H.264 Video Encoding Guide: 2 Pass Encoding FFmpeg trac article which gives definitive and easily followed information on 2 pass encoding to H.264.c:v libx265 -x265-params pass=2 -b:v 318k \Īnd this provides a 40mb file with quite reasonable quality.įrom these example you can experiment further by decreasing the required MiB in the formula and observing the subsequent viewing quality. This time the formula would be: (40 MiB * 8192 ) / 734 seconds = ~446 kBit/s total bitrateĤ46 - 128 kBit/s (desired audio bitrate) = 318 kBit/s video bitrateĪnd the FFmpeg 2 pass command line is: ffmpeg -y -i TearsOfSteel_720p_h265.mkv \ Pretty good for a 50% reduction in file size and a huge drop in video bitrate actually!Īnother choice (as suggested by emk2203) is to re-encode the existing HEVC stream with a lower bitrate, this time aiming for 40mb as HEVC claims better quality at a lower bitrate. The resulting file size is 49.4MiB with quite reasonable, but not amazing, viewing quality. c:a libmp3lame -b:a 128k TearsOfSteel_smaller.mp4 c:a libmp3lame -b:a 128k -f mp4 /dev/null & \ To accomplish this use the following FFmpeg 2 pass command: ffmpeg -y -i TearsOfSteel_720p_h265.mkv \ The formula to calculate the output bitrate for the desired 50mb would then be: (50 MiB * 8192 ) / 734 seconds = ~558 kBit/s total bitrateĥ58 - 128 kBit/s (desired audio bitrate) = 430 kBit/s video bitrate H.264 is widely accepted now and would be an excellent choice for your output video file. The arrows of course are my own! You then perhaps have 2 really good choices: Inform="General Duration=%Duration/String3%\nFile size=%FileSize/String1%" \ MediaInfo reveals the following for this downloaded file: mediainfo \ You can use this sample file to confirm the following results that I have given and perhaps experiment a little further yourself.
I am using the following sample file: wget Going from 100mb to 10mb is a slightly unrealistic 90% drop in size but I will give an example of reducing to 50mb creating an H.264 video, which is a more reasonable 50% reduction in size as well as reducing to 40mb using HEVC.
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