[FFmpeg-devel] [PATCH] lavc/cfhd:fixed alpha channel decoding in gbrap12

[Gagandeep Singh]

On Tue, 20 Mar 2018, 12:44 Gagandeep Singh, <deepgagan231197 at gmail.com>
wrote:

> alpha channel required a post processing after it's decoding
> ---
>  libavcodec/cfhd.c | 15 +++++++++++++++
>  1 file changed, 15 insertions(+)
>
> diff --git a/libavcodec/cfhd.c b/libavcodec/cfhd.c
> index a064cd1599..d64acab8d4 100644
> --- a/libavcodec/cfhd.c
> +++ b/libavcodec/cfhd.c
> @@ -94,6 +94,19 @@ static inline int dequant_and_decompand(int level, int
> quantisation)
>             FFSIGN(level) * quantisation;
>  }
>
> +static inline void process_alpha(int16_t *alpha, int width)
> +{
> +    int i, channel;
> +    for (i = 0; i < width; i++){
> +        channel   = alpha[i];
> +        channel  -= 16 << 4;
> +        channel <<= 8;
> +        channel  -= 128;
> +        channel  /= 223;
> +        alpha[i]  = channel;
> +    }
> +}
> +
>  static inline void filter(int16_t *output, ptrdiff_t out_stride,
>                            int16_t *low, ptrdiff_t low_stride,
>                            int16_t *high, ptrdiff_t high_stride,
> @@ -792,6 +805,8 @@ static int cfhd_decode(AVCodecContext *avctx, void
> *data, int *got_frame,
>          high = s->plane[plane].l_h[7];
>          for (i = 0; i < lowpass_height * 2; i++) {
>              horiz_filter_clip(dst, low, high, lowpass_width, s->bpc);
> +            if(act_plane == 3)
> +                process_alpha(dst, lowpass_width * 2);
>              low  += lowpass_width;
>              high += lowpass_width;
>              dst  += pic->linesize[act_plane] / 2;
> --
> 2.14.1
>

ticket #6265, oops forgot this

>