@@ -590,6 +590,10 @@ static int vaapi_encode_step(AVCodecContext *avctx,

     } else if (ctx->issue_mode == ISSUE_MODE_MAXIMISE_THROUGHPUT) {

         int activity;

+        // Run through the list of all available pictures repeatedly

+        // and issue the first one found which has all dependencies

+        // available (including previously-issued but not necessarily

+        // completed pictures).

         do {

             activity = 0;

             for (pic = ctx->pic_start; pic; pic = pic->next) {

@@ -605,9 +609,15 @@ static int vaapi_encode_step(AVCodecContext *avctx,

                 if (err < 0)

                     return err;

                 activity = 1;

+                // Start again from the beginning of the list,

+                // because issuing this picture may have satisfied

+                // forward dependencies of earlier ones.

+                break;

             }

         } while(activity);

+        // If we had a defined target for this step then it will

+        // always have been issued by now.

         if (target) {

             av_assert0(target->encode_issued && "broken dependencies?");

         }

@@ -639,8 +649,10 @@ static int vaapi_encode_get_next(AVCodecContext *avctx,

     if (!pic)

         return AVERROR(ENOMEM);

-    if (ctx->input_order == 0 || ctx->gop_counter >= avctx->gop_size) {

+    if (ctx->input_order == 0 || ctx->force_idr ||

+        ctx->gop_counter >= avctx->gop_size) {

         pic->type = PICTURE_TYPE_IDR;

+        ctx->force_idr = 0;

         ctx->gop_counter = 1;

         ctx->p_counter = 0;

     } else if (ctx->p_counter >= ctx->p_per_i) {

@@ -722,7 +734,7 @@ fail:

     return AVERROR(ENOMEM);

 }

-static int vaapi_encode_mangle_end(AVCodecContext *avctx)

+static int vaapi_encode_truncate_gop(AVCodecContext *avctx)

 {

     VAAPIEncodeContext *ctx = avctx->priv_data;

     VAAPIEncodePicture *pic, *last_pic, *next;

@@ -772,7 +784,7 @@ static int vaapi_encode_mangle_end(AVCodecContext *avctx)

         // mangle anything.

     }

-    av_log(avctx, AV_LOG_DEBUG, "Pictures at end of stream:");

+    av_log(avctx, AV_LOG_DEBUG, "Pictures ending truncated GOP:");

     for (pic = ctx->pic_start; pic; pic = pic->next) {

         av_log(avctx, AV_LOG_DEBUG, " %s (%"PRId64"/%"PRId64")",

                picture_type_name[pic->type],

@@ -826,6 +838,13 @@ int ff_vaapi_encode2(AVCodecContext *avctx, AVPacket *pkt,

         av_log(avctx, AV_LOG_DEBUG, "Encode frame: %ux%u (%"PRId64").\n",

                input_image->width, input_image->height, input_image->pts);

+        if (input_image->pict_type == AV_PICTURE_TYPE_I) {

+            err = vaapi_encode_truncate_gop(avctx);

+            if (err < 0)

+                goto fail;

+            ctx->force_idr = 1;

+        }

+

         err = vaapi_encode_get_next(avctx, &pic);

         if (err) {

             av_log(avctx, AV_LOG_ERROR, "Input setup failed: %d.\n", err);

@@ -854,7 +873,7 @@ int ff_vaapi_encode2(AVCodecContext *avctx, AVPacket *pkt,

     } else {

         if (!ctx->end_of_stream) {

-            err = vaapi_encode_mangle_end(avctx);

+            err = vaapi_encode_truncate_gop(avctx);

             if (err < 0)

                 goto fail;

             ctx->end_of_stream = 1;

@@ -192,6 +192,7 @@ typedef struct VAAPIEncodeContext {

     // Frame type decision.

     int p_per_i;

     int b_per_p;

+    int force_idr;

     int gop_counter;

     int p_counter;

     int end_of_stream;