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/*
* Winnov WNV1 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
* Winnov WNV1 codec.
*/
#include "libavutil/thread.h"
#define BITSTREAM_READER_LE
#include "avcodec.h"
#include "get_bits.h"
#include "internal.h"
static const uint8_t code_tab[16][2] = {
{ 7, 1 }, { 8, 3 }, { 6, 3 }, { 9, 4 }, { 5, 4 }, { 10, 5 }, { 4, 5 },
{ 11, 6 }, { 3, 6 }, { 12, 7 }, { 2, 7 }, { 13, 8 }, { 1, 8 }, { 14, 9 },
{ 0, 9 }, { 15, 8 }
};
#define CODE_VLC_BITS 9
static VLC code_vlc;
/* returns modified base_value */
static inline int wnv1_get_code(GetBitContext *gb, int shift, int base_value)
{
int v = get_vlc2(gb, code_vlc.table, CODE_VLC_BITS, 1);
if (v == 8)
return get_bits(gb, 8 - shift) << shift;
else
return base_value + v * (1 << shift);
}
static int decode_frame(AVCodecContext *avctx,
void *data, int *got_frame,
AVPacket *avpkt)
{
const uint8_t *buf = avpkt->data;
int buf_size = avpkt->size;
AVFrame * const p = data;
GetBitContext gb;
unsigned char *Y,*U,*V;
int i, j, ret, shift;
int prev_y = 0, prev_u = 0, prev_v = 0;
if (buf_size < 8 + avctx->height * (avctx->width/2)/8) {
av_log(avctx, AV_LOG_ERROR, "Packet size %d is too small\n", buf_size);
return AVERROR_INVALIDDATA;
}
if ((ret = ff_get_buffer(avctx, p, 0)) < 0)
return ret;
p->key_frame = 1;
if ((ret = init_get_bits8(&gb, buf + 8, buf_size - 8)) < 0)
return ret;
if (buf[2] >> 4 == 6)
shift = 2;
else {
shift = 8 - (buf[2] >> 4);
if (shift > 4) {
avpriv_request_sample(avctx,
"Unknown WNV1 frame header value %i",
buf[2] >> 4);
shift = 4;
}
if (shift < 1) {
avpriv_request_sample(avctx,
"Unknown WNV1 frame header value %i",
buf[2] >> 4);
shift = 1;
}
}
Y = p->data[0];
U = p->data[1];
V = p->data[2];
for (j = 0; j < avctx->height; j++) {
for (i = 0; i < avctx->width / 2; i++) {
Y[i * 2] = wnv1_get_code(&gb, shift, prev_y);
prev_u = U[i] = wnv1_get_code(&gb, shift, prev_u);
prev_y = Y[(i * 2) + 1] = wnv1_get_code(&gb, shift, Y[i * 2]);
prev_v = V[i] = wnv1_get_code(&gb, shift, prev_v);
}
Y += p->linesize[0];
U += p->linesize[1];
V += p->linesize[2];
}
*got_frame = 1;
return buf_size;
}
static av_cold void wnv1_init_static(void)
{
INIT_VLC_STATIC_FROM_LENGTHS(&code_vlc, CODE_VLC_BITS, 16,
&code_tab[0][1], 2,
&code_tab[0][0], 2, 1,
-7, INIT_VLC_OUTPUT_LE, 1 << CODE_VLC_BITS);
}
static av_cold int decode_init(AVCodecContext *avctx)
{
static AVOnce init_static_once = AV_ONCE_INIT;
if (avctx->width <= 1)
return AVERROR_INVALIDDATA;
avctx->pix_fmt = AV_PIX_FMT_YUV422P;
ff_thread_once(&init_static_once, wnv1_init_static);
return 0;
}
const AVCodec ff_wnv1_decoder = {
.name = "wnv1",
.long_name = NULL_IF_CONFIG_SMALL("Winnov WNV1"),
.type = AVMEDIA_TYPE_VIDEO,
.id = AV_CODEC_ID_WNV1,
.init = decode_init,
.decode = decode_frame,
.capabilities = AV_CODEC_CAP_DR1,
.caps_internal = FF_CODEC_CAP_INIT_THREADSAFE,
};
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