readme file from the version of FFmpeg that I downloaded, the build includes aom 20200620-8c113ea, which presumably means it was downloaded on June 20.