@@ -21,6 +21,7 @@

 #include "libavutil/eval.h"

 #include "libavutil/pixdesc.h"

+#include "libavutil/parseutils.h"

 #include "libavutil/audioconvert.h"

 #include "avfilter.h"

 #include "internal.h"

@@ -493,6 +494,17 @@ int ff_parse_sample_format(int *ret, const char *arg, void *log_ctx)

     return 0;

 }

+int ff_parse_time_base(AVRational *ret, const char *arg, void *log_ctx)

+{

+    AVRational r;

+    if(av_parse_ratio(&r, arg, INT_MAX, 0, log_ctx) < 0 ||r.num<=0  ||r.den<=0) {

+        av_log(log_ctx, AV_LOG_ERROR, "Invalid time base '%s'\n", arg);

+        return AVERROR(EINVAL);

+    }

+    *ret = r;

+    return 0;

+}

+

 int ff_parse_sample_rate(int *ret, const char *arg, void *log_ctx)

 {

     char *tail;

@@ -112,6 +112,16 @@ int ff_parse_pixel_format(enum PixelFormat *ret, const char *arg, void *log_ctx)

 int ff_parse_sample_rate(int *ret, const char *arg, void *log_ctx);

 /**

+ * Parse a time base.

+ *

+ * @param ret unsigned AVRational pointer to where the value should be written

+ * @param arg string to parse

+ * @param log_ctx log context

+ * @return 0 in case of success, a negative AVERROR code on error

+ */

+int ff_parse_time_base(AVRational *ret, const char *arg, void *log_ctx);

+

+/**

  * Parse a sample format name or a corresponding integer representation.

  *

  * @param ret integer pointer to where the value should be written