g726: Do not crash on user mistake

Properly report the sample rate as invalid

CC: libav-stable@libav.org

libavcodec/g726.c

@@ -23,7 +23,6 @@
  */
 #include <limits.h>
 
-#include "libavutil/avassert.h"
 #include "libavutil/channel_layout.h"
 #include "libavutil/opt.h"
 #include "avcodec.h"
@@ -315,7 +314,11 @@ static av_cold int g726_encode_init(AVCodecContext *avctx)
                "Resample or reduce the compliance level.\n");
         return AVERROR(EINVAL);
     }
-    av_assert0(avctx->sample_rate > 0);
+    if (avctx->sample_rate <= 0) {
+        av_log(avctx, AV_LOG_ERROR, "Invalid sample rate %d\n",
+               avctx->sample_rate);
+        return AVERROR(EINVAL);
+    }
 
     if(avctx->channels != 1){
         av_log(avctx, AV_LOG_ERROR, "Only mono is supported\n");