Hi,
On Tue, Aug 16, 2011 at 8:05 AM, Diego Biurrun <di...@biurrun.de> wrote:
> From: Jeff Downs <heydo...@somuchpressure.net>
>
> Correct computation of implicit weight tables when referencing pictures
> that are marked for long reference.
>
> Signed-off-by: Diego Biurrun <di...@biurrun.de>
> ---
> libavcodec/h264.c | 20 +++++++++++---------
> 1 files changed, 11 insertions(+), 9 deletions(-)
>
> diff --git a/libavcodec/h264.c b/libavcodec/h264.c
> index a9a6c8c..5d42ed3 100644
> --- a/libavcodec/h264.c
> +++ b/libavcodec/h264.c
> @@ -2174,15 +2174,17 @@ static void implicit_weight_table(H264Context *h, int
> field){
> for(ref0=ref_start; ref0 < ref_count0; ref0++){
> int poc0 = h->ref_list[0][ref0].poc;
> for(ref1=ref_start; ref1 < ref_count1; ref1++){
> - int poc1 = h->ref_list[1][ref1].poc;
> - int td = av_clip(poc1 - poc0, -128, 127);
> - int w= 32;
> - if(td){
> - int tb = av_clip(cur_poc - poc0, -128, 127);
> - int tx = (16384 + (FFABS(td) >> 1)) / td;
> - int dist_scale_factor = (tb*tx + 32) >> 8;
> - if(dist_scale_factor >= -64 && dist_scale_factor <= 128)
> - w = 64 - dist_scale_factor;
> + int w = 32;
> + if (!h->ref_list[0][ref0].long_ref &&
> !h->ref_list[1][ref1].long_ref) {
> + int poc1 = h->ref_list[1][ref1].poc;
> + int td = av_clip(poc1 - poc0, -128, 127);
> + if(td){
> + int tb = av_clip(cur_poc - poc0, -128, 127);
> + int tx = (16384 + (FFABS(td) >> 1)) / td;
> + int dist_scale_factor = (tb*tx + 32) >> 8;
> + if(dist_scale_factor >= -64 && dist_scale_factor <= 128)
> + w = 64 - dist_scale_factor;
> + }
Which sample/bug does this fix? I really have no idea if this is
correct without spending some significant time on the spec right
now... Jason, Loren, do you guys know?
Ronald
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