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

[Bohan Li]

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      | 17 +++++++++++++++++
 libavcodec/libaomenc.c |  5 +++++
 2 files changed, 22 insertions(+)

diff --git a/doc/encoders.texi b/doc/encoders.texi
index 0b1c69e982..c80a520a20 100644
--- a/doc/encoders.texi
+++ b/doc/encoders.texi
@@ -1685,6 +1685,23 @@ 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. Temporal filtering of key frames improves
+compression efficiency, but may introduce key frames that are blurred at times.
+Adding an overlay to filtered frames mitigates the blurring issue, but could
+potentially confuse video players when performing random access.
+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
+
 @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 },
 };
 
-- 
2.29.0.rc2.309.g374f81d7ae-goog