[FFmpeg-devel] [PATCH v5 3/5] lavc/libopenh264enc: add bit rate control select support

[Martin Storsjö]

On Tue, 28 Apr 2020, Linjie Fu wrote:

> RC_BITRATE_MODE:
>    set BITS_EXCEEDED to iCurrentBitsLevel and allows QP adjust
>    in RcCalculatePictureQp().
>
> RC_BUFFERBASED_MODE:
>    use buffer status to adjust the video quality, introduced in
>    release 1.2.
>
> RC_TIMESTAMP_MODE:
>    bit rate control based on timestamp, introduced in release 1.4.
>
> Default to use RC_QUALITY_MODE.
>
> Signed-off-by: Linjie Fu <linjie.fu at intel.com>
> ---
> libavcodec/libopenh264enc.c | 15 +++++++++++++++
> 1 file changed, 15 insertions(+)
>
> diff --git a/libavcodec/libopenh264enc.c b/libavcodec/libopenh264enc.c
> index 0951412..93d3de2 100644
> --- a/libavcodec/libopenh264enc.c
> +++ b/libavcodec/libopenh264enc.c
> @@ -49,6 +49,9 @@ typedef struct SVCContext {
>     int skip_frames;
>     int skipped;
>     int cabac;
> +
> +    // rate control mode
> +    int rc_mode;
> } SVCContext;
> 
> #define OFFSET(x) offsetof(SVCContext, x)
> @@ -73,6 +76,18 @@ static const AVOption options[] = {
>     { "max_nal_size", "set maximum NAL size in bytes", OFFSET(max_nal_size), AV_OPT_TYPE_INT, { .i64 = 0 }, 0, INT_MAX, VE },
>     { "allow_skip_frames", "allow skipping frames to hit the target bitrate", OFFSET(skip_frames), AV_OPT_TYPE_BOOL, { .i64 = 0 }, 0, 1, VE },
>     { "cabac", "Enable cabac", OFFSET(cabac), AV_OPT_TYPE_INT, { .i64 = 0 }, 0, 1, VE },
> +
> +    { "rc_mode", "Select rate control mode", OFFSET(rc_mode), AV_OPT_TYPE_INT, { .i64 = RC_QUALITY_MODE }, RC_OFF_MODE, RC_TIMESTAMP_MODE, VE, "rc_mode" },
> +        { "off",       "bit rate control off",                                                 0, AV_OPT_TYPE_CONST, { .i64 = RC_OFF_MODE },         0, 0, VE, "rc_mode" },
> +        { "quality",   "quality mode",                                                         0, AV_OPT_TYPE_CONST, { .i64 = RC_QUALITY_MODE },     0, 0, VE, "rc_mode" },
> +        { "bitrate",   "bitrate mode",                                                         0, AV_OPT_TYPE_CONST, { .i64 = RC_BITRATE_MODE },     0, 0, VE, "rc_mode" },
> +#if OPENH264_VER_AT_LEAST(1, 2)
> +        { "buffer",    "using buffer status to adjust the video quality (no bitrate control)", 0, AV_OPT_TYPE_CONST, { .i64 = RC_BUFFERBASED_MODE }, 0, 0, VE, "rc_mode" },
> +#endif

We don't need checks for 1.2 - the initial version of openh264 that we 
support is 1.3, so we only need checks for 1.4 and newer.

> +#if OPENH264_VER_AT_LEAST(1, 4)
> +        { "timestamp", "bit rate control based on timestamp",                                  0, AV_OPT_TYPE_CONST, { .i64 = RC_TIMESTAMP_MODE },   0, 0, VE, "rc_mode" },
> +#endif
> +
>     { NULL }
> };

This commit seems to lack something that actually sets the rc_mode value 
in the parameters struct though - wasn't that part of the previous version 
of the patch?

// Martin