mpegvideo: drop an unnecessary function parameter

It is always 0.

libavcodec/mpegvideo.c

@@ -346,9 +346,9 @@ av_cold void ff_mpv_idct_init(MpegEncContext *s)
     ff_init_scantable(s->idsp.idct_permutation, &s->intra_v_scantable, ff_alternate_vertical_scan);
 }
 
-static int alloc_picture(MpegEncContext *s, Picture *pic, int shared)
+static int alloc_picture(MpegEncContext *s, Picture *pic)
 {
-    return ff_alloc_picture(s->avctx, pic, &s->me, &s->sc, shared, 0,
+    return ff_alloc_picture(s->avctx, pic, &s->me, &s->sc, 0, 0,
                             s->chroma_x_shift, s->chroma_y_shift, s->out_format,
                             s->mb_stride, s->mb_width, s->mb_height, s->b8_stride,
                             &s->linesize, &s->uvlinesize);
@@ -1259,7 +1259,7 @@ int ff_mpv_frame_start(MpegEncContext *s, AVCodecContext *avctx)
 
     pic->f->coded_picture_number = s->coded_picture_number++;
 
-    if (alloc_picture(s, pic, 0) < 0)
+    if (alloc_picture(s, pic) < 0)
         return -1;
 
     s->current_picture_ptr = pic;
@@ -1320,7 +1320,7 @@ int ff_mpv_frame_start(MpegEncContext *s, AVCodecContext *avctx)
         s->last_picture_ptr->f->key_frame = 0;
         s->last_picture_ptr->f->pict_type = AV_PICTURE_TYPE_P;
 
-        if (alloc_picture(s, s->last_picture_ptr, 0) < 0) {
+        if (alloc_picture(s, s->last_picture_ptr) < 0) {
             s->last_picture_ptr = NULL;
             return -1;
         }
@@ -1361,7 +1361,7 @@ int ff_mpv_frame_start(MpegEncContext *s, AVCodecContext *avctx)
         s->next_picture_ptr->f->key_frame = 0;
         s->next_picture_ptr->f->pict_type = AV_PICTURE_TYPE_P;
 
-        if (alloc_picture(s, s->next_picture_ptr, 0) < 0) {
+        if (alloc_picture(s, s->next_picture_ptr) < 0) {
             s->next_picture_ptr = NULL;
             return -1;
         }