Implement av_get_codec_tag_string() and use it in ffprobe.

Originally committed as revision 23421 to svn://svn.ffmpeg.org/ffmpeg/trunk

ffprobe.c

@@ -120,7 +120,6 @@ static void show_stream(AVFormatContext *fmt_ctx, int stream_idx)
     AVCodec *dec;
     char val_str[128];
     AVMetadataTag *tag = NULL;
-    char a, b, c, d;
     AVRational display_aspect_ratio;
 
     printf("[STREAM]\n");
@@ -139,16 +138,9 @@ static void show_stream(AVFormatContext *fmt_ctx, int stream_idx)
         printf("codec_time_base=%d/%d\n", dec_ctx->time_base.num, dec_ctx->time_base.den);
 
         /* print AVI/FourCC tag */
-        a = dec_ctx->codec_tag     & 0xff;
-        b = dec_ctx->codec_tag>>8  & 0xff;
-        c = dec_ctx->codec_tag>>16 & 0xff;
-        d = dec_ctx->codec_tag>>24 & 0xff;
-        printf("codec_tag_string=");
-        if (isprint(a)) printf("%c", a); else printf("[%d]", a);
-        if (isprint(b)) printf("%c", b); else printf("[%d]", b);
-        if (isprint(c)) printf("%c", c); else printf("[%d]", c);
-        if (isprint(d)) printf("%c", d); else printf("[%d]", d);
-        printf("\ncodec_tag=0x%04x\n", dec_ctx->codec_tag);
+        av_get_codec_tag_string(val_str, sizeof(val_str), dec_ctx->codec_tag);
+        printf("codec_tag_string=%s\n", val_str);
+        printf("codec_tag=0x%04x\n", dec_ctx->codec_tag);
 
         switch (dec_ctx->codec_type) {
         case AVMEDIA_TYPE_VIDEO:

libavcodec/avcodec.h

@@ -30,8 +30,8 @@
 #include "libavutil/avutil.h"
 
 #define LIBAVCODEC_VERSION_MAJOR 52
-#define LIBAVCODEC_VERSION_MINOR 72
-#define LIBAVCODEC_VERSION_MICRO  1
+#define LIBAVCODEC_VERSION_MINOR 73
+#define LIBAVCODEC_VERSION_MICRO  0
 
 #define LIBAVCODEC_VERSION_INT  AV_VERSION_INT(LIBAVCODEC_VERSION_MAJOR, \
                                                LIBAVCODEC_VERSION_MINOR, \
@@ -3093,6 +3093,15 @@ attribute_deprecated enum PixelFormat avcodec_get_pix_fmt(const char* name);
  */
 unsigned int avcodec_pix_fmt_to_codec_tag(enum PixelFormat pix_fmt);
 
+/**
+ * Puts a string representing the codec tag codec_tag in buf.
+ *
+ * @param buf_size size in bytes of buf
+ * @return the length of the string that would have been generated if
+ * enough space had been available, excluding the trailing null
+ */
+size_t av_get_codec_tag_string(char *buf, size_t buf_size, unsigned int codec_tag);
+
 #define FF_LOSS_RESOLUTION  0x0001 /**< loss due to resolution change */
 #define FF_LOSS_DEPTH       0x0002 /**< loss due to color depth change */
 #define FF_LOSS_COLORSPACE  0x0004 /**< loss due to color space conversion */

libavcodec/utils.c

@@ -802,6 +802,21 @@ static int get_bit_rate(AVCodecContext *ctx)
     return bit_rate;
 }
 
+size_t av_get_codec_tag_string(char *buf, size_t buf_size, unsigned int codec_tag)
+{
+    int i, len, ret = 0;
+
+    for (i = 0; i < 4; i++) {
+        len = snprintf(buf, buf_size,
+                       isprint(codec_tag&0xFF) ? "%c" : "[%d]", codec_tag&0xFF);
+        buf      += len;
+        buf_size  = buf_size > len ? buf_size - len : 0;
+        ret      += len;
+        codec_tag>>=8;
+    }
+    return ret;
+}
+
 void avcodec_string(char *buf, int buf_size, AVCodecContext *enc, int encode)
 {
     const char *codec_name;