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mpv/TOOLS/mwallp/jpeg.c

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// based on vd_ijpg.c by Pontscho
#include <stdio.h>
#include <stdlib.h>
#include <jpeglib.h>
#define UINT16 IJPG_UINT16
#define INT16 IJPG_INT16
#include <setjmp.h>
#include <inttypes.h>
#include "img_format.h"
#include "swscale.h"
#include "rgb2rgb.h"
static struct SwsContext *swsContext=NULL;
typedef struct
{
struct jpeg_source_mgr pub;
unsigned char * inbuf;
int bufsize;
} my_source_mgr;
typedef my_source_mgr * my_src_ptr;
METHODDEF(void) init_source (j_decompress_ptr cinfo)
{
}
METHODDEF(boolean) fill_input_buffer (j_decompress_ptr cinfo)
{
my_src_ptr src = (my_src_ptr) cinfo->src;
size_t nbytes;
src->pub.next_input_byte = src->inbuf;
src->pub.bytes_in_buffer = src->bufsize;
return TRUE;
}
METHODDEF(void) skip_input_data (j_decompress_ptr cinfo, long num_bytes)
{
my_src_ptr src = (my_src_ptr) cinfo->src;
if (num_bytes > 0)
{
while (num_bytes > (long) src->pub.bytes_in_buffer)
{
num_bytes -= (long) src->pub.bytes_in_buffer;
(void) fill_input_buffer(cinfo);
}
src->pub.next_input_byte += (size_t) num_bytes;
src->pub.bytes_in_buffer -= (size_t) num_bytes;
}
}
METHODDEF(void) term_source (j_decompress_ptr cinfo) { }
GLOBAL(void) jpeg_buf_src ( j_decompress_ptr cinfo, char * inbuf,int bufsize )
{
my_src_ptr src;
if (cinfo->src == NULL) cinfo->src=malloc( sizeof( my_source_mgr ) );
src = (my_src_ptr) cinfo->src;
src->pub.init_source = init_source;
src->pub.fill_input_buffer = fill_input_buffer;
src->pub.skip_input_data = skip_input_data;
src->pub.resync_to_restart = jpeg_resync_to_restart;
src->pub.term_source = term_source;
src->inbuf = inbuf;
src->bufsize=bufsize;
src->pub.bytes_in_buffer = 0;
src->pub.next_input_byte = NULL;
}
struct my_error_mgr
{
struct jpeg_error_mgr pub;
jmp_buf setjmp_buffer;
};
typedef struct my_error_mgr * my_error_ptr;
METHODDEF(void) my_error_exit (j_common_ptr cinfo)
{
my_error_ptr myerr=(my_error_ptr) cinfo->err;
(*cinfo->err->output_message) (cinfo);
longjmp(myerr->setjmp_buffer, 1);
}
static struct jpeg_decompress_struct cinfo;
static struct my_error_mgr jerr;
// decode a frame
int decode_jpeg(void* data,int len,char* dbuffer,int dwidth,int dheight, int dstride,int dbpp){
int width,height,depth,i;
int row_stride;
unsigned char* img=NULL;
int in_fmt=0;
if ( len <= 0 ) return 0; // skipped frame
cinfo.err=jpeg_std_error( &jerr.pub );
jerr.pub.error_exit=my_error_exit;
if( setjmp( jerr.setjmp_buffer ) )
{
return 0;
}
jpeg_create_decompress( &cinfo );
jpeg_buf_src( &cinfo,data,len );
jpeg_read_header( &cinfo,TRUE );
width=cinfo.image_width;
height=cinfo.image_height;
jpeg_start_decompress( &cinfo );
depth=cinfo.output_components * 8;
switch( depth ) {
case 8: in_fmt=IMGFMT_Y8;break;
case 24: in_fmt=IMGFMT_RGB|24;break;
default: return 0;
}
row_stride=cinfo.output_width * cinfo.output_components;
img=malloc(row_stride * (height+1));
for ( i=0;i < height;i++ ){
// char* row=dbuffer+i*dstride;
char* row=img+row_stride*i;
jpeg_read_scanlines( &cinfo,(JSAMPLE**)&row,1 );
}
jpeg_finish_decompress(&cinfo);
jpeg_destroy_decompress(&cinfo);
swsContext= sws_getContext(width,height, in_fmt,
dwidth,dheight, IMGFMT_BGR|dbpp, SWS_BICUBIC, NULL, NULL, NULL);
sws_scale(swsContext,&img,&row_stride,0,height,&dbuffer, &dstride);
sws_freeContext(swsContext);
free(img);
return 1;
}