utils.c

        if (st->codec->codec_type == CODEC_TYPE_VIDEO) {
            if(b-frames){
                ppktl = &ic->packet_buffer;
                while(ppkt1){
                    if(ppkt1->stream_index != i)
                        continue;
                    if(ppkt1->pkt->dts < 0)
                        break;
                    if(ppkt1->pkt->pts != AV_NOPTS_VALUE)
                        break;
                    ppkt1->pkt->dts -= delta;
                    ppkt1= ppkt1->next;
                }
                if(ppkt1)
                    continue;
                st->cur_dts -= delta;
            }
        }
    }
#endif
    return ret;
}

/*******************************************************/

/**
 * start playing a network based stream (e.g. RTSP stream) at the
 * current position 
 */
int av_read_play(AVFormatContext *s)
{
    if (!s->iformat->read_play)
        return AVERROR_NOTSUPP;
    return s->iformat->read_play(s);
}

/**
 * Pause a network based stream (e.g. RTSP stream).
 *
 * Use av_read_play() to resume it.
 */
int av_read_pause(AVFormatContext *s)
{
    if (!s->iformat->read_pause)
        return AVERROR_NOTSUPP;
    return s->iformat->read_pause(s);
}

/**
 * Close a media file (but not its codecs).
 *
 * @param s media file handle
 */
void av_close_input_file(AVFormatContext *s)
{
    int i, must_open_file;
    AVStream *st;

    /* free previous packet */
    if (s->cur_st && s->cur_st->parser)
        av_free_packet(&s->cur_pkt); 

    if (s->iformat->read_close)
        s->iformat->read_close(s);
    for(i=0;i<s->nb_streams;i++) {
        /* free all data in a stream component */
        st = s->streams[i];
        if (st->parser) {
            av_parser_close(st->parser);
        }
        av_free(st->index_entries);
        av_free(st->codec);
        av_free(st);
    }
    flush_packet_queue(s);
    must_open_file = 1;
    if (s->iformat->flags & AVFMT_NOFILE) {
        must_open_file = 0;
    }
    if (must_open_file) {
        url_fclose(&s->pb);
    }
    av_freep(&s->priv_data);
    av_free(s);
}

/**
 * Add a new stream to a media file.
 *
 * Can only be called in the read_header() function. If the flag
 * AVFMTCTX_NOHEADER is in the format context, then new streams
 * can be added in read_packet too.
 *
 * @param s media file handle
 * @param id file format dependent stream id 
 */
AVStream *av_new_stream(AVFormatContext *s, int id)
{
    AVStream *st;

    if (s->nb_streams >= MAX_STREAMS)
        return NULL;

    st = av_mallocz(sizeof(AVStream));
    if (!st)
        return NULL;
    
    st->codec= avcodec_alloc_context();
    if (s->iformat) {
        /* no default bitrate if decoding */
        st->codec->bit_rate = 0;
    }
    st->index = s->nb_streams;
    st->id = id;
    st->start_time = AV_NOPTS_VALUE;
    st->duration = AV_NOPTS_VALUE;
    st->cur_dts = AV_NOPTS_VALUE;

    /* default pts settings is MPEG like */
    av_set_pts_info(st, 33, 1, 90000);
    st->last_IP_pts = AV_NOPTS_VALUE;

    s->streams[s->nb_streams++] = st;
    return st;
}

/************************************************************/
/* output media file */

int av_set_parameters(AVFormatContext *s, AVFormatParameters *ap)
{
    int ret;
    
    if (s->oformat->priv_data_size > 0) {
        s->priv_data = av_mallocz(s->oformat->priv_data_size);
        if (!s->priv_data)
            return AVERROR_NOMEM;
    } else
        s->priv_data = NULL;
	
    if (s->oformat->set_parameters) {
        ret = s->oformat->set_parameters(s, ap);
        if (ret < 0)
            return ret;
    }
    return 0;
}

/**
 * allocate the stream private data and write the stream header to an
 * output media file
 *
 * @param s media file handle
 * @return 0 if OK. AVERROR_xxx if error.  
 */
int av_write_header(AVFormatContext *s)
{
    int ret, i;
    AVStream *st;

    // some sanity checks
    for(i=0;i<s->nb_streams;i++) {
        st = s->streams[i];

        switch (st->codec->codec_type) {
        case CODEC_TYPE_AUDIO:
            if(st->codec->sample_rate<=0){
                av_log(s, AV_LOG_ERROR, "sample rate not set\n");
                return -1;
            }
            break;
        case CODEC_TYPE_VIDEO:
            if(st->codec->time_base.num<=0 || st->codec->time_base.den<=0){ //FIXME audio too?
                av_log(s, AV_LOG_ERROR, "time base not set\n");
                return -1;
            }
            if(st->codec->width<=0 || st->codec->height<=0){
                av_log(s, AV_LOG_ERROR, "dimensions not set\n");
                return -1;
            }
            break;
        }
    }

    ret = s->oformat->write_header(s);
    if (ret < 0)
        return ret;

    /* init PTS generation */
    for(i=0;i<s->nb_streams;i++) {
        int64_t den = AV_NOPTS_VALUE;
        st = s->streams[i];

        switch (st->codec->codec_type) {
        case CODEC_TYPE_AUDIO:
            den = (int64_t)st->time_base.num * st->codec->sample_rate;
            break;
        case CODEC_TYPE_VIDEO:
            den = (int64_t)st->time_base.num * st->codec->time_base.den;
            break;
        default:
            break;
        }
        if (den != AV_NOPTS_VALUE) {
            if (den <= 0)
                return AVERROR_INVALIDDATA;
            av_frac_init(&st->pts, 0, 0, den);
        }
    }
    return 0;
}

//FIXME merge with compute_pkt_fields
static int compute_pkt_fields2(AVStream *st, AVPacket *pkt){
    int b_frames = FFMAX(st->codec->has_b_frames, st->codec->max_b_frames);
    int num, den, frame_size;

//    av_log(NULL, AV_LOG_DEBUG, "av_write_frame: pts:%lld dts:%lld cur_dts:%lld b:%d size:%d st:%d\n", pkt->pts, pkt->dts, st->cur_dts, b_frames, pkt->size, pkt->stream_index);
    
/*    if(pkt->pts == AV_NOPTS_VALUE && pkt->dts == AV_NOPTS_VALUE)
        return -1;*/
            
    /* duration field */
    if (pkt->duration == 0) {
        compute_frame_duration(&num, &den, st, NULL, pkt);
        if (den && num) {
            pkt->duration = av_rescale(1, num * (int64_t)st->time_base.den, den * (int64_t)st->time_base.num);
        }
    }

    //XXX/FIXME this is a temporary hack until all encoders output pts
    if((pkt->pts == 0 || pkt->pts == AV_NOPTS_VALUE) && pkt->dts == AV_NOPTS_VALUE && !b_frames){
        pkt->dts=
//        pkt->pts= st->cur_dts;
        pkt->pts= st->pts.val;
    }

    //calculate dts from pts    
    if(pkt->pts != AV_NOPTS_VALUE && pkt->dts == AV_NOPTS_VALUE){
        if(b_frames){
            if(st->last_IP_pts == AV_NOPTS_VALUE){
                st->last_IP_pts= -pkt->duration;
            }
            if(st->last_IP_pts < pkt->pts){
                pkt->dts= st->last_IP_pts;
                st->last_IP_pts= pkt->pts;
            }else
                pkt->dts= pkt->pts;
        }else
            pkt->dts= pkt->pts;
    }
    
    if(st->cur_dts && st->cur_dts != AV_NOPTS_VALUE && st->cur_dts >= pkt->dts){
        av_log(NULL, AV_LOG_ERROR, "error, non monotone timestamps %Ld >= %Ld\n", st->cur_dts, pkt->dts);
        return -1;
    }
    if(pkt->dts != AV_NOPTS_VALUE && pkt->pts != AV_NOPTS_VALUE && pkt->pts < pkt->dts){
        av_log(NULL, AV_LOG_ERROR, "error, pts < dts\n");
        return -1;
    }

//    av_log(NULL, AV_LOG_DEBUG, "av_write_frame: pts2:%lld dts2:%lld\n", pkt->pts, pkt->dts);
    st->cur_dts= pkt->dts;
    st->pts.val= pkt->dts;

    /* update pts */
    switch (st->codec->codec_type) {
    case CODEC_TYPE_AUDIO:
        frame_size = get_audio_frame_size(st->codec, pkt->size);

        /* HACK/FIXME, we skip the initial 0-size packets as they are most likely equal to the encoder delay,
           but it would be better if we had the real timestamps from the encoder */
        if (frame_size >= 0 && (pkt->size || st->pts.num!=st->pts.den>>1 || st->pts.val)) {
            av_frac_add(&st->pts, (int64_t)st->time_base.den * frame_size);
        }
        break;
    case CODEC_TYPE_VIDEO:
        av_frac_add(&st->pts, (int64_t)st->time_base.den * st->codec->time_base.num);
        break;
    default:
        break;
    }
    return 0;
}

static void truncate_ts(AVStream *st, AVPacket *pkt){
    int64_t pts_mask = (2LL << (st->pts_wrap_bits-1)) - 1;
    
//    if(pkt->dts < 0)
//        pkt->dts= 0;  //this happens for low_delay=0 and b frames, FIXME, needs further invstigation about what we should do here
    
    pkt->pts &= pts_mask;
    pkt->dts &= pts_mask;
}

/**
 * Write a packet to an output media file.
 *
 * The packet shall contain one audio or video frame.
 *
 * @param s media file handle
 * @param pkt the packet, which contains the stream_index, buf/buf_size, dts/pts, ...
 * @return < 0 if error, = 0 if OK, 1 if end of stream wanted.
 */
int av_write_frame(AVFormatContext *s, AVPacket *pkt)
{
    int ret;

    ret=compute_pkt_fields2(s->streams[pkt->stream_index], pkt);
    if(ret<0)
        return ret;
    
    truncate_ts(s->streams[pkt->stream_index], pkt);

    ret= s->oformat->write_packet(s, pkt);
    if(!ret)
        ret= url_ferror(&s->pb);
    return ret;
}

/**
 * interleave_packet implementation which will interleave per DTS.
 * packets with pkt->destruct == av_destruct_packet will be freed inside this function. 
 * so they cannot be used after it, note calling av_free_packet() on them is still safe
 */
static int av_interleave_packet_per_dts(AVFormatContext *s, AVPacket *out, AVPacket *pkt, int flush){
    AVPacketList *pktl, **next_point, *this_pktl;
    int stream_count=0;
    int streams[MAX_STREAMS];

    if(pkt){
        AVStream *st= s->streams[ pkt->stream_index];

//        assert(pkt->destruct != av_destruct_packet); //FIXME

        this_pktl = av_mallocz(sizeof(AVPacketList));
        this_pktl->pkt= *pkt;
        if(pkt->destruct == av_destruct_packet)
            pkt->destruct= NULL; // non shared -> must keep original from being freed
        else
            av_dup_packet(&this_pktl->pkt);  //shared -> must dup

        next_point = &s->packet_buffer;
        while(*next_point){
            AVStream *st2= s->streams[ (*next_point)->pkt.stream_index];
            int64_t left=  st2->time_base.num * (int64_t)st ->time_base.den;
            int64_t right= st ->time_base.num * (int64_t)st2->time_base.den;
            if((*next_point)->pkt.dts * left > pkt->dts * right) //FIXME this can overflow
                break;
            next_point= &(*next_point)->next;
        }
        this_pktl->next= *next_point;
        *next_point= this_pktl;
    }
    
    memset(streams, 0, sizeof(streams));
    pktl= s->packet_buffer;
    while(pktl){
//av_log(s, AV_LOG_DEBUG, "show st:%d dts:%lld\n", pktl->pkt.stream_index, pktl->pkt.dts);
        if(streams[ pktl->pkt.stream_index ] == 0)
            stream_count++;
        streams[ pktl->pkt.stream_index ]++;
        pktl= pktl->next;
    }
    
    if(s->nb_streams == stream_count || (flush && stream_count)){
        pktl= s->packet_buffer;
        *out= pktl->pkt;
        
        s->packet_buffer= pktl->next;        
        av_freep(&pktl);
        return 1;
    }else{
        av_init_packet(out);
        return 0;
    }
}

/**
 * Interleaves a AVPacket correctly so it can be muxed.
 * @param out the interleaved packet will be output here
 * @param in the input packet
 * @param flush 1 if no further packets are available as input and all
 *              remaining packets should be output
 * @return 1 if a packet was output, 0 if no packet could be output, 
 *         < 0 if an error occured
 */
static int av_interleave_packet(AVFormatContext *s, AVPacket *out, AVPacket *in, int flush){
    if(s->oformat->interleave_packet)
        return s->oformat->interleave_packet(s, out, in, flush);
    else
        return av_interleave_packet_per_dts(s, out, in, flush);
}

/**
 * Writes a packet to an output media file ensuring correct interleaving.
 *
 * The packet must contain one audio or video frame.
 * If the packets are already correctly interleaved the application should
 * call av_write_frame() instead as its slightly faster, its also important
 * to keep in mind that completly non interleaved input will need huge amounts
 * of memory to interleave with this, so its prefereable to interleave at the
 * demuxer level
 *
 * @param s media file handle
 * @param pkt the packet, which contains the stream_index, buf/buf_size, dts/pts, ...
 * @return < 0 if error, = 0 if OK, 1 if end of stream wanted.
 */
int av_interleaved_write_frame(AVFormatContext *s, AVPacket *pkt){
    AVStream *st= s->streams[ pkt->stream_index];

    //FIXME/XXX/HACK drop zero sized packets
    if(st->codec->codec_type == CODEC_TYPE_AUDIO && pkt->size==0)
        return 0;

//av_log(NULL, AV_LOG_DEBUG, "av_interleaved_write_frame %d %Ld %Ld\n", pkt->size, pkt->dts, pkt->pts);
    if(compute_pkt_fields2(st, pkt) < 0)
        return -1;
    
    if(pkt->dts == AV_NOPTS_VALUE)
        return -1;

    for(;;){
        AVPacket opkt;
        int ret= av_interleave_packet(s, &opkt, pkt, 0);
        if(ret<=0) //FIXME cleanup needed for ret<0 ?
            return ret;
        
        truncate_ts(s->streams[opkt.stream_index], &opkt);
        ret= s->oformat->write_packet(s, &opkt);
        
        av_free_packet(&opkt);
        pkt= NULL;
        
        if(ret<0)
            return ret;
        if(url_ferror(&s->pb))
            return url_ferror(&s->pb);
    }
}

/**
 * @brief Write the stream trailer to an output media file and
 *        free the file private data.
 *
 * @param s media file handle
 * @return 0 if OK. AVERROR_xxx if error.
 */
int av_write_trailer(AVFormatContext *s)
{
    int ret, i;
    
    for(;;){
        AVPacket pkt;
        ret= av_interleave_packet(s, &pkt, NULL, 1);
        if(ret<0) //FIXME cleanup needed for ret<0 ?
            goto fail;
        if(!ret)
            break;
        
        truncate_ts(s->streams[pkt.stream_index], &pkt);
        ret= s->oformat->write_packet(s, &pkt);
        
        av_free_packet(&pkt);
        
        if(ret<0)
            goto fail;
        if(url_ferror(&s->pb))
            goto fail;
    }

    ret = s->oformat->write_trailer(s);
fail:
    if(ret == 0)
       ret=url_ferror(&s->pb);
    for(i=0;i<s->nb_streams;i++)
        av_freep(&s->streams[i]->priv_data);
    av_freep(&s->priv_data);
    return ret;
}

/* "user interface" functions */

void dump_format(AVFormatContext *ic,
                 int index, 
                 const char *url,
                 int is_output)
{
    int i, flags;
    char buf[256];

    av_log(NULL, AV_LOG_INFO, "%s #%d, %s, %s '%s':\n", 
            is_output ? "Output" : "Input",
            index, 
            is_output ? ic->oformat->name : ic->iformat->name, 
            is_output ? "to" : "from", url);
    if (!is_output) {
        av_log(NULL, AV_LOG_INFO, "  Duration: ");
        if (ic->duration != AV_NOPTS_VALUE) {
            int hours, mins, secs, us;
            secs = ic->duration / AV_TIME_BASE;
            us = ic->duration % AV_TIME_BASE;
            mins = secs / 60;
            secs %= 60;
            hours = mins / 60;
            mins %= 60;
            av_log(NULL, AV_LOG_INFO, "%02d:%02d:%02d.%01d", hours, mins, secs, 
                   (10 * us) / AV_TIME_BASE);
        } else {
            av_log(NULL, AV_LOG_INFO, "N/A");
        }
        if (ic->start_time != AV_NOPTS_VALUE) {
            int secs, us;
            av_log(NULL, AV_LOG_INFO, ", start: ");
            secs = ic->start_time / AV_TIME_BASE;
            us = ic->start_time % AV_TIME_BASE;
            av_log(NULL, AV_LOG_INFO, "%d.%06d",
                   secs, (int)av_rescale(us, 1000000, AV_TIME_BASE));
        }
        av_log(NULL, AV_LOG_INFO, ", bitrate: ");
        if (ic->bit_rate) {
            av_log(NULL, AV_LOG_INFO,"%d kb/s", ic->bit_rate / 1000);
        } else {
            av_log(NULL, AV_LOG_INFO, "N/A");
        }
        av_log(NULL, AV_LOG_INFO, "\n");
    }
    for(i=0;i<ic->nb_streams;i++) {
        AVStream *st = ic->streams[i];
        avcodec_string(buf, sizeof(buf), st->codec, is_output);
        av_log(NULL, AV_LOG_INFO, "  Stream #%d.%d", index, i);
        /* the pid is an important information, so we display it */
        /* XXX: add a generic system */
        if (is_output)
            flags = ic->oformat->flags;
        else
            flags = ic->iformat->flags;
        if (flags & AVFMT_SHOW_IDS) {
            av_log(NULL, AV_LOG_INFO, "[0x%x]", st->id);
        }
        if (strlen(st->language) > 0) {
            av_log(NULL, AV_LOG_INFO, "(%s)", st->language);
        }
        av_log(NULL, AV_LOG_INFO, ": %s\n", buf);
    }
}

typedef struct {
    const char *abv;
    int width, height;
    int frame_rate, frame_rate_base;
} AbvEntry;

static AbvEntry frame_abvs[] = {
    { "ntsc",      720, 480, 30000, 1001 },
    { "pal",       720, 576,    25,    1 },
    { "qntsc",     352, 240, 30000, 1001 }, /* VCD compliant ntsc */
    { "qpal",      352, 288,    25,    1 }, /* VCD compliant pal */
    { "sntsc",     640, 480, 30000, 1001 }, /* square pixel ntsc */
    { "spal",      768, 576,    25,    1 }, /* square pixel pal */
    { "film",      352, 240,    24,    1 },
    { "ntsc-film", 352, 240, 24000, 1001 },
    { "sqcif",     128,  96,     0,    0 },
    { "qcif",      176, 144,     0,    0 },
    { "cif",       352, 288,     0,    0 },
    { "4cif",      704, 576,     0,    0 },
};

/**
 * parses width and height out of string str.
 */
int parse_image_size(int *width_ptr, int *height_ptr, const char *str)
{
    int i;
    int n = sizeof(frame_abvs) / sizeof(AbvEntry);
    const char *p;
    int frame_width = 0, frame_height = 0;

    for(i=0;i<n;i++) {
        if (!strcmp(frame_abvs[i].abv, str)) {
            frame_width = frame_abvs[i].width;
            frame_height = frame_abvs[i].height;
            break;
        }
    }
    if (i == n) {
        p = str;
        frame_width = strtol(p, (char **)&p, 10);
        if (*p)
            p++;
        frame_height = strtol(p, (char **)&p, 10);
    }
    if (frame_width <= 0 || frame_height <= 0)
        return -1;
    *width_ptr = frame_width;
    *height_ptr = frame_height;
    return 0;
}

/**
 * Converts frame rate from string to a fraction.
 *
 * First we try to get an exact integer or fractional frame rate.
 * If this fails we convert the frame rate to a double and return
 * an approximate fraction using the DEFAULT_FRAME_RATE_BASE.
 */
int parse_frame_rate(int *frame_rate, int *frame_rate_base, const char *arg)
{
    int i;
    char* cp;
   
    /* First, we check our abbreviation table */
    for (i = 0; i < sizeof(frame_abvs)/sizeof(*frame_abvs); ++i)
         if (!strcmp(frame_abvs[i].abv, arg)) {
	     *frame_rate = frame_abvs[i].frame_rate;
	     *frame_rate_base = frame_abvs[i].frame_rate_base;
	     return 0;
	 }

    /* Then, we try to parse it as fraction */
    cp = strchr(arg, '/');
    if (!cp)
        cp = strchr(arg, ':');
    if (cp) {
        char* cpp;
	*frame_rate = strtol(arg, &cpp, 10);
	if (cpp != arg || cpp == cp) 
	    *frame_rate_base = strtol(cp+1, &cpp, 10);
	else
	   *frame_rate = 0;
    } 
    else {
        /* Finally we give up and parse it as double */
        *frame_rate_base = DEFAULT_FRAME_RATE_BASE; //FIXME use av_d2q()
        *frame_rate = (int)(strtod(arg, 0) * (*frame_rate_base) + 0.5);
    }
    if (!*frame_rate || !*frame_rate_base)
        return -1;
    else
        return 0;
}

/**
 * Converts date string to number of seconds since Jan 1st, 1970.
 *
 * @code
 * Syntax:
 * - If not a duration:
 *  [{YYYY-MM-DD|YYYYMMDD}]{T| }{HH[:MM[:SS[.m...]]][Z]|HH[MM[SS[.m...]]][Z]}
 * Time is localtime unless Z is suffixed to the end. In this case GMT
 * Return the date in micro seconds since 1970 
 *
 * - If a duration:
 *  HH[:MM[:SS[.m...]]]
 *  S+[.m...]
 * @endcode
 */
int64_t parse_date(const char *datestr, int duration)
{
    const char *p;
    int64_t t;
    struct tm dt;
    int i;
    static const char *date_fmt[] = {
        "%Y-%m-%d",
        "%Y%m%d",
    };
    static const char *time_fmt[] = {
        "%H:%M:%S",
        "%H%M%S",
    };
    const char *q;
    int is_utc, len;
    char lastch;
    int negative = 0;

#undef time
    time_t now = time(0);

    len = strlen(datestr);
    if (len > 0)
        lastch = datestr[len - 1];
    else
        lastch = '\0';
    is_utc = (lastch == 'z' || lastch == 'Z');

    memset(&dt, 0, sizeof(dt));

    p = datestr;
    q = NULL;
    if (!duration) {
        for (i = 0; i < sizeof(date_fmt) / sizeof(date_fmt[0]); i++) {
            q = small_strptime(p, date_fmt[i], &dt);
            if (q) {
                break;
            }
        }

        if (!q) {
            if (is_utc) {
                dt = *gmtime(&now);
            } else {
                dt = *localtime(&now);
            }
            dt.tm_hour = dt.tm_min = dt.tm_sec = 0;
        } else {
            p = q;
        }

        if (*p == 'T' || *p == 't' || *p == ' ')
            p++;

        for (i = 0; i < sizeof(time_fmt) / sizeof(time_fmt[0]); i++) {
            q = small_strptime(p, time_fmt[i], &dt);
            if (q) {
                break;
            }
        }
    } else {
	if (p[0] == '-') {
	    negative = 1;
	    ++p;
	}
        q = small_strptime(p, time_fmt[0], &dt);
        if (!q) {
            dt.tm_sec = strtol(p, (char **)&q, 10);
            dt.tm_min = 0;
            dt.tm_hour = 0;
        }
    }

    /* Now we have all the fields that we can get */
    if (!q) {
        if (duration)
            return 0;
        else
            return now * int64_t_C(1000000);
    }

    if (duration) {
        t = dt.tm_hour * 3600 + dt.tm_min * 60 + dt.tm_sec;
    } else {
        dt.tm_isdst = -1;       /* unknown */
        if (is_utc) {
            t = mktimegm(&dt);
        } else {
            t = mktime(&dt);
        }
    }

    t *= 1000000;

    if (*q == '.') {
        int val, n;
        q++;
        for (val = 0, n = 100000; n >= 1; n /= 10, q++) {
            if (!isdigit(*q)) 
                break;
            val += n * (*q - '0');
        }
        t += val;
    }
    return negative ? -t : t;
}

/**
 * Attempts to find a specific tag in a URL.
 *
 * syntax: '?tag1=val1&tag2=val2...'. Little URL decoding is done.
 * Return 1 if found.
 */
int find_info_tag(char *arg, int arg_size, const char *tag1, const char *info)
{
    const char *p;
    char tag[128], *q;

    p = info;
    if (*p == '?')
        p++;
    for(;;) {
        q = tag;
        while (*p != '\0' && *p != '=' && *p != '&') {
            if ((q - tag) < sizeof(tag) - 1)
                *q++ = *p;
            p++;
        }
        *q = '\0';
        q = arg;
        if (*p == '=') {
            p++;
            while (*p != '&' && *p != '\0') {
                if ((q - arg) < arg_size - 1) {
                    if (*p == '+')
                        *q++ = ' ';
                    else
                        *q++ = *p;
                }
                p++;
            }
            *q = '\0';
        }
        if (!strcmp(tag, tag1)) 
            return 1;
        if (*p != '&')
            break;
        p++;
    }
    return 0;
}

/**
 * Returns in 'buf' the path with '%d' replaced by number.
 *
 * Also handles the '%0nd' format where 'n' is the total number
 * of digits and '%%'. Return 0 if OK, and -1 if format error.
 */
int get_frame_filename(char *buf, int buf_size,
                       const char *path, int number)
{
    const char *p;
    char *q, buf1[20], c;
    int nd, len, percentd_found;

    q = buf;
    p = path;
    percentd_found = 0;
    for(;;) {
        c = *p++;
        if (c == '\0')
            break;
        if (c == '%') {
            do {
                nd = 0;
                while (isdigit(*p)) {
                    nd = nd * 10 + *p++ - '0';
                }
                c = *p++;
            } while (isdigit(c));

            switch(c) {
            case '%':
                goto addchar;
            case 'd':
                if (percentd_found)
                    goto fail;
                percentd_found = 1;
                snprintf(buf1, sizeof(buf1), "%0*d", nd, number);
                len = strlen(buf1);
                if ((q - buf + len) > buf_size - 1)
                    goto fail;
                memcpy(q, buf1, len);
                q += len;
                break;
            default:
                goto fail;
            }
        } else {
        addchar:
            if ((q - buf) < buf_size - 1)
                *q++ = c;
        }
    }
    if (!percentd_found)
        goto fail;
    *q = '\0';
    return 0;
 fail:
    *q = '\0';
    return -1;
}

/**
 * Print  nice hexa dump of a buffer
 * @param f stream for output
 * @param buf buffer
 * @param size buffer size
 */
void av_hex_dump(FILE *f, uint8_t *buf, int size)
{
    int len, i, j, c;

    for(i=0;i<size;i+=16) {
        len = size - i;
        if (len > 16)
            len = 16;
        fprintf(f, "%08x ", i);
        for(j=0;j<16;j++) {
            if (j < len)
                fprintf(f, " %02x", buf[i+j]);
            else
                fprintf(f, "   ");
        }
        fprintf(f, " ");
        for(j=0;j<len;j++) {
            c = buf[i+j];
            if (c < ' ' || c > '~')
                c = '.';
            fprintf(f, "%c", c);
        }
        fprintf(f, "\n");
    }
}

/**
 * Print on 'f' a nice dump of a packet
 * @param f stream for output
 * @param pkt packet to dump
 * @param dump_payload true if the payload must be displayed too
 */
 //FIXME needs to know the time_base
void av_pkt_dump(FILE *f, AVPacket *pkt, int dump_payload)
{
    fprintf(f, "stream #%d:\n", pkt->stream_index);
    fprintf(f, "  keyframe=%d\n", ((pkt->flags & PKT_FLAG_KEY) != 0));
    fprintf(f, "  duration=%0.3f\n", (double)pkt->duration / AV_TIME_BASE);
    /* DTS is _always_ valid after av_read_frame() */
    fprintf(f, "  dts=");
    if (pkt->dts == AV_NOPTS_VALUE)
        fprintf(f, "N/A");
    else
        fprintf(f, "%0.3f", (double)pkt->dts / AV_TIME_BASE);
    /* PTS may be not known if B frames are present */
    fprintf(f, "  pts=");
    if (pkt->pts == AV_NOPTS_VALUE)
        fprintf(f, "N/A");
    else
        fprintf(f, "%0.3f", (double)pkt->pts / AV_TIME_BASE);
    fprintf(f, "\n");
    fprintf(f, "  size=%d\n", pkt->size);
    if (dump_payload)
        av_hex_dump(f, pkt->data, pkt->size);
}

void url_split(char *proto, int proto_size,
               char *authorization, int authorization_size,
               char *hostname, int hostname_size,
               int *port_ptr,
               char *path, int path_size,
               const char *url)
{
    const char *p;
    char *q;
    int port;

    port = -1;

    p = url;
    q = proto;
    while (*p != ':' && *p != '\0') {
        if ((q - proto) < proto_size - 1)
            *q++ = *p;
        p++;
    }
    if (proto_size > 0)
        *q = '\0';
    if (authorization_size > 0)
        authorization[0] = '\0';
    if (*p == '\0') {
        if (proto_size > 0)
            proto[0] = '\0';
        if (hostname_size > 0)
            hostname[0] = '\0';
        p = url;
    } else {
        char *at,*slash; // PETR: position of '@' character and '/' character

        p++;
        if (*p == '/')
            p++;
        if (*p == '/')
            p++;
        at = strchr(p,'@'); // PETR: get the position of '@'
        slash = strchr(p,'/');  // PETR: get position of '/' - end of hostname
        if (at && slash && at > slash) at = NULL; // PETR: not interested in '@' behind '/'

        q = at ? authorization : hostname;  // PETR: if '@' exists starting with auth.

         while ((at || *p != ':') && *p != '/' && *p != '?' && *p != '\0') { // PETR:
            if (*p == '@') {    // PETR: passed '@'
              if (authorization_size > 0)
                  *q = '\0';
              q = hostname;
              at = NULL;
            } else if (!at) {   // PETR: hostname
              if ((q - hostname) < hostname_size - 1)
                  *q++ = *p;
            } else {
              if ((q - authorization) < authorization_size - 1)
                *q++ = *p;
            }
            p++;
        }
        if (hostname_size > 0)
            *q = '\0';
        if (*p == ':') {
            p++;
            port = strtoul(p, (char **)&p, 10);
        }
    }
    if (port_ptr)