![]() ![]() (This will generate a logfile that ffmpeg needs for the second pass.) In pass 1, output to a null file descriptor, not an actual file.In pass 1 and 2, use the -pass 1 and -pass 2 options, respectively. ![]() There are two different 2-pass encoding methods available in libvpx-vp9: a conventional mode for targeting an average bitrate, and a two-pass constant quality mode that uses the more contemporary CRF-style approach for the final pass to achieve a certain perceptual quality level while still gaining the aforementioned compression benefits by also doing a first pass.įor two-pass, you need to run ffmpeg twice, with almost the same settings, except for: Two-pass is the recommended encoding method for libvpx-vp9 as some quality-enhancing encoder features are only available in 2-pass mode. Note that you shouldn't leave out the -b:v option as the default settings will produce mediocre quality output. Instead, use Two-Pass or Constant Quality encoding.įfmpeg -i input.mp4 -c:v libvpx-vp9 -b:v 2M output.webmĬhoose a higher bit rate if you want better quality. It is not usually recommended to use this mode, as the output may not be compression-efficient, or lead to quality variations. In this mode, it will simply try to reach the specified bit rate on average, e.g. This is also sometimes called "Average Bitrate" or "Target Bitrate". Libvpx-vp9 offers a simple variable bitrate (VBR) mode by default. Variable Bitrate (VBR) Average Bitrate (ABR) VP9 offers different rate control modes, which determine the quality and file size: Note that the default audio encoder for WebM is libopus, but if it is not available libvorbis will be used instead. ![]() Note that for 10-bit encoding, you need to set the -enable-vp9-highbitdepth configuration option. To install FFmpeg with support for libvpx-vp9, look at the Compilation Guides and compile FFmpeg with the -enable-libvpx option. libvpx-vp9 can save about 20–50% bitrate compared to libx264 (the default H.264 encoder), while retaining the same visual quality. Libvpx-vp9 is the VP9 video encoder for WebM, an open, royalty-free media file format. ![]()
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