v4l2 access can now find optimal frame rate and dimensions

Default is now to use the best available dimensions at the best framerate unless framerate was explicitly set, where it would use that frame rate.

modules/access/v4l2.c

@@ -102,13 +102,13 @@ static void AccessClose( vlc_object_t * );
     "IO Method (READ, MMAP, USERPTR)." )
 #define WIDTH_TEXT N_( "Width" )
 #define WIDTH_LONGTEXT N_( \
-    "Force width (-1 for autodetect)." )
+    "Force width (-1 for autodetect, 0 for driver default)." )
 #define HEIGHT_TEXT N_( "Height" )
 #define HEIGHT_LONGTEXT N_( \
-    "Force height (-1 for autodetect)." )
+    "Force height (-1 for autodetect, 0 for driver default)." )
 #define FPS_TEXT N_( "Framerate" )
 #define FPS_LONGTEXT N_( "Framerate to capture, if applicable " \
-    "(-1 for autodetect)." )
+    "(0 for autodetect)." )
 
 #define CTRL_RESET_TEXT N_( "Reset v4l2 controls" )
 #define CTRL_RESET_LONGTEXT N_( \
@@ -264,9 +264,9 @@ vlc_module_begin ()
     add_integer( CFG_PREFIX "io", IO_METHOD_MMAP, NULL, IOMETHOD_TEXT,
                  IOMETHOD_LONGTEXT, true );
         change_integer_list( i_iomethod_list, psz_iomethod_list_text, NULL );
-    add_integer( CFG_PREFIX "width", 0, NULL, WIDTH_TEXT,
+    add_integer( CFG_PREFIX "width", -1, NULL, WIDTH_TEXT,
                 WIDTH_LONGTEXT, true );
-    add_integer( CFG_PREFIX "height", 0, NULL, HEIGHT_TEXT,
+    add_integer( CFG_PREFIX "height", -1, NULL, HEIGHT_TEXT,
                 HEIGHT_LONGTEXT, true );
     add_float( CFG_PREFIX "fps", 0, NULL, FPS_TEXT, FPS_LONGTEXT, true )
     add_integer( CFG_PREFIX "caching", DEFAULT_PTS_DELAY / 1000, NULL,
@@ -1500,6 +1500,175 @@ static bool IsPixelFormatSupported( demux_t *p_demux, unsigned int i_pixelformat
     return false;
 }
 
+static float GetMaxFrameRate( demux_t *p_demux, int i_fd,
+                              uint32_t i_pixel_format,
+                              uint32_t i_width, uint32_t i_height )
+{
+    (void)p_demux;
+#ifdef VIDIOC_ENUM_FRAMEINTERVALS
+    /* This is new in Linux 2.6.19 */
+    struct v4l2_frmivalenum frmival;
+    frmival.index = 0;
+    frmival.pixel_format = i_pixel_format;
+    frmival.width = i_width;
+    frmival.height = i_height;
+    if( v4l2_ioctl( i_fd, VIDIOC_ENUM_FRAMEINTERVALS, &frmival ) >= 0 )
+    {
+        switch( frmival.type )
+        {
+            case V4L2_FRMIVAL_TYPE_DISCRETE:
+            {
+                float f_fps_max = -1;
+                do
+                {
+                    float f_fps = (float)frmival.discrete.denominator
+                                / (float)frmival.discrete.numerator;
+                    if( f_fps > f_fps_max ) f_fps_max = f_fps;
+                    frmival.index++;
+                } while( v4l2_ioctl( i_fd, VIDIOC_ENUM_FRAMEINTERVALS,
+                                     &frmival ) >= 0 );
+                return f_fps_max;
+            }
+            case V4L2_FRMSIZE_TYPE_STEPWISE:
+            case V4L2_FRMIVAL_TYPE_CONTINUOUS:
+                return __MAX( (float)frmival.stepwise.max.denominator
+                            / (float)frmival.stepwise.max.numerator,
+                              (float)frmival.stepwise.min.denominator
+                            / (float)frmival.stepwise.min.numerator );
+        }
+    }
+#endif
+    return -1.;
+}
+
+static float GetAbsoluteMaxFrameRate( demux_t *p_demux, int i_fd,
+                                      uint32_t i_pixel_format )
+{
+    float f_fps_max = -1.;
+#ifdef VIDIOC_ENUM_FRAMESIZES
+    /* This is new in Linux 2.6.19 */
+    struct v4l2_frmsizeenum frmsize;
+    frmsize.index = 0;
+    frmsize.pixel_format = i_pixel_format;
+    if( v4l2_ioctl( i_fd, VIDIOC_ENUM_FRAMESIZES, &frmsize ) >= 0 )
+    {
+        switch( frmsize.type )
+        {
+            case V4L2_FRMSIZE_TYPE_DISCRETE:
+                do
+                {
+                    frmsize.index++;
+                    float f_fps = GetMaxFrameRate( p_demux, i_fd,
+                                                   i_pixel_format,
+                                                   frmsize.discrete.width,
+                                                   frmsize.discrete.height );
+                    if( f_fps > f_fps_max ) f_fps_max = f_fps;
+                } while( v4l2_ioctl( i_fd, VIDIOC_ENUM_FRAMESIZES,
+                         &frmsize ) >= 0 );
+                break;
+            case V4L2_FRMSIZE_TYPE_STEPWISE:
+            {
+                uint32_t i_width = frmsize.stepwise.min_width;
+                uint32_t i_height = frmsize.stepwise.min_height;
+                for( ;
+                     i_width <= frmsize.stepwise.max_width &&
+                     i_height <= frmsize.stepwise.max_width;
+                     i_width += frmsize.stepwise.step_width,
+                     i_height += frmsize.stepwise.step_height )
+                {
+                    float f_fps = GetMaxFrameRate( p_demux, i_fd,
+                                                   i_pixel_format,
+                                                   i_width, i_height );
+                    if( f_fps > f_fps_max ) f_fps_max = f_fps;
+                }
+                break;
+            }
+            case V4L2_FRMSIZE_TYPE_CONTINUOUS:
+                /* FIXME */
+                msg_Err( p_demux, "GetAbsoluteMaxFrameRate implementation for V4L2_FRMSIZE_TYPE_CONTINUOUS isn't correct" );
+                 f_fps_max = GetMaxFrameRate( p_demux, i_fd,
+                                              i_pixel_format,
+                                              frmsize.stepwise.max_width,
+                                              frmsize.stepwise.max_height );
+                break;
+        }
+    }
+#endif
+    return f_fps_max;
+}
+
+static void GetMaxDimensions( demux_t *p_demux, int i_fd,
+                              uint32_t i_pixel_format, float f_fps_min,
+                              uint32_t *pi_width, uint32_t *pi_height )
+{
+    *pi_width = 0;
+    *pi_height = 0;
+#ifdef VIDIOC_ENUM_FRAMESIZES
+    /* This is new in Linux 2.6.19 */
+    struct v4l2_frmsizeenum frmsize;
+    frmsize.index = 0;
+    frmsize.pixel_format = i_pixel_format;
+    if( v4l2_ioctl( i_fd, VIDIOC_ENUM_FRAMESIZES, &frmsize ) >= 0 )
+    {
+        switch( frmsize.type )
+        {
+            case V4L2_FRMSIZE_TYPE_DISCRETE:
+                do
+                {
+                    frmsize.index++;
+                    float f_fps = GetMaxFrameRate( p_demux, i_fd,
+                                                   i_pixel_format,
+                                                   frmsize.discrete.width,
+                                                   frmsize.discrete.height );
+                    if( f_fps >= f_fps_min &&
+                        frmsize.discrete.width > *pi_width )
+                    {
+                        *pi_width = frmsize.discrete.width;
+                        *pi_height = frmsize.discrete.height;
+                    }
+                } while( v4l2_ioctl( i_fd, VIDIOC_ENUM_FRAMESIZES,
+                         &frmsize ) >= 0 );
+                break;
+            case V4L2_FRMSIZE_TYPE_STEPWISE:
+            {
+                uint32_t i_width = frmsize.stepwise.min_width;
+                uint32_t i_height = frmsize.stepwise.min_height;
+                for( ;
+                     i_width <= frmsize.stepwise.max_width &&
+                     i_height <= frmsize.stepwise.max_width;
+                     i_width += frmsize.stepwise.step_width,
+                     i_height += frmsize.stepwise.step_height )
+                {
+                    float f_fps = GetMaxFrameRate( p_demux, i_fd,
+                                                   i_pixel_format,
+                                                   i_width, i_height );
+                    if( f_fps >= f_fps_min && i_width > *pi_width )
+                    {
+                        *pi_width = i_width;
+                        *pi_height = i_height;
+                    }
+                }
+                break;
+            }
+            case V4L2_FRMSIZE_TYPE_CONTINUOUS:
+                /* FIXME */
+                msg_Err( p_demux, "GetMaxDimension implementation for V4L2_FRMSIZE_TYPE_CONTINUOUS isn't correct" );
+                float f_fps = GetMaxFrameRate( p_demux, i_fd,
+                                               i_pixel_format,
+                                               frmsize.stepwise.max_width,
+                                               frmsize.stepwise.max_height );
+                if( f_fps >= f_fps_min &&
+                    frmsize.stepwise.max_width > *pi_width )
+                {
+                    *pi_width = frmsize.stepwise.max_width;
+                    *pi_height = frmsize.stepwise.max_height;
+                }
+                break;
+        }
+    }
+#endif
+}
+
 /*****************************************************************************
  * OpenVideoDev: open and set up the video device and probe for capabilities
  *****************************************************************************/
@@ -1684,8 +1853,9 @@ static int OpenVideoDev( vlc_object_t *p_obj, demux_sys_t *p_sys, bool b_demux )
     memset( &fmt, 0, sizeof(fmt) );
     fmt.type = V4L2_BUF_TYPE_VIDEO_CAPTURE;
 
-    if( p_sys->i_width <= 0 || p_sys->i_height <= 0 )
+    if( p_sys->i_width == 0 || p_sys->i_height == 0 )
     {
+        /* Use current width and height settings */
         if( v4l2_ioctl( i_fd, VIDIOC_G_FMT, &fmt ) < 0 )
         {
             msg_Err( p_demux, "Cannot get default width and height." );
@@ -1700,8 +1870,13 @@ static int OpenVideoDev( vlc_object_t *p_obj, demux_sys_t *p_sys, bool b_demux )
             p_sys->i_height = p_sys->i_height * 2;
         }
     }
+    else if( p_sys->i_width < 0 || p_sys->i_height < 0 )
+    {
+        msg_Dbg( p_demux, "will try to find optimal width and height." );
+    }
     else
     {
+        /* Use user specified width and height */
         msg_Dbg( p_demux, "trying specified size %dx%d", p_sys->i_width, p_sys->i_height );
     }
 
@@ -1755,6 +1930,22 @@ static int OpenVideoDev( vlc_object_t *p_obj, demux_sys_t *p_sys, bool b_demux )
         }
     }
 
+    if( p_sys->i_width < 0 || p_sys->i_height < 0 )
+    {
+        if( p_sys->f_fps <= 0 )
+        {
+            p_sys->f_fps = GetAbsoluteMaxFrameRate( p_demux, i_fd,
+                                                    fmt.fmt.pix.pixelformat );
+            msg_Dbg( p_demux, "Found maximum framerate of %f", p_sys->f_fps );
+        }
+        GetMaxDimensions( p_demux, i_fd,
+                          fmt.fmt.pix.pixelformat, p_sys->f_fps,
+                          &fmt.fmt.pix.width, &fmt.fmt.pix.height );
+        msg_Dbg( p_demux, "Found optimal dimensions for framerate %f of %dx%d",
+                 p_sys->f_fps, fmt.fmt.pix.width, fmt.fmt.pix.height );
+        if( v4l2_ioctl( i_fd, VIDIOC_S_FMT, &fmt ) < 0 ) {;}
+    }
+
     /* Reassign width, height and chroma incase driver override */
     p_sys->i_width = fmt.fmt.pix.width;
     p_sys->i_height = fmt.fmt.pix.height;
@@ -1829,6 +2020,7 @@ static int OpenVideoDev( vlc_object_t *p_obj, demux_sys_t *p_sys, bool b_demux )
     }
 #endif
 
+
     /* Init IO method */
     switch( p_sys->io )
     {
@@ -2248,11 +2440,10 @@ static bool ProbeVideoDev( vlc_object_t *p_obj, demux_sys_t *p_sys,
             if( !b_codec_supported )
             {
                     msg_Dbg( p_obj,
-                         "device codec %4s (%s) not supported as access_demux",
+                         "device codec %4s (%s) not supported",
                          psz_fourcc_v4l2,
                          p_sys->p_codecs[i_index].description );
             }
-
         }
     }