On Wed, 14 Nov 2012 03:42:37 -0500, Xi Wang <xi.w...@gmail.com> wrote: > The vertical offset mask 0x07 is suspicious. > > v_off = FFMIN(data[2] & 0x07, CDG_BORDER_HEIGHT - 1); > > Note that v_off is up to 11 (CDG_BORDER_HEIGHT - 1), the correct mask > should be 0x0F. > > Signed-off-by: Xi Wang <xi.w...@gmail.com> > --- > See "CD+G Revealed", section "Scroll Copy (subCode.instruction==24)". > > http://jbum.com/cdg_revealed.html > > SCmd = (vScroll & 0x30) >> 4; > VOffset = (vScroll & 0x0F); > > SCmd is a scrolliing instruction, which is either 0, 1 or 2. > 0 means don't scroll > 1 means scroll 12 pixels down, > 2 means scroll 12 pixels up. > > VOffset is a vertical offset which is used for offsetting the graphic > display by amounts less than 12 pixels. It can assume values from 0 to > 11. > --- > libavcodec/cdgraphics.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/libavcodec/cdgraphics.c b/libavcodec/cdgraphics.c > index 21de07e..631c415 100644 > --- a/libavcodec/cdgraphics.c > +++ b/libavcodec/cdgraphics.c > @@ -218,7 +218,7 @@ static void cdg_scroll(CDGraphicsContext *cc, uint8_t > *data, > vscmd = (data[2] & 0x30) >> 4; > > h_off = FFMIN(data[1] & 0x07, CDG_BORDER_WIDTH - 1); > - v_off = FFMIN(data[2] & 0x07, CDG_BORDER_HEIGHT - 1); > + v_off = FFMIN(data[2] & 0x0F, CDG_BORDER_HEIGHT - 1); > > /// find the difference and save the offset for cdg_tile_block usage > hinc = h_off - cc->hscroll; > -- > 1.7.10.4 >
LGTM, queueing. -- Anton Khirnov _______________________________________________ libav-devel mailing list libav-devel@libav.org https://lists.libav.org/mailman/listinfo/libav-devel
