[FFmpeg-devel] [PATCH 2/3] avcodec/exrenc: move float2half code to own header
Paul B Mahol
onemda at gmail.com
Sun Feb 28 14:53:26 EET 2021
Signed-off-by: Paul B Mahol <onemda at gmail.com>
---
libavcodec/exrenc.c | 52 +++-----------------------------
libavcodec/float2half.h | 67 +++++++++++++++++++++++++++++++++++++++++
2 files changed, 72 insertions(+), 47 deletions(-)
create mode 100644 libavcodec/float2half.h
diff --git a/libavcodec/exrenc.c b/libavcodec/exrenc.c
index f9d802543d..db9000a85c 100644
--- a/libavcodec/exrenc.c
+++ b/libavcodec/exrenc.c
@@ -34,6 +34,7 @@
#include "avcodec.h"
#include "bytestream.h"
#include "internal.h"
+#include "float2half.h"
enum ExrCompr {
EXR_RAW,
@@ -87,54 +88,11 @@ typedef struct EXRContext {
uint8_t shifttable[512];
} EXRContext;
-static void half_tables(EXRContext *s)
-{
- for (int i = 0; i < 256; i++) {
- int e = i - 127;
-
- if (e < -24) { // Very small numbers map to zero
- s->basetable[i|0x000] = 0x0000;
- s->basetable[i|0x100] = 0x8000;
- s->shifttable[i|0x000] = 24;
- s->shifttable[i|0x100] = 24;
- } else if (e < -14) { // Small numbers map to denorms
- s->basetable[i|0x000] = (0x0400>>(-e-14));
- s->basetable[i|0x100] = (0x0400>>(-e-14)) | 0x8000;
- s->shifttable[i|0x000] = -e-1;
- s->shifttable[i|0x100] = -e-1;
- } else if (e <= 15) { // Normal numbers just lose precision
- s->basetable[i|0x000] = ((e + 15) << 10);
- s->basetable[i|0x100] = ((e + 15) << 10) | 0x8000;
- s->shifttable[i|0x000] = 13;
- s->shifttable[i|0x100] = 13;
- } else if (e < 128) { // Large numbers map to Infinity
- s->basetable[i|0x000] = 0x7C00;
- s->basetable[i|0x100] = 0xFC00;
- s->shifttable[i|0x000] = 24;
- s->shifttable[i|0x100] = 24;
- } else{ // Infinity and NaN's stay Infinity and NaN's
- s->basetable[i|0x000] = 0x7C00;
- s->basetable[i|0x100] = 0xFC00;
- s->shifttable[i|0x000] = 13;
- s->shifttable[i|0x100] = 13;
- }
- }
-}
-
-static uint16_t float2half(EXRContext *s, uint32_t f)
-{
- uint16_t h;
-
- h = s->basetable[(f >> 23) & 0x1ff] + ((f & 0x007fffff) >> s->shifttable[(f >> 23) & 0x1ff]);
-
- return h;
-}
-
static int encode_init(AVCodecContext *avctx)
{
EXRContext *s = avctx->priv_data;
- half_tables(s);
+ float2half_tables(s->basetable, s->shifttable);
switch (avctx->pix_fmt) {
case AV_PIX_FMT_GBRPF32:
@@ -290,7 +248,7 @@ static int encode_scanline_rle(EXRContext *s, const AVFrame *frame)
uint32_t *src = (uint32_t *)(frame->data[ch] + y * frame->linesize[ch]);
for (int x = 0; x < frame->width; x++)
- dst[x] = float2half(s, src[x]);
+ dst[x] = float2half(src[x], s->basetable, s->shifttable);
}
break;
}
@@ -358,7 +316,7 @@ static int encode_scanline_zip(EXRContext *s, const AVFrame *frame)
uint32_t *src = (uint32_t *)(frame->data[ch] + (y * s->scanline_height + l) * frame->linesize[ch]);
for (int x = 0; x < frame->width; x++)
- dst[x] = float2half(s, src[x]);
+ dst[x] = float2half(src[x], s->basetable, s->shifttable);
}
}
break;
@@ -516,7 +474,7 @@ static int encode_frame(AVCodecContext *avctx, AVPacket *pkt,
uint32_t *src = (uint32_t *)(frame->data[ch] + y * frame->linesize[ch]);
for (int x = 0; x < frame->width; x++)
- bytestream2_put_le16(pb, float2half(s, src[x]));
+ bytestream2_put_le16(pb, float2half(src[x], s->basetable, s->shifttable));
}
}
}
diff --git a/libavcodec/float2half.h b/libavcodec/float2half.h
new file mode 100644
index 0000000000..ff547b490c
--- /dev/null
+++ b/libavcodec/float2half.h
@@ -0,0 +1,67 @@
+/*
+ * This file is part of FFmpeg.
+ *
+ * FFmpeg is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2.1 of the License, or (at your option) any later version.
+ *
+ * FFmpeg is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with FFmpeg; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
+ */
+
+#ifndef AVCODEC_FLOAT2HALF_H
+#define AVCODEC_FLOAT2HALF_H
+
+#include <stdint.h>
+
+static void float2half_tables(uint16_t *basetable, uint8_t *shifttable)
+{
+ for (int i = 0; i < 256; i++) {
+ int e = i - 127;
+
+ if (e < -24) { // Very small numbers map to zero
+ basetable[i|0x000] = 0x0000;
+ basetable[i|0x100] = 0x8000;
+ shifttable[i|0x000] = 24;
+ shifttable[i|0x100] = 24;
+ } else if (e < -14) { // Small numbers map to denorms
+ basetable[i|0x000] = (0x0400>>(-e-14));
+ basetable[i|0x100] = (0x0400>>(-e-14)) | 0x8000;
+ shifttable[i|0x000] = -e-1;
+ shifttable[i|0x100] = -e-1;
+ } else if (e <= 15) { // Normal numbers just lose precision
+ basetable[i|0x000] = ((e + 15) << 10);
+ basetable[i|0x100] = ((e + 15) << 10) | 0x8000;
+ shifttable[i|0x000] = 13;
+ shifttable[i|0x100] = 13;
+ } else if (e < 128) { // Large numbers map to Infinity
+ basetable[i|0x000] = 0x7C00;
+ basetable[i|0x100] = 0xFC00;
+ shifttable[i|0x000] = 24;
+ shifttable[i|0x100] = 24;
+ } else{ // Infinity and NaN's stay Infinity and NaN's
+ basetable[i|0x000] = 0x7C00;
+ basetable[i|0x100] = 0xFC00;
+ shifttable[i|0x000] = 13;
+ shifttable[i|0x100] = 13;
+ }
+ }
+}
+
+static uint16_t float2half(uint32_t f, uint16_t *basetable, uint8_t *shifttable)
+{
+ uint16_t h;
+
+ h = basetable[(f >> 23) & 0x1ff] + ((f & 0x007fffff) >> shifttable[(f >> 23) & 0x1ff]);
+
+ return h;
+}
+
+#endif /* AVCODEC_FLOAT2HALF_H */
--
2.17.1
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