command: allow changing filters before video chain initialization

Apparently this is more intuitive.

Somewhat tricky, because of the odd state after loading a file but
before initializing the VO.

3 files changed, 22 insertions, 6 deletions

diff --git a/DOCS/man/en/input.rst b/DOCS/man/en/input.rst
index 6fe4c90759..a1e4ee45e3 100644
--- a/DOCS/man/en/input.rst
+++ b/DOCS/man/en/input.rst
@@ -332,6 +332,12 @@ Input Commands that are Possibly Subject to Change
     ``show_text ${vf}``. Note that auto-inserted filters for format conversion
     are not shown on the list, only what was requested by the user.
 
+    Normally, the commands will check whether the video chain is recreated
+    successfully, and will undo the operation on failure. If the command is run
+    before video is configured (can happen if the command is run immediately
+    after opening a file and before a video frame is decoded), this check can't
+    be run. Then it can happen that creating the video chain fails.
+
     .. admonition:: Example for input.conf
 
         - ``a vf set flip`` turn video upside-down on the ``a`` key
diff --git a/player/audio.c b/player/audio.c
index 65c4ad74dd..12d03689eb 100644
--- a/player/audio.c
+++ b/player/audio.c
@@ -88,7 +88,7 @@ int reinit_audio_filters(struct MPContext *mpctx)
 {
     struct dec_audio *d_audio = mpctx->d_audio;
     if (!d_audio)
-        return -2;
+        return 0;
 
     af_uninit(mpctx->d_audio->afilter);
     if (af_init(mpctx->d_audio->afilter) < 0)
@@ -96,7 +96,7 @@ int reinit_audio_filters(struct MPContext *mpctx)
     if (recreate_audio_filters(mpctx) < 0)
         return -1;
 
-    return 0;
+    return 1;
 }
 
 void reinit_audio_chain(struct MPContext *mpctx)
diff --git a/player/video.c b/player/video.c
index 39a5b55a2a..8119c40c98 100644
--- a/player/video.c
+++ b/player/video.c
@@ -140,13 +140,19 @@ int reinit_video_filters(struct MPContext *mpctx)
 {
     struct dec_video *d_video = mpctx->d_video;
 
-    if (!d_video || !d_video->decoder_output.imgfmt)
-        return -2;
+    if (!d_video)
+        return 0;
+    bool need_reconfig = d_video->vfilter->initialized != 0;
 
     recreate_video_filters(mpctx);
-    reconfig_video(mpctx, &d_video->decoder_output, true);
 
-    return d_video->vfilter && d_video->vfilter->initialized > 0 ? 0 : -1;
+    if (need_reconfig)
+        reconfig_video(mpctx, &d_video->decoder_output, true);
+
+    if (!d_video->vfilter)
+        return 0;
+
+    return d_video->vfilter->initialized;
 }
 
 int reinit_video_chain(struct MPContext *mpctx)
@@ -246,6 +252,10 @@ no_video:
 void mp_force_video_refresh(struct MPContext *mpctx)
 {
     struct MPOpts *opts = mpctx->opts;
+    struct dec_video *d_video = mpctx->d_video;
+
+    if (!d_video || !d_video->decoder_output.imgfmt)
+        return;
 
     // If not paused, the next frame should come soon enough.
     if (opts->pause && mpctx->last_vo_pts != MP_NOPTS_VALUE)