qtdemux: extract interlaced information from jpeg video

This information is hidden in a small chunk of data.
Format found at https://developer.apple.com/standards/qtff-2001.pdf,
page 92, "Video Sample Description", under table 3.1.

https://bugzilla.gnome.org/show_bug.cgi?id=767771

1 files changed, 74 insertions, 0 deletions

diff --git a/gst/isomp4/qtdemux.c b/gst/isomp4/qtdemux.c
index 8b7b0f534..183f74cd7 100644
--- a/gst/isomp4/qtdemux.c
+++ b/gst/isomp4/qtdemux.c
@@ -10022,6 +10022,80 @@ qtdemux_parse_trak (GstQTDemux * qtdemux, GNode * trak)
           }
           break;
         }
+        case FOURCC_jpeg:
+        {
+          /* https://developer.apple.com/standards/qtff-2001.pdf,
+           * page 92, "Video Sample Description", under table 3.1 */
+          GstByteReader br;
+
+          const off_t compressor_offset =
+              16 + 4 + 4 * 3 + 2 * 2 + 2 * 4 + 4 + 2;
+          const off_t min_size = compressor_offset + 32 + 2 + 2;
+          GNode *jpeg;
+          guint32 len;
+          guint16 color_table_id;
+          gboolean ok;
+
+          GST_DEBUG_OBJECT (qtdemux, "found jpeg");
+
+          /* recover information on interlaced/progressive */
+          jpeg = qtdemux_tree_get_child_by_type (stsd, FOURCC_jpeg);
+          if (!jpeg)
+            break;
+
+          len = QT_UINT32 (jpeg->data);
+          GST_DEBUG_OBJECT (qtdemux, "Found jpeg: len %u, need %lu", len,
+              min_size);
+          if (len >= min_size) {
+            gst_byte_reader_init (&br, jpeg->data, len);
+
+            gst_byte_reader_skip (&br, compressor_offset + 32 + 2);
+            gst_byte_reader_get_uint16_le (&br, &color_table_id);
+            if (color_table_id != 0) {
+              /* the spec says there can be concatenated chunks in the data, and we want
+               * to find one called field. Walk through them. */
+              off_t offset = min_size;
+              while (offset + 8 < len) {
+                guint32 size, tag;
+                ok = gst_byte_reader_get_uint32_le (&br, &size);
+                ok &= gst_byte_reader_get_uint32_le (&br, &tag);
+                if (!ok || size < 8) {
+                  GST_WARNING_OBJECT (qtdemux,
+                      "Failed to walk optional chunk list");
+                  break;
+                }
+                GST_DEBUG_OBJECT (qtdemux,
+                    "Found optional %4.4s chunk, size %u", (const char *) &tag,
+                    size);
+                if (tag == FOURCC_fiel) {
+                  guint8 n_fields, ordering;
+                  gst_byte_reader_get_uint8 (&br, &n_fields);
+                  gst_byte_reader_get_uint8 (&br, &ordering);
+                  if (n_fields == 1 || n_fields == 2) {
+                    GST_DEBUG_OBJECT (qtdemux,
+                        "Found fiel tag with %u fields, ordering %u", n_fields,
+                        ordering);
+                    if (n_fields == 2)
+                      gst_caps_set_simple (stream->caps, "interlace-mode",
+                          G_TYPE_STRING, "interleaved", NULL);
+                  } else {
+                    GST_WARNING_OBJECT (qtdemux,
+                        "Found fiel tag with invalid fields (%u)", n_fields);
+                  }
+                }
+                offset += size;
+              }
+            } else {
+              GST_DEBUG_OBJECT (qtdemux,
+                  "Color table ID is 0, not trying to get interlacedness");
+            }
+          } else {
+            GST_WARNING_OBJECT (qtdemux,
+                "Length of jpeg chunk is too small, not trying to get interlacedness");
+          }
+
+          break;
+        }
         case FOURCC_SVQ3:
         case FOURCC_VP31:
         {