opencv/modules/highgui/src/cap_ffmpeg_impl.hpp

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#include "cap_ffmpeg_api.hpp"
#include <assert.h>
#include <algorithm>

#if defined _MSC_VER && _MSC_VER >= 1200
#pragma warning( disable: 4244 4510 4512 4610 )
#endif

#ifdef __cplusplus
extern "C" {
#endif

#include "ffmpeg_codecs.hpp"

#ifdef WIN32
  #define HAVE_FFMPEG_SWSCALE 1
  #include <libavcodec/avcodec.h>
  #include <libswscale/swscale.h>
#else

// if the header path is not specified explicitly, let's deduce it
#if !defined HAVE_FFMPEG_AVCODEC_H && !defined HAVE_LIBAVCODEC_AVCODEC_H

#if defined(HAVE_GENTOO_FFMPEG)
  #define HAVE_LIBAVCODEC_AVCODEC_H 1
  #if defined(HAVE_FFMPEG_SWSCALE)
    #define HAVE_LIBSWSCALE_SWSCALE_H 1
  #endif
#elif defined HAVE_FFMPEG
  #define HAVE_FFMPEG_AVCODEC_H 1
  #if defined(HAVE_FFMPEG_SWSCALE)
    #define HAVE_FFMPEG_SWSCALE_H 1
  #endif
#endif

#endif

#if defined(HAVE_FFMPEG_AVCODEC_H)
  #include <ffmpeg/avcodec.h>
#endif
#if defined(HAVE_FFMPEG_SWSCALE_H)
  #include <ffmpeg/swscale.h>
#endif

#if defined(HAVE_LIBAVCODEC_AVCODEC_H)
  #include <libavcodec/avcodec.h>
#endif
#if defined(HAVE_LIBSWSCALE_SWSCALE_H)
  #include <libswscale/swscale.h>
#endif

#endif

#ifdef __cplusplus
}
#endif

#if defined _MSC_VER && _MSC_VER >= 1200
#pragma warning( default: 4244 4510 4512 4610 )
#endif

#ifdef NDEBUG
#define CV_WARN(message)
#else
#define CV_WARN(message) fprintf(stderr, "warning: %s (%s:%d)\n", message, __FILE__, __LINE__)
#endif

/* PIX_FMT_RGBA32 macro changed in newer ffmpeg versions */
#ifndef PIX_FMT_RGBA32
#define PIX_FMT_RGBA32 PIX_FMT_RGB32
#endif

#define CALC_FFMPEG_VERSION(a,b,c) ( a<<16 | b<<8 | c )

#if defined WIN32 || defined _WIN32
    #include <windows.h>
#elif defined __linux__ || defined __APPLE__
    #include <unistd.h>
    #include <stdio.h>
    #include <sys/types.h> 
    #include <sys/sysctl.h>
#endif

int get_number_of_cpus(void)
{
#if defined WIN32 || defined _WIN32
    SYSTEM_INFO sysinfo;
    GetSystemInfo( &sysinfo );
    
    return (int)sysinfo.dwNumberOfProcessors;
#elif defined __linux__
    return (int)sysconf( _SC_NPROCESSORS_ONLN );
#elif defined __APPLE__
    int numCPU=0;
    int mib[4];
    size_t len = sizeof(numCPU); 
    
    /* set the mib for hw.ncpu */
    mib[0] = CTL_HW;
    mib[1] = HW_AVAILCPU;  // alternatively, try HW_NCPU;
    
    /* get the number of CPUs from the system */
    sysctl(mib, 2, &numCPU, &len, NULL, 0);
    
    if( numCPU < 1 ) 
    {
        mib[1] = HW_NCPU;
        sysctl( mib, 2, &numCPU, &len, NULL, 0 );
        
        if( numCPU < 1 )
            numCPU = 1;
    }

    return (int)numCPU;
#else
    return 1;
#endif
}


char * FOURCC2str( int fourcc )
{
    char * mystr=(char*)malloc(5);
    mystr[0]=(char)((fourcc    )&255);
    mystr[1]=(char)((fourcc>> 8)&255);
    mystr[2]=(char)((fourcc>>16)&255);
    mystr[3]=(char)((fourcc>>24)&255);
    mystr[4]=0;
    return mystr;
}


struct Image_FFMPEG
{
    unsigned char* data;
    int step;
    int width;
    int height;
    int cn;
};


inline void _opencv_ffmpeg_free(void** ptr)
{
    if(*ptr) free(*ptr);
    *ptr = 0;
}


struct CvCapture_FFMPEG
{
    bool open( const char* filename );
    void close();

    double getProperty(int);
    bool seekKeyAndRunOverFrames(int framenumber);
    bool setProperty(int, double);
    bool grabFrame();
    bool retrieveFrame(int, unsigned char** data, int* step, int* width, int* height, int* cn);

    void init();
    bool reopen();
    bool slowSeek( int framenumber );

    AVFormatContext   * ic;
    int                 video_stream;
    AVStream          * video_st;
    AVFrame           * picture;
    int64_t             picture_pts;
    AVFrame             rgb_picture;
    AVPacket            packet;
    Image_FFMPEG        frame;
#if defined(HAVE_FFMPEG_SWSCALE)
    struct SwsContext *img_convert_ctx;
#endif
/*
   'filename' contains the filename of the videosource,
   'filename==NULL' indicates that ffmpeg's seek support works
   for the particular file.
   'filename!=NULL' indicates that the slow fallback function is used for seeking,
   and so the filename is needed to reopen the file on backward seeking.
*/
    char              * filename;
};


void CvCapture_FFMPEG::init()
{
    ic = 0;
    video_stream = -1;
    video_st = 0;
    picture = 0;
    picture_pts = 0;
    memset( &rgb_picture, 0, sizeof(rgb_picture) );
    memset( &frame, 0, sizeof(frame) );
    filename = 0;
    packet.data = NULL;
#if defined(HAVE_FFMPEG_SWSCALE)
    img_convert_ctx = 0;
#endif
}


void CvCapture_FFMPEG::close()
{
    if( picture )
        av_free(picture);

    if( video_st )
    {
#if LIBAVFORMAT_BUILD > 4628
        avcodec_close( video_st->codec );
#else
        avcodec_close( &video_st->codec );
#endif
        video_st = NULL;
    }

    if( ic )
    {
        av_close_input_file(ic);
        ic = NULL;
    }

    if( rgb_picture.data[0] )
    {
        free( rgb_picture.data[0] );
        rgb_picture.data[0] = 0;
    }

    // free last packet if exist
    if (packet.data) {
        av_free_packet (&packet);
    }



    init();
}


/*
    Used to reopen a video if the slower fallback function for seeking is used.
*/
bool CvCapture_FFMPEG::reopen()
{
    if ( filename==NULL ) return false;

#if LIBAVFORMAT_BUILD > 4628
    avcodec_close( video_st->codec );
#else
    avcodec_close( &video_st->codec );
#endif
    av_close_input_file(ic);

    // reopen video
    av_open_input_file(&ic, filename, NULL, 0, NULL);
    av_find_stream_info(ic);
#if LIBAVFORMAT_BUILD > 4628
    AVCodecContext *enc = ic->streams[video_stream]->codec;
#else
    AVCodecContext *enc = &ic->streams[video_stream]->codec;
#endif

    avcodec_thread_init(enc, std::min(get_number_of_cpus(), 16));

    AVCodec *codec = avcodec_find_decoder(enc->codec_id);
    avcodec_open(enc, codec);
    video_st = ic->streams[video_stream];

    // reset framenumber to zero
    picture_pts=0;

    return true;
}

#ifndef AVSEEK_FLAG_FRAME
#define AVSEEK_FLAG_FRAME 0
#endif
#ifndef AVSEEK_FLAG_ANY
#define AVSEEK_FLAG_ANY 1
#endif
#ifndef SHORTER_DISTANCE_FOR_SEEK_TO_MAKE_IT_FASTER
#define SHORTER_DISTANCE_FOR_SEEK_TO_MAKE_IT_FASTER 25
#endif

bool CvCapture_FFMPEG::open( const char* _filename )
{
    unsigned i;
    bool valid = false;

    close();

    /* register all codecs, demux and protocols */
    av_register_all();

#ifndef _DEBUG
    // av_log_level = AV_LOG_QUIET;
#endif

    int err = av_open_input_file(&ic, _filename, NULL, 0, NULL);
    if (err < 0) {
	    CV_WARN("Error opening file");
	    goto exit_func;
    }
    err = av_find_stream_info(ic);
    if (err < 0) {
	    CV_WARN("Could not find codec parameters");
	    goto exit_func;
    }
    for(i = 0; i < ic->nb_streams; i++) {
#if LIBAVFORMAT_BUILD > 4628
        AVCodecContext *enc = ic->streams[i]->codec;
#else
        AVCodecContext *enc = &ic->streams[i]->codec;
#endif

        avcodec_thread_init(enc, get_number_of_cpus());

#if LIBAVFORMAT_BUILD < CALC_FFMPEG_VERSION(53, 2, 0)
#define AVMEDIA_TYPE_VIDEO CODEC_TYPE_VIDEO
#endif
        
        if( AVMEDIA_TYPE_VIDEO == enc->codec_type && video_stream < 0) {
            AVCodec *codec = avcodec_find_decoder(enc->codec_id);
            if (!codec ||
                avcodec_open(enc, codec) < 0)
                goto exit_func;
            video_stream = i;
            video_st = ic->streams[i];
            picture = avcodec_alloc_frame();

            rgb_picture.data[0] = (uint8_t*)malloc(
                    avpicture_get_size( PIX_FMT_BGR24,
                                        enc->width, enc->height ));
            avpicture_fill( (AVPicture*)&rgb_picture, rgb_picture.data[0],
                            PIX_FMT_BGR24, enc->width, enc->height );

            frame.width = enc->width;
            frame.height = enc->height;
            frame.cn = 3;
            frame.step = rgb_picture.linesize[0];
            frame.data = rgb_picture.data[0];
            break;
        }
    }

    if(video_stream >= 0) valid = true;

    // perform check if source is seekable via ffmpeg's seek function av_seek_frame(...)
    err = av_seek_frame(ic, video_stream, 10, 0);
    if (err < 0)
    {
        filename=(char*)malloc(strlen(_filename)+1);
        strcpy(filename, _filename);
        // reopen videofile to 'seek' back to first frame
        reopen();
    }
    else
    {
        // seek seems to work, so we don't need the filename,
        // but we still need to seek back to filestart
        filename=NULL;
        int64_t ts    = video_st->first_dts;
        int     flags = AVSEEK_FLAG_FRAME | AVSEEK_FLAG_BACKWARD;
        av_seek_frame(ic, video_stream, ts, flags);
    }
    exit_func:

    if( !valid )
        close();

    return valid;
}


bool CvCapture_FFMPEG::grabFrame()
{
    bool valid = false;
    static bool bFirstTime = true;
    int got_picture;

    // First time we're called, set packet.data to NULL to indicate it
    // doesn't have to be freed
    if (bFirstTime) {
        bFirstTime = false;
        packet.data = NULL;
    }

    if( !ic || !video_st )
        return false;

    // free last packet if exist
    if (packet.data != NULL) {
        av_free_packet (&packet);
    }

    // get the next frame
    while (!valid) {
        int ret = av_read_frame(ic, &packet);
        if (ret == AVERROR(EAGAIN))
            continue;
        if (ret < 0)
            break;
        
		if( packet.stream_index != video_stream ) {
            av_free_packet (&packet);
            continue;
        }

#if LIBAVFORMAT_BUILD >= CALC_FFMPEG_VERSION(53, 2, 0)
        avcodec_decode_video2(video_st->codec, picture, &got_picture, &packet);
#else
#if LIBAVFORMAT_BUILD > 4628
        avcodec_decode_video(video_st->codec,
                             picture, &got_picture,
                             packet.data, packet.size);
#else
        avcodec_decode_video(&video_st->codec,
                             picture, &got_picture,
                             packet.data, packet.size);
#endif
#endif

        if (got_picture) {
            // we have a new picture, so memorize it
            picture_pts = packet.pts;
            valid = 1;
        }

        if (packet.data)
        {
            av_free_packet(&packet);
            packet.data = NULL;
        }
    }

    // return if we have a new picture or not
    return valid;
}


bool CvCapture_FFMPEG::retrieveFrame(int, unsigned char** data, int* step, int* width, int* height, int* cn)
{
    if( !video_st || !picture->data[0] )
        return false;

#if !defined(HAVE_FFMPEG_SWSCALE)
#if LIBAVFORMAT_BUILD > 4628
    img_convert( (AVPicture*)&rgb_picture, PIX_FMT_BGR24,
                 (AVPicture*)picture,
                 video_st->codec->pix_fmt,
                 video_st->codec->width,
                 video_st->codec->height );
#else
    img_convert( (AVPicture*)&rgb_picture, PIX_FMT_BGR24,
                 (AVPicture*)picture,
                 video_st->codec.pix_fmt,
                 video_st->codec.width,
                 video_st->codec.height );
#endif
#else
    img_convert_ctx = sws_getContext(video_st->codec->width,
                                     video_st->codec->height,
                                     video_st->codec->pix_fmt,
                                     video_st->codec->width,
                                     video_st->codec->height,
                                     PIX_FMT_BGR24,
                                     SWS_BICUBIC,
                                     NULL, NULL, NULL);

    sws_scale(img_convert_ctx, picture->data,
              picture->linesize, 0,
              video_st->codec->height,
              rgb_picture.data, rgb_picture.linesize);
    sws_freeContext(img_convert_ctx);
#endif
    *data = frame.data;
    *step = frame.step;
    *width = frame.width;
    *height = frame.height;
    *cn = frame.cn;

    return true;
}

#if defined(__APPLE__)
#define AV_NOPTS_VALUE_ ((int64_t)0x8000000000000000LL)
#else
#define AV_NOPTS_VALUE_ ((int64_t)AV_NOPTS_VALUE)
#endif

double CvCapture_FFMPEG::getProperty( int property_id )
{
    // if( !capture || !video_st || !picture->data[0] ) return 0;
    if( !video_st ) return 0;

    double frameScale = av_q2d (video_st->time_base) * av_q2d (video_st->r_frame_rate);
    int64_t timestamp;
    timestamp = picture_pts;

    switch( property_id )
    {
    case CV_FFMPEG_CAP_PROP_POS_MSEC:        
        if(video_st->parser && video_st->parser->dts != AV_NOPTS_VALUE_)
            return (((double)video_st->parser->dts-1) *1000.0) * av_q2d (video_st->time_base);
        if(video_st->cur_dts != AV_NOPTS_VALUE_)
            return ((video_st->cur_dts-video_st->first_dts) * 1000.0 * av_q2d (video_st->time_base));
        break;
    case CV_FFMPEG_CAP_PROP_POS_FRAMES:
        if(video_st->parser && video_st->parser->dts != AV_NOPTS_VALUE_)
            return (double)video_st->parser->dts-1;
        if(video_st->cur_dts != AV_NOPTS_VALUE_)
            return((video_st->cur_dts-video_st->first_dts) * frameScale);
        break;
    case CV_FFMPEG_CAP_PROP_POS_AVI_RATIO:
        if(video_st->parser && video_st->parser->dts != AV_NOPTS_VALUE_)
            return (double)(video_st->parser->dts-1)/(double)video_st->duration;
        if(video_st->cur_dts != AV_NOPTS_VALUE_ && video_st->duration != AV_NOPTS_VALUE_)
            return(((video_st->cur_dts-video_st->first_dts)+(1.0/frameScale)) / (double)video_st->duration);
        break;
    case CV_FFMPEG_CAP_PROP_FRAME_COUNT:
        {
            int64_t nbf = ic->streams[video_stream]->nb_frames;
            double eps = 0.000025;
            if (nbf == 0)
            {
                double fps = static_cast<double>(ic->streams[video_stream]->r_frame_rate.num) / static_cast<double>(ic->streams[video_stream]->r_frame_rate.den);
                if (fps < eps)
                {
                    fps = 1.0 / (static_cast<double>(ic->streams[video_stream]->codec->time_base.num) / static_cast<double>(ic->streams[video_stream]->codec->time_base.den));
                }
                nbf = static_cast<int64_t>(round(ic->duration * fps) / AV_TIME_BASE);
            }
            return nbf;
        }
        break;
    case CV_FFMPEG_CAP_PROP_FRAME_WIDTH:
        return (double)frame.width;
        break;
    case CV_FFMPEG_CAP_PROP_FRAME_HEIGHT:
        return (double)frame.height;
        break;
    case CV_FFMPEG_CAP_PROP_FPS:
#if LIBAVCODEC_BUILD > 4753
        return av_q2d (video_st->r_frame_rate);
#else
        return (double)video_st->codec.frame_rate
                / (double)video_st->codec.frame_rate_base;
#endif
        break;
    case CV_FFMPEG_CAP_PROP_FOURCC:
#if LIBAVFORMAT_BUILD > 4628
        return (double)video_st->codec->codec_tag;
#else
        return (double)video_st->codec.codec_tag;
#endif
        break;
    }
	
    return 0;
}

// this is a VERY slow fallback function, ONLY used if ffmpeg's av_seek_frame delivers no correct result!
bool CvCapture_FFMPEG::slowSeek( int framenumber )
{
    if ( framenumber>picture_pts )
    {
        while ( picture_pts<framenumber )
            if ( !grabFrame() ) return false;
    }
    else if ( framenumber<picture_pts )
    {
        reopen();
        while ( picture_pts<framenumber )
            if ( !grabFrame() ) return false;
    }
    return true;
}

bool CvCapture_FFMPEG::seekKeyAndRunOverFrames(int framenumber)
{
    int ret;
    if (framenumber > video_st->cur_dts-1) {
        if (framenumber-(video_st->cur_dts-1) > SHORTER_DISTANCE_FOR_SEEK_TO_MAKE_IT_FASTER) {
            ret = av_seek_frame(ic, video_stream, framenumber, 1);
            assert(ret >= 0);
            if( ret < 0 )
                return false;
        }
        grabFrame();
        while ((video_st->cur_dts-1) < framenumber)
            if ( !grabFrame() ) return false;
    }
    else if ( framenumber < (video_st->cur_dts-1) ) {
        ret=av_seek_frame(ic, video_stream, framenumber, 1);
        assert( ret >= 0 );
        if( ret < 0 )
            return false;
        grabFrame();
        while ((video_st->cur_dts-1) < framenumber )
            if ( !grabFrame() ) return false;
    }
    return true;
}

bool CvCapture_FFMPEG::setProperty( int property_id, double value )
{
    if( !video_st ) return false;
    int framenumber = 0;

    switch( property_id )
    {
    case CV_FFMPEG_CAP_PROP_POS_MSEC:
    case CV_FFMPEG_CAP_PROP_POS_FRAMES:
    case CV_FFMPEG_CAP_PROP_POS_AVI_RATIO:
        {
            int64_t    timestamp  = ic->streams[video_stream]->first_dts;
            AVRational time_base  = ic->streams[video_stream]->time_base;
            AVRational frame_base = ic->streams[video_stream]->r_frame_rate;
            double     timeScale  = (time_base.den / (double)time_base.num) / (frame_base.num / (double)frame_base.den);
            switch( property_id )
            {
            case CV_FFMPEG_CAP_PROP_POS_FRAMES:
                framenumber=(int)value;
                seekKeyAndRunOverFrames(framenumber);
                break;

            case CV_FFMPEG_CAP_PROP_POS_MSEC:
                framenumber=(int)(value/(1000.0f * av_q2d (video_st->time_base)));
                seekKeyAndRunOverFrames(framenumber);
                break;

            case CV_FFMPEG_CAP_PROP_POS_AVI_RATIO:
                framenumber = (int)(value*ic->duration);
                seekKeyAndRunOverFrames(framenumber);
                break;
            }

            if ( filename )
            {
                // ffmpeg's seek doesn't work...
                if (!slowSeek((int)timestamp))
                {
                    fprintf(stderr, "HIGHGUI ERROR: AVI: could not (slow) seek to position %0.3f\n",
                            (double)timestamp / AV_TIME_BASE);
                    return false;
                }
            }
            else
            {
                int flags = AVSEEK_FLAG_ANY;
                if (timestamp < ic->streams[video_stream]->cur_dts)
                    flags |= AVSEEK_FLAG_BACKWARD;
                int ret = av_seek_frame(ic, video_stream, timestamp, flags);
                if (ret < 0)
                {
                    fprintf(stderr, "HIGHGUI ERROR: AVI: could not seek to position %0.3f\n",
                            (double)timestamp / AV_TIME_BASE);
                    return false;
                }
            }
            picture_pts=(int64_t)value;
        }
        break;
    default:
        return false;
    }

    return true;
}


///////////////// FFMPEG CvVideoWriter implementation //////////////////////////
struct CvVideoWriter_FFMPEG
{
    bool open( const char* filename, int fourcc,
               double fps, int width, int height, bool isColor );
    void close();
    bool writeFrame( const unsigned char* data, int step, int width, int height, int cn, int origin );

    void init();

    AVOutputFormat *fmt;
    AVFormatContext *oc;
    uint8_t         * outbuf;
    uint32_t          outbuf_size;
    FILE            * outfile;
    AVFrame         * picture;
    AVFrame         * input_picture;
    uint8_t         * picbuf;
    AVStream        * video_st;
    int               input_pix_fmt;
    Image_FFMPEG      temp_image;
#if defined(HAVE_FFMPEG_SWSCALE)
    struct SwsContext *img_convert_ctx;
#endif
};

static const char * icvFFMPEGErrStr(int err)
{
#if LIBAVFORMAT_BUILD >= CALC_FFMPEG_VERSION(53, 2, 0)
    switch(err) {
    case AVERROR_BSF_NOT_FOUND:
        return "Bitstream filter not found";
    case AVERROR_DECODER_NOT_FOUND:
        return "Decoder not found";
    case AVERROR_DEMUXER_NOT_FOUND:
        return "Demuxer not found";
    case AVERROR_ENCODER_NOT_FOUND:
        return "Encoder not found";
    case AVERROR_EOF:
        return "End of file";
    case AVERROR_EXIT:
        return "Immediate exit was requested; the called function should not be restarted";
    case AVERROR_FILTER_NOT_FOUND:
        return "Filter not found";
    case AVERROR_INVALIDDATA:
        return "Invalid data found when processing input";
    case AVERROR_MUXER_NOT_FOUND:
        return "Muxer not found";
    case AVERROR_OPTION_NOT_FOUND:
        return "Option not found";
    case AVERROR_PATCHWELCOME:
        return "Not yet implemented in FFmpeg, patches welcome";
    case AVERROR_PROTOCOL_NOT_FOUND:
        return "Protocol not found";
    case AVERROR_STREAM_NOT_FOUND:
        return "Stream not found";
    default:
        break;
 	}
#else
    switch(err) {
    case AVERROR_NUMEXPECTED:
		return "Incorrect filename syntax";
    case AVERROR_INVALIDDATA:
		return "Invalid data in header";
    case AVERROR_NOFMT:
		return "Unknown format";
    case AVERROR_IO:
		return "I/O error occurred";
    case AVERROR_NOMEM:
		return "Memory allocation error";
    default:
		break;
    }
#endif

 	return "Unspecified error";
}

/* function internal to FFMPEG (libavformat/riff.c) to lookup codec id by fourcc tag*/
extern "C" {
	enum CodecID codec_get_bmp_id(unsigned int tag);
}

void CvVideoWriter_FFMPEG::init()
{
    fmt = 0;
    oc = 0;
    outbuf = 0;
    outbuf_size = 0;
    outfile = 0;
    picture = 0;
    input_picture = 0;
    picbuf = 0;
    video_st = 0;
    input_pix_fmt = 0;
    memset(&temp_image, 0, sizeof(temp_image));
#if defined(HAVE_FFMPEG_SWSCALE)
    img_convert_ctx = 0;
#endif
}

/**
 * the following function is a modified version of code
 * found in ffmpeg-0.4.9-pre1/output_example.c
 */
static AVFrame * icv_alloc_picture_FFMPEG(int pix_fmt, int width, int height, bool alloc)
{
	AVFrame * picture;
	uint8_t * picture_buf;
	int size;

	picture = avcodec_alloc_frame();
	if (!picture)
		return NULL;
	size = avpicture_get_size( (PixelFormat) pix_fmt, width, height);
	if(alloc){
		picture_buf = (uint8_t *) malloc(size);
		if (!picture_buf)
		{
			av_free(picture);
			return NULL;
		}
		avpicture_fill((AVPicture *)picture, picture_buf,
                       (PixelFormat) pix_fmt, width, height);
	}
	else {
	}
	return picture;
}

/* add a video output stream to the container */
static AVStream *icv_add_video_stream_FFMPEG(AVFormatContext *oc,
		                                     CodecID codec_id,
											 int w, int h, int bitrate,
											 double fps, int pixel_format)
{
	AVCodecContext *c;
	AVStream *st;
	int frame_rate, frame_rate_base;
	AVCodec *codec;


	st = av_new_stream(oc, 0);
	if (!st) {
		CV_WARN("Could not allocate stream");
		return NULL;
	}

#if LIBAVFORMAT_BUILD > 4628
	c = st->codec;
#else
	c = &(st->codec);
#endif

#if LIBAVFORMAT_BUILD > 4621
	c->codec_id = av_guess_codec(oc->oformat, NULL, oc->filename, NULL, AVMEDIA_TYPE_VIDEO);
#else
	c->codec_id = oc->oformat->video_codec;
#endif

	if(codec_id != CODEC_ID_NONE){
		c->codec_id = codec_id;
	}

    //if(codec_tag) c->codec_tag=codec_tag;
	codec = avcodec_find_encoder(c->codec_id);

	c->codec_type = AVMEDIA_TYPE_VIDEO;

	/* put sample parameters */
	c->bit_rate = bitrate;

	/* resolution must be a multiple of two */
	c->width = w;
	c->height = h;

	/* time base: this is the fundamental unit of time (in seconds) in terms
       of which frame timestamps are represented. for fixed-fps content,
       timebase should be 1/framerate and timestamp increments should be
       identically 1. */
    frame_rate = static_cast<int>(fps+0.5);
    frame_rate_base = 1;
    while (fabs(static_cast<double>(frame_rate)/frame_rate_base) - fps > 0.001){
        frame_rate_base *= 10;
        frame_rate = static_cast<int>(fps*frame_rate_base + 0.5);
	}
#if LIBAVFORMAT_BUILD > 4752
    c->time_base.den = frame_rate;
    c->time_base.num = frame_rate_base;
	/* adjust time base for supported framerates */
	if(codec && codec->supported_framerates){
		const AVRational *p= codec->supported_framerates;
        AVRational req = {frame_rate, frame_rate_base};
		const AVRational *best=NULL;
		AVRational best_error= {INT_MAX, 1};
		for(; p->den!=0; p++){
			AVRational error= av_sub_q(req, *p);
			if(error.num <0) error.num *= -1;
			if(av_cmp_q(error, best_error) < 0){
				best_error= error;
				best= p;
			}
		}
		c->time_base.den= best->num;
		c->time_base.num= best->den;
	}
#else
	c->frame_rate = frame_rate;
	c->frame_rate_base = frame_rate_base;
#endif

	c->gop_size = 12; /* emit one intra frame every twelve frames at most */
	c->pix_fmt = (PixelFormat) pixel_format;

	if (c->codec_id == CODEC_ID_MPEG2VIDEO) {
        c->max_b_frames = 2;
    }
    if (c->codec_id == CODEC_ID_MPEG1VIDEO || c->codec_id == CODEC_ID_MSMPEG4V3){
        /* needed to avoid using macroblocks in which some coeffs overflow
           this doesnt happen with normal video, it just happens here as the
           motion of the chroma plane doesnt match the luma plane */
		/* avoid FFMPEG warning 'clipping 1 dct coefficients...' */
        c->mb_decision=2;
    }
#if LIBAVCODEC_VERSION_INT>0x000409
    // some formats want stream headers to be seperate
    if(oc->oformat->flags & AVFMT_GLOBALHEADER)
    {
        c->flags |= CODEC_FLAG_GLOBAL_HEADER;
    }
#endif

    return st;
}

int icv_av_write_frame_FFMPEG( AVFormatContext * oc, AVStream * video_st, uint8_t * outbuf, uint32_t outbuf_size, AVFrame * picture )
{

#if LIBAVFORMAT_BUILD > 4628
	AVCodecContext * c = video_st->codec;
#else
	AVCodecContext * c = &(video_st->codec);
#endif
	int out_size;
	int ret;

    if (oc->oformat->flags & AVFMT_RAWPICTURE) {
        /* raw video case. The API will change slightly in the near
           futur for that */
        AVPacket pkt;
        av_init_packet(&pkt);

#ifndef PKT_FLAG_KEY
#define PKT_FLAG_KEY AV_PKT_FLAG_KEY
#endif
		
        pkt.flags |= PKT_FLAG_KEY; 
        pkt.stream_index= video_st->index;
        pkt.data= (uint8_t *)picture;
        pkt.size= sizeof(AVPicture);

        ret = av_write_frame(oc, &pkt);
    } else {
        /* encode the image */
        out_size = avcodec_encode_video(c, outbuf, outbuf_size, picture);
        /* if zero size, it means the image was buffered */
        if (out_size > 0) {
            AVPacket pkt;
            av_init_packet(&pkt);

#if LIBAVFORMAT_BUILD > 4752
            if(c->coded_frame->pts != (int64_t)AV_NOPTS_VALUE)
                pkt.pts = av_rescale_q(c->coded_frame->pts, c->time_base, video_st->time_base);
#else
			pkt.pts = c->coded_frame->pts;
#endif
            if(c->coded_frame->key_frame)
                pkt.flags |= PKT_FLAG_KEY;
            pkt.stream_index= video_st->index;
            pkt.data= outbuf;
            pkt.size= out_size;

            /* write the compressed frame in the media file */
            ret = av_write_frame(oc, &pkt);
        } else {
            ret = 0;
        }
    }
    if (ret != 0) return -1;

	return 0;
}

/// write a frame with FFMPEG
bool CvVideoWriter_FFMPEG::writeFrame( const unsigned char* data, int step, int width, int height, int cn, int origin )
{
	bool ret = false;

	// typecast from opaque data type to implemented struct
#if LIBAVFORMAT_BUILD > 4628
    AVCodecContext *c = video_st->codec;
#else
    AVCodecContext *c = &(video_st->codec);
#endif

#if LIBAVFORMAT_BUILD < 5231
    // It is not needed in the latest versions of the ffmpeg
    if( c->codec_id == CODEC_ID_RAWVIDEO && origin != 1 )
    {
        if( !temp_image.data )
        {
            temp_image.step = (width*cn + 3) & -4;
            temp_image.width = width;
            temp_image.height = height;
            temp_image.cn = cn;
            temp_image.data = (unsigned char*)malloc(temp_image.step*temp_image.height);
        }
        for( int y = 0; y < height; y++ )
            memcpy(temp_image.data + y*temp_image.step, data + (height-1-y)*step, width*cn);
        data = temp_image.data;
        step = temp_image.step;
    }
#else
    if( width*cn != step )
    {
        if( !temp_image.data )
        {
            temp_image.step = width*cn;
            temp_image.width = width;
            temp_image.height = height;
            temp_image.cn = cn;
            temp_image.data = (unsigned char*)malloc(temp_image.step*temp_image.height);
        }
        if (origin == 1)
            for( int y = 0; y < height; y++ )
                memcpy(temp_image.data + y*temp_image.step, data + (height-1-y)*step, temp_image.step);
        else
            for( int y = 0; y < height; y++ )
                memcpy(temp_image.data + y*temp_image.step, data + y*step, temp_image.step);
        data = temp_image.data;
        step = temp_image.step;
    }
#endif

    // check parameters
    if (input_pix_fmt == PIX_FMT_BGR24) {
        if (cn != 3) {
            return false;
        }
    }
	else if (input_pix_fmt == PIX_FMT_GRAY8) {
        if (cn != 1) {
            return false;
        }
    }
	else {
        assert(false);
    }

	// check if buffer sizes match, i.e. image has expected format (size, channels, bitdepth, alignment)
    /*#if LIBAVCODEC_VERSION_INT >= ((52<<16)+(37<<8)+0)
	assert (image->imageSize == avpicture_get_size( (PixelFormat)input_pix_fmt, image->width, image->height ));
#else
	assert (image->imageSize == avpicture_get_size( input_pix_fmt, image->width, image->height ));
#endif*/

	if ( c->pix_fmt != input_pix_fmt ) {
		assert( input_picture );
		// let input_picture point to the raw data buffer of 'image'
		avpicture_fill((AVPicture *)input_picture, (uint8_t *) data,
                       (PixelFormat)input_pix_fmt, width, height);

#if !defined(HAVE_FFMPEG_SWSCALE)
		// convert to the color format needed by the codec
		if( img_convert((AVPicture *)picture, c->pix_fmt,
                        (AVPicture *)input_picture, (PixelFormat)input_pix_fmt,
                        width, height) < 0){
			return false;
		}
#else
		img_convert_ctx = sws_getContext(width,
                                         height,
                                         (PixelFormat)input_pix_fmt,
                                         c->width,
                                         c->height,
                                         c->pix_fmt,
                                         SWS_BICUBIC,
                                         NULL, NULL, NULL);

        if ( sws_scale(img_convert_ctx, input_picture->data,
                       input_picture->linesize, 0,
                       height,
                       picture->data, picture->linesize) < 0 )
        {
            return false;
        }
		sws_freeContext(img_convert_ctx);
#endif
	}
	else{
		avpicture_fill((AVPicture *)picture, (uint8_t *) data,
                       (PixelFormat)input_pix_fmt, width, height);
	}

	ret = icv_av_write_frame_FFMPEG( oc, video_st, outbuf, outbuf_size, picture) >= 0;

	return ret;
}

/// close video output stream and free associated memory
void CvVideoWriter_FFMPEG::close()
{
	unsigned i;

	// nothing to do if already released
	if ( !picture )
		return;

	/* no more frame to compress. The codec has a latency of a few
	   frames if using B frames, so we get the last frames by
	   passing the same picture again */
	// TODO -- do we need to account for latency here?

	/* write the trailer, if any */
	av_write_trailer(oc);

	// free pictures
#if LIBAVFORMAT_BUILD > 4628
	if( video_st->codec->pix_fmt != input_pix_fmt){
#else
        if( video_st->codec.pix_fmt != input_pix_fmt){
#endif
            if(picture->data[0])
                free(picture->data[0]);
            picture->data[0] = 0;
        }
        av_free(picture);

        if (input_picture) {
            av_free(input_picture);
        }

        /* close codec */
#if LIBAVFORMAT_BUILD > 4628
        avcodec_close(video_st->codec);
#else
        avcodec_close(&(video_st->codec));
#endif

        av_free(outbuf);

        /* free the streams */
        for(i = 0; i < oc->nb_streams; i++) {
            av_freep(&oc->streams[i]->codec);
            av_freep(&oc->streams[i]);
        }

        if (!(fmt->flags & AVFMT_NOFILE)) {
            /* close the output file */


#if LIBAVCODEC_VERSION_INT >= ((51<<16)+(49<<8)+0)
            url_fclose(oc->pb);
#else
            url_fclose(&oc->pb);
#endif

        }

        /* free the stream */
        av_free(oc);

        if( temp_image.data )
        {
            free(temp_image.data);
            temp_image.data = 0;
        }

        init();
    }

    /// Create a video writer object that uses FFMPEG
    bool CvVideoWriter_FFMPEG::open( const char * filename, int fourcc,
                                     double fps, int width, int height, bool is_color )
    {
        CodecID codec_id = CODEC_ID_NONE;
        int err, codec_pix_fmt, bitrate_scale = 64;

        close();

        // check arguments
        assert(filename);
        assert(fps > 0);
        assert(width > 0  &&  height > 0);

        // tell FFMPEG to register codecs
        av_register_all();

        /* auto detect the output format from the name and fourcc code. */

#if LIBAVFORMAT_BUILD >= CALC_FFMPEG_VERSION(53, 2, 0)
        fmt = av_guess_format(NULL, filename, NULL);
#else
        fmt = guess_format(NULL, filename, NULL);
#endif

        if (!fmt)
            return false;

        /* determine optimal pixel format */
        if (is_color) {
            input_pix_fmt = PIX_FMT_BGR24;
        }
        else {
            input_pix_fmt = PIX_FMT_GRAY8;
        }

        /* Lookup codec_id for given fourcc */
#if LIBAVCODEC_VERSION_INT<((51<<16)+(49<<8)+0)
        if( (codec_id = codec_get_bmp_id( fourcc )) == CODEC_ID_NONE )
            return false;
#else
        const struct AVCodecTag * tags[] = { codec_bmp_tags, NULL};
        if( (codec_id = av_codec_get_id(tags, fourcc)) == CODEC_ID_NONE )
            return false;
#endif

        // alloc memory for context
#if LIBAVFORMAT_BUILD >= CALC_FFMPEG_VERSION(53, 2, 0)
        oc = avformat_alloc_context();
#else
        oc = av_alloc_format_context();
#endif
        assert (oc);

        /* set file name */
        oc->oformat = fmt;
        snprintf(oc->filename, sizeof(oc->filename), "%s", filename);

        /* set some options */
        oc->max_delay = (int)(0.7*AV_TIME_BASE);  /* This reduces buffer underrun warnings with MPEG */

        // set a few optimal pixel formats for lossless codecs of interest..
        switch (codec_id) {
#if LIBAVCODEC_VERSION_INT>((50<<16)+(1<<8)+0)
        case CODEC_ID_JPEGLS:
            // BGR24 or GRAY8 depending on is_color...
            codec_pix_fmt = input_pix_fmt;
            break;
#endif
        case CODEC_ID_HUFFYUV:
            codec_pix_fmt = PIX_FMT_YUV422P;
            break;
        case CODEC_ID_MJPEG:
        case CODEC_ID_LJPEG:
            codec_pix_fmt = PIX_FMT_YUVJ420P;
            bitrate_scale = 128;
            break;
        case CODEC_ID_RAWVIDEO:
            codec_pix_fmt = input_pix_fmt == PIX_FMT_GRAY8 ||
                            input_pix_fmt == PIX_FMT_GRAY16LE ||
                            input_pix_fmt == PIX_FMT_GRAY16BE ? input_pix_fmt : PIX_FMT_YUV420P;
            break;
        default:
            // good for lossy formats, MPEG, etc.
            codec_pix_fmt = PIX_FMT_YUV420P;
            break;
        }

        // TODO -- safe to ignore output audio stream?
        video_st = icv_add_video_stream_FFMPEG(oc, codec_id,
                                               width, height, width*height*bitrate_scale,
                                               fps, codec_pix_fmt);


        /* set the output parameters (must be done even if no
       parameters). */
        if (av_set_parameters(oc, NULL) < 0) {
            return false;
        }

        dump_format(oc, 0, filename, 1);

        /* now that all the parameters are set, we can open the audio and
       video codecs and allocate the necessary encode buffers */
        if (!video_st){
            return false;
        }

        AVCodec *codec;
        AVCodecContext *c;

#if LIBAVFORMAT_BUILD > 4628
        c = (video_st->codec);
#else
        c = &(video_st->codec);
#endif

        c->codec_tag = fourcc;
        /* find the video encoder */
        codec = avcodec_find_encoder(c->codec_id);
        if (!codec) {
            fprintf(stderr, "Could not find encoder for codec id %d: %s", c->codec_id, icvFFMPEGErrStr(
            #if LIBAVFORMAT_BUILD >= CALC_FFMPEG_VERSION(53, 2, 0)
                    AVERROR_ENCODER_NOT_FOUND
            #else
                    -1
            #endif
                    ));
            return false;
        }

        c->bit_rate_tolerance = c->bit_rate;

        /* open the codec */
        if ( (err=avcodec_open(c, codec)) < 0 ) {
            fprintf(stderr, "Could not open codec '%s': %s", codec->name, icvFFMPEGErrStr(err));
            return false;
        }

        outbuf = NULL;

        if (!(oc->oformat->flags & AVFMT_RAWPICTURE)) {
            /* allocate output buffer */
            /* assume we will never get codec output with more than 4 bytes per pixel... */
            outbuf_size = width*height*4;
            outbuf = (uint8_t *) av_malloc(outbuf_size);
        }

        bool need_color_convert;
        need_color_convert = (c->pix_fmt != input_pix_fmt);

        /* allocate the encoded raw picture */
        picture = icv_alloc_picture_FFMPEG(c->pix_fmt, c->width, c->height, need_color_convert);
        if (!picture) {
            return false;
        }

        /* if the output format is not our input format, then a temporary
       picture of the input format is needed too. It is then converted
	   to the required output format */
        input_picture = NULL;
        if ( need_color_convert ) {
            input_picture = icv_alloc_picture_FFMPEG(input_pix_fmt, c->width, c->height, false);
            if (!input_picture) {
                return false;
            }
        }

        /* open the output file, if needed */
        if (!(fmt->flags & AVFMT_NOFILE)) {
            if (url_fopen(&oc->pb, filename, URL_WRONLY) < 0) {
                return false;
            }
        }

        /* write the stream header, if any */
        av_write_header( oc );

        return true;
    }



    CvCapture_FFMPEG* cvCreateFileCapture_FFMPEG( const char* filename )
    {
        CvCapture_FFMPEG* capture = (CvCapture_FFMPEG*)malloc(sizeof(*capture));
        capture->init();
        if( capture->open( filename ))
            return capture;
        capture->close();
        free(capture);
        return 0;
    }


    void cvReleaseCapture_FFMPEG(CvCapture_FFMPEG** capture)
    {
        if( capture && *capture )
        {
            (*capture)->close();
            free(*capture);
            *capture = 0;
        }
    }

    int cvSetCaptureProperty_FFMPEG(CvCapture_FFMPEG* capture, int prop_id, double value)
    {
        return capture->setProperty(prop_id, value);
    }

    double cvGetCaptureProperty_FFMPEG(CvCapture_FFMPEG* capture, int prop_id)
    {
        return capture->getProperty(prop_id);
    }

    int cvGrabFrame_FFMPEG(CvCapture_FFMPEG* capture)
    {
        return capture->grabFrame();
    }

    int cvRetrieveFrame_FFMPEG(CvCapture_FFMPEG* capture, unsigned char** data, int* step, int* width, int* height, int* cn)
    {
        return capture->retrieveFrame(0, data, step, width, height, cn);
    }



    CvVideoWriter_FFMPEG* cvCreateVideoWriter_FFMPEG( const char* filename, int fourcc, double fps,
                                                      int width, int height, int isColor )
    {
        CvVideoWriter_FFMPEG* writer = (CvVideoWriter_FFMPEG*)malloc(sizeof(*writer));
        writer->init();
        if( writer->open( filename, fourcc, fps, width, height, isColor != 0 ))
            return writer;
        writer->close();
        free(writer);
        return 0;
    }


    void cvReleaseVideoWriter_FFMPEG( CvVideoWriter_FFMPEG** writer )
    {
        if( writer && *writer )
        {
            (*writer)->close();
            free(*writer);
            *writer = 0;
        }
    }


    int cvWriteFrame_FFMPEG( CvVideoWriter_FFMPEG* writer,
                             const unsigned char* data, int step,
                             int width, int height, int cn, int origin)
    {
        return writer->writeFrame(data, step, width, height, cn, origin);
    }