avcodec/nellymoserenc: Make encoder init-threadsafe

Signed-off-by: Andreas Rheinhardt <andreas.rheinhardt@gmail.com>

libavcodec/nellymoserenc.c

@@ -38,6 +38,7 @@
 #include "libavutil/common.h"
 #include "libavutil/float_dsp.h"
 #include "libavutil/mathematics.h"
+#include "libavutil/thread.h"
 
 #include "audio_frame_queue.h"
 #include "avcodec.h"
@@ -147,10 +148,29 @@ static av_cold int encode_end(AVCodecContext *avctx)
     return 0;
 }
 
+static av_cold void nellymoser_init_static(void)
+{
+    /* faster way of doing
+    for (int i = 0; i < POW_TABLE_SIZE; i++)
+       pow_table[i] = 2^(-i / 2048.0 - 3.0 + POW_TABLE_OFFSET); */
+    pow_table[0] = 1;
+    pow_table[1024] = M_SQRT1_2;
+    for (int i = 1; i < 513; i++) {
+        double tmp = exp2(-i / 2048.0);
+        pow_table[i] = tmp;
+        pow_table[1024-i] = M_SQRT1_2 / tmp;
+        pow_table[1024+i] = tmp * M_SQRT1_2;
+        pow_table[2048-i] = 0.5 / tmp;
+    }
+    /* Generate overlap window */
+    ff_init_ff_sine_windows(7);
+}
+
 static av_cold int encode_init(AVCodecContext *avctx)
 {
+    static AVOnce init_static_once = AV_ONCE_INIT;
     NellyMoserEncodeContext *s = avctx->priv_data;
-    int i, ret;
+    int ret;
 
     if (avctx->channels != 1) {
         av_log(avctx, AV_LOG_ERROR, "Nellymoser supports only 1 channel\n");
@@ -175,21 +195,6 @@ static av_cold int encode_init(AVCodecContext *avctx)
     if (!s->fdsp)
         return AVERROR(ENOMEM);
 
-    /* Generate overlap window */
-    ff_init_ff_sine_windows(7);
-    /* faster way of doing
-    for (i = 0; i < POW_TABLE_SIZE; i++)
-       pow_table[i] = 2^(-i / 2048.0 - 3.0 + POW_TABLE_OFFSET); */
-    pow_table[0] = 1;
-    pow_table[1024] = M_SQRT1_2;
-    for (i = 1; i < 513; i++) {
-        double tmp = exp2(-i / 2048.0);
-        pow_table[i] = tmp;
-        pow_table[1024-i] = M_SQRT1_2 / tmp;
-        pow_table[1024+i] = tmp * M_SQRT1_2;
-        pow_table[2048-i] = 0.5 / tmp;
-    }
-
     if (s->avctx->trellis) {
         s->opt  = av_malloc(NELLY_BANDS * OPT_SIZE * sizeof(float  ));
         s->path = av_malloc(NELLY_BANDS * OPT_SIZE * sizeof(uint8_t));
@@ -197,6 +202,8 @@ static av_cold int encode_init(AVCodecContext *avctx)
             return AVERROR(ENOMEM);
     }
 
+    ff_thread_once(&init_static_once, nellymoser_init_static);
+
     return 0;
 }
 
@@ -424,5 +431,5 @@ AVCodec ff_nellymoser_encoder = {
     .capabilities   = AV_CODEC_CAP_SMALL_LAST_FRAME | AV_CODEC_CAP_DELAY,
     .sample_fmts    = (const enum AVSampleFormat[]){ AV_SAMPLE_FMT_FLT,
                                                      AV_SAMPLE_FMT_NONE },
-    .caps_internal  = FF_CODEC_CAP_INIT_CLEANUP,
+    .caps_internal  = FF_CODEC_CAP_INIT_THREADSAFE | FF_CODEC_CAP_INIT_CLEANUP,
 };