7月 2021

关于x265的high-tier启用问题

最近研究x265编码时如何启用high profile(后来才了解到对x265来说应该是high tier),之前接触x264的时候了解到的是直接在编码指定profile时就会有main和high的profile之分,如main、high、high10、high422等,但到了x265时却发现可指定的profile只有这么几个:

static const char * const x265_profile_names[] = {
    /* HEVC v1 */
    "main", "main10", "mainstillpicture", /* alias */ "msp",

    /* HEVC v2 (Range Extensions) */
    "main-intra", "main10-intra",
    "main444-8",  "main444-intra", "main444-stillpicture",

    "main422-10", "main422-10-intra",
    "main444-10", "main444-10-intra",

    "main12",     "main12-intra",
    "main422-12", "main422-12-intra",
    "main444-12", "main444-12-intra",

    "main444-16-intra", "main444-16-stillpicture", /* Not Supported! */
    0
};

并没有像x264的各种high,后经研究发现x265的high profile是通过另一个参数:“high-tier”来控制的,于是用ffmpeg命令行作了如下测试:

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