[FFmpeg-devel] [PATCH] avcodec/svt-av1: Set pic_type only when gop_size == 1

[Vignesh Venkatasubramanian]

SVT-AV1 does not support requesting keyframes at arbitrary points
by setting pic_type to EB_AV1_KEY_PICTURE.

This patch changes the following:
 * Set pic_type to EB_AV1_KEY_PICTURE only when gop_size == 1. This
   only has an effect in this case (combined with force_key_frames).
   In all other cases, setting this has no effect.
 * Set force_key_frames to 1 only when gop_size == 1, this is
   needed for pic_type request above to work.

Please see the comments in
https://gitlab.com/AOMediaCodec/SVT-AV1/-/issues/2076 for a bit more
details.

Signed-off-by: Vignesh Venkatasubramanian <vigneshv at google.com>
---
 libavcodec/libsvtav1.c | 22 +++++++---------------
 1 file changed, 7 insertions(+), 15 deletions(-)

diff --git a/libavcodec/libsvtav1.c b/libavcodec/libsvtav1.c
index 5015169244..3247c30f60 100644
--- a/libavcodec/libsvtav1.c
+++ b/libavcodec/libsvtav1.c
@@ -253,8 +253,11 @@ static int config_enc_params(EbSvtAv1EncConfiguration *param,
     // In order for SVT-AV1 to force keyframes by setting pic_type to
     // EB_AV1_KEY_PICTURE on any frame, force_key_frames has to be set. Note
     // that this does not force all frames to be keyframes (it only forces a
-    // keyframe with pic_type is set to EB_AV1_KEY_PICTURE).
-    param->force_key_frames = 1;
+    // keyframe with pic_type is set to EB_AV1_KEY_PICTURE). As of now, SVT-AV1
+    // does not support arbitrary keyframe requests by setting pic_type to
+    // EB_AV1_KEY_PICTURE, so it is done only when gop_size == 1.
+    if (avctx->gop_size == 1)
+        param->force_key_frames = 1;
 
     if (avctx->framerate.num > 0 && avctx->framerate.den > 0) {
         param->frame_rate_numerator   = avctx->framerate.num;
@@ -462,19 +465,8 @@ static int eb_send_frame(AVCodecContext *avctx, const AVFrame *frame)
     headerPtr->flags         = 0;
     headerPtr->p_app_private = NULL;
     headerPtr->pts           = frame->pts;
-
-    switch (frame->pict_type) {
-    case AV_PICTURE_TYPE_I:
-        headerPtr->pic_type = EB_AV1_KEY_PICTURE;
-        break;
-    default:
-        // Actually means auto, or default.
-        headerPtr->pic_type = EB_AV1_INVALID_PICTURE;
-        break;
-    }
-
-    if (avctx->gop_size == 1)
-        headerPtr->pic_type = EB_AV1_KEY_PICTURE;
+    // EB_AV1_INVALID_PICTURE means auto, or default.
+    headerPtr->pic_type = (avctx->gop_size == 1) ? EB_AV1_KEY_PICTURE : EB_AV1_INVALID_PICTURE;
 
     svt_av1_enc_send_picture(svt_enc->svt_handle, headerPtr);
 
-- 
2.42.0.515.g380fc7ccd1-goog