[FFmpeg-devel] [PATCH] swscale: implement YA8 output

[Paul B Mahol]

Signed-off-by: Paul B Mahol <onemda at gmail.com>
---

Are _1_c and _2_c actually needed?

---
 libswscale/output.c | 99 +++++++++++++++++++++++++++++++++++++++++++++++++++++
 libswscale/utils.c  |  2 +-
 2 files changed, 100 insertions(+), 1 deletion(-)

diff --git a/libswscale/output.c b/libswscale/output.c
index f63af3b..6538c6f 100644
--- a/libswscale/output.c
+++ b/libswscale/output.c
@@ -1917,6 +1917,100 @@ yuv2gbrp_full_X_c(SwsContext *c, const int16_t *lumFilter,
     }
 }
 
+static void
+yuv2ya8_1_c(SwsContext *c, const int16_t *buf0,
+            const int16_t *ubuf[2], const int16_t *vbuf[2],
+            const int16_t *abuf0, uint8_t *dest, int dstW,
+            int uvalpha, int y)
+{
+    const AVPixFmtDescriptor *desc = av_pix_fmt_desc_get(c->dstFormat);
+    int hasAlpha = (desc->flags & AV_PIX_FMT_FLAG_ALPHA) && abuf0;
+    int i;
+
+    for (i = 0; i < dstW; i++) {
+        int Y = (buf0[i] + 64) >> 7;
+        int A;
+
+        Y = av_clip_uint8(Y);
+
+        if (hasAlpha) {
+            A = (abuf0[i] + 64) >> 7;
+            if (A & 0x100)
+                A = av_clip_uint8(A);
+        }
+
+        dest[i * 2    ] = Y;
+        dest[i * 2 + 1] = hasAlpha ? A : 255;
+    }
+}
+
+static void
+yuv2ya8_2_c(SwsContext *c, const int16_t *buf[2],
+            const int16_t *ubuf[2], const int16_t *vbuf[2],
+            const int16_t *abuf[2], uint8_t *dest, int dstW,
+            int yalpha, int uvalpha, int y)
+{
+    const AVPixFmtDescriptor *desc = av_pix_fmt_desc_get(c->dstFormat);
+    int hasAlpha = (desc->flags & AV_PIX_FMT_FLAG_ALPHA) && abuf[0];
+    const int16_t *buf0  = buf[0],  *buf1  = buf[1],
+                  *abuf0 = hasAlpha ? abuf[0] : NULL,
+                  *abuf1 = hasAlpha ? abuf[1] : NULL;
+    int  yalpha1 = 4096 - yalpha;
+    int i;
+
+    for (i = 0; i < dstW; i++) {
+        int Y = (buf0[i * 2] * yalpha1 + buf1[i * 2] * yalpha) >> 19;
+        int A;
+
+        Y = av_clip_uint8(Y);
+
+        if (hasAlpha) {
+            A = (abuf0[i * 2] * yalpha1 + abuf1[i * 2] * yalpha) >> 19;
+            A = av_clip_uint8(A);
+        }
+
+        dest[i * 2    ] = Y;
+        dest[i * 2 + 1] = hasAlpha ? A : 255;
+    }
+}
+
+static void
+yuv2ya8_X_c(SwsContext *c, const int16_t *lumFilter,
+            const int16_t **lumSrc, int lumFilterSize,
+            const int16_t *chrFilter, const int16_t **chrUSrc,
+            const int16_t **chrVSrc, int chrFilterSize,
+            const int16_t **alpSrc, uint8_t *dest, int dstW, int y)
+{
+    const AVPixFmtDescriptor *desc = av_pix_fmt_desc_get(c->dstFormat);
+    int hasAlpha = (desc->flags & AV_PIX_FMT_FLAG_ALPHA) && alpSrc;
+    int i;
+
+    for (i = 0; i < dstW; i++) {
+        int j;
+        int Y = 1 << 18, A = 1 << 18;
+
+        for (j = 0; j < lumFilterSize; j++)
+            Y += lumSrc[j][i] * lumFilter[j];
+
+        Y >>= 19;
+        if (Y  & 0x100)
+            Y = av_clip_uint8(Y);
+
+        if (hasAlpha) {
+            for (j = 0; j < lumFilterSize; j++)
+                A += alpSrc[j][i] * lumFilter[j];
+
+            A >>= 19;
+
+            if (A & 0x100)
+                A = av_clip_uint8(A);
+        }
+
+        dest[2 * i    ] = Y;
+        dest[2 * i + 1] = hasAlpha ? A : 255;
+    }
+}
+
 av_cold void ff_sws_init_output_funcs(SwsContext *c,
                                       yuv2planar1_fn *yuv2plane1,
                                       yuv2planarX_fn *yuv2planeX,
@@ -2361,5 +2455,10 @@ av_cold void ff_sws_init_output_funcs(SwsContext *c,
         *yuv2packed2 = yuv2uyvy422_2_c;
         *yuv2packedX = yuv2uyvy422_X_c;
         break;
+    case AV_PIX_FMT_YA8:
+        *yuv2packed1 = yuv2ya8_1_c;
+        *yuv2packed2 = yuv2ya8_2_c;
+        *yuv2packedX = yuv2ya8_X_c;
+        break;
     }
 }
diff --git a/libswscale/utils.c b/libswscale/utils.c
index 074f8c0..c384aa5 100644
--- a/libswscale/utils.c
+++ b/libswscale/utils.c
@@ -166,7 +166,7 @@ static const FormatEntry format_entries[AV_PIX_FMT_NB] = {
     [AV_PIX_FMT_RGB444BE]    = { 1, 1 },
     [AV_PIX_FMT_BGR444LE]    = { 1, 1 },
     [AV_PIX_FMT_BGR444BE]    = { 1, 1 },
-    [AV_PIX_FMT_YA8]         = { 1, 0 },
+    [AV_PIX_FMT_YA8]         = { 1, 1 },
     [AV_PIX_FMT_YA16BE]      = { 1, 0 },
     [AV_PIX_FMT_YA16LE]      = { 1, 0 },
     [AV_PIX_FMT_BGR48BE]     = { 1, 1 },
-- 
1.7.11.2