16 bpp video stream capture, render and createImageBitmap(video) using (CPU) shared memory buffers

media/capture/video/linux/v4l2_capture_delegate.cc

Index: media/capture/video/linux/v4l2_capture_delegate.cc
diff --git a/media/capture/video/linux/v4l2_capture_delegate.cc b/media/capture/video/linux/v4l2_capture_delegate.cc
index de0e35b79f43cc3f4c0a8fefc74d8cfa09764b8a..b6442327419ce55d6c5a169478d8c2267d2db420 100644
--- a/media/capture/video/linux/v4l2_capture_delegate.cc
+++ b/media/capture/video/linux/v4l2_capture_delegate.cc
@@ -16,8 +16,18 @@
 #include "base/strings/stringprintf.h"
 #include "build/build_config.h"
 #include "media/base/bind_to_current_loop.h"
-#include "media/capture/video/blob_utils.h"
 #include "media/capture/video/linux/video_capture_device_linux.h"
+#include "media/capture/video/video_capture_utils.h"
+
+// TODO(astojilj): Remove V4L2_PIX_FMT_Z16/INVZ when videodev2.h gets updated.
+#ifndef V4L2_PIX_FMT_Z16
+// 16 bit depth, Realsense F200.
+#define V4L2_PIX_FMT_Z16 v4l2_fourcc('Z', '1', '6', ' ')
+#endif
+#ifndef V4L2_PIX_FMT_INVZ
+// 16 bit depth, Realsense SR300.
+#define V4L2_PIX_FMT_INVZ v4l2_fourcc('I', 'N', 'V', 'Z')
+#endif
 
 namespace media {
 
@@ -50,6 +60,9 @@ static struct {
   size_t num_planes;
 } const kSupportedFormatsAndPlanarity[] = {
     {V4L2_PIX_FMT_YUV420, PIXEL_FORMAT_I420, 1},
+    {V4L2_PIX_FMT_Y16, PIXEL_FORMAT_Y16, 1},
+    {V4L2_PIX_FMT_Z16, PIXEL_FORMAT_Y16, 1},
+    {V4L2_PIX_FMT_INVZ, PIXEL_FORMAT_Y16, 1},
     {V4L2_PIX_FMT_YUYV, PIXEL_FORMAT_YUY2, 1},
     {V4L2_PIX_FMT_UYVY, PIXEL_FORMAT_UYVY, 1},
     {V4L2_PIX_FMT_RGB24, PIXEL_FORMAT_RGB24, 1},
@@ -567,9 +580,16 @@ void V4L2CaptureDelegate::DoCapture() {
     base::TimeDelta timestamp =
         base::TimeDelta::FromSeconds(buffer.timestamp.tv_sec) +
         base::TimeDelta::FromMicroseconds(buffer.timestamp.tv_usec);
-    client_->OnIncomingCapturedData(
-        buffer_tracker->start(), buffer_tracker->payload_size(),
-        capture_format_, rotation_, base::TimeTicks::Now(), timestamp);
+#ifdef V4L2_BUF_FLAG_ERROR

[mcasas, 2016/10/21 00:10:50]

This is not representative enough, instead, check the
Linux Kernel version, and add a comment, most likely
with a TODO().

Same applies to l.22 and vicinity: it's hard to monitor 
the definition of a given preprocessor definition, but
it's easy to verify the kernel version.

[aleksandar.stojiljkovic, 2016/10/21 22:11:10]

Noticed the crash with Realsense cameras on multiple kernel versions (if I
remember correctly on Ubuntu 16.04 and recent ChromeOS, without other changes).
The patch here is orthogonal to the other changes here and I should have opened
a bug and commit this separately. Should I do it now or it is fine to have it
here?
V4L2_BUF_FLAG_ERROR is handled this way in ffmpeg [1], so just copied the whole
approach.

[1]
https://cs.chromium.org/chromium/src/third_party/ffmpeg/libavdevice/v4l2.c?rc...

+    if (buffer.flags & V4L2_BUF_FLAG_ERROR) {
+      LOG(ERROR) << "Dequeued v4l2 buffer contains corrupted data ("
+                 << buffer.bytesused << " bytes).";
+      buffer.bytesused = 0;
+    } else
+#endif
+      client_->OnIncomingCapturedData(
+          buffer_tracker->start(), buffer_tracker->payload_size(),
+          capture_format_, rotation_, base::TimeTicks::Now(), timestamp);

[mcasas, 2016/10/21 00:10:50]

Indent is incorrect.

[aleksandar.stojiljkovic, 2016/10/21 22:11:10]

git cl format is doing it because of else shared by both ifdef paths:
#ifdef
if()
<indent>
else
#endif
<indent>

 
     while (!take_photo_callbacks_.empty()) {
       VideoCaptureDevice::TakePhotoCallback cb =