FFMPEG has presets
ultrafast, superfast, veryfast, faster, fast, medium, slow, slower, veryslow, placebo. I downloaded the source code. Did a
grep -r "veryfast" .. Found
./libavcodec/qsvenc.h and in
./libavcodec/qsvenc.c, I found
if (avctx->compression_level > MFX_TARGETUSAGE_BEST_SPEED). So is that it? Is it only used to decide the compression level?
Reason for asking: I wanted to use
bufsize to limit the bitrate, but wondered if it could be used while using
preset, or whether it’d override anything, if
preset used any settings that influenced the bitrate. I haven’t (yet) seen examples where constrained encoding (VBV / maximum bit rate) uses
preset. Wonder why.
In any case, it would be nice to know what
preset uses under-the-hood. I see some settings here, but it’s unclear.
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