diff options
| -rw-r--r-- | libhb/scan.c | 52 |
1 files changed, 38 insertions, 14 deletions
diff --git a/libhb/scan.c b/libhb/scan.c index 960332dfc..060daaecf 100644 --- a/libhb/scan.c +++ b/libhb/scan.c @@ -291,24 +291,26 @@ static int row_all_dark( hb_title_t *title, uint8_t* luma, int row ) return 1; } -static int column_all_dark( hb_title_t *title, uint8_t* luma, int top, int col ) +static int column_all_dark( hb_title_t *title, uint8_t* luma, int top, int bottom, + int col ) { int stride = title->width; + int height = title->height - top - bottom; luma += stride * top + col; // compute the average value of the column - int i = title->height - top, avg = 0, row = 0; + int i = height, avg = 0, row = 0; for ( ; --i >= 0; row += stride ) { avg += clampBlack( luma[row] ); } - avg /= title->height - top; + avg /= height; if ( avg >= DARK ) return 0; // since we're trying to detect smooth borders, only take the column if // all pixels are within +-16 of the average. - i = title->height - top, row = 0; + i = height, row = 0; for ( ; --i >= 0; row += stride ) { if ( absdiff( avg, clampBlack( luma[row] ) ) > 16 ) @@ -581,39 +583,61 @@ static int DecodePreviews( hb_scan_t * data, hb_title_t * title ) #define Y vid_buf->data int top, bottom, left, right; int h4 = title->height / 4, w4 = title->width / 4; - for ( top = 4; top < h4; ++top ) + + // When widescreen content is matted to 16:9 or 4:3 there's sometimes + // a thin border on the outer edge of the matte. On TV content it can be + // "line 21" VBI data that's normally hidden in the overscan. For HD + // content it can just be a diagnostic added in post production so that + // the frame borders are visible. We try to ignore these borders so + // we can crop the matte. The border width depends on the resolution + // (12 pixels on 1080i looks visually the same as 4 pixels on 480i) + // so we allow the border to be up to 1% of the frame height. + const int border = title->height / 100; + + for ( top = border; top < h4; ++top ) { if ( ! row_all_dark( title, Y, top ) ) break; } - if ( top < 5 ) + if ( top <= border ) { - // we started at row 4 to avoid the "line 21" noise that shows - // up on row 0 & 1 of some TV shows. Since we stopped before row 4 - // check if the missed rows are dark or if we shouldn't crop at all. - for ( top = 0; top < 4; ++top ) + // we never made it past the border region - see if the rows we + // didn't check are dark or if we shouldn't crop at all. + for ( top = 0; top < border; ++top ) { if ( ! row_all_dark( title, Y, top ) ) break; } - if ( top >= 4 ) + if ( top >= border ) { top = 0; } } - for ( bottom = 0; bottom < h4; ++bottom ) + for ( bottom = border; bottom < h4; ++bottom ) { if ( ! row_all_dark( title, Y, title->height - 1 - bottom ) ) break; } + if ( bottom <= border ) + { + for ( bottom = 0; bottom < border; ++bottom ) + { + if ( ! row_all_dark( title, Y, title->height - 1 - bottom ) ) + break; + } + if ( bottom >= border ) + { + bottom = 0; + } + } for ( left = 0; left < w4; ++left ) { - if ( ! column_all_dark( title, Y, top, left ) ) + if ( ! column_all_dark( title, Y, top, bottom, left ) ) break; } for ( right = 0; right < w4; ++right ) { - if ( ! column_all_dark( title, Y, top, title->width - 1 - right ) ) + if ( ! column_all_dark( title, Y, top, bottom, title->width - 1 - right ) ) break; } |