Changes between Version 83 and Version 84 of HWAccelIntro


Ignore:
Timestamp:
Dec 22, 2022, 9:52:02 AM (4 years ago)
Author:
slhck
Comment:

add note on CQ mode for videotoolbox

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  • HWAccelIntro

    v83 v84  
    113113= !VideoToolbox =
    114114
    115 [https://developer.apple.com/documentation/videotoolbox VideoToolbox], only supported on macOS.
    116 
    117 H.263, H.264, HEVC, MPEG1, MPEG2, MPEG4, ProRes decoding is available in FFmpeg/libavcodec.
    118 
    119 H.264, HEVC, ProRes encoding is available in FFmpeg/libavcodec.
    120 
    121 To use H.264/HEVC hardware encoding in macOS, just use the encoder `-c:v h264_videotoolbox` or `-c:v hevc_videotoolbox` for H.264 or HEVC respectively. Check `ffmpeg -h encoder=...` to see encoder options. It's worth noting that !VideoToolbox does not support constant quality (CRF) encoding.  Bit rate, `-b:v ...`, is your main lever to balance size vs quality. 
    122 
     115[https://developer.apple.com/documentation/videotoolbox VideoToolbox] is the macOS framework for video decoding and encoding.
     116
     117The following codecs are supported:
     118
     119* Decoding: H.263, H.264, HEVC, MPEG-1, MPEG-2, MPEG-4 Part 2, ProRes
     120* Encoding: H.264, HEVC, ProRes
     121
     122To use H.264/HEVC hardware encoding in macOS, just use the encoder `-c:v h264_videotoolbox` or `-c:v hevc_videotoolbox` for H.264 or HEVC respectively.
     123
     124Check `ffmpeg -h encoder=...` to see encoder options.
     125
     126VideoToolbox supports two types of rate control:
     127
     128* Bitrate-based using `-b:v`
     129* Constant quality with `-q:v`. Note that the scale is 1-100, with 1 being the lowest and 100 the highest. Constant quality mode is only available for Apple Silicon and from ffmpeg 4.4 and higher.
    123130
    124131= CUDA (NVENC/NVDEC) =