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ffmpeg / vhook / ppm.c @ 582b3549

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/*
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 * PPM Video Hook
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 * Copyright (c) 2003 Charles Yates
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 *
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 * This file is part of FFmpeg.
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 *
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 * FFmpeg is free software; you can redistribute it and/or
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 * modify it under the terms of the GNU Lesser General Public
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 * License as published by the Free Software Foundation; either
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 * version 2.1 of the License, or (at your option) any later version.
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 *
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 * FFmpeg is distributed in the hope that it will be useful,
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 * but WITHOUT ANY WARRANTY; without even the implied warranty of
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 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
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 * Lesser General Public License for more details.
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 *
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 * You should have received a copy of the GNU Lesser General Public
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 * License along with FFmpeg; if not, write to the Free Software
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 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
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 */
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#include <stdio.h>
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#include <unistd.h>
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#include <fcntl.h>
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#include <sys/types.h>
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#include <sys/wait.h>
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#include <ctype.h>
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#include "libavutil/avstring.h"
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#include "libavformat/framehook.h"
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#include "libavformat/avformat.h"
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#include "libswscale/swscale.h"
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static int sws_flags = SWS_BICUBIC;
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/** Bi-directional pipe structure.
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*/
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typedef struct rwpipe
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{
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    int pid;
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    FILE *reader;
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    FILE *writer;
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}
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rwpipe;
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/** Create a bidirectional pipe for the given command.
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*/
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static rwpipe *rwpipe_open( int argc, char *argv[] )
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{
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    rwpipe *this = av_mallocz( sizeof( rwpipe ) );
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    if ( this != NULL )
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    {
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        int input[ 2 ];
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        int output[ 2 ];
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        pipe( input );
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        pipe( output );
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        this->pid = fork();
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        if ( this->pid == 0 )
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        {
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#define COMMAND_SIZE 10240
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            char *command = av_mallocz( COMMAND_SIZE );
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            int i;
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            strcpy( command, "" );
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            for ( i = 0; i < argc; i ++ )
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            {
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                av_strlcat( command, argv[ i ], COMMAND_SIZE );
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                av_strlcat( command, " ", COMMAND_SIZE );
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            }
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            dup2( output[ 0 ], STDIN_FILENO );
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            dup2( input[ 1 ], STDOUT_FILENO );
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            close( input[ 0 ] );
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            close( input[ 1 ] );
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            close( output[ 0 ] );
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            close( output[ 1 ] );
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            execl("/bin/sh", "sh", "-c", command, (char*)NULL );
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            _exit( 255 );
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        }
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        else
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        {
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            close( input[ 1 ] );
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            close( output[ 0 ] );
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            this->reader = fdopen( input[ 0 ], "r" );
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            this->writer = fdopen( output[ 1 ], "w" );
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        }
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    }
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    return this;
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}
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/** Read data from the pipe.
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*/
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static FILE *rwpipe_reader( rwpipe *this )
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{
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    if ( this != NULL )
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        return this->reader;
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    else
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        return NULL;
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}
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/** Write data to the pipe.
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*/
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static FILE *rwpipe_writer( rwpipe *this )
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{
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    if ( this != NULL )
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        return this->writer;
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    else
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        return NULL;
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}
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/* Read a number from the pipe - assumes PNM style headers.
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*/
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static int rwpipe_read_number( rwpipe *rw )
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{
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    int value = 0;
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    int c = 0;
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    FILE *in = rwpipe_reader( rw );
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    do
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    {
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        c = fgetc( in );
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        while( c != EOF && !isdigit( c ) && c != '#' )
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            c = fgetc( in );
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        if ( c == '#' )
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            while( c != EOF && c != '\n' )
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                c = fgetc( in );
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    }
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    while ( c != EOF && !isdigit( c ) );
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    while( c != EOF && isdigit( c ) )
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    {
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        value = value * 10 + ( c - '0' );
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        c = fgetc( in );
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    }
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    return value;
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}
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/** Read a PPM P6 header.
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*/
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static int rwpipe_read_ppm_header( rwpipe *rw, int *width, int *height )
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{
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    char line[ 3 ];
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    FILE *in = rwpipe_reader( rw );
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    int max;
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    fgets( line, 3, in );
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    if ( !strncmp( line, "P6", 2 ) )
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    {
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        *width = rwpipe_read_number( rw );
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        *height = rwpipe_read_number( rw );
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        max = rwpipe_read_number( rw );
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        return max != 255 || *width <= 0 || *height <= 0;
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    }
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    return 1;
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}
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/** Close the pipe and process.
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*/
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static void rwpipe_close( rwpipe *this )
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{
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    if ( this != NULL )
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    {
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        fclose( this->reader );
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        fclose( this->writer );
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        waitpid( this->pid, NULL, 0 );
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        av_free( this );
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    }
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}
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/** Context info for this vhook - stores the pipe and image buffers.
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*/
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typedef struct
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{
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    rwpipe *rw;
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    int size1;
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    char *buf1;
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    int size2;
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    char *buf2;
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    // This vhook first converts frame to RGB ...
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    struct SwsContext *toRGB_convert_ctx;
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    // ... then processes it via a PPM command pipe ...
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    // ... and finally converts back frame from RGB to initial format
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    struct SwsContext *fromRGB_convert_ctx;
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}
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ContextInfo;
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/** Initialise the context info for this vhook.
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*/
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int Configure(void **ctxp, int argc, char *argv[])
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{
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    if ( argc > 1 )
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    {
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        *ctxp = av_mallocz(sizeof(ContextInfo));
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        if ( *ctxp != NULL && argc > 1 )
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        {
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            ContextInfo *info = (ContextInfo *)*ctxp;
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            info->rw = rwpipe_open( argc - 1, &argv[ 1 ] );
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            return 0;
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        }
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    }
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    return 1;
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}
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/** Process a frame.
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*/
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void Process(void *ctx, AVPicture *picture, enum PixelFormat pix_fmt, int width, int height, int64_t pts)
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{
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    int err = 0;
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    ContextInfo *ci = (ContextInfo *) ctx;
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    AVPicture picture1;
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    AVPicture picture2;
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    AVPicture *pict = picture;
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    int out_width;
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    int out_height;
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    int i;
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    uint8_t *ptr = NULL;
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    FILE *in = rwpipe_reader( ci->rw );
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    FILE *out = rwpipe_writer( ci->rw );
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    /* Check that we have a pipe to talk to. */
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    if ( in == NULL || out == NULL )
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        err = 1;
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    /* Convert to RGB24 if necessary */
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    if ( !err && pix_fmt != PIX_FMT_RGB24 )
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    {
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        int size = avpicture_get_size(PIX_FMT_RGB24, width, height);
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        if ( size != ci->size1 )
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        {
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            av_free( ci->buf1 );
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            ci->buf1 = av_malloc(size);
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            ci->size1 = size;
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            err = ci->buf1 == NULL;
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        }
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        if ( !err )
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        {
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            avpicture_fill(&picture1, ci->buf1, PIX_FMT_RGB24, width, height);
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            // if we already got a SWS context, let's realloc if is not re-useable
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            ci->toRGB_convert_ctx = sws_getCachedContext(ci->toRGB_convert_ctx,
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                                        width, height, pix_fmt,
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                                        width, height, PIX_FMT_RGB24,
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                                        sws_flags, NULL, NULL, NULL);
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            if (ci->toRGB_convert_ctx == NULL) {
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                av_log(NULL, AV_LOG_ERROR,
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                       "Cannot initialize the toRGB conversion context\n");
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                return;
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            }
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// img_convert parameters are          2 first destination, then 4 source
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// sws_scale   parameters are context, 4 first source,      then 2 destination
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            sws_scale(ci->toRGB_convert_ctx,
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                     picture->data, picture->linesize, 0, height,
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                     picture1.data, picture1.linesize);
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            pict = &picture1;
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        }
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    }
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    /* Write out the PPM */
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    if ( !err )
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    {
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        ptr = pict->data[ 0 ];
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        fprintf( out, "P6\n%d %d\n255\n", width, height );
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        for ( i = 0; !err && i < height; i ++ )
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        {
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            err = !fwrite( ptr, width * 3, 1, out );
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            ptr += pict->linesize[ 0 ];
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        }
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        if ( !err )
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            err = fflush( out );
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    }
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    /* Read the PPM returned. */
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    if ( !err && !rwpipe_read_ppm_header( ci->rw, &out_width, &out_height ) )
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    {
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        int size = avpicture_get_size(PIX_FMT_RGB24, out_width, out_height);
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        if ( size != ci->size2 )
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        {
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            av_free( ci->buf2 );
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            ci->buf2 = av_malloc(size);
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            ci->size2 = size;
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            err = ci->buf2 == NULL;
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        }
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        if ( !err )
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        {
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            avpicture_fill(&picture2, ci->buf2, PIX_FMT_RGB24, out_width, out_height);
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            ptr = picture2.data[ 0 ];
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            for ( i = 0; !err && i < out_height; i ++ )
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            {
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                err = !fread( ptr, out_width * 3, 1, in );
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                ptr += picture2.linesize[ 0 ];
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            }
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        }
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    }
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    /* Convert the returned PPM back to the input format */
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    if ( !err )
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    {
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        /* The out_width/out_height returned from the PPM
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         * filter won't necessarily be the same as width and height
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         * but it will be scaled anyway to width/height.
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         */
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        av_log(NULL, AV_LOG_DEBUG,
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                  "PPM vhook: Input dimensions: %d x %d Output dimensions: %d x %d\n",
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                  width, height, out_width, out_height);
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        ci->fromRGB_convert_ctx = sws_getCachedContext(ci->fromRGB_convert_ctx,
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                                        out_width, out_height, PIX_FMT_RGB24,
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                                        width,     height,     pix_fmt,
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                                        sws_flags, NULL, NULL, NULL);
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        if (ci->fromRGB_convert_ctx == NULL) {
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            av_log(NULL, AV_LOG_ERROR,
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                   "Cannot initialize the fromRGB conversion context\n");
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            return;
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        }
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// img_convert parameters are          2 first destination, then 4 source
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// sws_scale   parameters are context, 4 first source,      then 2 destination
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        sws_scale(ci->fromRGB_convert_ctx,
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                 picture2.data, picture2.linesize, 0, out_height,
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                 picture->data, picture->linesize);
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    }
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}
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/** Clean up the effect.
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*/
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void Release(void *ctx)
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{
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    ContextInfo *ci;
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    ci = (ContextInfo *) ctx;
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    if (ctx)
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    {
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        rwpipe_close( ci->rw );
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        av_free( ci->buf1 );
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        av_free( ci->buf2 );
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        sws_freeContext(ci->toRGB_convert_ctx);
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        sws_freeContext(ci->fromRGB_convert_ctx);
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        av_free(ctx);
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    }
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}
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