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FFmpeg/libavcodec/bmp.c

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/*
* BMP image format decoder
* Copyright (c) 2005 Mans Rullgard
*
* 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 "avcodec.h"
#include "bytestream.h"
#include "bmp.h"
#include "msrledec.h"
static av_cold int bmp_decode_init(AVCodecContext *avctx){
BMPContext *s = avctx->priv_data;
avcodec_get_frame_defaults((AVFrame*)&s->picture);
avctx->coded_frame = (AVFrame*)&s->picture;
return 0;
}
static int bmp_decode_frame(AVCodecContext *avctx,
void *data, int *data_size,
AVPacket *avpkt)
{
const uint8_t *buf = avpkt->data;
int buf_size = avpkt->size;
BMPContext *s = avctx->priv_data;
AVFrame *picture = data;
AVFrame *p = &s->picture;
unsigned int fsize, hsize;
int width, height;
unsigned int depth;
BiCompression comp;
unsigned int ihsize;
int i, j, n, linesize;
uint32_t rgb[3];
uint8_t *ptr;
int dsize;
const uint8_t *buf0 = buf;
if(buf_size < 14){
av_log(avctx, AV_LOG_ERROR, "buf size too small (%d)\n", buf_size);
return -1;
}
if(bytestream_get_byte(&buf) != 'B' ||
bytestream_get_byte(&buf) != 'M') {
av_log(avctx, AV_LOG_ERROR, "bad magic number\n");
return -1;
}
fsize = bytestream_get_le32(&buf);
if(buf_size < fsize){
av_log(avctx, AV_LOG_ERROR, "not enough data (%d < %d), trying to decode anyway\n",
buf_size, fsize);
fsize = buf_size;
}
buf += 2; /* reserved1 */
buf += 2; /* reserved2 */
hsize = bytestream_get_le32(&buf); /* header size */
ihsize = bytestream_get_le32(&buf); /* more header size */
if(ihsize + 14 > hsize){
av_log(avctx, AV_LOG_ERROR, "invalid header size %d\n", hsize);
return -1;
}
/* sometimes file size is set to some headers size, set a real size in that case */
if(fsize == 14 || fsize == ihsize + 14)
fsize = buf_size - 2;
if(fsize <= hsize){
av_log(avctx, AV_LOG_ERROR, "declared file size is less than header size (%d < %d)\n",
fsize, hsize);
return -1;
}
switch(ihsize){
case 40: // windib v3
case 64: // OS/2 v2
case 108: // windib v4
case 124: // windib v5
width = bytestream_get_le32(&buf);
height = bytestream_get_le32(&buf);
break;
case 12: // OS/2 v1
width = bytestream_get_le16(&buf);
height = bytestream_get_le16(&buf);
break;
default:
av_log(avctx, AV_LOG_ERROR, "unsupported BMP file, patch welcome\n");
return -1;
}
if(bytestream_get_le16(&buf) != 1){ /* planes */
av_log(avctx, AV_LOG_ERROR, "invalid BMP header\n");
return -1;
}
depth = bytestream_get_le16(&buf);
if(ihsize == 40)
comp = bytestream_get_le32(&buf);
else
comp = BMP_RGB;
if(comp != BMP_RGB && comp != BMP_BITFIELDS && comp != BMP_RLE4 && comp != BMP_RLE8){
av_log(avctx, AV_LOG_ERROR, "BMP coding %d not supported\n", comp);
return -1;
}
if(comp == BMP_BITFIELDS){
buf += 20;
rgb[0] = bytestream_get_le32(&buf);
rgb[1] = bytestream_get_le32(&buf);
rgb[2] = bytestream_get_le32(&buf);
}
avctx->width = width;
avctx->height = height > 0? height: -height;
avctx->pix_fmt = PIX_FMT_NONE;
switch(depth){
case 32:
if(comp == BMP_BITFIELDS){
rgb[0] = (rgb[0] >> 15) & 3;
rgb[1] = (rgb[1] >> 15) & 3;
rgb[2] = (rgb[2] >> 15) & 3;
if(rgb[0] + rgb[1] + rgb[2] != 3 ||
rgb[0] == rgb[1] || rgb[0] == rgb[2] || rgb[1] == rgb[2]){
break;
}
} else {
rgb[0] = 2;
rgb[1] = 1;
rgb[2] = 0;
}
avctx->pix_fmt = PIX_FMT_BGR24;
break;
case 24:
avctx->pix_fmt = PIX_FMT_BGR24;
break;
case 16:
if(comp == BMP_RGB)
avctx->pix_fmt = PIX_FMT_RGB555;
if(comp == BMP_BITFIELDS)
avctx->pix_fmt = rgb[1] == 0x07E0 ? PIX_FMT_RGB565 : PIX_FMT_RGB555;
break;
case 8:
if(hsize - ihsize - 14 > 0)
avctx->pix_fmt = PIX_FMT_PAL8;
else
avctx->pix_fmt = PIX_FMT_GRAY8;
break;
case 4:
if(hsize - ihsize - 14 > 0){
avctx->pix_fmt = PIX_FMT_PAL8;
}else{
av_log(avctx, AV_LOG_ERROR, "Unknown palette for 16-colour BMP\n");
return -1;
}
break;
case 1:
avctx->pix_fmt = PIX_FMT_MONOBLACK;
break;
default:
av_log(avctx, AV_LOG_ERROR, "depth %d not supported\n", depth);
return -1;
}
if(avctx->pix_fmt == PIX_FMT_NONE){
av_log(avctx, AV_LOG_ERROR, "unsupported pixel format\n");
return -1;
}
if(p->data[0])
avctx->release_buffer(avctx, p);
p->reference = 0;
if(avctx->get_buffer(avctx, p) < 0){
av_log(avctx, AV_LOG_ERROR, "get_buffer() failed\n");
return -1;
}
p->pict_type = AV_PICTURE_TYPE_I;
p->key_frame = 1;
buf = buf0 + hsize;
dsize = buf_size - hsize;
/* Line size in file multiple of 4 */
n = ((avctx->width * depth) / 8 + 3) & ~3;
if(n * avctx->height > dsize && comp != BMP_RLE4 && comp != BMP_RLE8){
av_log(avctx, AV_LOG_ERROR, "not enough data (%d < %d)\n",
dsize, n * avctx->height);
return -1;
}
// RLE may skip decoding some picture areas, so blank picture before decoding
if(comp == BMP_RLE4 || comp == BMP_RLE8)
memset(p->data[0], 0, avctx->height * p->linesize[0]);
if(depth == 4 || depth == 8)
memset(p->data[1], 0, 1024);
if(height > 0){
ptr = p->data[0] + (avctx->height - 1) * p->linesize[0];
linesize = -p->linesize[0];
} else {
ptr = p->data[0];
linesize = p->linesize[0];
}
if(avctx->pix_fmt == PIX_FMT_PAL8){
int colors = 1 << depth;
if(ihsize >= 36){
int t;
buf = buf0 + 46;
t = bytestream_get_le32(&buf);
if(t < 0 || t > (1 << depth)){
av_log(avctx, AV_LOG_ERROR, "Incorrect number of colors - %X for bitdepth %d\n", t, depth);
}else if(t){
colors = t;
}
}
buf = buf0 + 14 + ihsize; //palette location
if((hsize-ihsize-14) < (colors << 2)){ // OS/2 bitmap, 3 bytes per palette entry
for(i = 0; i < colors; i++)
((uint32_t*)p->data[1])[i] = (0xff<<24) | bytestream_get_le24(&buf);
}else{
for(i = 0; i < colors; i++)
((uint32_t*)p->data[1])[i] = bytestream_get_le32(&buf);
}
buf = buf0 + hsize;
}
if(comp == BMP_RLE4 || comp == BMP_RLE8){
if(height < 0){
p->data[0] += p->linesize[0] * (avctx->height - 1);
p->linesize[0] = -p->linesize[0];
}
ff_msrle_decode(avctx, (AVPicture*)p, depth, buf, dsize);
if(height < 0){
p->data[0] += p->linesize[0] * (avctx->height - 1);
p->linesize[0] = -p->linesize[0];
}
}else{
switch(depth){
case 1:
case 8:
case 24:
for(i = 0; i < avctx->height; i++){
memcpy(ptr, buf, n);
buf += n;
ptr += linesize;
}
break;
case 4:
for(i = 0; i < avctx->height; i++){
int j;
for(j = 0; j < n; j++){
ptr[j*2+0] = (buf[j] >> 4) & 0xF;
ptr[j*2+1] = buf[j] & 0xF;
}
buf += n;
ptr += linesize;
}
break;
case 16:
for(i = 0; i < avctx->height; i++){
const uint16_t *src = (const uint16_t *) buf;
uint16_t *dst = (uint16_t *) ptr;
for(j = 0; j < avctx->width; j++)
*dst++ = av_le2ne16(*src++);
buf += n;
ptr += linesize;
}
break;
case 32:
for(i = 0; i < avctx->height; i++){
const uint8_t *src = buf;
uint8_t *dst = ptr;
for(j = 0; j < avctx->width; j++){
dst[0] = src[rgb[2]];
dst[1] = src[rgb[1]];
dst[2] = src[rgb[0]];
dst += 3;
src += 4;
}
buf += n;
ptr += linesize;
}
break;
default:
av_log(avctx, AV_LOG_ERROR, "BMP decoder is broken\n");
return -1;
}
}
*picture = s->picture;
*data_size = sizeof(AVPicture);
return buf_size;
}
static av_cold int bmp_decode_end(AVCodecContext *avctx)
{
BMPContext* c = avctx->priv_data;
if (c->picture.data[0])
avctx->release_buffer(avctx, &c->picture);
return 0;
}
AVCodec ff_bmp_decoder = {
"bmp",
AVMEDIA_TYPE_VIDEO,
CODEC_ID_BMP,
sizeof(BMPContext),
bmp_decode_init,
NULL,
bmp_decode_end,
bmp_decode_frame,
CODEC_CAP_DR1,
.long_name = NULL_IF_CONFIG_SMALL("BMP image"),
};
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