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ffmpeg/libavcodec/qpeg.c

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/*
* QPEG codec
* Copyright (c) 2004 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
* QPEG codec.
*/
#include "avcodec.h"
typedef struct QpegContext{
AVCodecContext *avctx;
AVFrame pic, ref;
uint32_t pal[256];
} QpegContext;
static void qpeg_decode_intra(const uint8_t *src, uint8_t *dst, int size,
int stride, int width, int height)
{
int i;
int code;
int c0, c1;
int run, copy;
int filled = 0;
int rows_to_go;
rows_to_go = height;
height--;
dst = dst + height * stride;
while((size > 0) && (rows_to_go > 0)) {
code = *src++;
size--;
run = copy = 0;
if(code == 0xFC) /* end-of-picture code */
break;
if(code >= 0xF8) { /* very long run */
c0 = *src++;
c1 = *src++;
size -= 2;
run = ((code & 0x7) << 16) + (c0 << 8) + c1 + 2;
} else if (code >= 0xF0) { /* long run */
c0 = *src++;
size--;
run = ((code & 0xF) << 8) + c0 + 2;
} else if (code >= 0xE0) { /* short run */
run = (code & 0x1F) + 2;
} else if (code >= 0xC0) { /* very long copy */
c0 = *src++;
c1 = *src++;
size -= 2;
copy = ((code & 0x3F) << 16) + (c0 << 8) + c1 + 1;
} else if (code >= 0x80) { /* long copy */
c0 = *src++;
size--;
copy = ((code & 0x7F) << 8) + c0 + 1;
} else { /* short copy */
copy = code + 1;
}
/* perform actual run or copy */
if(run) {
int p;
p = *src++;
size--;
for(i = 0; i < run; i++) {
dst[filled++] = p;
if (filled >= width) {
filled = 0;
dst -= stride;
rows_to_go--;
if(rows_to_go <= 0)
break;
}
}
} else {
size -= copy;
for(i = 0; i < copy; i++) {
dst[filled++] = *src++;
if (filled >= width) {
filled = 0;
dst -= stride;
rows_to_go--;
if(rows_to_go <= 0)
break;
}
}
}
}
}
static const int qpeg_table_h[16] =
{ 0x00, 0x20, 0x20, 0x20, 0x18, 0x10, 0x10, 0x20, 0x10, 0x08, 0x18, 0x08, 0x08, 0x18, 0x10, 0x04};
static const int qpeg_table_w[16] =
{ 0x00, 0x20, 0x18, 0x08, 0x18, 0x10, 0x20, 0x10, 0x08, 0x10, 0x20, 0x20, 0x08, 0x10, 0x18, 0x04};
/* Decodes delta frames */
static void qpeg_decode_inter(const uint8_t *src, uint8_t *dst, int size,
int stride, int width, int height,
int delta, const uint8_t *ctable, uint8_t *refdata)
{
int i, j;
int code;
int filled = 0;
int orig_height;
if(!refdata)
refdata= dst;
/* copy prev frame */
for(i = 0; i < height; i++)
memcpy(dst + (i * stride), refdata + (i * stride), width);
orig_height = height;
height--;
dst = dst + height * stride;
while((size > 0) && (height >= 0)) {
code = *src++;
size--;
if(delta) {
/* motion compensation */
while((code & 0xF0) == 0xF0) {
if(delta == 1) {
int me_idx;
int me_w, me_h, me_x, me_y;
uint8_t *me_plane;
int corr, val;
/* get block size by index */
me_idx = code & 0xF;
me_w = qpeg_table_w[me_idx];
me_h = qpeg_table_h[me_idx];
/* extract motion vector */
corr = *src++;
size--;
val = corr >> 4;
if(val > 7)
val -= 16;
me_x = val;
val = corr & 0xF;
if(val > 7)
val -= 16;
me_y = val;
/* check motion vector */
if ((me_x + filled < 0) || (me_x + me_w + filled > width) ||
(height - me_y - me_h < 0) || (height - me_y > orig_height) ||
(filled + me_w > width) || (height - me_h < 0))
av_log(NULL, AV_LOG_ERROR, "Bogus motion vector (%i,%i), block size %ix%i at %i,%i\n",
me_x, me_y, me_w, me_h, filled, height);
else {
/* do motion compensation */
me_plane = refdata + (filled + me_x) + (height - me_y) * stride;
for(j = 0; j < me_h; j++) {
for(i = 0; i < me_w; i++)
dst[filled + i - (j * stride)] = me_plane[i - (j * stride)];
}
}
}
code = *src++;
size--;
}
}
if(code == 0xE0) /* end-of-picture code */
break;
if(code > 0xE0) { /* run code: 0xE1..0xFF */
int p;
code &= 0x1F;
p = *src++;
size--;
for(i = 0; i <= code; i++) {
dst[filled++] = p;
if(filled >= width) {
filled = 0;
dst -= stride;
height--;
}
}
} else if(code >= 0xC0) { /* copy code: 0xC0..0xDF */
code &= 0x1F;
for(i = 0; i <= code; i++) {
dst[filled++] = *src++;
if(filled >= width) {
filled = 0;
dst -= stride;
height--;
}
}
size -= code + 1;
} else if(code >= 0x80) { /* skip code: 0x80..0xBF */
int skip;
code &= 0x3F;
/* codes 0x80 and 0x81 are actually escape codes,
skip value minus constant is in the next byte */
if(!code)
skip = (*src++) + 64;
else if(code == 1)
skip = (*src++) + 320;
else
skip = code;
filled += skip;
while( filled >= width) {
filled -= width;
dst -= stride;
height--;
if(height < 0)
break;
}
} else {
/* zero code treated as one-pixel skip */
if(code)
dst[filled++] = ctable[code & 0x7F];
else
filled++;
if(filled >= width) {
filled = 0;
dst -= stride;
height--;
}
}
}
}
static int decode_frame(AVCodecContext *avctx,
void *data, int *data_size,
AVPacket *avpkt)
{
const uint8_t *buf = avpkt->data;
int buf_size = avpkt->size;
QpegContext * const a = avctx->priv_data;
AVFrame * p= (AVFrame*)&a->pic;
AVFrame * ref= (AVFrame*)&a->ref;
uint8_t* outdata;
int delta;
const uint8_t *pal = av_packet_get_side_data(avpkt, AV_PKT_DATA_PALETTE, NULL);
if(ref->data[0])
avctx->release_buffer(avctx, ref);
FFSWAP(AVFrame, *ref, *p);
p->reference= 3;
if(avctx->get_buffer(avctx, p) < 0){
av_log(avctx, AV_LOG_ERROR, "get_buffer() failed\n");
return -1;
}
outdata = a->pic.data[0];
if(buf[0x85] == 0x10) {
qpeg_decode_intra(buf+0x86, outdata, buf_size - 0x86, a->pic.linesize[0], avctx->width, avctx->height);
} else {
delta = buf[0x85];
qpeg_decode_inter(buf+0x86, outdata, buf_size - 0x86, a->pic.linesize[0], avctx->width, avctx->height, delta, buf + 4, a->ref.data[0]);
}
/* make the palette available on the way out */
if (pal) {
a->pic.palette_has_changed = 1;
memcpy(a->pal, pal, AVPALETTE_SIZE);
}
memcpy(a->pic.data[1], a->pal, AVPALETTE_SIZE);
*data_size = sizeof(AVFrame);
*(AVFrame*)data = a->pic;
return buf_size;
}
static av_cold int decode_init(AVCodecContext *avctx){
QpegContext * const a = avctx->priv_data;
avcodec_get_frame_defaults(&a->pic);
avcodec_get_frame_defaults(&a->ref);
a->avctx = avctx;
avctx->pix_fmt= PIX_FMT_PAL8;
return 0;
}
static av_cold int decode_end(AVCodecContext *avctx){
QpegContext * const a = avctx->priv_data;
AVFrame * const p= (AVFrame*)&a->pic;
AVFrame * const ref= (AVFrame*)&a->ref;
if(p->data[0])
avctx->release_buffer(avctx, p);
if(ref->data[0])
avctx->release_buffer(avctx, ref);
return 0;
}
AVCodec ff_qpeg_decoder = {
"qpeg",
AVMEDIA_TYPE_VIDEO,
CODEC_ID_QPEG,
sizeof(QpegContext),
decode_init,
NULL,
decode_end,
decode_frame,
CODEC_CAP_DR1,
.long_name = NULL_IF_CONFIG_SMALL("Q-team QPEG"),
};
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