[FFmpeg-devel] [PATCH] lavu/tx: stop using av_log(NULL, )

[Lynne]

Its not feasible to add an AVClass in the main context, as
it would waste space, as the main context is recursive, and
every bit of assembly would need to be changed.

While its true that on paper av_log has access to the main
context, that functionality is not used as no options are
available for setting. No options will be exposed either,
and it makes no sense.

mpv has recently started warning if a NULL AVClass is used
as an FFmpeg bug. While I don't fully agree nor disagree with
this, this is a simple patch which fixes the issue.
---
 libavutil/tx.c | 16 +++++++++++-----
 1 file changed, 11 insertions(+), 5 deletions(-)

diff --git a/libavutil/tx.c b/libavutil/tx.c
index 0aae4c7cf7..136d10c374 100644
--- a/libavutil/tx.c
+++ b/libavutil/tx.c
@@ -30,6 +30,12 @@
      ((x) == AV_TX_DOUBLE_ ## type) || \
      ((x) == AV_TX_INT32_ ## type))
 
+static const AVClass tx_class = {
+    .class_name                = "tx",
+    .item_name                 = av_default_item_name,
+    .version                   = LIBAVUTIL_VERSION_INT,
+};
+
 /* Calculates the modular multiplicative inverse */
 static av_always_inline int mulinv(int n, int m)
 {
@@ -645,7 +651,7 @@ static void print_cd_info(const FFTXCodelet *cd, int prio, int len, int print_pr
     if (print_prio)
         av_bprintf(&bp, ", prio: %i", prio);
 
-    av_log(NULL, log_level, "%s\n", bp.str);
+    av_log((void *)&tx_class, log_level, "%s\n", bp.str);
 }
 
 static void print_tx_structure(AVTXContext *s, int depth)
@@ -653,7 +659,7 @@ static void print_tx_structure(AVTXContext *s, int depth)
     const FFTXCodelet *cd = s->cd_self;
 
     for (int i = 0; i <= depth; i++)
-        av_log(NULL, AV_LOG_DEBUG, "    ");
+        av_log((void *)&tx_class, AV_LOG_DEBUG, "    ");
 
     print_cd_info(cd, cd->prio, s->len, 0, AV_LOG_DEBUG);
 
@@ -818,10 +824,10 @@ av_cold int ff_tx_init_subtx(AVTXContext *s, enum AVTXType type,
     AV_QSORT(cd_matches, nb_cd_matches, TXCodeletMatch, cmp_matches);
 
 #if !CONFIG_SMALL
-    av_log(NULL, AV_LOG_TRACE, "%s\n", bp.str);
+    av_log((void *)&tx_class, AV_LOG_TRACE, "%s\n", bp.str);
 
     for (int i = 0; i < nb_cd_matches; i++) {
-        av_log(NULL, AV_LOG_TRACE, "    %i: ", i + 1);
+        av_log((void *)&tx_class, AV_LOG_TRACE, "    %i: ", i + 1);
         print_cd_info(cd_matches[i].cd, cd_matches[i].prio, 0, 1, AV_LOG_TRACE);
     }
 #endif
@@ -931,7 +937,7 @@ av_cold int av_tx_init(AVTXContext **ctx, av_tx_fn *tx, enum AVTXType type,
     *tx  = tmp.fn[0];
 
 #if !CONFIG_SMALL
-    av_log(NULL, AV_LOG_DEBUG, "Transform tree:\n");
+    av_log((void *)&tx_class, AV_LOG_DEBUG, "Transform tree:\n");
     print_tx_structure(*ctx, 0);
 #endif
 
-- 
2.45.2.753.g447d99e1c3b