static picture_t *Filter( filter_t *, picture_t * );
static int alloc_init( filter_t *, void * );
-#define WIDTH_TEXT N_( "Image width" )
+/* This module effectively implements a form of picture-in-picture.
+ * - The outer picture is called the canvas.
+ * - The innter picture is callsed the subpicture.
+ *
+ * NB, all of the following operatons take into account aspect ratio
+ *
+ * A canvas is of canvas_{width,height}.
+ * In Pad mode:
+ * - The subpicture is upconverted with a inverse scalefactor of:
+ * (The size of subpicture's largest dimension)
+ * --------------------------------------------
+ * (The size of canvas's equivalent dimension)
+ *
+ * Ie, The subpicture's largest dimension is made equal to the
+ * equivalent canvas dimension.
+ *
+ * - The upconverted subpicture's smallest dimension is then padded
+ * to make the upconverted subpicture have the same dimensions of
+ * the canvas.
+ *
+ * In Crop mode:
+ * - The subpicture is upconverted with an inverse scalefactor of:
+ * (The size of subpicture's smallest dimension)
+ * --------------------------------------------
+ * (The size of canvas's equivalent dimension)
+ *
+ * Ie, The subpicture's smallest dimension is made equal to the
+ * equivalent canvas dimension. (The subpicture will then be
+ * larger than the canvas)
+ *
+ * - The upconverted subpicture's largest dimension is then cropped
+ * to make the upconverted subpicture have the same dimensions of
+ * the canvas.
+ */
+
+/* NB, use of `padd' in this module is a 16-17th Century spelling of `pad' */
+
+#define WIDTH_TEXT N_( "Output width" )
#define WIDTH_LONGTEXT N_( \
- "Image width" )
-#define HEIGHT_TEXT N_( "Image height" )
+ "Output (canvas) image width" )
+#define HEIGHT_TEXT N_( "Output height" )
#define HEIGHT_LONGTEXT N_( \
- "Image height" )
-#define ASPECT_TEXT N_( "Aspect ratio" )
+ "Output (canvas) image height" )
+#define ASPECT_TEXT N_( "Output picture aspect ratio" )
#define ASPECT_LONGTEXT N_( \
- "Set aspect (like 4:3) of the video canvas" )
-#define PADD_TEXT N_( "Padd video" )
+ "Set the canvas' picture aspect ratio. " \
+ "If omitted, the canvas is assumed to have the same SAR as the input." )
+#define PADD_TEXT N_( "Pad video" )
#define PADD_LONGTEXT N_( \
"If enabled, video will be padded to fit in canvas after scaling. " \
"Otherwise, video will be cropped to fix in canvas after scaling." )
* Module descriptor
*****************************************************************************/
vlc_module_begin ()
- set_description( N_("Automatically resize and padd a video") )
+ set_description( N_("Automatically resize and pad a video") )
set_capability( "video filter2", 0 )
set_callbacks( Activate, Destroy )
add_integer_with_range( CFG_PREFIX "height", 0, 0, INT_MAX, NULL,
HEIGHT_TEXT, HEIGHT_LONGTEXT, false )
- add_string( CFG_PREFIX "aspect", "4:3", NULL,
+ add_string( CFG_PREFIX "aspect", NULL, NULL,
ASPECT_TEXT, ASPECT_LONGTEXT, false )
add_bool( CFG_PREFIX "padd", true, NULL,
static int Activate( vlc_object_t *p_this )
{
filter_t *p_filter = (filter_t *)p_this;
- unsigned int i_width, i_height;
- es_format_t fmt;
+ unsigned i_canvas_width; /* width of output canvas */
+ unsigned i_canvas_height; /* height of output canvas */
+ unsigned i_canvas_aspect; /* canvas PictureAspectRatio */
+ es_format_t fmt; /* target format after up/down conversion */
char psz_croppadd[100];
int i_padd,i_offset;
char *psz_aspect, *psz_parser;
- int i_aspect;
bool b_padd;
if( !p_filter->b_allow_fmt_out_change )
config_ChainParse( p_filter, CFG_PREFIX, ppsz_filter_options,
p_filter->p_cfg );
- i_width = var_CreateGetInteger( p_filter, CFG_PREFIX "width" );
- i_height = var_CreateGetInteger( p_filter, CFG_PREFIX "height" );
+ i_canvas_width = var_CreateGetInteger( p_filter, CFG_PREFIX "width" );
+ i_canvas_height = var_CreateGetInteger( p_filter, CFG_PREFIX "height" );
- if( i_width == 0 || i_height == 0 )
+ if( i_canvas_width == 0 || i_canvas_height == 0 )
{
msg_Err( p_filter, "Width and height options must be set" );
return VLC_EGENERIC;
}
- if( i_width & 1 || i_height & 1 )
+ if( i_canvas_width & 1 || i_canvas_height & 1 )
{
+ /* If this restriction were ever relaxed, it is very important to
+ * get the field polatiry correct */
msg_Err( p_filter, "Width and height options must be even integers" );
return VLC_EGENERIC;
}
psz_aspect = var_CreateGetNonEmptyString( p_filter, CFG_PREFIX "aspect" );
- if( !psz_aspect )
+ if( psz_aspect )
{
- msg_Err( p_filter, "Aspect ratio must be set" );
- return VLC_EGENERIC;
+ psz_parser = strchr( psz_aspect, ':' );
+ int numerator = atoi( psz_aspect );
+ int denominator = psz_parser ? atoi( psz_parser+1 ) : 0;
+ denominator = denominator == 0 ? 1 : denominator;
+ i_canvas_aspect = numerator * VOUT_ASPECT_FACTOR / denominator;
+ free( psz_aspect );
+
+ if( numerator <= 0 || denominator < 0 )
+ {
+ msg_Err( p_filter, "Aspect ratio must be strictly positive" );
+ return VLC_EGENERIC;
+ }
}
- psz_parser = strchr( psz_aspect, ':' );
- if( psz_parser ) psz_parser++;
- if( psz_parser && atoi( psz_parser ) > 0 )
- i_aspect = atoi( psz_aspect ) * VOUT_ASPECT_FACTOR / atoi( psz_parser );
else
- i_aspect = atof( psz_aspect ) * VOUT_ASPECT_FACTOR;
- free( psz_aspect );
-
- if( i_aspect <= 0 )
{
- msg_Err( p_filter, "Aspect ratio must be strictly positive" );
- return VLC_EGENERIC;
+ /* if there is no user supplied aspect ratio, assume the canvas
+ * has the same sample aspect ratio as the subpicture */
+ /* aspect = subpic_sar * canvas_width / canvas_height
+ * where subpic_sar = subpic_ph * subpic_par / subpic_pw */
+ i_canvas_aspect = (uint64_t) p_filter->fmt_in.video.i_height
+ * p_filter->fmt_in.video.i_aspect
+ * i_canvas_width
+ / (i_canvas_height * p_filter->fmt_in.video.i_width);
}
b_padd = var_CreateGetBool( p_filter, CFG_PREFIX "padd" );
es_format_Copy( &fmt, &p_filter->fmt_in );
- fmt.video.i_width = i_width;
- fmt.video.i_height = ( p_filter->fmt_in.video.i_height * i_width )
- / p_filter->fmt_in.video.i_width;
- fmt.video.i_height = ( fmt.video.i_height * i_aspect )
- / p_filter->fmt_in.video.i_aspect;
+ /* one dimension will end up with one of the following: */
+ fmt.video.i_width = i_canvas_width;
+ fmt.video.i_height = i_canvas_height;
if( b_padd )
{
/* Padd */
- if( fmt.video.i_height > i_height )
+ if( i_canvas_aspect > p_filter->fmt_in.video.i_aspect )
{
- fmt.video.i_height = i_height;
- fmt.video.i_width = ( p_filter->fmt_in.video.i_width * i_height )
- / p_filter->fmt_in.video.i_height;
- fmt.video.i_width = ( fmt.video.i_width * p_filter->fmt_in.video.i_aspect )
- / i_aspect;
+ /* The canvas has a wider aspect than the subpicture:
+ * ie, pillarbox the [scaled] subpicture */
+ /* The following is derived form:
+ * width = upconverted_subpic_height * subpic_par / canvas_sar
+ * where canvas_sar = canvas_width / (canvas_height * canvas_par)
+ * then simplify */
+ fmt.video.i_width = i_canvas_width
+ * p_filter->fmt_in.video.i_aspect
+ / i_canvas_aspect;
if( fmt.video.i_width & 1 ) fmt.video.i_width -= 1;
- i_padd = (i_width - fmt.video.i_width) / 2;
+ i_padd = (i_canvas_width - fmt.video.i_width) / 2;
i_offset = (i_padd & 1);
- /* Gruik */
snprintf( psz_croppadd, 100, "croppadd{paddleft=%d,paddright=%d}",
i_padd - i_offset, i_padd + i_offset );
}
else
{
+ /* The canvas has a taller aspect than the subpicture:
+ * ie, letterbox the [scaled] subpicture */
+ fmt.video.i_height = i_canvas_height
+ * i_canvas_aspect
+ / p_filter->fmt_in.video.i_aspect;
if( fmt.video.i_height & 1 ) fmt.video.i_height -= 1;
- i_padd = (i_height - fmt.video.i_height ) / 2;
+
+ i_padd = (i_canvas_height - fmt.video.i_height ) / 2;
i_offset = (i_padd & 1);
- /* Gruik */
snprintf( psz_croppadd, 100, "croppadd{paddtop=%d,paddbottom=%d}",
i_padd - i_offset, i_padd + i_offset );
}
else
{
/* Crop */
- if( fmt.video.i_height < i_height )
+ if( i_canvas_aspect < p_filter->fmt_in.video.i_aspect )
{
- fmt.video.i_height = i_height;
- fmt.video.i_width = ( p_filter->fmt_in.video.i_width * i_height )
- / p_filter->fmt_in.video.i_height;
- fmt.video.i_width = ( fmt.video.i_width * p_filter->fmt_in.video.i_aspect )
- / i_aspect;
+ /* The canvas has a narrower aspect than the subpicture:
+ * ie, crop the [scaled] subpicture horizontally */
+ fmt.video.i_width = i_canvas_width
+ * p_filter->fmt_in.video.i_aspect
+ / i_canvas_aspect;
if( fmt.video.i_width & 1 ) fmt.video.i_width -= 1;
- i_padd = (fmt.video.i_width - i_width) / 2;
- i_offset = (i_padd & 1);
- /* Gruik */
+ i_padd = (fmt.video.i_width - i_canvas_width) / 2;
+ i_offset = (i_padd & 1);
snprintf( psz_croppadd, 100, "croppadd{cropleft=%d,cropright=%d}",
i_padd - i_offset, i_padd + i_offset );
}
else
{
+ /* The canvas has a shorter aspect than the subpicture:
+ * ie, crop the [scaled] subpicture vertically */
+ fmt.video.i_height = i_canvas_height
+ * i_canvas_aspect
+ / p_filter->fmt_in.video.i_aspect;
if( fmt.video.i_height & 1 ) fmt.video.i_height -= 1;
- i_padd = (fmt.video.i_height - i_height) / 2;
+
+ i_padd = (fmt.video.i_height - i_canvas_height) / 2;
i_offset = (i_padd & 1);
- /* Gruik */
snprintf( psz_croppadd, 100, "croppadd{croptop=%d,cropbottom=%d}",
i_padd - i_offset, i_padd + i_offset );
}
}
+ /* xxx, should the clean area include the letter-boxing?
+ * probably not, as some codecs can make use of that information
+ * and it should be a scaled version of the input clean area
+ * -- davidf */
fmt.video.i_visible_width = fmt.video.i_width;
fmt.video.i_visible_height = fmt.video.i_height;
fmt = *filter_chain_GetFmtOut( p_sys->p_chain );
es_format_Copy( &p_filter->fmt_out, &fmt );
- p_filter->fmt_out.video.i_aspect = i_aspect * i_width / i_height;
+ p_filter->fmt_out.video.i_aspect = i_canvas_aspect;
- if( p_filter->fmt_out.video.i_width != i_width
- || p_filter->fmt_out.video.i_height != i_height )
+ if( p_filter->fmt_out.video.i_width != i_canvas_width
+ || p_filter->fmt_out.video.i_height != i_canvas_height )
{
msg_Warn( p_filter, "Looks like something went wrong. "
"Output size is %dx%d while we asked for %dx%d",
p_filter->fmt_out.video.i_width,
p_filter->fmt_out.video.i_height,
- i_width, i_height );
+ i_canvas_width, i_canvas_height );
}
p_filter->pf_video_filter = Filter;
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