sw_scale: Add specializations for hscale 16 to 15

Add arm64 neon implementations for hscale 16 to 15 with filter
sizes 4, 8 and X4.

The tests and benchmarks run on AWS Graviton 2 instances.
The results from a checkasm tool are shown below.

hscale_16_to_15__fs_4_dstW_512_c: 6703.5
hscale_16_to_15__fs_4_dstW_512_neon: 2298.0
hscale_16_to_15__fs_8_dstW_512_c: 10983.0
hscale_16_to_15__fs_8_dstW_512_neon: 3216.5
hscale_16_to_15__fs_12_dstW_512_c: 15526.0
hscale_16_to_15__fs_12_dstW_512_neon: 3993.0
hscale_16_to_15__fs_16_dstW_512_c: 20183.5
hscale_16_to_15__fs_16_dstW_512_neon: 5369.7
hscale_16_to_15__fs_32_dstW_512_c: 39315.2
hscale_16_to_15__fs_32_dstW_512_neon: 9511.2
hscale_16_to_15__fs_40_dstW_512_c: 48995.7
hscale_16_to_15__fs_40_dstW_512_neon: 11570.0

(Note, the checkasm tests for these functions haven't been
merged since they fail on x86.)

Signed-off-by: Hubert Mazur <hum@semihalf.com>
Signed-off-by: Martin Storsjö <martin@martin.st>

1 files changed, 61 insertions, 0 deletions

diff --git a/libswscale/aarch64/swscale.c b/libswscale/aarch64/swscale.c
index 171fb51329..5d0887cfe5 100644
--- a/libswscale/aarch64/swscale.c
+++ b/libswscale/aarch64/swscale.c
@@ -22,6 +22,63 @@
 #include "libswscale/swscale_internal.h"
 #include "libavutil/aarch64/cpu.h"
 
+void ff_hscale16to15_4_neon_asm(int shift, int16_t *_dst, int dstW,
+                      const uint8_t *_src, const int16_t *filter,
+                      const int32_t *filterPos, int filterSize);
+void ff_hscale16to15_X8_neon_asm(int shift, int16_t *_dst, int dstW,
+                      const uint8_t *_src, const int16_t *filter,
+                      const int32_t *filterPos, int filterSize);
+void ff_hscale16to15_X4_neon_asm(int shift, int16_t *_dst, int dstW,
+                      const uint8_t *_src, const int16_t *filter,
+                      const int32_t *filterPos, int filterSize);
+
+static void ff_hscale16to15_4_neon(SwsContext *c, int16_t *_dst, int dstW,
+                      const uint8_t *_src, const int16_t *filter,
+                      const int32_t *filterPos, int filterSize)
+{
+    const AVPixFmtDescriptor *desc = av_pix_fmt_desc_get(c->srcFormat);
+    int sh              = desc->comp[0].depth - 1;
+
+    if (sh<15) {
+        sh = isAnyRGB(c->srcFormat) || c->srcFormat==AV_PIX_FMT_PAL8 ? 13 : (desc->comp[0].depth - 1);
+    } else if (desc->flags & AV_PIX_FMT_FLAG_FLOAT) { /* float input are process like uint 16bpc */
+        sh = 16 - 1;
+    }
+    ff_hscale16to15_4_neon_asm(sh, _dst, dstW, _src, filter, filterPos, filterSize);
+
+}
+
+static void ff_hscale16to15_X8_neon(SwsContext *c, int16_t *_dst, int dstW,
+                      const uint8_t *_src, const int16_t *filter,
+                      const int32_t *filterPos, int filterSize)
+{
+    const AVPixFmtDescriptor *desc = av_pix_fmt_desc_get(c->srcFormat);
+    int sh              = desc->comp[0].depth - 1;
+
+    if (sh<15) {
+        sh = isAnyRGB(c->srcFormat) || c->srcFormat==AV_PIX_FMT_PAL8 ? 13 : (desc->comp[0].depth - 1);
+    } else if (desc->flags & AV_PIX_FMT_FLAG_FLOAT) { /* float input are process like uint 16bpc */
+        sh = 16 - 1;
+    }
+    ff_hscale16to15_X8_neon_asm(sh, _dst, dstW, _src, filter, filterPos, filterSize);
+
+}
+
+static void ff_hscale16to15_X4_neon(SwsContext *c, int16_t *_dst, int dstW,
+                      const uint8_t *_src, const int16_t *filter,
+                      const int32_t *filterPos, int filterSize)
+{
+    const AVPixFmtDescriptor *desc = av_pix_fmt_desc_get(c->srcFormat);
+    int sh              = desc->comp[0].depth - 1;
+
+    if (sh<15) {
+        sh = isAnyRGB(c->srcFormat) || c->srcFormat==AV_PIX_FMT_PAL8 ? 13 : (desc->comp[0].depth - 1);
+    } else if (desc->flags & AV_PIX_FMT_FLAG_FLOAT) { /* float input are process like uint 16bpc */
+        sh = 16 - 1;
+    }
+    ff_hscale16to15_X4_neon_asm(sh, _dst, dstW, _src, filter, filterPos, filterSize);
+}
+
 #define SCALE_FUNC(filter_n, from_bpc, to_bpc, opt) \
 void ff_hscale ## from_bpc ## to ## to_bpc ## _ ## filter_n ## _ ## opt( \
                                                 SwsContext *c, int16_t *data, \
@@ -56,6 +113,10 @@ void ff_yuv2plane1_8_neon(
         } else                                                          \
             hscalefn =                                                  \
                 ff_hscale8to19_ ## filtersize ## _ ## opt;              \
+    } else {                                                            \
+        if (c->dstBpc <= 14)                                            \
+            hscalefn =                                                  \
+                ff_hscale16to15_ ## filtersize ## _ ## opt;             \
     }                                                                   \
 } while (0)