[vlc-devel] [PATCH] bmp: fix demuxing for some BMP formats

[Tristan Matthews]

---
 modules/demux/image.c | 42 ++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 42 insertions(+)

diff --git a/modules/demux/image.c b/modules/demux/image.c
index 43c4847..033627f 100644
--- a/modules/demux/image.c
+++ b/modules/demux/image.c
@@ -603,6 +603,42 @@ static const image_format_t formats[] = {
     { .codec = 0 }
 };
 
+static int parse_bmp(stream_t *stream, video_format_t *fmt)
+{
+/* See:
+   https://en.wikipedia.org/wiki/BMP_file_format#DIB_header_.28bitmap_information_header.29
+ */
+    const uint8_t *header;
+    if (stream_Peek(stream, &header, 18 + 12) < 18 + 12)
+        return VLC_EGENERIC;
+    uint32_t header_size = GetDWLE(&header[14]);
+    switch (header_size) {
+        case  12: { /* BITMAPCOREHEADER, OS21XBITMAPHEADER */
+            if( stream_Peek(stream, &header, 18 + 12) < 18 + 12 )
+                return VLC_EGENERIC;
+            fmt->i_width = fmt->i_visible_width = GetWLE(&header[18]);
+            fmt->i_height = fmt->i_visible_height = GetWLE(&header[20]);
+            fmt->i_bits_per_pixel = GetWLE(&header[24]);
+            break;
+        }
+        case  40: /* BITMAPINFOHEADER */
+        case  52: /* BITMAPV2INFOHEADER */
+        case  56: /* BITMAPV3INFOHEADER */
+        case  64: /* OS22XBITMAPHEADER */
+        case 108: /* BITMAPV4HEADER */
+        case 124: /* BITMAPV5HEADER */
+        {
+            fmt->i_width = fmt->i_visible_width = GetDWLE(&header[18]);
+            fmt->i_height = fmt->i_visible_height = GetDWLE(&header[22]);
+            fmt->i_bits_per_pixel = GetWLE(&header[28]);
+            break;
+        }
+        default:
+            return VLC_EGENERIC;
+    }
+    return VLC_SUCCESS;
+}
+
 static int Open(vlc_object_t *object)
 {
     demux_t *demux = (demux_t*)object;
@@ -641,6 +677,12 @@ static int Open(vlc_object_t *object)
     es_format_Init(&fmt, VIDEO_ES, img->codec);
     fmt.video.i_chroma = fmt.i_codec;
 
+    if( img->codec == VLC_CODEC_BMP )
+    {
+        if (parse_bmp(demux->s, &fmt.video) < 0)
+            return VLC_EGENERIC; /* let avformat demux this file */
+    }
+
     block_t *data = Load(demux);
     if (data && var_InheritBool(demux, "image-decode")) {
         char *string = var_InheritString(demux, "image-chroma");
-- 
1.9.1