ffmpeg.c

/*
 * FFmpeg main 
 * Copyright (c) 2000, 2001, 2002 Fabrice Bellard
 *
 * This library 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 of the License, or (at your option) any later version.
 *
 * This library 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 this library; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
 */
#define HAVE_AV_CONFIG_H
#include "avformat.h"

#ifndef CONFIG_WIN32
#include <unistd.h>
#include <fcntl.h>
#include <sys/ioctl.h>
#include <sys/time.h>
#include <termios.h>
#include <sys/resource.h>
#endif
#ifdef __BEOS__
/* for snooze() */
#include <OS.h>
#endif
#include <time.h>
#include <ctype.h>


#define MAXINT64 INT64_C(0x7fffffffffffffff)

typedef struct {
    const char *name;
    int flags;
#define HAS_ARG    0x0001
#define OPT_BOOL   0x0002
#define OPT_EXPERT 0x0004
#define OPT_STRING 0x0008
    union {
        void (*func_arg)();
        int *int_arg;
        char **str_arg;
    } u;
    const char *help;
    const char *argname;
} OptionDef;

/* select an input stream for an output stream */
typedef struct AVStreamMap {
    int file_index;
    int stream_index;
} AVStreamMap;

extern const OptionDef options[];

void show_help(void);

#define MAX_FILES 20

static AVFormatContext *input_files[MAX_FILES];
static int nb_input_files = 0;

static AVFormatContext *output_files[MAX_FILES];
static int nb_output_files = 0;

static AVStreamMap stream_maps[MAX_FILES];
static int nb_stream_maps;

static AVInputFormat *file_iformat;
static AVOutputFormat *file_oformat;
static int frame_width  = 160;
static int frame_height = 128;
static int frame_topBand  = 0;
static int frame_bottomBand = 0;
static int frame_leftBand  = 0;
static int frame_rightBand = 0;
static int frame_rate = 25 * FRAME_RATE_BASE;
static int video_bit_rate = 200*1000;
static int video_bit_rate_tolerance = 4000*1000;
static int video_qscale = 0;
static int video_qmin = 2;
static int video_qmax = 31;
static int video_qdiff = 3;
static float video_qblur = 0.5;
static float video_qcomp = 0.5;
#if 0 //experimental, (can be removed)
static float video_rc_qsquish=1.0;
static float video_rc_qmod_amp=0;
static int video_rc_qmod_freq=0;
#endif
static char *video_rc_override_string=NULL;
static char *video_rc_eq="tex^qComp";
static int video_rc_buffer_size=0;
static float video_rc_buffer_aggressivity=1.0;
static int video_rc_max_rate=0;
static int video_rc_min_rate=0;
static float video_rc_initial_cplx=0;
static float video_b_qfactor = 1.25;
static float video_b_qoffset = 1.25;
static float video_i_qfactor = -0.8;
static float video_i_qoffset = 0.0;
static int me_method = 0;
static int video_disable = 0;
static int video_codec_id = CODEC_ID_NONE;
static int same_quality = 0;
static int b_frames = 0;
static int use_hq = 0;
static int use_4mv = 0;
static int do_deinterlace = 0;
static int workaround_bugs = FF_BUG_AUTODETECT;
static int error_resilience = 2;
static int error_concealment = 3;
static int dct_algo = 0;
static int idct_algo = 0;
static int use_part = 0;
static int packet_size = 0;

static int gop_size = 12;
static int intra_only = 0;
static int audio_sample_rate = 44100;
static int audio_bit_rate = 64000;
static int audio_disable = 0;
static int audio_channels = 1;
static int audio_codec_id = CODEC_ID_NONE;

static INT64 recording_time = 0;
static int file_overwrite = 0;
static char *str_title = NULL;
static char *str_author = NULL;
static char *str_copyright = NULL;
static char *str_comment = NULL;
static int do_benchmark = 0;
static int do_hex_dump = 0;
static int do_play = 0;
static int do_psnr = 0;
static int do_vstats = 0;
static int do_pass = 0;
static char *pass_logfilename = NULL;
static int audio_stream_copy = 0;
static int video_stream_copy = 0;

#define DEFAULT_PASS_LOGFILENAME "ffmpeg2pass"

#ifndef CONFIG_AUDIO_OSS
const char *audio_device = "none";
#endif
#ifndef CONFIG_VIDEO4LINUX
const char *v4l_device = "none";
#endif

typedef struct AVOutputStream {
    int file_index;          /* file index */
    int index;               /* stream index in the output file */
    int source_index;        /* AVInputStream index */
    AVStream *st;            /* stream in the output file */
    int encoding_needed;     /* true if encoding needed for this stream */
    int frame_number;
    /* input pts and corresponding output pts
       for A/V sync */
    double sync_ipts;
    INT64 sync_opts;
    /* video only */
    AVPicture pict_tmp;         /* temporary image for resizing */
    int video_resample;
    ImgReSampleContext *img_resample_ctx; /* for image resampling */
    
    /* audio only */
    int audio_resample;
    ReSampleContext *resample; /* for audio resampling */
    FifoBuffer fifo;     /* for compression: one audio fifo per codec */
    FILE *logfile;
} AVOutputStream;

typedef struct AVInputStream {
    int file_index;
    int index;
    AVStream *st;
    int discard;             /* true if stream data should be discarded */
    int decoding_needed;     /* true if the packets must be decoded in 'raw_fifo' */
    INT64 sample_index;      /* current sample */
    int frame_decoded;       /* true if a video or audio frame has been decoded */
} AVInputStream;

typedef struct AVInputFile {
    int eof_reached;      /* true if eof reached */
    int ist_index;        /* index of first stream in ist_table */
    int buffer_size;      /* current total buffer size */
    int buffer_size_max;  /* buffer size at which we consider we can stop
                             buffering */
    int nb_streams;       /* nb streams we are aware of */
} AVInputFile;

#ifndef CONFIG_WIN32

/* init terminal so that we can grab keys */
static struct termios oldtty;

static void term_exit(void)
{
    tcsetattr (0, TCSANOW, &oldtty);
}

static void term_init(void)
{
    struct termios tty;

    tcgetattr (0, &tty);
    oldtty = tty;

    tty.c_iflag &= ~(IGNBRK|BRKINT|PARMRK|ISTRIP
                          |INLCR|IGNCR|ICRNL|IXON);
    tty.c_oflag |= OPOST;
    tty.c_lflag &= ~(ECHO|ECHONL|ICANON|IEXTEN);
    tty.c_cflag &= ~(CSIZE|PARENB);
    tty.c_cflag |= CS8;
    tty.c_cc[VMIN] = 1;
    tty.c_cc[VTIME] = 0;
    
    tcsetattr (0, TCSANOW, &tty);

    atexit(term_exit);
}

/* read a key without blocking */
static int read_key(void)
{
    struct timeval tv;
    int n;
    unsigned char ch;
    fd_set rfds;

    FD_ZERO(&rfds);
    FD_SET(0, &rfds);
    tv.tv_sec = 0;
    tv.tv_usec = 0;
    n = select(1, &rfds, NULL, NULL, &tv);
    if (n > 0) {
        n = read(0, &ch, 1);
        if (n == 1)
            return ch;

        return n;
    }
    return -1;
}

#else

/* no interactive support */
static void term_exit(void)
{
}

static void term_init(void)
{
}

static int read_key(void)
{
    return 0;
}

#endif

int read_ffserver_streams(AVFormatContext *s, const char *filename)
{
    int i, err;
    AVFormatContext *ic;

    err = av_open_input_file(&ic, filename, NULL, FFM_PACKET_SIZE, NULL);
    if (err < 0)
        return err;
    /* copy stream format */
    s->nb_streams = ic->nb_streams;
    for(i=0;i<ic->nb_streams;i++) {
        AVStream *st;
        st = av_mallocz(sizeof(AVFormatContext));
        memcpy(st, ic->streams[i], sizeof(AVStream));
        s->streams[i] = st;
    }

    av_close_input_file(ic);
    return 0;
}

#define MAX_AUDIO_PACKET_SIZE 16384

static void do_audio_out(AVFormatContext *s, 
                         AVOutputStream *ost, 
                         AVInputStream *ist,
                         unsigned char *buf, int size)
{
    UINT8 *buftmp;
    UINT8 audio_buf[2*MAX_AUDIO_PACKET_SIZE]; /* XXX: allocate it */
    UINT8 audio_out[MAX_AUDIO_PACKET_SIZE]; /* XXX: allocate it */
    int size_out, frame_bytes, ret;
    AVCodecContext *enc;

    enc = &ost->st->codec;

    if (ost->audio_resample) {
        buftmp = audio_buf;
        size_out = audio_resample(ost->resample, 
                                  (short *)buftmp, (short *)buf,
                                  size / (ist->st->codec.channels * 2));
        size_out = size_out * enc->channels * 2;
    } else {
        buftmp = buf;
        size_out = size;
    }

    /* now encode as many frames as possible */
    if (enc->frame_size > 1) {
        /* output resampled raw samples */
        fifo_write(&ost->fifo, buftmp, size_out, 
                   &ost->fifo.wptr);

        frame_bytes = enc->frame_size * 2 * enc->channels;
        
        while (fifo_read(&ost->fifo, audio_buf, frame_bytes, 
                     &ost->fifo.rptr) == 0) {
            ret = avcodec_encode_audio(enc, audio_out, sizeof(audio_out), 
                                       (short *)audio_buf);
            av_write_frame(s, ost->index, audio_out, ret);
        }
    } else {
        /* output a pcm frame */
        /* XXX: change encoding codec API to avoid this ? */
        switch(enc->codec->id) {
        case CODEC_ID_PCM_S16LE:
        case CODEC_ID_PCM_S16BE:
        case CODEC_ID_PCM_U16LE:
        case CODEC_ID_PCM_U16BE:
            break;
        default:
            size_out = size_out >> 1;
            break;
        }
        ret = avcodec_encode_audio(enc, audio_out, size_out, 
                                   (short *)buftmp);
        av_write_frame(s, ost->index, audio_out, ret);
    }
}

/* write a picture to a raw mux */
static void write_picture(AVFormatContext *s, int index, AVPicture *picture, 
                          int pix_fmt, int w, int h)
{
    UINT8 *buf, *src, *dest;
    int size, j, i;

    /* XXX: not efficient, should add test if we can take
       directly the AVPicture */
    switch(pix_fmt) {
    case PIX_FMT_YUV420P:
        size = avpicture_get_size(pix_fmt, w, h);
        buf = av_malloc(size);
        if (!buf)
            return;
        dest = buf;
        for(i=0;i<3;i++) {
            if (i == 1) {
                w >>= 1;
                h >>= 1;
            }
            src = picture->data[i];
            for(j=0;j<h;j++) {
                memcpy(dest, src, w);
                dest += w;
                src += picture->linesize[i];
            }
        }
        break;
    case PIX_FMT_YUV422P:
        size = (w * h) * 2; 
        buf = av_malloc(size);
        if (!buf)
            return;
        dest = buf;
        for(i=0;i<3;i++) {
            if (i == 1) {
                w >>= 1;
            }
            src = picture->data[i];
            for(j=0;j<h;j++) {
                memcpy(dest, src, w);
                dest += w;
                src += picture->linesize[i];
            }
        }
        break;
    case PIX_FMT_YUV444P:
        size = (w * h) * 3; 
        buf = av_malloc(size);
        if (!buf)
            return;
        dest = buf;
        for(i=0;i<3;i++) {
            src = picture->data[i];
            for(j=0;j<h;j++) {
                memcpy(dest, src, w);
                dest += w;
                src += picture->linesize[i];
            }
        }
        break;
    case PIX_FMT_YUV422:
        size = (w * h) * 2; 
        buf = av_malloc(size);
        if (!buf)
            return;
        dest = buf;
        src = picture->data[0];
        for(j=0;j<h;j++) {
            memcpy(dest, src, w * 2);
            dest += w * 2;
            src += picture->linesize[0];
        }
        break;
    case PIX_FMT_RGB24:
    case PIX_FMT_BGR24:
        size = (w * h) * 3; 
        buf = av_malloc(size);
        if (!buf)
            return;
        dest = buf;
        src = picture->data[0];
        for(j=0;j<h;j++) {
            memcpy(dest, src, w * 3);
            dest += w * 3;
            src += picture->linesize[0];
        }
        break;
    default:
        return;
    }
    av_write_frame(s, index, buf, size);
    av_free(buf);
}

/* we begin to correct av delay at this threshold */
#define AV_DELAY_MAX 0.100

static void do_video_out(AVFormatContext *s, 
                         AVOutputStream *ost, 
                         AVInputStream *ist,
                         AVPicture *picture1,
                         int *frame_size, AVOutputStream *audio_sync)
{
    int nb_frames, i, ret;
    AVPicture *picture, *picture2, *pict;
    AVPicture picture_tmp1, picture_tmp2;
    static UINT8 *video_buffer;
    UINT8 *buf = NULL, *buf1 = NULL;
    AVCodecContext *enc, *dec;

#define VIDEO_BUFFER_SIZE (1024*1024)

    enc = &ost->st->codec;
    dec = &ist->st->codec;

    /* by default, we output a single frame */
    nb_frames = 1;

    /* NOTE: the A/V sync is always done by considering the audio is
       the master clock. It is suffisant for transcoding or playing,
       but not for the general case */
    if (audio_sync) {
        /* compute the A-V delay and duplicate/remove frames if needed */
        double adelta, vdelta, apts, vpts, av_delay;
        
        if (audio_sync->sync_ipts != AV_NOPTS_VALUE &&
            ost->sync_ipts != AV_NOPTS_VALUE) {
            
            adelta = (double)(ost->st->pts.val - audio_sync->sync_opts) * 
                s->pts_num / s->pts_den;
            apts = audio_sync->sync_ipts + adelta; 
            
            vdelta = (double)(ost->st->pts.val - ost->sync_opts) *
                s->pts_num / s->pts_den;
            vpts = ost->sync_ipts + vdelta;
            
            av_delay = apts - vpts;
            //            printf("delay=%f\n", av_delay);
            if (av_delay < -AV_DELAY_MAX)
                nb_frames = 2;
            else if (av_delay > AV_DELAY_MAX)
                nb_frames = 0;
        }
    }
    /* XXX: also handle frame rate conversion */
    if (nb_frames <= 0) 
        return;

    if (!video_buffer)
        video_buffer = av_malloc(VIDEO_BUFFER_SIZE);
    if (!video_buffer)
        return;

    /* deinterlace : must be done before any resize */
    if (do_deinterlace) {
        int size;

        /* create temporary picture */
        size = avpicture_get_size(dec->pix_fmt, dec->width, dec->height);
        buf1 = av_malloc(size);
        if (!buf1)
            return;
        
        picture2 = &picture_tmp2;
        avpicture_fill(picture2, buf1, dec->pix_fmt, dec->width, dec->height);

        if (avpicture_deinterlace(picture2, picture1, 
                                  dec->pix_fmt, dec->width, dec->height) < 0) {
            /* if error, do not deinterlace */
            av_free(buf1);
            buf1 = NULL;
            picture2 = picture1;
        }
    } else {
        picture2 = picture1;
    }

    /* convert pixel format if needed */
    if (enc->pix_fmt != dec->pix_fmt) {
        int size;

        /* create temporary picture */
        size = avpicture_get_size(enc->pix_fmt, dec->width, dec->height);
        buf = av_malloc(size);
        if (!buf)
            return;
        pict = &picture_tmp1;
        avpicture_fill(pict, buf, enc->pix_fmt, dec->width, dec->height);
        
        if (img_convert(pict, enc->pix_fmt, 
                        picture2, dec->pix_fmt, 
                        dec->width, dec->height) < 0) {
            fprintf(stderr, "pixel format conversion not handled\n");
            goto the_end;
        }
    } else {
        pict = picture2;
    }

    /* XXX: resampling could be done before raw format convertion in
       some cases to go faster */
    /* XXX: only works for YUV420P */
    if (ost->video_resample) {
        picture = &ost->pict_tmp;
        img_resample(ost->img_resample_ctx, picture, pict);
    } else {
        picture = pict;
    }
    /* duplicates frame if needed */
    /* XXX: pb because no interleaving */
    for(i=0;i<nb_frames;i++) {
        if (enc->codec_id != CODEC_ID_RAWVIDEO) {
            /* handles sameq here. This is not correct because it may
               not be a global option */
            if (same_quality) {
                enc->quality = dec->quality;
            }
            
            ret = avcodec_encode_video(enc, 
                                       video_buffer, VIDEO_BUFFER_SIZE,
                                       picture);
            //enc->frame_number = enc->real_pict_num;
            av_write_frame(s, ost->index, video_buffer, ret);
            *frame_size = ret;
            //fprintf(stderr,"\nFrame: %3d %3d size: %5d type: %d",
            //        enc->frame_number-1, enc->real_pict_num, ret,
            //        enc->pict_type);
            /* if two pass, output log */
            if (ost->logfile && enc->stats_out) {
                fprintf(ost->logfile, "%s", enc->stats_out);
            }
        } else {
            if (s->oformat->flags & AVFMT_RAWPICTURE) {
                /* raw pictures are written as AVPicture structure to
                   avoid any copies. We support temorarily the older
                   method. */
                av_write_frame(s, ost->index, 
                               (UINT8 *)picture, sizeof(AVPicture));
            } else {
                write_picture(s, ost->index, picture, enc->pix_fmt, 
                              enc->width, enc->height);
            }
        }
        ost->frame_number++;
    }
 the_end:
    av_free(buf);
    av_free(buf1);
}

static void do_video_stats(AVFormatContext *os, AVOutputStream *ost, 
                           int frame_size)
{
    static FILE *fvstats=NULL;
    static INT64 total_size = 0;
    char filename[40];
    time_t today2;
    struct tm *today;
    AVCodecContext *enc;
    int frame_number;
    INT64 ti;
    double ti1, bitrate, avg_bitrate;
    
    if (!fvstats) {
        today2 = time(NULL);
        today = localtime(&today2);
        sprintf(filename, "vstats_%02d%02d%02d.log", today->tm_hour,
                                               today->tm_min,
                                               today->tm_sec);
        fvstats = fopen(filename,"w");
        if (!fvstats) {
            perror("fopen");
            exit(1);
        }
    }
    
    ti = MAXINT64;
    enc = &ost->st->codec;
    total_size += frame_size;
    if (enc->codec_type == CODEC_TYPE_VIDEO) {
        frame_number = ost->frame_number;
        fprintf(fvstats, "frame= %5d q= %2d ", frame_number, enc->quality);
        if (do_psnr)
            fprintf(fvstats, "PSNR= %6.2f ", enc->psnr_y);
        
        fprintf(fvstats,"f_size= %6d ", frame_size);
        /* compute pts value */
        ti1 = (double)ost->st->pts.val * os->pts_num / os->pts_den;
        if (ti1 < 0.01)
            ti1 = 0.01;
    
        bitrate = (double)(frame_size * 8) * enc->frame_rate / FRAME_RATE_BASE / 1000.0;
        avg_bitrate = (double)(total_size * 8) / ti1 / 1000.0;
        fprintf(fvstats, "s_size= %8.0fkB time= %0.3f br= %7.1fkbits/s avg_br= %7.1fkbits/s ",
            (double)total_size / 1024, ti1, bitrate, avg_bitrate);
        fprintf(fvstats,"type= %s\n", enc->key_frame == 1 ? "I" : "P");        
    }
}

void print_report(AVFormatContext **output_files, 
                  AVOutputStream **ost_table, int nb_ostreams,
                  int is_last_report)
{
    char buf[1024];
    AVOutputStream *ost;
    AVFormatContext *oc, *os;
    INT64 total_size;
    AVCodecContext *enc;
    int frame_number, vid, i;
    double bitrate, ti1, pts;
    static INT64 last_time = -1;
    
    if (!is_last_report) {
        INT64 cur_time;
        /* display the report every 0.5 seconds */
        cur_time = av_gettime();
        if (last_time == -1) {
            last_time = cur_time;
            return;
        } 
        if ((cur_time - last_time) < 500000)
            return;
        last_time = cur_time;
    }


    oc = output_files[0];

    total_size = url_ftell(&oc->pb);
    
    buf[0] = '\0';
    ti1 = 1e10;
    vid = 0;
    for(i=0;i<nb_ostreams;i++) {
        ost = ost_table[i];
        os = output_files[ost->file_index];
        enc = &ost->st->codec;
        if (!vid && enc->codec_type == CODEC_TYPE_VIDEO) {
            frame_number = ost->frame_number;
            sprintf(buf + strlen(buf), "frame=%5d q=%2d ",
                    frame_number, enc->quality);
            if (do_psnr)
                sprintf(buf + strlen(buf), "PSNR=%6.2f ", enc->psnr_y);
            vid = 1;
        }
        /* compute min output value */
        pts = (double)ost->st->pts.val * os->pts_num / os->pts_den;
        if ((pts < ti1) && (pts > 0))
            ti1 = pts;
    }
    if (ti1 < 0.01)
        ti1 = 0.01;
    bitrate = (double)(total_size * 8) / ti1 / 1000.0;
    
    sprintf(buf + strlen(buf), 
            "size=%8.0fkB time=%0.1f bitrate=%6.1fkbits/s",
            (double)total_size / 1024, ti1, bitrate);
    
    fprintf(stderr, "%s   ", buf);
    
    if (is_last_report) {
        fprintf(stderr, "\n");
    } else {
        fprintf(stderr, "\r");
        fflush(stderr);
    }
}

/*
 * The following code is the main loop of the file converter
 */
static int av_encode(AVFormatContext **output_files,
                     int nb_output_files,
                     AVFormatContext **input_files,
                     int nb_input_files,
                     AVStreamMap *stream_maps, int nb_stream_maps)
{
    int ret, i, j, k, n, nb_istreams = 0, nb_ostreams = 0, pts_set;
    AVFormatContext *is, *os;
    AVCodecContext *codec, *icodec;
    AVOutputStream *ost, **ost_table = NULL;
    AVInputStream *ist, **ist_table = NULL;
    AVInputFile *file_table;
    AVFormatContext *stream_no_data;
    int key;

    file_table= (AVInputFile*) av_mallocz(nb_input_files * sizeof(AVInputFile));
    if (!file_table)
        goto fail;

    /* input stream init */
    j = 0;
    for(i=0;i<nb_input_files;i++) {
        is = input_files[i];
        file_table[i].ist_index = j;
        file_table[i].nb_streams = is->nb_streams;
        j += is->nb_streams;
    }
    nb_istreams = j;

    ist_table = av_mallocz(nb_istreams * sizeof(AVInputStream *));
    if (!ist_table)
        goto fail;
    
    for(i=0;i<nb_istreams;i++) {
        ist = av_mallocz(sizeof(AVInputStream));
        if (!ist)
            goto fail;
        ist_table[i] = ist;
    }
    j = 0;
    for(i=0;i<nb_input_files;i++) {
        is = input_files[i];
        for(k=0;k<is->nb_streams;k++) {
            ist = ist_table[j++];
            ist->st = is->streams[k];
            ist->file_index = i;
            ist->index = k;
            ist->discard = 1; /* the stream is discarded by default
                                 (changed later) */
        }
    }

    /* output stream init */
    nb_ostreams = 0;
    for(i=0;i<nb_output_files;i++) {
        os = output_files[i];
        nb_ostreams += os->nb_streams;
    }
    if (nb_stream_maps > 0 && nb_stream_maps != nb_ostreams) {
        fprintf(stderr, "Number of stream maps must match number of output streams\n");
        exit(1);
    }

    ost_table = av_mallocz(sizeof(AVOutputStream *) * nb_ostreams);
    if (!ost_table)
        goto fail;
    for(i=0;i<nb_ostreams;i++) {
        ost = av_mallocz(sizeof(AVOutputStream));
        if (!ost)
            goto fail;
        ost_table[i] = ost;
    }
    
    n = 0;
    for(k=0;k<nb_output_files;k++) {
        os = output_files[k];
        for(i=0;i<os->nb_streams;i++) {
            int found;
            ost = ost_table[n++];
            ost->file_index = k;
            ost->index = i;
            ost->st = os->streams[i];
            if (nb_stream_maps > 0) {
                ost->source_index = file_table[stream_maps[n-1].file_index].ist_index + 
                    stream_maps[n-1].stream_index;
            } else {
                /* get corresponding input stream index : we select the first one with the right type */
                found = 0;
                for(j=0;j<nb_istreams;j++) {
                    ist = ist_table[j];
                    if (ist->discard && 
                        ist->st->codec.codec_type == ost->st->codec.codec_type) {
                        ost->source_index = j;
                        found = 1;
                    }
                }
                
                if (!found) {
                    /* try again and reuse existing stream */
                    for(j=0;j<nb_istreams;j++) {
                        ist = ist_table[j];
                        if (ist->st->codec.codec_type == ost->st->codec.codec_type) {
                            ost->source_index = j;
                            found = 1;
                        }
                    }
                    if (!found) {
                        fprintf(stderr, "Could not find input stream matching output stream #%d.%d\n",
                                ost->file_index, ost->index);
                        exit(1);
                    }
                }
            }
            ist = ist_table[ost->source_index];
            ist->discard = 0;
        }
    }

    /* for each output stream, we compute the right encoding parameters */
    for(i=0;i<nb_ostreams;i++) {
        ost = ost_table[i];
        ist = ist_table[ost->source_index];

        codec = &ost->st->codec;
        icodec = &ist->st->codec;

        if (ost->st->stream_copy) {
            /* if stream_copy is selected, no need to decode or encode */
            codec->codec_id = icodec->codec_id;
            codec->codec_type = icodec->codec_type;
            codec->codec_tag = icodec->codec_tag;
            codec->bit_rate = icodec->bit_rate;
            switch(codec->codec_type) {
            case CODEC_TYPE_AUDIO:
                codec->sample_rate = icodec->sample_rate;
                codec->channels = icodec->channels;
                break;
            case CODEC_TYPE_VIDEO:
                codec->frame_rate = icodec->frame_rate;
                codec->width = icodec->width;
                codec->height = icodec->height;
                break;
            default:
                av_abort();
            }
        } else {
            switch(codec->codec_type) {
            case CODEC_TYPE_AUDIO:
                if (fifo_init(&ost->fifo, 2 * MAX_AUDIO_PACKET_SIZE))
                    goto fail;
                
                if (codec->channels == icodec->channels &&
                    codec->sample_rate == icodec->sample_rate) {
                    ost->audio_resample = 0;
                } else {
                    if (codec->channels != icodec->channels &&
                        icodec->codec_id == CODEC_ID_AC3) {
                        /* Special case for 5:1 AC3 input */
                        /* and mono or stereo output      */
                        /* Request specific number of channels */
                        icodec->channels = codec->channels;
                        if (codec->sample_rate == icodec->sample_rate)
                            ost->audio_resample = 0;
                        else {
                            ost->audio_resample = 1;
                            ost->resample = audio_resample_init(codec->channels, icodec->channels,
                                                        codec->sample_rate, 
                                                        icodec->sample_rate);
                        }
                        /* Request specific number of channels */
                        icodec->channels = codec->channels;
                    } else {
                        ost->audio_resample = 1; 
                        ost->resample = audio_resample_init(codec->channels, icodec->channels,
                                                        codec->sample_rate, 
                                                        icodec->sample_rate);
                    }
                }
                ist->decoding_needed = 1;
                ost->encoding_needed = 1;
                break;
            case CODEC_TYPE_VIDEO:
                if (codec->width == icodec->width &&
                    codec->height == icodec->height) {
                    ost->video_resample = 0;
                } else {
                    UINT8 *buf;
                    ost->video_resample = 1;
                    buf = av_malloc((codec->width * codec->height * 3) / 2);
                    if (!buf)
                        goto fail;
                    ost->pict_tmp.data[0] = buf;
                    ost->pict_tmp.data[1] = ost->pict_tmp.data[0] + (codec->width * codec->height);
                    ost->pict_tmp.data[2] = ost->pict_tmp.data[1] + (codec->width * codec->height) / 4;
                    ost->pict_tmp.linesize[0] = codec->width;
                    ost->pict_tmp.linesize[1] = codec->width / 2;
                    ost->pict_tmp.linesize[2] = codec->width / 2;

                    ost->img_resample_ctx = img_resample_full_init( 
                                      ost->st->codec.width, ost->st->codec.height,
                                      ist->st->codec.width, ist->st->codec.height,
                                      frame_topBand, frame_bottomBand,
                                      frame_leftBand, frame_rightBand);
                }
                ost->encoding_needed = 1;
                ist->decoding_needed = 1;
                break;
            default:
                av_abort();
            }
            /* two pass mode */
            if (ost->encoding_needed && 
                (codec->flags & (CODEC_FLAG_PASS1 | CODEC_FLAG_PASS2))) {
                char logfilename[1024];
                FILE *f;
                int size;
                char *logbuffer;
                
                snprintf(logfilename, sizeof(logfilename), "%s-%d.log", 
                         pass_logfilename ? 
                         pass_logfilename : DEFAULT_PASS_LOGFILENAME, i);
                if (codec->flags & CODEC_FLAG_PASS1) {
                    f = fopen(logfilename, "w");
                    if (!f) {
                        perror(logfilename);
                        exit(1);
                    }
                    ost->logfile = f;
                } else {
                    /* read the log file */
                    f = fopen(logfilename, "r");
                    if (!f) {
                        perror(logfilename);
                        exit(1);
                    }
                    fseek(f, 0, SEEK_END);
                    size = ftell(f);
                    fseek(f, 0, SEEK_SET);
                    logbuffer = av_malloc(size + 1);
                    if (!logbuffer) {
                        fprintf(stderr, "Could not allocate log buffer\n");
                        exit(1);
                    }
                    fread(logbuffer, 1, size, f);
                    fclose(f);
                    logbuffer[size] = '\0';
                    codec->stats_in = logbuffer;
                }
            }
        }
    }

    /* dump the file output parameters - cannot be done before in case
       of stream copy */
    for(i=0;i<nb_output_files;i++) {
        dump_format(output_files[i], i, output_files[i]->filename, 1);
    }

    /* dump the stream mapping */
    fprintf(stderr, "Stream mapping:\n");
    for(i=0;i<nb_ostreams;i++) {
        ost = ost_table[i];
        fprintf(stderr, "  Stream #%d.%d -> #%d.%d\n",
                ist_table[ost->source_index]->file_index,
                ist_table[ost->source_index]->index,
                ost->file_index, 
                ost->index);
    }

    /* open each encoder */
    for(i=0;i<nb_ostreams;i++) {
        ost = ost_table[i];
        if (ost->encoding_needed) {
            AVCodec *codec;
            codec = avcodec_find_encoder(ost->st->codec.codec_id);