typefinding: improve image/bmp typefinder

Detect more variations and also bail out in more cases where the values
don't make sense. Furthermore, add width/height and bpp to the caps,
because we can.
This commit is contained in:
Tim-Philipp Müller 2009-03-11 12:59:05 +00:00
parent 8285d7fdb0
commit a622ff74b0

View file

@ -2320,16 +2320,58 @@ static GstStaticCaps bmp_caps = GST_STATIC_CAPS ("image/bmp");
static void
bmp_type_find (GstTypeFind * tf, gpointer unused)
{
guint8 *data = gst_type_find_peek (tf, 0, 18);
DataScanCtx c = { 0, NULL, 0 };
guint32 struct_size, w, h, planes, bpp;
if (data && memcmp (data, "BM", 2) == 0) {
if ((data[14] == 0x0C ||
data[14] == 0x28 ||
data[14] == 0xF0) &&
data[15] == 0 && data[16] == 0 && data[17] == 0) {
gst_type_find_suggest (tf, GST_TYPE_FIND_MAXIMUM, BMP_CAPS);
}
if (G_UNLIKELY (!data_scan_ctx_ensure_data (tf, &c, 54)))
return;
if (c.data[0] != 'B' || c.data[1] != 'M')
return;
/* skip marker + size */
data_scan_ctx_advance (tf, &c, 2 + 4);
/* reserved, must be 0 */
if (c.data[0] != 0 || c.data[1] != 0 || c.data[2] != 0 || c.data[3] != 0)
return;
data_scan_ctx_advance (tf, &c, 2 + 2);
/* offset to start of image data in bytes (check for sanity) */
GST_LOG ("offset=%u", GST_READ_UINT32_LE (c.data));
if (GST_READ_UINT32_LE (c.data) > (10 * 1024 * 1024))
return;
struct_size = GST_READ_UINT32_LE (c.data + 4);
GST_LOG ("struct_size=%u", struct_size);
data_scan_ctx_advance (tf, &c, 4 + 4);
if (struct_size == 0x0C) {
w = GST_READ_UINT16_LE (c.data);
h = GST_READ_UINT16_LE (c.data + 2);
planes = GST_READ_UINT16_LE (c.data + 2 + 2);
bpp = GST_READ_UINT16_LE (c.data + 2 + 2 + 2);
} else if (struct_size == 40 || struct_size == 64 || struct_size == 108
|| struct_size == 124 || struct_size == 0xF0) {
w = GST_READ_UINT32_LE (c.data);
h = GST_READ_UINT32_LE (c.data + 4);
planes = GST_READ_UINT16_LE (c.data + 4 + 4);
bpp = GST_READ_UINT16_LE (c.data + 4 + 4 + 2);
} else {
return;
}
/* image sizes sanity check */
GST_LOG ("w=%u, h=%u, planes=%u, bpp=%u", w, h, planes, bpp);
if (w == 0 || w > 0xfffff || h == 0 || h > 0xfffff || planes != 1 ||
(bpp != 1 && bpp != 4 && bpp != 8 && bpp != 16 && bpp != 24 && bpp != 32))
return;
gst_type_find_suggest_simple (tf, GST_TYPE_FIND_MAXIMUM, "image/bmp",
"width", G_TYPE_INT, w, "height", G_TYPE_INT, h, "bpp", G_TYPE_INT, bpp,
NULL);
}
/*** image/tiff ***/