avcodec/error_resilience: Make applying decode_error_flags optional

Add a pointer parameter that if supplied will be used to return
the updated decode_error_flags. This will allow to fix several
races when using frame-threading; these resulted from AVFrame
that the earlier code updated concurrently being used as source
in an av_frame_ref() call in the decoder's update_thread_context.

Signed-off-by: Andreas Rheinhardt <andreas.rheinhardt@outlook.com>

libavcodec/error_resilience.c

@@ -889,7 +889,7 @@ void ff_er_add_slice(ERContext *s, int startx, int starty,
     }
 }
 
-void ff_er_frame_end(ERContext *s)
+void ff_er_frame_end(ERContext *s, int *decode_error_flags)
 {
     int *linesize = NULL;
     int i, mb_x, mb_y, error, error_type, dc_error, mv_error, ac_error;
@@ -1114,6 +1114,9 @@ void ff_er_frame_end(ERContext *s)
     av_log(s->avctx, AV_LOG_INFO, "concealing %d DC, %d AC, %d MV errors in %c frame\n",
            dc_error, ac_error, mv_error, av_get_picture_type_char(s->cur_pic.f->pict_type));
 
+    if (decode_error_flags)
+        *decode_error_flags |= FF_DECODE_ERROR_CONCEALMENT_ACTIVE;
+    else
         s->cur_pic.f->decode_error_flags |= FF_DECODE_ERROR_CONCEALMENT_ACTIVE;
 
     is_intra_likely = is_intra_more_likely(s);

libavcodec/error_resilience.h

@@ -90,7 +90,17 @@ typedef struct ERContext {
 } ERContext;
 
 void ff_er_frame_start(ERContext *s);
-void ff_er_frame_end(ERContext *s);
+
+/**
+ * Indicate that a frame has finished decoding and perform error concealment
+ * in case it has been enabled and is necessary and supported.
+ *
+ * @param s                  ERContext in use
+ * @param decode_error_flags pointer where updated decode_error_flags are written
+ *                           if supplied; if not, the new flags are directly
+ *                           applied to the AVFrame whose errors are concealed
+ */
+void ff_er_frame_end(ERContext *s, int *decode_error_flags);
 void ff_er_add_slice(ERContext *s, int startx, int starty, int endx, int endy,
                      int status);
 

libavcodec/h263dec.c

@@ -622,7 +622,7 @@ retry:
     av_assert1(s->bitstream_buffer_size == 0);
 frame_end:
     if (!s->studio_profile)
-        ff_er_frame_end(&s->er);
+        ff_er_frame_end(&s->er, NULL);
 
     if (avctx->hwaccel) {
         ret = FF_HW_SIMPLE_CALL(avctx, end_frame);

libavcodec/h264dec.c

@@ -779,7 +779,7 @@ end:
         if (sl->ref_count[1])
             ff_h264_set_erpic(&h->er.next_pic, sl->ref_list[1][0].parent);
 
-        ff_er_frame_end(&h->er);
+        ff_er_frame_end(&h->er, NULL);
         if (use_last_pic)
             memset(&sl->ref_list[0][0], 0, sizeof(sl->ref_list[0][0]));
     }

libavcodec/mpeg12dec.c

@@ -2033,7 +2033,7 @@ static int slice_end(AVCodecContext *avctx, AVFrame *pict)
     if (/* s->mb_y << field_pic == s->mb_height && */ !s->first_field && !s1->first_slice) {
         /* end of image */
 
-        ff_er_frame_end(&s->er);
+        ff_er_frame_end(&s->er, NULL);
 
         ff_mpv_frame_end(s);
 

libavcodec/mss2.c

@@ -422,7 +422,7 @@ static int decode_wmv9(AVCodecContext *avctx, const uint8_t *buf, int buf_size,
     ff_vc1_decode_blocks(v);
 
     if (v->end_mb_x == s->mb_width && s->end_mb_y == s->mb_height) {
-        ff_er_frame_end(&s->er);
+        ff_er_frame_end(&s->er, NULL);
     } else {
         av_log(v->s.avctx, AV_LOG_WARNING,
                "disabling error correction due to block count mismatch %dx%d != %dx%d\n",

libavcodec/rv10.c

@@ -477,7 +477,7 @@ static int rv10_decode_packet(AVCodecContext *avctx, const uint8_t *buf,
     if ((s->mb_x == 0 && s->mb_y == 0) || !s->current_picture_ptr) {
         // FIXME write parser so we always have complete frames?
         if (s->current_picture_ptr) {
-            ff_er_frame_end(&s->er);
+            ff_er_frame_end(&s->er, NULL);
             ff_mpv_frame_end(s);
             s->mb_x = s->mb_y = s->resync_mb_x = s->resync_mb_y = 0;
         }
@@ -649,7 +649,7 @@ static int rv10_decode_frame(AVCodecContext *avctx, AVFrame *pict,
     }
 
     if (s->current_picture_ptr && s->mb_y >= s->mb_height) {
-        ff_er_frame_end(&s->er);
+        ff_er_frame_end(&s->er, NULL);
         ff_mpv_frame_end(s);
 
         if (s->pict_type == AV_PICTURE_TYPE_B || s->low_delay) {

libavcodec/rv34.c

@@ -1560,7 +1560,7 @@ static int finish_frame(AVCodecContext *avctx, AVFrame *pict)
     MpegEncContext *s = &r->s;
     int got_picture = 0, ret;
 
-    ff_er_frame_end(&s->er);
+    ff_er_frame_end(&s->er, NULL);
     ff_mpv_frame_end(s);
     s->mb_num_left = 0;
 
@@ -1655,7 +1655,7 @@ int ff_rv34_decode_frame(AVCodecContext *avctx, AVFrame *pict,
             av_log(avctx, AV_LOG_ERROR, "New frame but still %d MB left.\n",
                    s->mb_num_left);
             if (!s->context_reinit)
-                ff_er_frame_end(&s->er);
+                ff_er_frame_end(&s->er, NULL);
             ff_mpv_frame_end(s);
         }
 
@@ -1790,7 +1790,7 @@ int ff_rv34_decode_frame(AVCodecContext *avctx, AVFrame *pict,
             av_log(avctx, AV_LOG_INFO, "marking unfished frame as finished\n");
             /* always mark the current frame as finished, frame-mt supports
              * only complete frames */
-            ff_er_frame_end(&s->er);
+            ff_er_frame_end(&s->er, NULL);
             ff_mpv_frame_end(s);
             s->mb_num_left = 0;
             ff_thread_report_progress(&s->current_picture_ptr->tf, INT_MAX, 0);

libavcodec/vc1dec.c

@@ -1348,7 +1348,7 @@ static int vc1_decode_frame(AVCodecContext *avctx, AVFrame *pict,
         if (   !v->field_mode
             && avctx->codec_id != AV_CODEC_ID_WMV3IMAGE
             && avctx->codec_id != AV_CODEC_ID_VC1IMAGE)
-            ff_er_frame_end(&s->er);
+            ff_er_frame_end(&s->er, NULL);
     }
 
     ff_mpv_frame_end(s);