avfilter/formats: Avoid using non public AV_SAMPLE_FMT_NB

Signed-off-by: Michael Niedermayer <michaelni@gmx.at>

libavfilter/formats.c

@@ -376,7 +376,7 @@ AVFilterFormats *ff_planar_sample_fmts(void)
     AVFilterFormats *ret = NULL;
     int fmt;
 
-    for (fmt = 0; fmt < AV_SAMPLE_FMT_NB; fmt++)
+    for (fmt = 0; av_get_bytes_per_sample(fmt)>0; fmt++)
         if (av_sample_fmt_is_planar(fmt))
             ff_add_format(&ret, fmt);
 
@@ -587,7 +587,7 @@ int ff_parse_sample_format(int *ret, const char *arg, void *log_ctx)
     int sfmt = av_get_sample_fmt(arg);
     if (sfmt == AV_SAMPLE_FMT_NONE) {
         sfmt = strtol(arg, &tail, 0);
-        if (*tail || (unsigned)sfmt >= AV_SAMPLE_FMT_NB) {
+        if (*tail || av_get_bytes_per_sample(sfmt)<=0) {
             av_log(log_ctx, AV_LOG_ERROR, "Invalid sample format '%s'\n", arg);
             return AVERROR(EINVAL);
         }