[FFmpeg-devel] h264.c: interlaced_frame decission based on sei_ct_type seems to be incorrect

[Michael Niedermayer]

On Mon, Aug 02, 2010 at 12:54:48AM +0200, Reinhard Nissl wrote:
> Hi,
> 
> according to the specs, sei_ct_type values 0 and 2 are likely to
> indicate a progressive frame while 1 indicates an interlaced
> frame. So it looks to me like a typo, that the wrong bit is
> tested to derive interlaced_frame. Please see attached patch for
> a possible fix.
> 
> Bye.
> -- 
> Dipl.-Inform. (FH) Reinhard Nissl
> mailto:rnissl at gmx.de

>  h264.c |    2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 4f3b4271f60bd5b6479bd051eac0dabd6451c29f  h264_ct_type.diff
> Index: h264.c
> ===================================================================
> --- h264.c	(revision 24643)
> +++ h264.c	(working copy)
> @@ -3063,7 +3063,7 @@
>                  }
>  
>                  if ((h->sei_ct_type & 3) && h->sei_pic_struct <= SEI_PIC_STRUCT_BOTTOM_TOP)
> -                    cur->interlaced_frame = (h->sei_ct_type & (1<<1)) != 0;
> +                    cur->interlaced_frame = (h->sei_ct_type & (1<<0)) != 0;

you possibly missed how the field is initialized

h->sei_ct_type |= 1<<get_bits(&s->gb, 2);

[...]


-- 
Michael     GnuPG fingerprint: 9FF2128B147EF6730BADF133611EC787040B0FAB

The worst form of inequality is to try to make unequal things equal.
-- Aristotle
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