[vlc-devel] [PATCH] Improved support for USF subtitles

Rémi Denis-Courmont remi at remlab.net
Mon May 29 13:24:46 CEST 2017


On May 29, 2017 1:48:54 PM GMT+03:00, Christopher Gundler <c.gundler at mail.de> wrote:
>From: Julius Schoening <julius.schoening at uni-osnabrueck.de>
>
>Hello Filip,
>thank you for your review of the patch. I have improve the code (and
>change the author to Julius) and re-sent it now that you might have a
>second look on it.
>
>Best Regards,
>Christopher
>
>---
>modules/codec/subsusf.c | 338
>++++++++++++++++++++++++++++++++++++++++++++++++
> 1 file changed, 338 insertions(+)
>
>diff --git a/modules/codec/subsusf.c b/modules/codec/subsusf.c
>index 1a94b6b4fd..a2f3dbdd8f 100644
>--- a/modules/codec/subsusf.c
>+++ b/modules/codec/subsusf.c
>@@ -24,6 +24,7 @@
> # include "config.h"
> #endif
> #include <assert.h>
>+#include <limits.h>
> 
> #include <vlc_common.h>
> #include <vlc_plugin.h>
>@@ -821,7 +822,166 @@ static void ParseUSFHeaderTags( decoder_t *p_dec,
>xml_reader_t *p_xml_reader )
>     free( p_ssa_style );
> }
> 
>+/**
>+ * Create a region with a white transparent picture.
>+ */
>+static subpicture_region_t *CreatePaintRegion( int x, int y, int
>width, int height )
>+{
>+    video_palette_t palette = {
>+        .i_entries = 2,
>+        .palette = {
>+            [0] = { 0xff, 0x80, 0x80, 0x00 },
>+            [1] = { 0xff, 0x80, 0x80, 0xff },
>+        },
>+    };
>+
>+    video_format_t fmt;
>+    video_format_Init( &fmt, VLC_CODEC_YUVP );
>+    fmt.i_width          =
>+    fmt.i_visible_width  = width;
>+    fmt.i_height         =
>+    fmt.i_visible_height = height;
>+    fmt.i_sar_num        = 1;
>+    fmt.i_sar_den        = 1;
>+    fmt.p_palette        = &palette;
>+
>+    subpicture_region_t *r = subpicture_region_New( &fmt );
>+    video_format_Clean( &fmt );
>+
>+    if ( !r )
>+        return NULL;
>+    r->i_x = x;
>+    r->i_y = y;
>+    memset( r->p_picture->p->p_pixels, 0, r->p_picture->p->i_pitch *
>height );
>+
>+    return r;
>+}
>+
>+/**
>+ * Draw a rectangle into a paint region
>+ */
>+static void DrawRect( subpicture_region_t *r,
>+                     int x1, int y1, int x2, int y2 )
>+{
>+    uint8_t *p    = r->p_picture->p->p_pixels;
>+    int     pitch = r->p_picture->p->i_pitch;
>+
>+    for ( int y = y1; y <= y2; y++ )
>+    {
>+        p[x1 + pitch * y] = 1;
>+        p[x2 + pitch * y] = 1;
>+    }
>+
>+    for ( int x = x1; x <= x2; x++ ) {
>+        p[x + pitch * y1] = 1;
>+        p[x + pitch * y2] = 1;
>+    }
>+}
>+
>+struct polydata {
>+    int x;
>+    int y;
>+    struct polydata *next;
>+};
>+typedef struct polydata polydata;
>+
>+static void DrawPoly( subpicture_region_t *r, polydata *root )
>+{
>+    uint8_t *pY    = r->p_picture->p[Y_PLANE].p_pixels;
>+    int     pitchY = r->p_picture->p[Y_PLANE].i_pitch;
>+
>+    polydata *curr = root;
>+
>+    do
>+    {
>+        // if end of list, set next to root for closed polygon
>+        polydata *next = curr->next == NULL ? root : curr->next;
>+
>+        int x0 = curr->x;
>+        int y0 = curr->y;
>+        int x1 = next->x;
>+        int y1 = next->y;
>+
>+        // bresenham's line algorithm
>+        // from
>http://rosettacode.org/wiki/Bitmap/Bresenham%27s_line_algorithm#C
>+        int dx = abs( x1 - x0 ), sx = x0 < x1 ? 1 : -1;
>+        int dy = abs( y1 - y0 ), sy = y0 < y1 ? 1 : -1;
>+        int err = ( dx > dy ? dx : -dy ) / 2, e2;
>+
>+        for( ; ; )
>+        {
>+            pY[ x0 + pitchY * y0 ] = 1;
>+            if ( x0 == x1 && y0 == y1 )
>+              break;
>+
>+            e2 = err;
>+
>+            if ( e2 >- dx )
>+            {
>+                err -= dy;
>+                x0 += sx;
>+            }
>+
>+            if ( e2 < dy )
>+            {
>+                err += dx;
>+                y0 += sy;
>+            }
>+        }
>+    }
>+    while( ( curr = curr->next ) != NULL );
>+}
>+
>+static void DrawCircle( subpicture_region_t *r, int x0, int y0, int
>diameter )
>+{
>+    uint8_t *pY    = r->p_picture->p[Y_PLANE].p_pixels;
>+    int     pitchY = r->p_picture->p[Y_PLANE].i_pitch;
> 
>+    // bresenham's circle algorithm
>+    // slightly optimized from
>https://de.wikipedia.org/wiki/Bresenham-Algorithmus#Kreisvariante_des_Algorithmus
>+    int x = diameter / 2;
>+    int y = 0;
>+    int err = x;
>+
>+    while( y <= x )
>+    {
>+        pY[ ( x0 + x ) + pitchY * ( y0 + y ) ] = 1;
>+        pY[ ( x0 - x ) + pitchY * ( y0 + y ) ] = 1;
>+        pY[ ( x0 + x ) + pitchY * ( y0 - y ) ] = 1;
>+        pY[ ( x0 - x ) + pitchY * ( y0 - y ) ] = 1;
>+        pY[ ( x0 + y ) + pitchY * ( y0 + x ) ] = 1;
>+        pY[ ( x0 - y ) + pitchY * ( y0 + x ) ] = 1;
>+        pY[ ( x0 + y ) + pitchY * ( y0 - x ) ] = 1;
>+        pY[ ( x0 - y ) + pitchY * ( y0 - x ) ] = 1;
>+        err -= 2 * y;
>+        err++;
>+        y++;
>+
>+        if(err < 0)
>+        {
>+            err--;
>+            err += 2*x;
>+            x--;
>+        }
>+    }
>+}
>+
>+static int ParseInteger(char *str)
>+{
>+    long int value = strtol( str, NULL, 10 );
>+    if ( value >= INT_MIN && value <= INT_MAX)
>+    {
>+        return (int) value;
>+    }
>+    else if( value < INT_MIN )
>+    {
>+        return INT_MIN;
>+    }
>+    else
>+    {
>+        return INT_MAX;
>+    }
>+}
> 
> static subpicture_region_t *ParseUSFString( decoder_t *p_dec,
>                                             char *psz_subtitle )
>@@ -917,6 +1077,184 @@ static subpicture_region_t *ParseUSFString(
>decoder_t *p_dec,
>                     p_region_upto = p_region_upto->p_next;
>                 }
>             }
>+            else if(( !strncasecmp( psz_subtitle, "<polygon ", 9 )) ||
>+                    ( !strncasecmp( psz_subtitle, "<polygon>", 9 )))
>+            {
>+                psz_end = strstr ( psz_subtitle, "</polygon>" );
>+
>+                polydata *p_root = NULL;
>+                polydata **pp_next = &p_root;
>+
>+                char *psz_point_start, *psz_point_end = NULL;
>+
>+                // Iterate thought the points of the polygon by moving
>the pointer.
>+                // For performance and readability reasons, the
>assignments are exceptionally made in the condition part.
>+                for(char *data = psz_subtitle;
>+                  data < psz_end && ( psz_point_start = strstr( data,
>"<point " ) ) != NULL && ( psz_point_end = strstr( psz_point_start,
>"/>" ) ) != NULL;
>+                  data = psz_point_end + 2)
>+                {
>+                    char *psz_point_x = GrabAttributeValue( "posx",
>psz_point_start );
>+                    char *psz_point_y = GrabAttributeValue( "posy",
>psz_point_start );
>+                    *pp_next = malloc( sizeof( polydata ) );
>+
>+                    if ( psz_point_x && psz_point_y && pp_next )
>+                    {
>+                        ( *pp_next )->x = ParseInteger( psz_point_x );
>+                        ( *pp_next )->y = ParseInteger( psz_point_y );
>+                        pp_next = &( ( *pp_next )->next );
>+                    }
>+                    else
>+                    {
>+                        pp_next = NULL;
>+                    }
>+
>+                    free( psz_point_x );
>+                    free( psz_point_y );
>+                }
>+
>+                if ( pp_next )
>+                {
>+                    // create and draw picture region
>+                    subpicture_region_t *p_paint_region;
>+                    p_paint_region = CreatePaintRegion( 0, 0,
>p_sys->i_original_width + 1, p_sys->i_original_height + 1 );
>+
>+                    if( p_paint_region != NULL )
>+                    {
>+                        DrawPoly( p_paint_region, p_root );
>+
>+                        // save picture region in list
>+                        if( !p_region_first )
>+                        {
>+                            p_region_first = p_region_upto =
>p_paint_region;
>+                        }
>+                        else if( p_paint_region )
>+                        {
>+                            p_region_upto->p_next = p_paint_region;
>+                            p_region_upto = p_region_upto->p_next;
>+                        }
>+                    }
>+                }
>+
>+                // free linked list
>+                while( p_root )
>+                {
>+                    polydata *p_tmp = p_root;
>+                    p_root = p_root->next;
>+                    free(p_tmp);
>+                }
>+            }
>+            else if ( !strncasecmp( psz_subtitle, "<rectangle ", 11 ))
>+            {
>+                // get the end of the rectangle
>+                psz_end = strstr ( psz_subtitle,"/>" );
>+
>+                // read attributes of rectangle
>+                char *psz_rec_x = GrabAttributeValue( "posx",
>psz_subtitle );
>+                char *psz_rec_y = GrabAttributeValue( "posy",
>psz_subtitle );
>+                char *psz_rec_width = GrabAttributeValue( "width",
>psz_subtitle );
>+                char *psz_rec_height = GrabAttributeValue( "height",
>psz_subtitle );
>+
>+                if ( psz_rec_x && psz_rec_y && psz_rec_width &&
>psz_rec_height )
>+                {
>+                    // create and draw picture region
>+                    subpicture_region_t *p_paint_region;
>+                    p_paint_region = CreatePaintRegion( 0, 0,
>p_sys->i_original_width + 1, p_sys->i_original_height + 1 );
>+
>+                    if( p_paint_region != NULL )
>+                    {
>+                        // convert to int
>+                        int x = ParseInteger( psz_rec_x );
>+                        int y = ParseInteger( psz_rec_y );
>+                        int w = ParseInteger( psz_rec_width );
>+                        int h = ParseInteger( psz_rec_height );
>+
>+                        DrawRect( p_paint_region, x, y, x + w, y + h
>);
>+
>+                        // save picture region in list
>+                        if( !p_region_first )
>+                        {
>+                          p_region_first = p_region_upto =
>p_paint_region;
>+                        }
>+                        else if( p_paint_region )
>+                        {
>+                          p_region_upto->p_next = p_paint_region;
>+                          p_region_upto = p_region_upto->p_next;
>+                        }
>+                    }
>+                }
>+
>+                free( psz_rec_x );
>+                free( psz_rec_y );
>+                free( psz_rec_width );
>+                free( psz_rec_height );
>+            }
>+            else if ( !strncasecmp( psz_subtitle, "<point ", 7 ) )
>+            {
>+                // get the end of the point
>+                psz_end = strstr ( psz_subtitle, "/>" );
>+
>+                // read attributes of point
>+                char *psz_point_x = GrabAttributeValue( "posx",
>psz_subtitle );
>+                char *psz_point_y = GrabAttributeValue( "posy",
>psz_subtitle );
>+                char *psz_point_d = GrabAttributeValue( "diameter",
>psz_subtitle );
>+
>+                if ( psz_point_x && psz_point_y && psz_point_d )
>+                {
>+                     // create and draw picture region
>+                    subpicture_region_t *p_paint_region;
>+                    p_paint_region = CreatePaintRegion( 0, 0,
>p_sys->i_original_width + 1, p_sys->i_original_height + 1 );
>+
>+                    if( p_paint_region != NULL )
>+                    {
>+                        // convert to int
>+                        int x = ParseInteger( psz_point_x );
>+                        int y = ParseInteger( psz_point_y );
>+                        int d = ParseInteger( psz_point_d );
>+
>+                        DrawCircle( p_paint_region, x, y, d );
>+
>+                        // save picture region in list
>+                        if( !p_region_first )
>+                        {
>+                          p_region_first = p_region_upto =
>p_paint_region;
>+                        }
>+                        else if( p_paint_region )
>+                        {
>+                          p_region_upto->p_next = p_paint_region;
>+                          p_region_upto = p_region_upto->p_next;
>+                        }
>+                    }
>+                }
>+
>+                free( psz_point_x );
>+                free( psz_point_y );
>+                free( psz_point_d );
>+            }
>+            else if(( !strncasecmp( psz_subtitle, "<text ", 6 )) ||
>+                    ( !strncasecmp( psz_subtitle, "<text>", 6 )))
>+            {
>+                subpicture_region_t  *p_text_region;
>+                psz_end = strstr( psz_subtitle, "</text>" );
>+                p_text_region = CreateTextRegion( p_dec,
>+                                                  psz_subtitle,
>+                                                  p_sys->i_align );
>+
>+                if( p_text_region )
>+                {
>+                    free( p_text_region->p_text->psz_text );
>+                    p_text_region->p_text->psz_text = CreatePlainText(
>psz_subtitle );
>+                }
>+
>+                if( !p_region_first )
>+                {
>+                    p_region_first = p_region_upto = p_text_region;
>+                }
>+                else if( p_text_region )
>+                {
>+                    p_region_upto->p_next = p_text_region;
>+                    p_region_upto = p_region_upto->p_next;
>+                }
>+            }
>             else
>             {
>                 subpicture_region_t  *p_text_region;
>-- 
>2.12.2
>
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There is a glaring invalid free in the first few lines. I stopped reviewing there.
-- 
Rémi Denis-Courmont


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