avcodec/h263data, ituh263*: Make initializing RL inter table thread-safe

Up until now, ff_h263_rl_inter was initialized by both ituh263dec and
ituh263enc; this is an obstacle in making the codecs that use this code
init-threadsafe.

This obstacle is eliminated by only initializing this RLTable from
a single place that is guarded by a dedicated AVOnce.

Reviewed-by: Anton Khirnov <anton@khirnov.net>
Signed-off-by: Andreas Rheinhardt <andreas.rheinhardt@gmail.com>

1 files changed, 14 insertions, 2 deletions

diff --git a/libavcodec/h263data.c b/libavcodec/h263data.c
index f649d58f4e..604a0425e1 100644
--- a/libavcodec/h263data.c
+++ b/libavcodec/h263data.c
@@ -25,11 +25,11 @@
 
 #include <stdint.h>
 
+#include "libavutil/thread.h"
+
 #include "h263data.h"
 #include "mpegvideo.h"
 
-uint8_t ff_h263_static_rl_table_store[2][2][2 * MAX_RUN + MAX_LEVEL + 3];
-
 /* intra MCBPC, mb_type = (intra), then (intraq) */
 const uint8_t ff_h263_intra_MCBPC_code[9] = { 1, 1, 2, 3, 1, 1, 2, 3, 1 };
 const uint8_t ff_h263_intra_MCBPC_bits[9] = { 1, 3, 3, 3, 4, 6, 6, 6, 9 };
@@ -290,3 +290,15 @@ const AVRational ff_h263_pixel_aspect[16] = {
     {  0,  1 },
     {  0,  1 },
 };
+
+static av_cold void h263_init_rl_inter(void)
+{
+    static uint8_t h263_rl_inter_table[2][2 * MAX_RUN + MAX_LEVEL + 3];
+    ff_rl_init(&ff_h263_rl_inter, h263_rl_inter_table);
+}
+
+av_cold void ff_h263_init_rl_inter(void)
+{
+    static AVOnce init_static_once = AV_ONCE_INIT;
+    ff_thread_once(&init_static_once, h263_init_rl_inter);
+}