[FFmpeg-devel] [PATCH] Add enable_keyframe_filtering option for libaom-av1 encoder.

[Mark Thompson]

On 26/10/2020 22:04, Bohan Li wrote:
> Add the option to use -enable-keyframe-filtering with libaom-av1
> codec.  The option controls the encoder behavior on performing
> temporal filtering on keyframes.
> 
> Signed-off-by: Bohan Li <bohanli at google.com>
> ---
>   doc/encoders.texi      | 13 +++++++++++++
>   libavcodec/libaomenc.c |  5 +++++
>   2 files changed, 18 insertions(+)
> 
> diff --git a/doc/encoders.texi b/doc/encoders.texi
> index 0b1c69e982..8914546694 100644
> --- a/doc/encoders.texi
> +++ b/doc/encoders.texi
> @@ -1685,6 +1685,19 @@ Enable interintra compound. Default is true.
>   @item enable-smooth-interintra (@emph{boolean}) (Requires libaom >= v2.0.0)
>   Enable smooth interintra mode. Default is true.
>   
> + at item enable-keyframe-filtering (Requires libaom >= v2.0.0)
> +Filtering type for key frames. Possible values:
> + at table @samp
> + at item @emph{-1}
> +Use the default in libaom (default).
> + at item @emph{0}
> +Do not filter key frames.
> + at item @emph{1}
> +Filter key frames but do not apply overlays.
> + at item @emph{2}
> +Filter key frames and apply overlays to them (experimental).
> + at end table

This documentation does not seem helpful.  Suppose I am a normal end-user; what effect does this option have on the output and under what circumstances would I set it?  If never, why is the option in the user manual?

(I would like to ask the same question of some of the options above this one as well.)

> +
>   @end table
>   
>   @section libsvtav1
> diff --git a/libavcodec/libaomenc.c b/libavcodec/libaomenc.c
> index 2b0581b15a..77c25770a4 100644
> --- a/libavcodec/libaomenc.c
> +++ b/libavcodec/libaomenc.c
> @@ -124,6 +124,7 @@ typedef struct AOMEncoderContext {
>       int enable_diff_wtd_comp;
>       int enable_dist_wtd_comp;
>       int enable_dual_filter;
> +    int enable_keyframe_filtering;
>   } AOMContext;
>   
>   static const char *const ctlidstr[] = {
> @@ -192,6 +193,7 @@ static const char *const ctlidstr[] = {
>       [AV1E_SET_REDUCED_REFERENCE_SET]    = "AV1E_SET_REDUCED_REFERENCE_SET",
>       [AV1E_SET_ENABLE_SMOOTH_INTERINTRA] = "AV1E_SET_ENABLE_SMOOTH_INTERINTRA",
>       [AV1E_SET_ENABLE_REF_FRAME_MVS]     = "AV1E_SET_ENABLE_REF_FRAME_MVS",
> +    [AV1E_SET_ENABLE_KEYFRAME_FILTERING] = "AV1E_SET_ENABLE_KEYFRAME_FILTERING"
>   #endif
>   };
>   
> @@ -812,6 +814,8 @@ static av_cold int aom_init(AVCodecContext *avctx,
>           codecctl_int(avctx, AV1E_SET_ENABLE_ONESIDED_COMP, ctx->enable_onesided_comp);
>       if (ctx->enable_smooth_interintra >= 0)
>           codecctl_int(avctx, AV1E_SET_ENABLE_SMOOTH_INTERINTRA, ctx->enable_smooth_interintra);
> +    if (ctx->enable_keyframe_filtering >= 0)
> +        codecctl_int(avctx, AV1E_SET_ENABLE_KEYFRAME_FILTERING, ctx->enable_keyframe_filtering);
>   #endif
>   
>       codecctl_int(avctx, AOME_SET_STATIC_THRESHOLD, ctx->static_thresh);
> @@ -1261,6 +1265,7 @@ static const AVOption options[] = {
>       { "enable-masked-comp",           "Enable masked compound",                            OFFSET(enable_masked_comp),           AV_OPT_TYPE_BOOL, {.i64 = -1}, -1, 1, VE},
>       { "enable-interintra-comp",       "Enable interintra compound",                        OFFSET(enable_interintra_comp),       AV_OPT_TYPE_BOOL, {.i64 = -1}, -1, 1, VE},
>       { "enable-smooth-interintra",     "Enable smooth interintra mode",                     OFFSET(enable_smooth_interintra),     AV_OPT_TYPE_BOOL, {.i64 = -1}, -1, 1, VE},
> +    { "enable-keyframe-filtering",    "Keyframe filtering type",                           OFFSET(enable_keyframe_filtering),    AV_OPT_TYPE_INT,  {.i64 = -1}, -1, 3, VE},
>       { NULL },
>   };
>   
> 

- Mark