ffmpeg/libavcodec/indeo2.c
Andreas Rheinhardt 05577d2c76 avcodec/indeo2: Avoid unnecessary VLC structure
Everything besides VLC.table is basically write-only
and even VLC.table can be removed by accessing the
underlying table directly.

Signed-off-by: Andreas Rheinhardt <andreas.rheinhardt@outlook.com>
2023-10-31 20:47:00 +01:00

272 lines
8.2 KiB
C

/*
* Intel Indeo 2 codec
* Copyright (c) 2005 Konstantin Shishkov
*
* 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
*/
/**
* @file
* Intel Indeo 2 decoder.
*/
#include "libavutil/attributes.h"
#include "libavutil/thread.h"
#define BITSTREAM_READER_LE
#include "avcodec.h"
#include "codec_internal.h"
#include "decode.h"
#include "get_bits.h"
#include "indeo2data.h"
typedef struct Ir2Context{
AVCodecContext *avctx;
AVFrame *picture;
GetBitContext gb;
int decode_delta;
} Ir2Context;
#define CODE_VLC_BITS 14
static VLCElem ir2_vlc[1 << CODE_VLC_BITS];
/* Indeo 2 codes are in range 0x01..0x7F and 0x81..0x90 */
static inline int ir2_get_code(GetBitContext *gb)
{
return get_vlc2(gb, ir2_vlc, CODE_VLC_BITS, 1);
}
static int ir2_decode_plane(Ir2Context *ctx, int width, int height, uint8_t *dst,
int pitch, const uint8_t *table)
{
int i;
int j;
int out = 0;
if ((width & 1) || width * height / (2*(IR2_CODES - 0x7F)) > get_bits_left(&ctx->gb))
return AVERROR_INVALIDDATA;
/* first line contain absolute values, other lines contain deltas */
while (out < width) {
int c = ir2_get_code(&ctx->gb);
if (c >= 0x80) { /* we have a run */
c -= 0x7F;
if (out + c*2 > width)
return AVERROR_INVALIDDATA;
for (i = 0; i < c * 2; i++)
dst[out++] = 0x80;
} else { /* copy two values from table */
if (c <= 0)
return AVERROR_INVALIDDATA;
dst[out++] = table[c * 2];
dst[out++] = table[(c * 2) + 1];
}
}
dst += pitch;
for (j = 1; j < height; j++) {
out = 0;
while (out < width) {
int c;
if (get_bits_left(&ctx->gb) <= 0)
return AVERROR_INVALIDDATA;
c = ir2_get_code(&ctx->gb);
if (c >= 0x80) { /* we have a skip */
c -= 0x7F;
if (out + c*2 > width)
return AVERROR_INVALIDDATA;
for (i = 0; i < c * 2; i++) {
dst[out] = dst[out - pitch];
out++;
}
} else { /* add two deltas from table */
int t;
if (c <= 0)
return AVERROR_INVALIDDATA;
t = dst[out - pitch] + (table[c * 2] - 128);
t = av_clip_uint8(t);
dst[out] = t;
out++;
t = dst[out - pitch] + (table[(c * 2) + 1] - 128);
t = av_clip_uint8(t);
dst[out] = t;
out++;
}
}
dst += pitch;
}
return 0;
}
static int ir2_decode_plane_inter(Ir2Context *ctx, int width, int height, uint8_t *dst,
int pitch, const uint8_t *table)
{
int j;
int out = 0;
int c;
int t;
if (width & 1)
return AVERROR_INVALIDDATA;
for (j = 0; j < height; j++) {
out = 0;
while (out < width) {
if (get_bits_left(&ctx->gb) <= 0)
return AVERROR_INVALIDDATA;
c = ir2_get_code(&ctx->gb);
if (c >= 0x80) { /* we have a skip */
c -= 0x7F;
out += c * 2;
} else { /* add two deltas from table */
if (c <= 0)
return AVERROR_INVALIDDATA;
t = dst[out] + (((table[c * 2] - 128)*3) >> 2);
t = av_clip_uint8(t);
dst[out] = t;
out++;
t = dst[out] + (((table[(c * 2) + 1] - 128)*3) >> 2);
t = av_clip_uint8(t);
dst[out] = t;
out++;
}
}
dst += pitch;
}
return 0;
}
static int ir2_decode_frame(AVCodecContext *avctx, AVFrame *picture,
int *got_frame, AVPacket *avpkt)
{
Ir2Context * const s = avctx->priv_data;
const uint8_t *buf = avpkt->data;
int buf_size = avpkt->size;
AVFrame * const p = s->picture;
int start, ret;
int ltab, ctab;
if ((ret = ff_reget_buffer(avctx, p, 0)) < 0)
return ret;
start = 48; /* hardcoded for now */
if (start >= buf_size) {
av_log(s->avctx, AV_LOG_ERROR, "input buffer size too small (%d)\n", buf_size);
return AVERROR_INVALIDDATA;
}
s->decode_delta = buf[18];
/* decide whether frame uses deltas or not */
if ((ret = init_get_bits8(&s->gb, buf + start, buf_size - start)) < 0)
return ret;
ltab = buf[0x22] & 3;
ctab = buf[0x22] >> 2;
if (ctab > 3) {
av_log(avctx, AV_LOG_ERROR, "ctab %d is invalid\n", ctab);
return AVERROR_INVALIDDATA;
}
if (s->decode_delta) { /* intraframe */
if ((ret = ir2_decode_plane(s, avctx->width, avctx->height,
p->data[0], p->linesize[0],
ir2_delta_table[ltab])) < 0)
return ret;
/* swapped U and V */
if ((ret = ir2_decode_plane(s, avctx->width >> 2, avctx->height >> 2,
p->data[2], p->linesize[2],
ir2_delta_table[ctab])) < 0)
return ret;
if ((ret = ir2_decode_plane(s, avctx->width >> 2, avctx->height >> 2,
p->data[1], p->linesize[1],
ir2_delta_table[ctab])) < 0)
return ret;
} else { /* interframe */
if ((ret = ir2_decode_plane_inter(s, avctx->width, avctx->height,
p->data[0], p->linesize[0],
ir2_delta_table[ltab])) < 0)
return ret;
/* swapped U and V */
if ((ret = ir2_decode_plane_inter(s, avctx->width >> 2, avctx->height >> 2,
p->data[2], p->linesize[2],
ir2_delta_table[ctab])) < 0)
return ret;
if ((ret = ir2_decode_plane_inter(s, avctx->width >> 2, avctx->height >> 2,
p->data[1], p->linesize[1],
ir2_delta_table[ctab])) < 0)
return ret;
}
if ((ret = av_frame_ref(picture, p)) < 0)
return ret;
*got_frame = 1;
return buf_size;
}
static av_cold void ir2_init_static(void)
{
VLC_INIT_STATIC_TABLE_FROM_LENGTHS(ir2_vlc, CODE_VLC_BITS, IR2_CODES,
&ir2_tab[0][1], 2, &ir2_tab[0][0], 2, 1,
0, VLC_INIT_OUTPUT_LE);
}
static av_cold int ir2_decode_init(AVCodecContext *avctx)
{
static AVOnce init_static_once = AV_ONCE_INIT;
Ir2Context * const ic = avctx->priv_data;
ic->avctx = avctx;
avctx->pix_fmt= AV_PIX_FMT_YUV410P;
ic->picture = av_frame_alloc();
if (!ic->picture)
return AVERROR(ENOMEM);
ff_thread_once(&init_static_once, ir2_init_static);
return 0;
}
static av_cold int ir2_decode_end(AVCodecContext *avctx)
{
Ir2Context * const ic = avctx->priv_data;
av_frame_free(&ic->picture);
return 0;
}
const FFCodec ff_indeo2_decoder = {
.p.name = "indeo2",
CODEC_LONG_NAME("Intel Indeo 2"),
.p.type = AVMEDIA_TYPE_VIDEO,
.p.id = AV_CODEC_ID_INDEO2,
.priv_data_size = sizeof(Ir2Context),
.init = ir2_decode_init,
.close = ir2_decode_end,
FF_CODEC_DECODE_CB(ir2_decode_frame),
.p.capabilities = AV_CODEC_CAP_DR1,
};