Enumerate MJPEG as the prefered format if set.

media/video/capture/win/sink_input_pin_win.cc

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "media/video/capture/win/sink_input_pin_win.h"
 
 #include <cstring>
 
 // Avoid including strsafe.h via dshow as it will cause build warnings.
 #define NO_DSHOW_STRSAFE
@@ skipping 27 matching lines @@
   pvi->bmiHeader.biClrUsed = 0;
   if (requested_format_.frame_rate > 0) {
     pvi->AvgTimePerFrame =
         kSecondsToReferenceTime / requested_format_.frame_rate;
   }
 
   media_type->majortype = MEDIATYPE_Video;
   media_type->formattype = FORMAT_VideoInfo;
   media_type->bTemporalCompression = FALSE;
 
+  if (requested_format_.pixel_format == PIXEL_FORMAT_MJPEG) {
+    // If the requested pixel format is MJPEG, accept only MJPEG.
+    // This is ok since the capabilities of the capturer have been
+    // enumerated and we know that it is supported.
+    if (index != 0)
+      return false;
+
+    pvi->bmiHeader.biCompression = MAKEFOURCC('M', 'J', 'P', 'G');
+    pvi->bmiHeader.biBitCount = 0;
+    pvi->bmiHeader.biWidth = requested_format_.frame_size.width();
+    pvi->bmiHeader.biHeight = requested_format_.frame_size.height();
+    pvi->bmiHeader.biSizeImage = 0;
+    media_type->subtype = MEDIASUBTYPE_MJPG;
+    media_type->bFixedSizeSamples = FALSE;
+    media_type->lSampleSize = pvi->bmiHeader.biSizeImage;
+    return true;
+  }
+
   switch (index) {
     case 0: {
       pvi->bmiHeader.biCompression = MAKEFOURCC('I', '4', '2', '0');
       pvi->bmiHeader.biBitCount = 12;  // bit per pixel
       pvi->bmiHeader.biWidth = requested_format_.frame_size.width();
       pvi->bmiHeader.biHeight = requested_format_.frame_size.height();
       pvi->bmiHeader.biSizeImage =
           requested_format_.frame_size.GetArea() * 3 / 2;
       media_type->subtype = kMediaSubTypeI420;
       break;
     }
     case 1: {
       pvi->bmiHeader.biCompression = MAKEFOURCC('Y', 'U', 'Y', '2');
       pvi->bmiHeader.biBitCount = 16;
       pvi->bmiHeader.biWidth = requested_format_.frame_size.width();
       pvi->bmiHeader.biHeight = requested_format_.frame_size.height();
       pvi->bmiHeader.biSizeImage = requested_format_.frame_size.GetArea() * 2;
       media_type->subtype = MEDIASUBTYPE_YUY2;
       break;
     }
     case 2: {
-      pvi->bmiHeader.biCompression = MAKEFOURCC('M', 'J', 'P', 'G');
-      pvi->bmiHeader.biBitCount = 0;
-      pvi->bmiHeader.biWidth = requested_format_.frame_size.width();
-      pvi->bmiHeader.biHeight = requested_format_.frame_size.height();
-      pvi->bmiHeader.biSizeImage = 0;
-      media_type->subtype = MEDIASUBTYPE_MJPG;
-      break;
-    }
-    case 3: {
       pvi->bmiHeader.biCompression = BI_RGB;
       pvi->bmiHeader.biBitCount = 24;
       pvi->bmiHeader.biWidth = requested_format_.frame_size.width();
       pvi->bmiHeader.biHeight = requested_format_.frame_size.height();
       pvi->bmiHeader.biSizeImage = requested_format_.frame_size.GetArea() * 3;
       media_type->subtype = MEDIASUBTYPE_RGB24;
       break;
     }
     default:
       return false;
@@ skipping 67 matching lines @@
   resulting_format_.frame_size.SetSize(0, 0);
   resulting_format_.frame_rate = 0;
   resulting_format_.pixel_format = PIXEL_FORMAT_UNKNOWN;
 }
 
 const VideoCaptureFormat& SinkInputPin::ResultingFormat() {
   return resulting_format_;
 }
 
 }  // namespace media