Implement setting gain control for video devices (usually webcams)

in v4l2 tv:// driver.


git-svn-id: svn://svn.mplayerhq.hu/mplayer/trunk@24573 b3059339-0415-0410-9bf9-f77b7e298cf2

DOCS/man/en/mplayer.1

@@ -1854,6 +1854,11 @@ These options set parameters of the mixer on the video capture card.
 They will have no effect, if your card does not have one.
 For v4l2 50 maps to the default value of the
 control, as reported by the driver.
+.IPs "gain=<0\-100> (v4l2)"
+Set gain control for video devices (usually webcams) to the desired
+value and switch off automatic control.
+A value of 0 enables automatic control.
+If this option is omitted, gain control will not be modified.
 .IPs immediatemode=<bool>
 A value of 0 means capture and buffer audio and video together
 (default for MEncoder).

cfg-common.h

@@ -436,6 +436,7 @@ m_option_t tvopts_conf[]={
 	{"contrast", &stream_tv_defaults.contrast, CONF_TYPE_INT, CONF_RANGE, -100, 100, NULL},
 	{"hue", &stream_tv_defaults.hue, CONF_TYPE_INT, CONF_RANGE, -100, 100, NULL},
 	{"saturation", &stream_tv_defaults.saturation, CONF_TYPE_INT, CONF_RANGE, -100, 100, NULL},
+	{"gain", &stream_tv_defaults.gain, CONF_TYPE_INT, CONF_RANGE, -1, 100, NULL},
 #if defined(HAVE_TV_V4L) || defined(HAVE_TV_V4L2)
 	{"amode", &stream_tv_defaults.amode, CONF_TYPE_INT, CONF_RANGE, 0, 3, NULL},
 	{"volume", &stream_tv_defaults.volume, CONF_TYPE_INT, CONF_RANGE, 0, 65535, NULL},

stream/stream_tv.c

@@ -72,6 +72,7 @@ tv_param_t stream_tv_defaults = {
     0,             //contrast
     0,             //hue
     0,             //saturation
+    -1,            //gain
     NULL,          //tdevice
     0,             //tformat
     100,           //tpage

stream/tv.c

@@ -759,6 +759,10 @@ no_audio:
     tv_set_color_options(tvh, TV_COLOR_SATURATION, tvh->tv_param->saturation);
     tv_set_color_options(tvh, TV_COLOR_CONTRAST, tvh->tv_param->contrast);
 
+    if(tvh->tv_param->gain!=-1)
+        if(funcs->control(tvh->priv,TVI_CONTROL_VID_SET_GAIN,&tvh->tv_param->gain)!=TVI_CONTROL_TRUE)
+            mp_msg(MSGT_TV,MSGL_WARN,"Unable to set gain control!\n");
+
     funcs->control(tvh->priv,TV_VBI_CONTROL_RESET,tvh->tv_param);
 
     return demuxer;

stream/tv.h

@@ -47,6 +47,7 @@ typedef struct tv_param_s {
     int contrast;
     int hue;
     int saturation;
+    int gain;
     char *tdevice;  ///< teletext device
     int tformat;    ///< teletext display format
     int tpage;      ///< start teletext page
@@ -151,6 +152,8 @@ typedef struct {
 #define TVI_CONTROL_VID_SET_CONTRAST	0x11c
 #define TVI_CONTROL_VID_GET_PICTURE	0x11d
 #define TVI_CONTROL_VID_SET_PICTURE	0x11e
+#define TVI_CONTROL_VID_SET_GAIN	0x11f
+#define TVI_CONTROL_VID_GET_GAIN	0x120
 
 /* TUNER controls */
 #define TVI_CONTROL_TUN_GET_FREQ	0x201

stream/tvi_v4l2.c

@@ -478,7 +478,6 @@ static int set_mute(priv_t *priv, int value)
 */
 static int set_control(priv_t *priv, struct v4l2_control *control, int val_signed) {
     struct v4l2_queryctrl        qctrl;
-
     qctrl.id = control->id;
     if (ioctl(priv->video_fd, VIDIOC_QUERYCTRL, &qctrl) < 0) {
         mp_msg(MSGT_TV, MSGL_ERR, "%s: ioctl query control failed: %s\n",
@@ -806,6 +805,40 @@ static int control(priv_t *priv, int cmd, void *arg)
             control.id = V4L2_CID_SATURATION;
             control.value = *(int *)arg;
             return set_control(priv, &control, 1);
+        case TVI_CONTROL_VID_GET_GAIN:
+        {
+
+            control.id = V4L2_CID_AUTOGAIN;
+            if(get_control(priv,&control,0)!=TVI_CONTROL_TRUE)
+                return TVI_CONTROL_FALSE;
+
+            if(control.value){ //Auto Gain control is enabled
+                *(int*)arg=0;
+                return TVI_CONTROL_TRUE;
+            }
+
+            //Manual Gain control
+            control.id = V4L2_CID_GAIN;
+            if(get_control(priv,&control,0)!=TVI_CONTROL_TRUE)
+                return TVI_CONTROL_FALSE;
+
+            *(int*)arg=control.value?control.value:1;
+
+            return TVI_CONTROL_TRUE;
+        }
+        case TVI_CONTROL_VID_SET_GAIN:
+        {
+            //value==0 means automatic gain control
+	    int value=*(int*)arg;
+
+            if (value < 0 || value>100)
+                return TVI_CONTROL_FALSE;
+
+            control.id=value?V4L2_CID_GAIN:V4L2_CID_AUTOGAIN;
+            control.value=value?value:1;
+
+            return set_control(priv,&control,0);
+        }
         case TVI_CONTROL_VID_GET_CONTRAST:
             control.id = V4L2_CID_CONTRAST;
             if (get_control(priv, &control, 1) == TVI_CONTROL_TRUE) {