decompanding curve or offset were required ticket #6265
---
libavcodec/cfhd.c | 19 +++++++++++++++++++
1 file changed, 19 insertions(+)
diff --git a/libavcodec/cfhd.c b/libavcodec/cfhd.c
index a064cd1599..480bf93566 100644
--- a/libavcodec/cfhd.c
+++ b/libavcodec/cfhd.c
@@ -94,6 +94,22 @@ static inline int dequant_and_decompand(int level, int
quantisation)
FFSIGN(level) * quantisation;
}
+static inline void process_alpha(int16_t *alpha, int width)
+{
+ int alphacompandDCoffset = 256;
+ int alphacompandGain = 9400;
+ int i, channel;
+ for (i = 0; i < width; i++) {
+ channel = alpha[i];
+ channel -= alphacompandDCoffset;
+ channel <<= 3;
+ channel *= alphacompandGain;
+ 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 +808,9 @@ 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
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