y4m: add color mappings

Now the chroma subsampling tag will include the chroma site. Tests
where updated accordingly.

Part-of: <https://gitlab.freedesktop.org/gstreamer/gstreamer/-/merge_requests/8719>

subprojects/gst-plugins-good/gst/y4m/gsty4mdec.c

@@ -160,78 +160,6 @@ gst_y4m_dec_stop (GstBaseParse * parse)
   return TRUE;
 }
 
-static GstVideoFormat
-parse_colorspace (const char *param)
-{
-  char *end;
-  guint iformat = g_ascii_strtoull (param, &end, 10);
-
-  if (*end == '\0') {
-    switch (iformat) {
-      case 420:
-        return GST_VIDEO_FORMAT_I420;
-      case 411:
-        return GST_VIDEO_FORMAT_Y41B;
-      case 422:
-        return GST_VIDEO_FORMAT_Y42B;
-      case 444:
-        return GST_VIDEO_FORMAT_Y444;
-    }
-  }
-
-  /*
-   * Parse non-standard (i.e., unknown to mjpegtools) streams that are
-   * generated by FFmpeg:
-   * https://wiki.multimedia.cx/index.php/YUV4MPEG2
-   * https://github.com/FFmpeg/FFmpeg/blob/eee3b7e2/libavformat/yuv4mpegenc.c#L74-L166
-   * Will assume little-endian because this is an on-disk serialization format.
-   */
-
-  // TODO: Differentiate between:
-  // * C420jpeg: biaxially-displaced chroma planes
-  // * C420paldv: coincident R and vertically-displaced B
-  // * C420mpeg2: vertically-displaced chroma planes
-  if (iformat == 420 && (g_strcmp0 (end, "jpeg") == 0 ||
-          g_strcmp0 (end, "paldv") == 0 || g_strcmp0 (end, "mpeg2") == 0))
-    return GST_VIDEO_FORMAT_I420;
-
-  if (iformat == 0 && strncmp (end, "mono", 4) == 0) {
-    char *type = end + 4;
-    if (*type == '\0')
-      return GST_VIDEO_FORMAT_GRAY8;
-    if (g_strcmp0 (type, "16") == 0)
-      return GST_VIDEO_FORMAT_GRAY16_LE;
-  }
-
-  if (*end == 'p') {
-    guint depth = g_ascii_strtoull (end + 1, NULL, 10);
-    if (depth == 10) {
-      switch (iformat) {
-        case 420:
-          return GST_VIDEO_FORMAT_I420_10LE;
-        case 422:
-          return GST_VIDEO_FORMAT_I422_10LE;
-        case 444:
-          return GST_VIDEO_FORMAT_Y444_10LE;
-      }
-    } else if (depth == 12) {
-      switch (iformat) {
-        case 420:
-          return GST_VIDEO_FORMAT_I420_12LE;
-        case 422:
-          return GST_VIDEO_FORMAT_I422_12LE;
-        case 444:
-          return GST_VIDEO_FORMAT_Y444_12LE;
-      }
-    } else if (depth == 16 && iformat == 444) {
-      return GST_VIDEO_FORMAT_Y444_16LE;
-    }
-  }
-
-  GST_WARNING ("%s is not a supported format", param);
-  return GST_VIDEO_FORMAT_UNKNOWN;
-}
-
 static gboolean
 parse_ratio (const char *param, gulong * n, gulong * d)
 {
@@ -259,6 +187,7 @@ gst_y4m_dec_parse_header (GstY4mDec * y4mdec, const char *header)
   gulong par_n = 0, par_d = 0;
   gulong width = 0, height = 0;
   GstVideoFormat format = GST_VIDEO_FORMAT_I420;
+  GstVideoChromaSite chroma_site = GST_VIDEO_CHROMA_SITE_NONE;
   GstVideoInterlaceMode interlace_mode;
 
   if (memcmp (header, "YUV4MPEG2 ", 10) != 0) {
@@ -282,8 +211,8 @@ gst_y4m_dec_parse_header (GstY4mDec * y4mdec, const char *header)
     const char *param_value = param + 1;
     switch (param_type) {
       case 'C':
-        format = parse_colorspace (param_value);
+        if (!gst_y4m_video_get_format_from_chroma_tag (param_value, &format,
-        if (format == GST_VIDEO_FORMAT_UNKNOWN) {
+                &chroma_site)) {
           GST_ERROR_OBJECT (y4mdec, "Failed to parse colorspace: %s", param);
           return FALSE;
         }
@@ -321,6 +250,7 @@ gst_y4m_dec_parse_header (GstY4mDec * y4mdec, const char *header)
         }
         continue;
     }
+    /* TODO: parse common metadata ('X') such as YSCSS and color range */
     GST_WARNING_OBJECT (y4mdec, "Unknown y4m param field '%s', ignoring",
         param);
   }

subprojects/gst-plugins-good/gst/y4m/gsty4menc.c

@@ -144,22 +144,11 @@ gst_y4m_encode_set_format (GstVideoEncoder * encoder,
   y4menc = GST_Y4M_ENCODE (encoder);
   info = &state->info;
 
-  switch (GST_VIDEO_INFO_FORMAT (info)) {
+  y4menc->colorspace =
-    case GST_VIDEO_FORMAT_I420:
+      gst_y4m_video_get_chroma_tag_from_format (GST_VIDEO_INFO_FORMAT (info),
-      y4menc->colorspace = "420";
+      GST_VIDEO_INFO_CHROMA_SITE (info));
-      break;
+  if (y4menc->colorspace == NULL)
-    case GST_VIDEO_FORMAT_Y42B:
+    goto invalid_format;
-      y4menc->colorspace = "422";
-      break;
-    case GST_VIDEO_FORMAT_Y41B:
-      y4menc->colorspace = "411";
-      break;
-    case GST_VIDEO_FORMAT_Y444:
-      y4menc->colorspace = "444";
-      break;
-    default:
-      goto invalid_format;
-  }
 
   if (!gst_y4m_video_unpadded_info (&out_info, info))
     goto invalid_format;
@@ -199,6 +188,7 @@ gst_y4m_encode_get_stream_header (GstY4mEncode * filter, gboolean tff)
     interlaced = 'p';
   }
 
+  /* TODO: add YSCSS and color range */
   header = g_strdup_printf ("YUV4MPEG2 C%s W%d H%d I%c F%d:%d A%d:%d\n",
       filter->colorspace, GST_VIDEO_INFO_WIDTH (&filter->info),
       GST_VIDEO_INFO_HEIGHT (&filter->info), interlaced,

subprojects/gst-plugins-good/gst/y4m/gsty4mformat.c

@@ -91,3 +91,143 @@ gst_y4m_video_unpadded_info (GstVideoInfo * y4m_info,
 
   return TRUE;
 }
+
+/*
+ * Parse non-standard (i.e., unknown to mjpegtools) streams that are
+ * generated by FFmpeg:
+ * https://wiki.multimedia.cx/index.php/YUV4MPEG2
+ * https://github.com/FFmpeg/FFmpeg/blob/eee3b7e2/libavformat/yuv4mpegenc.c#L74-L166
+ * Will assume little-endian because this is an on-disk serialization format.
+ */
+
+/* *INDENT-OFF* */
+static const struct {
+  const char *chroma_tag;
+  const char *yscss_tag;
+  GstVideoFormat format;
+  GstVideoChromaSite chroma_site;
+} ChromaSubsamplingMap[] = {
+  { "420jpeg", "420JPEG", GST_VIDEO_FORMAT_I420, GST_VIDEO_CHROMA_SITE_JPEG },
+  { "420mpeg2", "420MPEG2", GST_VIDEO_FORMAT_I420, GST_VIDEO_CHROMA_SITE_MPEG2 },
+  { "420paldv", "420PALDV", GST_VIDEO_FORMAT_I420, GST_VIDEO_CHROMA_SITE_DV },
+  /* { "420p16", "420P16", GST_VIDEO_FORMAT_I420_16LE, GST_VIDEO_CHROMA_SITE_UNKNOWN }, */
+  /* { "422p16", "422P16", GST_VIDEO_FORMAT_I422_16LE, GST_VIDEO_CHROMA_SITE_UNKNOWN }, */
+  /* { "444p16", "444P16", GST_VIDEO_FORMAT_Y444_16LE, GST_VIDEO_CHROMA_SITE_UNKNOWN }, */
+  /* { "420p14", "420P14", GST_VIDEO_FORMAT_I420_14LE, GST_VIDEO_CHROMA_SITE_UNKNOWN }, */
+  /* { "422p14", "422P14", GST_VIDEO_FORMAT_I422_14LE, GST_VIDEO_CHROMA_SITE_UNKNOWN }, */
+  /* { "444p14", "444P14", GST_VIDEO_FORMAT_Y444_14LE, GST_VIDEO_CHROMA_SITE_UNKNOWN }, */
+  { "420p12", "420P12", GST_VIDEO_FORMAT_I420_12LE, GST_VIDEO_CHROMA_SITE_NONE },
+  { "422p12", "422P12", GST_VIDEO_FORMAT_I422_12LE, GST_VIDEO_CHROMA_SITE_NONE },
+  { "444p12", "444P12", GST_VIDEO_FORMAT_Y444_12LE, GST_VIDEO_CHROMA_SITE_NONE },
+  { "420p10", "420P10", GST_VIDEO_FORMAT_I420_10LE, GST_VIDEO_CHROMA_SITE_NONE },
+  { "422p10", "422P10", GST_VIDEO_FORMAT_I422_10LE, GST_VIDEO_CHROMA_SITE_NONE },
+  { "444p10", "444P10", GST_VIDEO_FORMAT_Y444_10LE, GST_VIDEO_CHROMA_SITE_NONE },
+  /* { "420p9", GST_VIDEO_FORMAT_I420_9LE, GST_VIDEO_CHROMA_SITE_UNKNOWN }, */
+  /* { "422p9", GST_VIDEO_FORMAT_I422_9LE, GST_VIDEO_CHROMA_SITE_UNKNOWN }, */
+  /* { "444p9", GST_VIDEO_FORMAT_Y444_9LE, GST_VIDEO_CHROMA_SITE_UNKNOWN }, */
+  { "420", NULL, GST_VIDEO_FORMAT_I420, GST_VIDEO_CHROMA_SITE_NONE },
+  { "411", "411", GST_VIDEO_FORMAT_Y41B, GST_VIDEO_CHROMA_SITE_NONE },
+  { "422", "422", GST_VIDEO_FORMAT_Y42B, GST_VIDEO_CHROMA_SITE_NONE },
+  { "444alpha", NULL, GST_VIDEO_FORMAT_A444, GST_VIDEO_CHROMA_SITE_NONE },
+  { "444", "444", GST_VIDEO_FORMAT_Y444, GST_VIDEO_CHROMA_SITE_NONE },
+  { "mono16", NULL, GST_VIDEO_FORMAT_GRAY16_LE, GST_VIDEO_CHROMA_SITE_UNKNOWN },
+  /* { "mono12", AV_PIX_FMT_GRAY12, GST_VIDEO_CHROMA_SITE_UNKNOWN }, */
+  { "mono10", NULL, GST_VIDEO_FORMAT_GRAY10_LE16, GST_VIDEO_CHROMA_SITE_UNKNOWN },
+  /* { "mono9", AV_PIX_FMT_GRAY9, GST_VIDEO_CHROMA_SITE_UNKNOWN }, */
+  { "mono", NULL, GST_VIDEO_FORMAT_GRAY8, GST_VIDEO_CHROMA_SITE_UNKNOWN },
+};
+/* *INDENT-ON* */
+
+gboolean
+gst_y4m_video_get_format_from_chroma_tag (const char *chroma_tag,
+    GstVideoFormat * format, GstVideoChromaSite * chroma_site)
+{
+  for (guint i = 0; i < G_N_ELEMENTS (ChromaSubsamplingMap); i++) {
+    if (g_strcmp0 (ChromaSubsamplingMap[i].chroma_tag, chroma_tag) == 0) {
+      if (format)
+        *format = ChromaSubsamplingMap[i].format;
+      if (chroma_site)
+        *chroma_site = ChromaSubsamplingMap[i].chroma_site;
+      return TRUE;
+    }
+  }
+
+  return FALSE;
+}
+
+const char *
+gst_y4m_video_get_chroma_tag_from_format (GstVideoFormat format,
+    GstVideoChromaSite chroma_site)
+{
+  for (guint i = 0; i < G_N_ELEMENTS (ChromaSubsamplingMap); i++) {
+    if (ChromaSubsamplingMap[i].format == format
+        && ChromaSubsamplingMap[i].chroma_site == chroma_site)
+      return ChromaSubsamplingMap[i].chroma_tag;
+  }
+
+  return NULL;
+}
+
+gboolean
+gst_y4m_video_get_format_from_yscss_tag (const char *yscss_tag,
+    GstVideoFormat * format, GstVideoChromaSite * chroma_site)
+{
+  for (guint i = 0; i < G_N_ELEMENTS (ChromaSubsamplingMap); i++) {
+    if (g_strcmp0 (ChromaSubsamplingMap[i].chroma_tag, yscss_tag) == 0) {
+      if (format)
+        *format = ChromaSubsamplingMap[i].format;
+      if (chroma_site)
+        *chroma_site = ChromaSubsamplingMap[i].chroma_site;
+      return TRUE;
+    }
+  }
+
+  return FALSE;
+}
+
+const char *
+gst_y4m_video_get_yscss_tag_from_format (GstVideoFormat format,
+    GstVideoChromaSite chroma_site)
+{
+  for (guint i = 0; i < G_N_ELEMENTS (ChromaSubsamplingMap); i++) {
+    if (ChromaSubsamplingMap[i].format == format
+        && ChromaSubsamplingMap[i].chroma_site == chroma_site)
+      return ChromaSubsamplingMap[i].yscss_tag;
+  }
+
+  return NULL;
+}
+
+/* *INDENT-OFF* */
+static const struct {
+  const char *range_tag;
+  GstVideoColorRange range;
+} ColorRangeMap[] = {
+  { "FULL", GST_VIDEO_COLOR_RANGE_0_255 },
+  { "LIMITED", GST_VIDEO_COLOR_RANGE_16_235 },
+};
+/* *INDENT-ON* */
+
+GstVideoColorRange
+gst_y4m_video_get_color_range_from_range_tag (const char *range_tag)
+{
+  for (guint i = 0; i < G_N_ELEMENTS (ColorRangeMap); i++) {
+    if (g_strcmp0 (range_tag, ColorRangeMap[i].range_tag) == 0) {
+      return ColorRangeMap[i].range;
+    }
+  }
+
+  return GST_VIDEO_COLOR_RANGE_UNKNOWN;
+}
+
+const char *
+gst_y4m_video_get_range_tag_from_color_range (GstVideoColorRange range)
+{
+  for (guint i = 0; i < G_N_ELEMENTS (ColorRangeMap); i++) {
+    if (range == ColorRangeMap[i].range) {
+      return ColorRangeMap[i].range_tag;
+    }
+  }
+
+  return NULL;
+}

subprojects/gst-plugins-good/gst/y4m/gsty4mformat.h

@@ -25,3 +25,21 @@
 
 gboolean              gst_y4m_video_unpadded_info (GstVideoInfo * y4m_info,
                                                    const GstVideoInfo * vinfo);
+
+gboolean              gst_y4m_video_get_format_from_chroma_tag (const char * chroma_tag,
+                                                                GstVideoFormat * format,
+                                                                GstVideoChromaSite * chroma_site);
+
+const char *          gst_y4m_video_get_chroma_tag_from_format (GstVideoFormat format,
+                                                                GstVideoChromaSite chroma_site);
+
+gboolean              gst_y4m_video_get_format_from_yscss_tag  (const char * yscss_tag,
+                                                                GstVideoFormat * format,
+                                                                GstVideoChromaSite * chroma_site);
+
+const char *          gst_y4m_video_get_yscss_tag_from_format  (GstVideoFormat format,
+                                                                GstVideoChromaSite chroma_site);
+
+GstVideoColorRange    gst_y4m_video_get_color_range_from_range_tag (const char * range_tag);
+
+const char *          gst_y4m_video_get_range_tag_from_color_range (GstVideoColorRange range);

subprojects/gst-plugins-good/tests/check/elements/y4mdata.c

@@ -52,7 +52,7 @@ unsigned int red_box_i420_15x15_yuv_len = 384;
 
 unsigned char red_box_y4m[] = {
   0x59, 0x55, 0x56, 0x34, 0x4d, 0x50, 0x45, 0x47, 0x32, 0x20, 0x43, 0x34,
-  0x32, 0x30, 0x20, 0x57, 0x31, 0x35, 0x20, 0x48, 0x31, 0x35, 0x20, 0x49,
+  0x32, 0x30, 0x6a, 0x70, 0x65, 0x67, 0x20, 0x57, 0x31, 0x35, 0x20, 0x48, 0x31, 0x35, 0x20, 0x49,
   0x70, 0x20, 0x46, 0x33, 0x30, 0x3a, 0x31, 0x20, 0x41, 0x31, 0x3a, 0x31,
   0x0a, 0x46, 0x52, 0x41, 0x4d, 0x45, 0x0a, 0x51, 0x51, 0x51, 0x51, 0x51,
   0x51, 0x51, 0x51, 0x51, 0x51, 0x51, 0x51, 0x51, 0x51, 0x51, 0x51, 0x51,
@@ -85,7 +85,7 @@ unsigned char red_box_y4m[] = {
   0xf0, 0xf0, 0xf0, 0xf0, 0xf0, 0xf0, 0xf0, 0xf0, 0xf0, 0xf0, 0xf0, 0xf0,
   0xf0, 0xf0, 0xf0, 0xf0, 0xf0, 0xf0, 0xf0, 0xf0, 0xf0, 0xf0, 0xf0, 0xf0
 };
-unsigned int red_box_y4m_len = 396;
+unsigned int red_box_y4m_len = 400;
 
 unsigned char red_box_y42b_16x16_yuv[] = {
   0x51, 0x51, 0x51, 0x51, 0x51, 0x51, 0x51, 0x51, 0x51, 0x51, 0x51, 0x51,

subprojects/gst-plugins-good/tests/check/elements/y4menc.c

@@ -85,7 +85,7 @@ GST_START_TEST (test_y4m)
   GstCaps *caps;
   int i, num_buffers, size;
   const gchar *data0 = "YUV4MPEG2 W384 H288 Ip F25:1 A1:1\n";
-  const gchar *data1 = "YUV4MPEG2 C420 W384 H288 Ip F25:1 A1:1\n";
+  const gchar *data1 = "YUV4MPEG2 C420jpeg W384 H288 Ip F25:1 A1:1\n";
   const gchar *data2 = "FRAME\n";
 
   y4menc = setup_y4menc ();