vd_lavc: fix decoder initialization when no VO is available

The VO is available during decoder initialization mostly for direct
rendering purposes, so if f.ex. a complex filter chain is utilized,
there is no video renderer information available via
mp_filter_find_stream_info during creation of the decoder filter.

Thus, check for whether the VO is available before attempting to
check the capabilities flag from it.

Additionally - to simplify logic - makes explicitly requesting GPU
film grain to always disable decoder film grain functionality. The
warning is still shown if the VO is available and no support for
film grain application is available.

Fixes #10079

1 files changed, 20 insertions, 6 deletions

diff --git a/video/decode/vd_lavc.c b/video/decode/vd_lavc.c
index c45d205f10..d6e0a0338c 100644
--- a/video/decode/vd_lavc.c
+++ b/video/decode/vd_lavc.c
@@ -698,13 +698,27 @@ static void init_avctx(struct mp_filter *vd)
     if (lavc_codec->id == AV_CODEC_ID_H264 && lavc_param->old_x264)
         av_opt_set(avctx, "x264_build", "150", AV_OPT_SEARCH_CHILDREN);
 
-    if (ctx->opts->film_grain != 0 /*CPU*/) {
-        if (ctx->vo->driver->caps & VO_CAP_FILM_GRAIN) {
-            avctx->export_side_data |= AV_CODEC_EXPORT_DATA_FILM_GRAIN;
-        } else if (ctx->opts->film_grain == 1 /*GPU*/) {
-            MP_WARN(vd, "GPU film grain requested, but VO does not support "
-                    "applying film grain, disabling.\n");
+    switch(ctx->opts->film_grain) {
+    case 0: /*CPU*/
+        // default lavc flags handle film grain within the decoder.
+        break;
+    case 1: /*GPU*/
+        if (!ctx->vo ||
+            (ctx->vo && !(ctx->vo->driver->caps & VO_CAP_FILM_GRAIN))) {
+            MP_MSG(vd, ctx->vo ? MSGL_WARN : MSGL_V,
+                   "GPU film grain requested, but VO %s, expect wrong output.\n",
+                   ctx->vo ?
+                   "does not support applying film grain" :
+                   "is not available at decoder initialization to verify support");
         }
+
+        avctx->export_side_data |= AV_CODEC_EXPORT_DATA_FILM_GRAIN;
+        break;
+    default:
+        if (ctx->vo && (ctx->vo->driver->caps & VO_CAP_FILM_GRAIN))
+            avctx->export_side_data |= AV_CODEC_EXPORT_DATA_FILM_GRAIN;
+
+        break;
     }
 
     mp_set_avopts(vd->log, avctx, lavc_param->avopts);