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ymollard/two_pass_ffmpeg.md

Created May 19, 2017 14:45
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Two pass FFMPEG
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two_pass_ffmpeg.md

Your video is 10 minutes (600 seconds) long and an output of 200 MiB is desired. Since bitrate = file size / duration:

(200 MiB * 8192 [converts MiB to kBit]) / 600 seconds = ~2730 kBit/s total bitrate 2730 - 128 kBit/s (desired audio bitrate) = 2602 kBit/s video bitrate

ffmpeg -y -i input -c:v libx264 -preset medium -b:v 2600k -pass 1 -c:a aac -b:a 128k -f mp4 /dev/null
ffmpeg -i input -c:v libx264 -preset medium -b:v 2600k -pass 2 -c:a aac -b:a 128k output.mp4

From FFMPEG H264 documentation.

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