Create a stereo_mode metadata tag to specify the stereo 3d video layout using...

Create a stereo_mode metadata tag to specify the stereo 3d video layout using the StereoMode tag in a matroska/webm video track.

libavformat/matroska.h

@@ -111,7 +111,7 @@
 #define MATROSKA_ID_VIDEOPIXELCROPR 0x54DD
 #define MATROSKA_ID_VIDEODISPLAYUNIT 0x54B2
 #define MATROSKA_ID_VIDEOFLAGINTERLACED 0x9A
-#define MATROSKA_ID_VIDEOSTEREOMODE 0x53B9
+#define MATROSKA_ID_VIDEOSTEREOMODE 0x53B8
 #define MATROSKA_ID_VIDEOASPECTRATIO 0x54B3
 #define MATROSKA_ID_VIDEOCOLORSPACE 0x2EB524
 
@@ -218,6 +218,24 @@ typedef enum {
   MATROSKA_TRACK_ENCODING_COMP_HEADERSTRIP = 3,
 } MatroskaTrackEncodingCompAlgo;
 
+typedef enum {
+  MATROSKA_VIDEO_STEREOMODE_TYPE_MONO               = 0,
+  MATROSKA_VIDEO_STEREOMODE_TYPE_LEFT_RIGHT         = 1,
+  MATROSKA_VIDEO_STEREOMODE_TYPE_BOTTOM_TOP         = 2,
+  MATROSKA_VIDEO_STEREOMODE_TYPE_TOP_BOTTOM         = 3,
+  MATROSKA_VIDEO_STEREOMODE_TYPE_CHECKERBOARD_RL    = 4,
+  MATROSKA_VIDEO_STEREOMODE_TYPE_CHECKERBOARD_LR    = 5,
+  MATROSKA_VIDEO_STEREOMODE_TYPE_ROW_INTERLEAVED_RL = 6,
+  MATROSKA_VIDEO_STEREOMODE_TYPE_ROW_INTERLEAVED_LR = 7,
+  MATROSKA_VIDEO_STEREOMODE_TYPE_COL_INTERLEAVED_RL = 8,
+  MATROSKA_VIDEO_STEREOMODE_TYPE_COL_INTERLEAVED_LR = 9,
+  MATROSKA_VIDEO_STEREOMODE_TYPE_ANAGLYPH_CYAN_RED  = 10,
+  MATROSKA_VIDEO_STEREOMODE_TYPE_RIGHT_LEFT         = 11,
+  MATROSKA_VIDEO_STEREOMODE_TYPE_ANAGLYPH_GREEN_MAG = 12,
+  MATROSKA_VIDEO_STEREOMODE_TYPE_BOTH_EYES_BLOCK_LR = 13,
+  MATROSKA_VIDEO_STEREOMODE_TYPE_BOTH_EYES_BLOCK_RL = 14,
+} MatroskaVideoStereoModeType;
+
 /*
  * Matroska Codec IDs, strings
  */

libavformat/matroskaenc.c

@@ -586,6 +586,25 @@ static int mkv_write_tracks(AVFormatContext *s)
                 // XXX: interlace flag?
                 put_ebml_uint (pb, MATROSKA_ID_VIDEOPIXELWIDTH , codec->width);
                 put_ebml_uint (pb, MATROSKA_ID_VIDEOPIXELHEIGHT, codec->height);
+                if ((tag = av_metadata_get(s->metadata, "stereo_mode", NULL, 0))) {
+                    uint8_t stereo_fmt = atoi(tag->value);
+                    int valid_fmt = 0;
+
+                    switch (mkv->mode) {
+                    case MODE_WEBM:
+                        if (stereo_fmt <= MATROSKA_VIDEO_STEREOMODE_TYPE_TOP_BOTTOM
+                            || stereo_fmt == MATROSKA_VIDEO_STEREOMODE_TYPE_RIGHT_LEFT)
+                            valid_fmt = 1;
+                        break;
+                    case MODE_MATROSKAv2:
+                        if (stereo_fmt <= MATROSKA_VIDEO_STEREOMODE_TYPE_BOTH_EYES_BLOCK_RL)
+                            valid_fmt = 1;
+                        break;
+                    }
+
+                    if (valid_fmt)
+                        put_ebml_uint (pb, MATROSKA_ID_VIDEOSTEREOMODE, stereo_fmt);
+                }
                 if (st->sample_aspect_ratio.num) {
                     int d_width = codec->width*av_q2d(st->sample_aspect_ratio);
                     put_ebml_uint(pb, MATROSKA_ID_VIDEODISPLAYWIDTH , d_width);