From 7b70159842fcd93bc7cbd025305f58202fcf4b0c Mon Sep 17 00:00:00 2001
From: josh <josh@bd8a9e45-a331-0410-811e-c64571078777>
Date: Wed, 12 Aug 2009 02:52:39 +0000
Subject: [PATCH] added setFormat() to call ioctl VIDIOC_S_FMT and deallocating
 a buffer no longer blocks!!

git-svn-id: svn://anubis/misc/WebcamTracker@125 bd8a9e45-a331-0410-811e-c64571078777
---
 WebcamTracker.cc | 30 +++++++++++++++++++++++++++++-
 WebcamTracker.h  |  1 +
 2 files changed, 30 insertions(+), 1 deletion(-)

diff --git a/WebcamTracker.cc b/WebcamTracker.cc
index 9329730..5cb76ac 100644
--- a/WebcamTracker.cc
+++ b/WebcamTracker.cc
@@ -8,6 +8,7 @@
 #include <unistd.h>
 #include <sys/mman.h>               /* mmap() */
 #include <errno.h>
+#include <string.h>                 /* memset() */
 #include <iostream>
 #include "WebcamTracker.h"
 using namespace std;
@@ -58,6 +59,7 @@ bool WebcamTracker::open(const char * device)
 
 void WebcamTracker::start()
 {
+    setFormat();
     requestBuffers(20);
     for (int i = 0; i < m_numbufs; i++)
     {
@@ -91,7 +93,6 @@ void WebcamTracker::requestBuffers(int num)
     else
     {
         m_numbufs = reqbuf.count;
-        cout << "Got " << m_numbufs << " buffers" << endl;
         m_buffers = new void *[m_numbufs];
         m_lengths = new int[m_numbufs];
     }
@@ -238,3 +239,30 @@ WebcamTracker::~WebcamTracker()
         close(m_fd);
     }
 }
+
+void WebcamTracker::setFormat()
+{
+    v4l2_format fmt;
+    memset(&fmt, 0, sizeof(fmt));
+    fmt.type = V4L2_BUF_TYPE_VIDEO_CAPTURE;
+    int ret = ioctl(m_fd, VIDIOC_G_FMT, &fmt);
+    if (ret != 0)
+    {
+        cerr << "Warning: VIDIOC_G_FMT ioctl failed, errno " << errno;
+        if (errno == EBUSY)
+            cerr << " (EBUSY)";
+        if (errno == EINVAL)
+            cerr << " (EINVAL)";
+        cerr << endl;
+    }
+    cerr << "width: " << fmt.fmt.pix.width << endl;
+    cerr << "height: " << fmt.fmt.pix.height << endl;
+    cerr << "pixelformat: " << fmt.fmt.pix.pixelformat << endl;
+    cerr << "field: " << fmt.fmt.pix.field << endl;
+    cerr << "bytesperline: " << fmt.fmt.pix.bytesperline << endl;
+    ret = ioctl(m_fd, VIDIOC_S_FMT, &fmt);
+    if (ret != 0)
+    {
+        cerr << "Warning: VIDIOC_S_FMT ioctl failed, errno " << errno << endl;
+    }
+}
diff --git a/WebcamTracker.h b/WebcamTracker.h
index b19463f..6f972fe 100644
--- a/WebcamTracker.h
+++ b/WebcamTracker.h
@@ -25,6 +25,7 @@ class WebcamTracker
         void dequeueBuffer(v4l2_buffer * dqbuf);
         void unmapBuffer(int i);
         void freeBuffers();
+        void setFormat();
 
         bool    m_open;
         int     m_fd;