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/*
* Creative YUV (CYUV) Video Decoder
* by Mike Melanson (melanson@pcisys.net)
* based on "Creative YUV (CYUV) stream format for AVI":
* http://www.csse.monash.edu.au/~timf/videocodec/cyuv.txt
*
* Copyright (C) 2003 the ffmpeg project
*
* 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 libavcodec/cyuv.c
* Creative YUV (CYUV) Video Decoder.
*/
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include "avcodec.h"
#include "dsputil.h"
typedef struct CyuvDecodeContext {
AVCodecContext *avctx;
int width, height;
AVFrame frame;
} CyuvDecodeContext;
static av_cold int cyuv_decode_init(AVCodecContext *avctx)
{
CyuvDecodeContext *s = avctx->priv_data;
s->avctx = avctx;
s->width = avctx->width;
/* width needs to be divisible by 4 for this codec to work */
if (s->width & 0x3)
return -1;
s->height = avctx->height;
avctx->pix_fmt = PIX_FMT_YUV411P;
return 0;
}
static int cyuv_decode_frame(AVCodecContext *avctx,
void *data, int *data_size,
const uint8_t *buf, int buf_size)
{
CyuvDecodeContext *s=avctx->priv_data;
unsigned char *y_plane;
unsigned char *u_plane;
unsigned char *v_plane;
int y_ptr;
int u_ptr;
int v_ptr;
/* prediction error tables (make it clear that they are signed values) */
const signed char *y_table = (const signed char*)buf + 0;
const signed char *u_table = (const signed char*)buf + 16;
const signed char *v_table = (const signed char*)buf + 32;
unsigned char y_pred, u_pred, v_pred;
int stream_ptr;
unsigned char cur_byte;
int pixel_groups;
/* sanity check the buffer size: A buffer has 3x16-bytes tables
* followed by (height) lines each with 3 bytes to represent groups
* of 4 pixels. Thus, the total size of the buffer ought to be:
* (3 * 16) + height * (width * 3 / 4) */
if (buf_size != 48 + s->height * (s->width * 3 / 4)) {
av_log(avctx, AV_LOG_ERROR, "ffmpeg: cyuv: got a buffer with %d bytes when %d were expected\n",
buf_size,
48 + s->height * (s->width * 3 / 4));
return -1;
}
/* pixel data starts 48 bytes in, after 3x16-byte tables */
stream_ptr = 48;
if(s->frame.data[0])
avctx->release_buffer(avctx, &s->frame);
s->frame.buffer_hints = FF_BUFFER_HINTS_VALID;
s->frame.reference = 0;
if(avctx->get_buffer(avctx, &s->frame) < 0) {
av_log(avctx, AV_LOG_ERROR, "get_buffer() failed\n");
return -1;
}
y_plane = s->frame.data[0];
u_plane = s->frame.data[1];
v_plane = s->frame.data[2];
/* iterate through each line in the height */
for (y_ptr = 0, u_ptr = 0, v_ptr = 0;
y_ptr < (s->height * s->frame.linesize[0]);
y_ptr += s->frame.linesize[0] - s->width,
u_ptr += s->frame.linesize[1] - s->width / 4,
v_ptr += s->frame.linesize[2] - s->width / 4) {
/* reset predictors */
cur_byte = buf[stream_ptr++];
u_plane[u_ptr++] = u_pred = cur_byte & 0xF0;
y_plane[y_ptr++] = y_pred = (cur_byte & 0x0F) << 4;
cur_byte = buf[stream_ptr++];
v_plane[v_ptr++] = v_pred = cur_byte & 0xF0;
y_pred += y_table[cur_byte & 0x0F];
y_plane[y_ptr++] = y_pred;
cur_byte = buf[stream_ptr++];
y_pred += y_table[cur_byte & 0x0F];
y_plane[y_ptr++] = y_pred;
y_pred += y_table[(cur_byte & 0xF0) >> 4];
y_plane[y_ptr++] = y_pred;
/* iterate through the remaining pixel groups (4 pixels/group) */
pixel_groups = s->width / 4 - 1;
while (pixel_groups--) {
cur_byte = buf[stream_ptr++];
u_pred += u_table[(cur_byte & 0xF0) >> 4];
u_plane[u_ptr++] = u_pred;
y_pred += y_table[cur_byte & 0x0F];
y_plane[y_ptr++] = y_pred;
cur_byte = buf[stream_ptr++];
v_pred += v_table[(cur_byte & 0xF0) >> 4];
v_plane[v_ptr++] = v_pred;
y_pred += y_table[cur_byte & 0x0F];
y_plane[y_ptr++] = y_pred;
cur_byte = buf[stream_ptr++];
y_pred += y_table[cur_byte & 0x0F];
y_plane[y_ptr++] = y_pred;
y_pred += y_table[(cur_byte & 0xF0) >> 4];
y_plane[y_ptr++] = y_pred;
}
}
*data_size=sizeof(AVFrame);
*(AVFrame*)data= s->frame;
return buf_size;
}
AVCodec cyuv_decoder = {
"cyuv",
CODEC_TYPE_VIDEO,
CODEC_ID_CYUV,
sizeof(CyuvDecodeContext),
cyuv_decode_init,
NULL,
NULL,
cyuv_decode_frame,
CODEC_CAP_DR1,
NULL,
.long_name = NULL_IF_CONFIG_SMALL("Creative YUV (CYUV)"),
};
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