Add support for listing the supported pixel formats using the option

-pix_fmt list
patch by Stefano Sabatini stefano sabatini minus lala chez poste it
original thread: [FFmpeg-devel] [PATCH] List supported pixel formats
date: 05/25/2007 05:46 PM

Originally committed as revision 9162 to svn://svn.ffmpeg.org/ffmpeg/trunk

doc/ffmpeg-doc.texi

@@ -415,7 +415,8 @@ Add a new video stream to the current output stream.
 
 @table @option
 @item -pix_fmt format
-Set pixel format.
+Set pixel format. Use 'list' as parameter to show all the supported
+pixel formats.
 @item -sws_flags flags
 Set SwScaler flags (only available when compiled with SwScaler support).
 @item -g gop_size

ffmpeg.c

@@ -2243,10 +2243,24 @@ static void opt_frame_pad_right(const char *arg)
     }
 }
 
+void list_pix_fmts(void)
+{
+    int i;
+    char pix_fmt_str[128];
+    for (i=-1; i < PIX_FMT_NB; i++) {
+        avcodec_pix_fmt_string (pix_fmt_str, sizeof(pix_fmt_str), i);
+        fprintf(stdout, "%s\n", pix_fmt_str);
+    }
+}
 
 static void opt_frame_pix_fmt(const char *arg)
 {
-    frame_pix_fmt = avcodec_get_pix_fmt(arg);
+    if (strcmp(arg, "list"))
+        frame_pix_fmt = avcodec_get_pix_fmt(arg);
+    else {
+        list_pix_fmts();
+        exit(0);
+    }
 }
 
 static void opt_frame_aspect_ratio(const char *arg)
@@ -3596,7 +3610,7 @@ const OptionDef options[] = {
     { "r", HAS_ARG | OPT_VIDEO, {(void*)opt_frame_rate}, "set frame rate (Hz value, fraction or abbreviation)", "rate" },
     { "s", HAS_ARG | OPT_VIDEO, {(void*)opt_frame_size}, "set frame size (WxH or abbreviation)", "size" },
     { "aspect", HAS_ARG | OPT_VIDEO, {(void*)opt_frame_aspect_ratio}, "set aspect ratio (4:3, 16:9 or 1.3333, 1.7777)", "aspect" },
-    { "pix_fmt", HAS_ARG | OPT_EXPERT | OPT_VIDEO, {(void*)opt_frame_pix_fmt}, "set pixel format", "format" },
+    { "pix_fmt", HAS_ARG | OPT_EXPERT | OPT_VIDEO, {(void*)opt_frame_pix_fmt}, "set pixel format, 'list' as argument shows all the pixel formats supported", "format" },
     { "croptop", HAS_ARG | OPT_VIDEO, {(void*)opt_frame_crop_top}, "set top crop band size (in pixels)", "size" },
     { "cropbottom", HAS_ARG | OPT_VIDEO, {(void*)opt_frame_crop_bottom}, "set bottom crop band size (in pixels)", "size" },
     { "cropleft", HAS_ARG | OPT_VIDEO, {(void*)opt_frame_crop_left}, "set left crop band size (in pixels)", "size" },

libavcodec/avcodec.h

@@ -2615,6 +2615,19 @@ int avcodec_get_pix_fmt_loss(int dst_pix_fmt, int src_pix_fmt,
 int avcodec_find_best_pix_fmt(int pix_fmt_mask, int src_pix_fmt,
                               int has_alpha, int *loss_ptr);
 
+
+/**
+ * Print in buf the string corresponding to the pixel format with
+ * number pix_fmt, or an header if pix_fmt is negative.
+ *
+ * @param buf[in] the buffer where to write the string
+ * @param buf_size[in] the size of buf
+ * @param pix_fmt[in] the number of the pixel format to print the corresponding info string, or
+ * a negative value to print the corresponding header.
+ * Meaningful values for obtaining a pixel format info vary from 0 to PIX_FMT_NB -1.
+ */
+void avcodec_pix_fmt_string (char *buf, int buf_size, int pix_fmt);
+
 #define FF_ALPHA_TRANSP       0x0001 /* image has some totally transparent pixels */
 #define FF_ALPHA_SEMI_TRANSP  0x0002 /* image has some transparent pixels */
 

libavcodec/imgconvert.c

@@ -378,6 +378,27 @@ enum PixelFormat avcodec_get_pix_fmt(const char* name)
     return i;
 }
 
+void avcodec_pix_fmt_string (char *buf, int buf_size, int pix_fmt)
+{
+    PixFmtInfo info= pix_fmt_info[pix_fmt];
+
+    char is_alpha_char= info.is_alpha ? 'y' : 'n';
+
+    /* print header */
+    if (pix_fmt < 0)
+        snprintf (buf, buf_size,
+                  "name      " " nb_channels" " depth" " is_alpha"
+            );
+    else
+        snprintf (buf, buf_size,
+                  "%-10s" "      %1d     " "   %2d " "     %c   ",
+                  info.name,
+                  info.nb_channels,
+                  info.depth,
+                  is_alpha_char
+            );
+}
+
 int avpicture_fill(AVPicture *picture, uint8_t *ptr,
                    int pix_fmt, int width, int height)
 {