[FFmpeg-devel] [PATCH 06/29] avcodec/g2meet, mjpegdec: Factor out common VLC initialization code
Andreas Rheinhardt
andreas.rheinhardt at gmail.com
Thu Feb 18 05:41:51 EET 2021
While just at it, remove the nb_codes parameter: It is redundant
(the number of codes is implicitly contained in the array containing how
many entries of a specific size there are) and for this reason it might
even be wrong, so it is better to check what is actually used instead.
Signed-off-by: Andreas Rheinhardt <andreas.rheinhardt at gmail.com>
---
libavcodec/Makefile | 4 +--
libavcodec/g2meet.c | 38 ++++++------------------
libavcodec/mjpegdec.c | 48 +++++-------------------------
libavcodec/mjpegdec.h | 2 ++
libavcodec/mjpegdec_common.c | 57 ++++++++++++++++++++++++++++++++++++
5 files changed, 77 insertions(+), 72 deletions(-)
create mode 100644 libavcodec/mjpegdec_common.c
diff --git a/libavcodec/Makefile b/libavcodec/Makefile
index 332a9bc766..c427de78be 100644
--- a/libavcodec/Makefile
+++ b/libavcodec/Makefile
@@ -341,7 +341,7 @@ OBJS-$(CONFIG_FMVC_DECODER) += fmvc.o
OBJS-$(CONFIG_FOURXM_DECODER) += 4xm.o
OBJS-$(CONFIG_FRAPS_DECODER) += fraps.o
OBJS-$(CONFIG_FRWU_DECODER) += frwu.o
-OBJS-$(CONFIG_G2M_DECODER) += g2meet.o elsdec.o
+OBJS-$(CONFIG_G2M_DECODER) += g2meet.o elsdec.o mjpegdec_common.o
OBJS-$(CONFIG_G723_1_DECODER) += g723_1dec.o g723_1.o \
acelp_vectors.o celp_filters.o celp_math.o
OBJS-$(CONFIG_G723_1_ENCODER) += g723_1enc.o g723_1.o \
@@ -450,7 +450,7 @@ OBJS-$(CONFIG_METASOUND_DECODER) += metasound.o metasound_data.o \
twinvq.o
OBJS-$(CONFIG_MICRODVD_DECODER) += microdvddec.o ass.o
OBJS-$(CONFIG_MIMIC_DECODER) += mimic.o
-OBJS-$(CONFIG_MJPEG_DECODER) += mjpegdec.o
+OBJS-$(CONFIG_MJPEG_DECODER) += mjpegdec.o mjpegdec_common.o
OBJS-$(CONFIG_MJPEG_QSV_DECODER) += qsvdec.o
OBJS-$(CONFIG_MJPEG_ENCODER) += mjpegenc.o mjpegenc_common.o \
mjpegenc_huffman.o
diff --git a/libavcodec/g2meet.c b/libavcodec/g2meet.c
index 70dc8c72a3..68b1b9dc74 100644
--- a/libavcodec/g2meet.c
+++ b/libavcodec/g2meet.c
@@ -41,6 +41,7 @@
#include "internal.h"
#include "jpegtables.h"
#include "mjpeg.h"
+#include "mjpegdec.h"
#define EPIC_PIX_STACK_SIZE 1024
#define EPIC_PIX_STACK_MAX (EPIC_PIX_STACK_SIZE - 1)
@@ -159,45 +160,24 @@ typedef struct G2MContext {
int cursor_hot_x, cursor_hot_y;
} G2MContext;
-static av_cold int build_vlc(VLC *vlc, const uint8_t *bits_table,
- const uint8_t *val_table, int nb_codes,
- int is_ac)
-{
- uint8_t huff_size[256] = { 0 };
- uint16_t huff_code[256];
- uint16_t huff_sym[256];
- int i;
-
- ff_mjpeg_build_huffman_codes(huff_size, huff_code, bits_table, val_table);
-
- for (i = 0; i < 256; i++)
- huff_sym[i] = i + 16 * is_ac;
-
- if (is_ac)
- huff_sym[0] = 16 * 256;
-
- return ff_init_vlc_sparse(vlc, 9, nb_codes, huff_size, 1, 1,
- huff_code, 2, 2, huff_sym, 2, 2, 0);
-}
-
static av_cold int jpg_init(AVCodecContext *avctx, JPGContext *c)
{
int ret;
- ret = build_vlc(&c->dc_vlc[0], avpriv_mjpeg_bits_dc_luminance,
- avpriv_mjpeg_val_dc, 12, 0);
+ ret = ff_mjpeg_build_vlc(&c->dc_vlc[0], avpriv_mjpeg_bits_dc_luminance,
+ avpriv_mjpeg_val_dc, 0, avctx);
if (ret)
return ret;
- ret = build_vlc(&c->dc_vlc[1], avpriv_mjpeg_bits_dc_chrominance,
- avpriv_mjpeg_val_dc, 12, 0);
+ ret = ff_mjpeg_build_vlc(&c->dc_vlc[1], avpriv_mjpeg_bits_dc_chrominance,
+ avpriv_mjpeg_val_dc, 0, avctx);
if (ret)
return ret;
- ret = build_vlc(&c->ac_vlc[0], avpriv_mjpeg_bits_ac_luminance,
- avpriv_mjpeg_val_ac_luminance, 251, 1);
+ ret = ff_mjpeg_build_vlc(&c->ac_vlc[0], avpriv_mjpeg_bits_ac_luminance,
+ avpriv_mjpeg_val_ac_luminance, 1, avctx);
if (ret)
return ret;
- ret = build_vlc(&c->ac_vlc[1], avpriv_mjpeg_bits_ac_chrominance,
- avpriv_mjpeg_val_ac_chrominance, 251, 1);
+ ret = ff_mjpeg_build_vlc(&c->ac_vlc[1], avpriv_mjpeg_bits_ac_chrominance,
+ avpriv_mjpeg_val_ac_chrominance, 1, avctx);
if (ret)
return ret;
diff --git a/libavcodec/mjpegdec.c b/libavcodec/mjpegdec.c
index fa4c607085..f35bbeedee 100644
--- a/libavcodec/mjpegdec.c
+++ b/libavcodec/mjpegdec.c
@@ -51,40 +51,6 @@
#include "bytestream.h"
-static void build_huffman_codes(uint8_t *huff_size, const uint8_t *bits_table)
-{
- for (int i = 1, k = 0; i <= 16; i++) {
- int nb = bits_table[i];
- for (int j = 0; j < nb;j++) {
- huff_size[k] = i;
- k++;
- }
- }
-}
-
-static int build_vlc(VLC *vlc, const uint8_t *bits_table,
- const uint8_t *val_table, int nb_codes,
- int is_ac, void *logctx)
-{
- uint8_t huff_size[256];
- uint16_t huff_sym[256];
- int i;
-
- av_assert0(nb_codes <= 256);
-
- build_huffman_codes(huff_size, bits_table);
-
- for (i = 0; i < nb_codes; i++) {
- huff_sym[i] = val_table[i] + 16 * is_ac;
-
- if (is_ac && !val_table[i])
- huff_sym[i] = 16 * 256;
- }
-
- return ff_init_vlc_from_lengths(vlc, 9, nb_codes, huff_size, 1,
- huff_sym, 2, 2, 0, 0, logctx);
-}
-
static int init_default_huffman_tables(MJpegDecodeContext *s)
{
static const struct {
@@ -110,9 +76,9 @@ static int init_default_huffman_tables(MJpegDecodeContext *s)
int i, ret;
for (i = 0; i < FF_ARRAY_ELEMS(ht); i++) {
- ret = build_vlc(&s->vlcs[ht[i].class][ht[i].index],
- ht[i].bits, ht[i].values, ht[i].length,
- ht[i].class == 1, s->avctx);
+ ret = ff_mjpeg_build_vlc(&s->vlcs[ht[i].class][ht[i].index],
+ ht[i].bits, ht[i].values,
+ ht[i].class == 1, s->avctx);
if (ret < 0)
return ret;
@@ -307,14 +273,14 @@ int ff_mjpeg_decode_dht(MJpegDecodeContext *s)
ff_free_vlc(&s->vlcs[class][index]);
av_log(s->avctx, AV_LOG_DEBUG, "class=%d index=%d nb_codes=%d\n",
class, index, n);
- if ((ret = build_vlc(&s->vlcs[class][index], bits_table, val_table,
- n, class > 0, s->avctx)) < 0)
+ if ((ret = ff_mjpeg_build_vlc(&s->vlcs[class][index], bits_table,
+ val_table, class > 0, s->avctx)) < 0)
return ret;
if (class > 0) {
ff_free_vlc(&s->vlcs[2][index]);
- if ((ret = build_vlc(&s->vlcs[2][index], bits_table, val_table,
- n, 0, s->avctx)) < 0)
+ if ((ret = ff_mjpeg_build_vlc(&s->vlcs[2][index], bits_table,
+ val_table, 0, s->avctx)) < 0)
return ret;
}
diff --git a/libavcodec/mjpegdec.h b/libavcodec/mjpegdec.h
index a824b5029c..732aeab994 100644
--- a/libavcodec/mjpegdec.h
+++ b/libavcodec/mjpegdec.h
@@ -161,6 +161,8 @@ typedef struct MJpegDecodeContext {
void *hwaccel_picture_private;
} MJpegDecodeContext;
+int ff_mjpeg_build_vlc(VLC *vlc, const uint8_t *bits_table,
+ const uint8_t *val_table, int is_ac, void *logctx);
int ff_mjpeg_decode_init(AVCodecContext *avctx);
int ff_mjpeg_decode_end(AVCodecContext *avctx);
int ff_mjpeg_receive_frame(AVCodecContext *avctx, AVFrame *frame);
diff --git a/libavcodec/mjpegdec_common.c b/libavcodec/mjpegdec_common.c
new file mode 100644
index 0000000000..701ddfec06
--- /dev/null
+++ b/libavcodec/mjpegdec_common.c
@@ -0,0 +1,57 @@
+/*
+ * MJPEG decoder VLC code
+ * Copyright (c) 2000, 2001 Fabrice Bellard
+ * Copyright (c) 2003 Alex Beregszaszi
+ * Copyright (c) 2003-2004 Michael Niedermayer
+ *
+ * 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
+ */
+
+#include <stdint.h>
+#include "libavutil/avassert.h"
+#include "mjpegdec.h"
+#include "vlc.h"
+
+static int build_huffman_codes(uint8_t *huff_size, const uint8_t *bits_table)
+{
+ int nb_codes = 0;
+ for (int i = 1, j = 0; i <= 16; i++) {
+ nb_codes += bits_table[i];
+ av_assert1(nb_codes <= 256);
+ for (; j < nb_codes; j++)
+ huff_size[j] = i;
+ }
+ return nb_codes;
+}
+
+int ff_mjpeg_build_vlc(VLC *vlc, const uint8_t *bits_table,
+ const uint8_t *val_table, int is_ac, void *logctx)
+{
+ uint8_t huff_size[256];
+ uint16_t huff_sym[256];
+ int nb_codes = build_huffman_codes(huff_size, bits_table);
+
+ for (int i = 0; i < nb_codes; i++) {
+ huff_sym[i] = val_table[i] + 16 * is_ac;
+
+ if (is_ac && !val_table[i])
+ huff_sym[i] = 16 * 256;
+ }
+
+ return ff_init_vlc_from_lengths(vlc, 9, nb_codes, huff_size, 1,
+ huff_sym, 2, 2, 0, 0, logctx);
+}
--
2.27.0
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