On Wed, 21 Mar 2018, 22:20 Gagandeep Singh, <deepgagan231...@gmail.com> wrote:
> alpha decompanding curve added to post process the decoded alpha channel > --- > libavcodec/cfhd.c | 19 +++++++++++++++++++ > 1 file changed, 19 insertions(+) > > diff --git a/libavcodec/cfhd.c b/libavcodec/cfhd.c > index fd5555834b..e35732df45 100644 > --- a/libavcodec/cfhd.c > +++ b/libavcodec/cfhd.c > @@ -37,6 +37,9 @@ > #include "thread.h" > #include "cfhd.h" > > +#define ALPHA_COMPAND_DC_OFFSET 256 > +#define ALPHA_COMPAND_GAIN 9400 > + > enum CFHDParam { > ChannelCount = 12, > SubbandCount = 14, > @@ -94,6 +97,20 @@ 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 -= ALPHA_COMPAND_DC_OFFSET; > + channel <<= 3; > + channel *= ALPHA_COMPAND_GAIN; > + channel >>= 16; > + channel = av_clip_uintp2(channel, 12); > + 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 +809,8 @@ 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 > _______________________________________________ ffmpeg-devel mailing list ffmpeg-devel@ffmpeg.org http://ffmpeg.org/mailman/listinfo/ffmpeg-devel