lavc: propagate hwaccel errors

At least the new videotoolbox decoder does not actually set a frame if
end_frame fails. This causes the API to return success and signals that
a picture was decoded, even though AVFrame->data[0] is NULL.

Fix this by propagating end_frame errors.

libavcodec/h264.c

@@ -1844,7 +1844,8 @@ static int h264_decode_frame(AVCodecContext *avctx, void *data,
         if (avctx->flags2 & AV_CODEC_FLAG2_CHUNKS)
             decode_postinit(h, 1);
 
-        ff_h264_field_end(h, &h->slice_ctx[0], 0);
+        if ((ret = ff_h264_field_end(h, &h->slice_ctx[0], 0)) < 0)
+            return ret;
 
         /* Wait for second field. */
         *got_frame = 0;

libavcodec/h264_picture.c

@@ -172,7 +172,8 @@ int ff_h264_field_end(H264Context *h, H264SliceContext *sl, int in_setup)
     }
 
     if (avctx->hwaccel) {
-        if (avctx->hwaccel->end_frame(avctx) < 0)
+        err = avctx->hwaccel->end_frame(avctx);
+        if (err < 0)
             av_log(avctx, AV_LOG_ERROR,
                    "hardware accelerator failed to decode picture\n");
     }

libavcodec/h264_slice.c

@@ -1170,15 +1170,19 @@ int ff_h264_decode_slice_header(H264Context *h, H264SliceContext *sl)
         if (h->current_slice) {
             av_assert0(!h->setup_finished);
             if (h->cur_pic_ptr && FIELD_PICTURE(h) && h->first_field) {
-                ff_h264_field_end(h, h->slice_ctx, 1);
+                ret = ff_h264_field_end(h, h->slice_ctx, 1);
                 h->current_slice = 0;
+                if (ret < 0)
+                    return ret;
             } else if (h->cur_pic_ptr && !FIELD_PICTURE(h) && !h->first_field && h->nal_unit_type  == NAL_IDR_SLICE) {
                 av_log(h, AV_LOG_WARNING, "Broken frame packetizing\n");
-                ff_h264_field_end(h, h->slice_ctx, 1);
+                ret = ff_h264_field_end(h, h->slice_ctx, 1);
                 h->current_slice = 0;
                 ff_thread_report_progress(&h->cur_pic_ptr->tf, INT_MAX, 0);
                 ff_thread_report_progress(&h->cur_pic_ptr->tf, INT_MAX, 1);
                 h->cur_pic_ptr = NULL;
+                if (ret < 0)
+                    return ret;
             } else
                 return AVERROR_INVALIDDATA;
         }

libavcodec/hevc.c

@@ -2896,9 +2896,12 @@ static int hevc_decode_frame(AVCodecContext *avctx, void *data, int *got_output,
         return ret;
 
     if (avctx->hwaccel) {
-        if (s->ref && avctx->hwaccel->end_frame(avctx) < 0)
+        if (s->ref && (ret = avctx->hwaccel->end_frame(avctx)) < 0) {
             av_log(avctx, AV_LOG_ERROR,
                    "hardware accelerator failed to decode picture\n");
+            ff_hevc_unref_frame(s, s->ref, ~0);
+            return ret;
+        }
     } else {
         /* verify the SEI checksum */
         if (avctx->err_recognition & AV_EF_CRCCHECK && s->is_decoded &&

libavcodec/mpeg12dec.c

@@ -1723,9 +1723,11 @@ static int mpeg_field_start(MpegEncContext *s, const uint8_t *buf, int buf_size)
 
         if (s->avctx->hwaccel &&
             (s->avctx->slice_flags & SLICE_FLAG_ALLOW_FIELD)) {
-            if (s->avctx->hwaccel->end_frame(s->avctx) < 0)
+            if ((ret = s->avctx->hwaccel->end_frame(s->avctx)) < 0) {
                 av_log(avctx, AV_LOG_ERROR,
                        "hardware accelerator failed to decode first field\n");
+                return ret;
+            }
         }
 
         for (i = 0; i < 4; i++) {
@@ -2082,9 +2084,12 @@ static int slice_end(AVCodecContext *avctx, AVFrame *pict)
         return 0;
 
     if (s->avctx->hwaccel) {
-        if (s->avctx->hwaccel->end_frame(s->avctx) < 0)
+        int ret = s->avctx->hwaccel->end_frame(s->avctx);
+        if (ret < 0) {
             av_log(avctx, AV_LOG_ERROR,
                    "hardware accelerator failed to decode picture\n");
+            return ret;
+        }
     }
 
     /* end of slice reached */