lavc/vaapi_av1: Avoid sending the same slice buffer multiple times

When there are multiple tiles in one slice buffer, use multiple slice
params to avoid sending the same slice buffer multiple times and thus
increasing the bitstream size the driver will need to upload to hw.

libavcodec/vaapi_av1.c

@@ -19,6 +19,7 @@
  */
 
 #include "libavutil/frame.h"
+#include "libavutil/mem.h"
 #include "hwaccel_internal.h"
 #include "vaapi_decode.h"
 #include "internal.h"
@@ -393,13 +394,17 @@ static int vaapi_av1_decode_slice(AVCodecContext *avctx,
 {
     const AV1DecContext *s = avctx->priv_data;
     VAAPIDecodePicture *pic = s->cur_frame.hwaccel_picture_private;
-    VASliceParameterBufferAV1 slice_param;
-    int err = 0;
+    VASliceParameterBufferAV1 *slice_params;
+    int err = 0, nb_params = 0;
 
-    for (int i = s->tg_start; i <= s->tg_end; i++) {
-        memset(&slice_param, 0, sizeof(VASliceParameterBufferAV1));
+    slice_params = av_calloc(s->tg_end - s->tg_start + 1, sizeof(*slice_params));
+    if (!slice_params) {
+        err = AVERROR(ENOMEM);
+        goto fail;
+    }
 
-        slice_param = (VASliceParameterBufferAV1) {
+    for (int i = s->tg_start; i <= s->tg_end; i++) {
+        slice_params[nb_params++] = (VASliceParameterBufferAV1) {
             .slice_data_size   = s->tile_group_info[i].tile_size,
             .slice_data_offset = s->tile_group_info[i].tile_offset,
             .slice_data_flag   = VA_SLICE_DATA_FLAG_ALL,
@@ -408,18 +413,22 @@ static int vaapi_av1_decode_slice(AVCodecContext *avctx,
             .tg_start          = s->tg_start,
             .tg_end            = s->tg_end,
         };
-
-        err = ff_vaapi_decode_make_slice_buffer(avctx, pic, &slice_param, 1,
-                                                sizeof(VASliceParameterBufferAV1),
-                                                buffer,
-                                                size);
-        if (err) {
-            ff_vaapi_decode_cancel(avctx, pic);
-            return err;
-        }
     }
 
+    err = ff_vaapi_decode_make_slice_buffer(avctx, pic, slice_params, nb_params,
+                                            sizeof(VASliceParameterBufferAV1),
+                                            buffer,
+                                            size);
+    av_free(slice_params);
+
+    if (err)
+        goto fail;
+
     return 0;
+
+fail:
+    ff_vaapi_decode_cancel(avctx, pic);
+    return err;
 }
 
 const FFHWAccel ff_av1_vaapi_hwaccel = {