lavu: introduce av_parse_ratio() and use it in ffmpeg and lavfi/aspect

Factorize code and provide ratio parsing consistency.

doc/APIchanges

@@ -13,6 +13,12 @@ libavutil:   2011-04-18
 
 API changes, most recent first:
 
+2012-02-06 - xxxxxxx - lavu 51.38.100
+  Add av_parse_ratio() function to parseutils.h.
+
+2012-02-06 - xxxxxxx - lavu 51.38.100
+  Add AV_LOG_MAX_OFFSET macro to log.h.
+
 2012-02-02 - xxxxxxx - lavu 51.37.100
   Add public timecode helpers.
 

ffmpeg.c

@@ -3141,30 +3141,6 @@ static int opt_pad(const char *opt, const char *arg)
     return -1;
 }
 
-static double parse_frame_aspect_ratio(const char *arg)
-{
-    int x = 0, y = 0;
-    double ar = 0;
-    const char *p;
-    char *end;
-
-    p = strchr(arg, ':');
-    if (p) {
-        x = strtol(arg, &end, 10);
-        if (end == p)
-            y = strtol(end + 1, &end, 10);
-        if (x > 0 && y > 0)
-            ar = (double)x / (double)y;
-    } else
-        ar = strtod(arg, NULL);
-
-    if (!ar) {
-        av_log(NULL, AV_LOG_FATAL, "Incorrect aspect ratio specification.\n");
-        exit_program(1);
-    }
-    return ar;
-}
-
 static int opt_video_channel(const char *opt, const char *arg)
 {
     av_log(NULL, AV_LOG_WARNING, "This option is deprecated, use -channel.\n");
@@ -3986,8 +3962,15 @@ static OutputStream *new_video_stream(OptionsContext *o, AVFormatContext *oc)
         }
 
         MATCH_PER_STREAM_OPT(frame_aspect_ratios, str, frame_aspect_ratio, oc, st);
-        if (frame_aspect_ratio)
-            ost->frame_aspect_ratio = parse_frame_aspect_ratio(frame_aspect_ratio);
+        if (frame_aspect_ratio) {
+            AVRational q;
+            if (av_parse_ratio(&q, frame_aspect_ratio, 255, 0, NULL) < 0 ||
+                q.num <= 0 || q.den <= 0) {
+                av_log(NULL, AV_LOG_FATAL, "Invalid aspect ratio: %s\n", frame_aspect_ratio);
+                exit_program(1);
+            }
+            ost->frame_aspect_ratio = av_q2d(q);
+        }
 
         video_enc->bits_per_raw_sample = frame_bits_per_raw_sample;
         MATCH_PER_STREAM_OPT(frame_pix_fmts, str, frame_pix_fmt, oc, st);

libavfilter/vf_aspect.c

@@ -24,6 +24,7 @@
  */
 
 #include "libavutil/mathematics.h"
+#include "libavutil/parseutils.h"
 #include "avfilter.h"
 
 typedef struct {
@@ -33,32 +34,18 @@ typedef struct {
 static av_cold int init(AVFilterContext *ctx, const char *args, void *opaque)
 {
     AspectContext *aspect = ctx->priv;
-    double  ratio;
-    int64_t gcd;
-    char c = 0;
+    int ret;
 
     if (args) {
-        if (sscanf(args, "%d:%d%c", &aspect->aspect.num, &aspect->aspect.den, &c) != 2)
-            if (sscanf(args, "%lf%c", &ratio, &c) == 1)
-                aspect->aspect = av_d2q(ratio, 100);
-
-        if (c || aspect->aspect.num <= 0 || aspect->aspect.den <= 0) {
+        if ((ret = av_parse_ratio(&aspect->aspect, args, 100, 0, ctx)) < 0 ||
+            aspect->aspect.num < 0 || aspect->aspect.den <= 0) {
             av_log(ctx, AV_LOG_ERROR,
                    "Invalid string '%s' for aspect ratio.\n", args);
-            return AVERROR(EINVAL);
+            return ret;
         }
 
-        gcd = av_gcd(FFABS(aspect->aspect.num), FFABS(aspect->aspect.den));
-        if (gcd) {
-            aspect->aspect.num /= gcd;
-            aspect->aspect.den /= gcd;
-        }
-    }
-
-    if (aspect->aspect.den == 0)
-        aspect->aspect = (AVRational) {0, 1};
-
         av_log(ctx, AV_LOG_INFO, "a:%d/%d\n", aspect->aspect.num, aspect->aspect.den);
+    }
     return 0;
 }
 

libavutil/avutil.h

@@ -154,7 +154,7 @@
  */
 
 #define LIBAVUTIL_VERSION_MAJOR 51
-#define LIBAVUTIL_VERSION_MINOR 37
+#define LIBAVUTIL_VERSION_MINOR 38
 #define LIBAVUTIL_VERSION_MICRO 100
 
 #define LIBAVUTIL_VERSION_INT   AV_VERSION_INT(LIBAVUTIL_VERSION_MAJOR, \

libavutil/log.h

@@ -124,6 +124,8 @@ typedef struct AVClass {
  */
 #define AV_LOG_DEBUG    48
 
+#define AV_LOG_MAX_OFFSET (AV_LOG_DEBUG - AV_LOG_QUIET)
+
 /**
  * Send the specified message to the log if the level is less than or equal
  * to the current av_log_level. By default, all logging messages are sent to

libavutil/parseutils.c

@@ -31,6 +31,32 @@
 #include "random_seed.h"
 #include "parseutils.h"
 
+int av_parse_ratio(AVRational *q, const char *str, int max,
+                   int log_offset, void *log_ctx)
+{
+    char c;
+    int ret;
+    int64_t gcd;
+
+    if (sscanf(str, "%d:%d%c", &q->num, &q->den, &c) != 2) {
+        double d;
+        ret = av_expr_parse_and_eval(&d, str, NULL, NULL,
+                                     NULL, NULL, NULL, NULL,
+                                     NULL, log_offset, log_ctx);
+        if (ret < 0)
+            return ret;
+        *q = av_d2q(d, max);
+    }
+
+    gcd = av_gcd(FFABS(q->num), FFABS(q->den));
+    if (gcd) {
+        q->num /= gcd;
+        q->den /= gcd;
+    }
+
+    return 0;
+}
+
 typedef struct {
     const char *abbr;
     int width, height;
@@ -124,7 +150,6 @@ int av_parse_video_rate(AVRational *rate, const char *arg)
 {
     int i, ret;
     int n = FF_ARRAY_ELEMS(video_rate_abbrs);
-    double res;
 
     /* First, we check our abbreviation table */
     for (i = 0; i < n; ++i)
@@ -134,10 +159,8 @@ int av_parse_video_rate(AVRational *rate, const char *arg)
         }
 
     /* Then, we try to parse it as fraction */
-    if ((ret = av_expr_parse_and_eval(&res, arg, NULL, NULL, NULL, NULL, NULL, NULL,
-                                      NULL, 0, NULL)) < 0)
+    if ((ret = av_parse_ratio_quiet(rate, arg, 1001000)) < 0)
         return ret;
-    *rate = av_d2q(res, 1001000);
     if (rate->num <= 0 || rate->den <= 0)
         return AVERROR(EINVAL);
     return 0;

libavutil/parseutils.h

@@ -28,6 +28,30 @@
  * misc parsing utilities
  */
 
+/**
+ * Parse str and store the parsed ratio in q.
+ *
+ * Note that a ratio with infinite (1/0) or negative value is
+ * considered valid, so you should check on the returned value if you
+ * want to exclude those values.
+ *
+ * The undefined value can be expressed using the "0:0" string.
+ *
+ * @param[in,out] q pointer to the AVRational which will contain the ratio
+ * @param[in] str the string to parse: it has to be a string in the format
+ * num:den, a float number or an expression
+ * @param[in] max the maximum allowed numerator and denominator
+ * @param[in] log_offset log level offset which is applied to the log
+ * level of log_ctx
+ * @param[in] log_ctx parent logging context
+ * @return >= 0 on success, a negative error code otherwise
+ */
+int av_parse_ratio(AVRational *q, const char *str, int max,
+                   int log_offset, void *log_ctx);
+
+#define av_parse_ratio_quiet(rate, str, max) \
+    av_parse_ratio(rate, str, max, AV_LOG_MAX_OFFSET, NULL)
+
 /**
  * Parse str and put in width_ptr and height_ptr the detected values.
  *