utils.c

    if(compute_pkt_fields2(s, st, pkt) < 0 && !(s->oformat->flags & AVFMT_NOTIMESTAMPS))
        return -1;

    if(pkt->dts == AV_NOPTS_VALUE && !(s->oformat->flags & AVFMT_NOTIMESTAMPS))
        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;

        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);
    }
}

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;

        ret= s->oformat->write_packet(s, &pkt);

        av_free_packet(&pkt);

        if(ret<0)
            goto fail;
        if(url_ferror(s->pb))
            goto fail;
    }

    if(s->oformat->write_trailer)
        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->streams[i]->index_entries);
    }
    av_freep(&s->priv_data);
    return ret;
}

void ff_program_add_stream_index(AVFormatContext *ac, int progid, unsigned int idx)
{
    int i, j;
    AVProgram *program=NULL;
    void *tmp;

    if (idx >= ac->nb_streams) {
        av_log(ac, AV_LOG_ERROR, "stream index %d is not valid\n", idx);
        return;
    }

    for(i=0; i<ac->nb_programs; i++){
        if(ac->programs[i]->id != progid)
            continue;
        program = ac->programs[i];
        for(j=0; j<program->nb_stream_indexes; j++)
            if(program->stream_index[j] == idx)
                return;

        tmp = av_realloc(program->stream_index, sizeof(unsigned int)*(program->nb_stream_indexes+1));
        if(!tmp)
            return;
        program->stream_index = tmp;
        program->stream_index[program->nb_stream_indexes++] = idx;
        return;
    }
}

static void print_fps(double d, const char *postfix){
    uint64_t v= lrintf(d*100);
    if     (v% 100      ) av_log(NULL, AV_LOG_INFO, ", %3.2f %s", d, postfix);
    else if(v%(100*1000)) av_log(NULL, AV_LOG_INFO, ", %1.0f %s", d, postfix);
    else                  av_log(NULL, AV_LOG_INFO, ", %1.0fk %s", d/1000, postfix);
}

static void dump_metadata(void *ctx, AVMetadata *m, const char *indent)
{
    if(m && !(m->count == 1 && av_metadata_get(m, "language", NULL, 0))){
        AVMetadataTag *tag=NULL;

        av_log(ctx, AV_LOG_INFO, "%sMetadata:\n", indent);
        while((tag=av_metadata_get(m, "", tag, AV_METADATA_IGNORE_SUFFIX))) {
            if(strcmp("language", tag->key))
                av_log(ctx, AV_LOG_INFO, "%s  %-16s: %s\n", indent, tag->key, tag->value);
        }
    }
}

/* "user interface" functions */
static void dump_stream_format(AVFormatContext *ic, int i, int index, int is_output)
{
    char buf[256];
    int flags = (is_output ? ic->oformat->flags : ic->iformat->flags);
    AVStream *st = ic->streams[i];
    int g = av_gcd(st->time_base.num, st->time_base.den);
    AVMetadataTag *lang = av_metadata_get(st->metadata, "language", NULL, 0);
    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 (flags & AVFMT_SHOW_IDS)
        av_log(NULL, AV_LOG_INFO, "[0x%x]", st->id);
    if (lang)
        av_log(NULL, AV_LOG_INFO, "(%s)", lang->value);
    av_log(NULL, AV_LOG_DEBUG, ", %d, %d/%d", st->codec_info_nb_frames, st->time_base.num/g, st->time_base.den/g);
    av_log(NULL, AV_LOG_INFO, ": %s", buf);
    if (st->sample_aspect_ratio.num && // default
        av_cmp_q(st->sample_aspect_ratio, st->codec->sample_aspect_ratio)) {
        AVRational display_aspect_ratio;
        av_reduce(&display_aspect_ratio.num, &display_aspect_ratio.den,
                  st->codec->width*st->sample_aspect_ratio.num,
                  st->codec->height*st->sample_aspect_ratio.den,
                  1024*1024);
        av_log(NULL, AV_LOG_INFO, ", PAR %d:%d DAR %d:%d",
                 st->sample_aspect_ratio.num, st->sample_aspect_ratio.den,
                 display_aspect_ratio.num, display_aspect_ratio.den);
    }
    if(st->codec->codec_type == AVMEDIA_TYPE_VIDEO){
        if(st->avg_frame_rate.den && st->avg_frame_rate.num)
            print_fps(av_q2d(st->avg_frame_rate), "fps");
        if(st->r_frame_rate.den && st->r_frame_rate.num)
            print_fps(av_q2d(st->r_frame_rate), "tbr");
        if(st->time_base.den && st->time_base.num)
            print_fps(1/av_q2d(st->time_base), "tbn");
        if(st->codec->time_base.den && st->codec->time_base.num)
            print_fps(1/av_q2d(st->codec->time_base), "tbc");
    }
    av_log(NULL, AV_LOG_INFO, "\n");
    dump_metadata(NULL, st->metadata, "    ");
}

void dump_format(AVFormatContext *ic,
                 int index,
                 const char *url,
                 int is_output)
{
    int i;
    uint8_t *printed = av_mallocz(ic->nb_streams);
    if (ic->nb_streams && !printed)
        return;

    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);
    dump_metadata(NULL, ic->metadata, "  ");
    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.%02d", hours, mins, secs,
                   (100 * 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 = abs(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_chapters; i++) {
        AVChapter *ch = ic->chapters[i];
        av_log(NULL, AV_LOG_INFO, "    Chapter #%d.%d: ", index, i);
        av_log(NULL, AV_LOG_INFO, "start %f, ", ch->start * av_q2d(ch->time_base));
        av_log(NULL, AV_LOG_INFO, "end %f\n",   ch->end   * av_q2d(ch->time_base));

        dump_metadata(NULL, ch->metadata, "    ");
    }
    if(ic->nb_programs) {
        int j, k, total = 0;
        for(j=0; j<ic->nb_programs; j++) {
            AVMetadataTag *name = av_metadata_get(ic->programs[j]->metadata,
                                                  "name", NULL, 0);
            av_log(NULL, AV_LOG_INFO, "  Program %d %s\n", ic->programs[j]->id,
                   name ? name->value : "");
            dump_metadata(NULL, ic->programs[j]->metadata, "    ");
            for(k=0; k<ic->programs[j]->nb_stream_indexes; k++) {
                dump_stream_format(ic, ic->programs[j]->stream_index[k], index, is_output);
                printed[ic->programs[j]->stream_index[k]] = 1;
            }
            total += ic->programs[j]->nb_stream_indexes;
        }
        if (total < ic->nb_streams)
            av_log(NULL, AV_LOG_INFO, "  No Program\n");
    }
    for(i=0;i<ic->nb_streams;i++)
        if (!printed[i])
            dump_stream_format(ic, i, index, is_output);

    av_free(printed);
}

#if FF_API_PARSE_FRAME_PARAM
#include "libavcore/parseutils.h"

int parse_image_size(int *width_ptr, int *height_ptr, const char *str)
{
    return av_parse_video_size(width_ptr, height_ptr, str);
}

int parse_frame_rate(int *frame_rate_num, int *frame_rate_den, const char *arg)
{
    AVRational frame_rate;
    int ret = av_parse_video_rate(&frame_rate, arg);
    *frame_rate_num= frame_rate.num;
    *frame_rate_den= frame_rate.den;
    return ret;
}
#endif

int64_t av_gettime(void)
{
    struct timeval tv;
    gettimeofday(&tv,NULL);
    return (int64_t)tv.tv_sec * 1000000 + tv.tv_usec;
}

uint64_t ff_ntp_time(void)
{
  return (av_gettime() / 1000) * 1000 + NTP_OFFSET_US;
}

int64_t parse_date(const char *datestr, int duration)
{
    const char *p;
    int64_t t;
    struct tm dt;
    int i;
    static const char * const date_fmt[] = {
        "%Y-%m-%d",
        "%Y%m%d",
    };
    static const char * const 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) {
        if (!strncasecmp(datestr, "now", len))
            return (int64_t) now * 1000000;

        /* parse the year-month-day part */
        for (i = 0; i < FF_ARRAY_ELEMS(date_fmt); i++) {
            q = small_strptime(p, date_fmt[i], &dt);
            if (q) {
                break;
            }
        }

        /* if the year-month-day part is missing, then take the
         * current year-month-day time */
        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++;

        /* parse the hour-minute-second part */
        for (i = 0; i < FF_ARRAY_ELEMS(time_fmt); i++) {
            q = small_strptime(p, time_fmt[i], &dt);
            if (q) {
                break;
            }
        }
    } else {
        /* parse datestr as a duration */
        if (p[0] == '-') {
            negative = 1;
            ++p;
        }
        /* parse datestr as HH:MM:SS */
        q = small_strptime(p, time_fmt[0], &dt);
        if (!q) {
            /* parse datestr as S+ */
            dt.tm_sec = strtol(p, (char **)&q, 10);
            if (q == p)
                /* the parsing didn't succeed */
                return INT64_MIN;
            dt.tm_min = 0;
            dt.tm_hour = 0;
        }
    }

    /* Now we have all the fields that we can get */
    if (!q) {
        return INT64_MIN;
    }

    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;

    /* parse the .m... part */
    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;
}

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;
}

int av_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;
}

static void hex_dump_internal(void *avcl, FILE *f, int level, uint8_t *buf, int size)
{
    int len, i, j, c;
#undef fprintf
#define PRINT(...) do { if (!f) av_log(avcl, level, __VA_ARGS__); else fprintf(f, __VA_ARGS__); } while(0)

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

void av_hex_dump(FILE *f, uint8_t *buf, int size)
{
    hex_dump_internal(NULL, f, 0, buf, size);
}

void av_hex_dump_log(void *avcl, int level, uint8_t *buf, int size)
{
    hex_dump_internal(avcl, NULL, level, buf, size);
}

 //FIXME needs to know the time_base
static void pkt_dump_internal(void *avcl, FILE *f, int level, AVPacket *pkt, int dump_payload)
{
#undef fprintf
#define PRINT(...) do { if (!f) av_log(avcl, level, __VA_ARGS__); else fprintf(f, __VA_ARGS__); } while(0)
    PRINT("stream #%d:\n", pkt->stream_index);
    PRINT("  keyframe=%d\n", ((pkt->flags & AV_PKT_FLAG_KEY) != 0));
    PRINT("  duration=%0.3f\n", (double)pkt->duration / AV_TIME_BASE);
    /* DTS is _always_ valid after av_read_frame() */
    PRINT("  dts=");
    if (pkt->dts == AV_NOPTS_VALUE)
        PRINT("N/A");
    else
        PRINT("%0.3f", (double)pkt->dts / AV_TIME_BASE);
    /* PTS may not be known if B-frames are present. */
    PRINT("  pts=");
    if (pkt->pts == AV_NOPTS_VALUE)
        PRINT("N/A");
    else
        PRINT("%0.3f", (double)pkt->pts / AV_TIME_BASE);
    PRINT("\n");
    PRINT("  size=%d\n", pkt->size);
#undef PRINT
    if (dump_payload)
        av_hex_dump(f, pkt->data, pkt->size);
}

void av_pkt_dump(FILE *f, AVPacket *pkt, int dump_payload)
{
    pkt_dump_internal(NULL, f, 0, pkt, dump_payload);
}

void av_pkt_dump_log(void *avcl, int level, AVPacket *pkt, int dump_payload)
{
    pkt_dump_internal(avcl, NULL, level, pkt, dump_payload);
}

#if FF_API_URL_SPLIT
attribute_deprecated
void ff_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)
{
    av_url_split(proto, proto_size,
                 authorization, authorization_size,
                 hostname, hostname_size,
                 port_ptr,
                 path, path_size,
                 url);
}
#endif

void av_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, *ls, *at, *col, *brk;

    if (port_ptr)               *port_ptr = -1;
    if (proto_size > 0)         proto[0] = 0;
    if (authorization_size > 0) authorization[0] = 0;
    if (hostname_size > 0)      hostname[0] = 0;
    if (path_size > 0)          path[0] = 0;

    /* parse protocol */
    if ((p = strchr(url, ':'))) {
        av_strlcpy(proto, url, FFMIN(proto_size, p + 1 - url));
        p++; /* skip ':' */
        if (*p == '/') p++;
        if (*p == '/') p++;
    } else {
        /* no protocol means plain filename */
        av_strlcpy(path, url, path_size);
        return;
    }

    /* separate path from hostname */
    ls = strchr(p, '/');
    if(!ls)
        ls = strchr(p, '?');
    if(ls)
        av_strlcpy(path, ls, path_size);
    else
        ls = &p[strlen(p)]; // XXX

    /* the rest is hostname, use that to parse auth/port */
    if (ls != p) {
        /* authorization (user[:pass]@hostname) */
        if ((at = strchr(p, '@')) && at < ls) {
            av_strlcpy(authorization, p,
                       FFMIN(authorization_size, at + 1 - p));
            p = at + 1; /* skip '@' */
        }

        if (*p == '[' && (brk = strchr(p, ']')) && brk < ls) {
            /* [host]:port */
            av_strlcpy(hostname, p + 1,
                       FFMIN(hostname_size, brk - p));
            if (brk[1] == ':' && port_ptr)
                *port_ptr = atoi(brk + 2);
        } else if ((col = strchr(p, ':')) && col < ls) {
            av_strlcpy(hostname, p,
                       FFMIN(col + 1 - p, hostname_size));
            if (port_ptr) *port_ptr = atoi(col + 1);
        } else
            av_strlcpy(hostname, p,
                       FFMIN(ls + 1 - p, hostname_size));
    }
}

char *ff_data_to_hex(char *buff, const uint8_t *src, int s, int lowercase)
{
    int i;
    static const char hex_table_uc[16] = { '0', '1', '2', '3',
                                           '4', '5', '6', '7',
                                           '8', '9', 'A', 'B',
                                           'C', 'D', 'E', 'F' };
    static const char hex_table_lc[16] = { '0', '1', '2', '3',
                                           '4', '5', '6', '7',
                                           '8', '9', 'a', 'b',
                                           'c', 'd', 'e', 'f' };
    const char *hex_table = lowercase ? hex_table_lc : hex_table_uc;

    for(i = 0; i < s; i++) {
        buff[i * 2]     = hex_table[src[i] >> 4];
        buff[i * 2 + 1] = hex_table[src[i] & 0xF];
    }

    return buff;
}

int ff_hex_to_data(uint8_t *data, const char *p)
{
    int c, len, v;

    len = 0;
    v = 1;
    for (;;) {
        p += strspn(p, SPACE_CHARS);
        if (*p == '\0')
            break;
        c = toupper((unsigned char) *p++);
        if (c >= '0' && c <= '9')
            c = c - '0';
        else if (c >= 'A' && c <= 'F')
            c = c - 'A' + 10;
        else
            break;
        v = (v << 4) | c;
        if (v & 0x100) {
            if (data)
                data[len] = v;
            len++;
            v = 1;
        }
    }
    return len;
}

void av_set_pts_info(AVStream *s, int pts_wrap_bits,
                     unsigned int pts_num, unsigned int pts_den)
{
    s->pts_wrap_bits = pts_wrap_bits;

    if(av_reduce(&s->time_base.num, &s->time_base.den, pts_num, pts_den, INT_MAX)){
        if(s->time_base.num != pts_num)
            av_log(NULL, AV_LOG_DEBUG, "st:%d removing common factor %d from timebase\n", s->index, pts_num/s->time_base.num);
    }else
        av_log(NULL, AV_LOG_WARNING, "st:%d has too large timebase, reducing\n", s->index);

    if(!s->time_base.num || !s->time_base.den)
        s->time_base.num= s->time_base.den= 0;
}

int ff_url_join(char *str, int size, const char *proto,
                const char *authorization, const char *hostname,
                int port, const char *fmt, ...)
{
#if CONFIG_NETWORK
    struct addrinfo hints, *ai;
#endif

    str[0] = '\0';
    if (proto)
        av_strlcatf(str, size, "%s://", proto);
    if (authorization && authorization[0])
        av_strlcatf(str, size, "%s@", authorization);
#if CONFIG_NETWORK && defined(AF_INET6)
    /* Determine if hostname is a numerical IPv6 address,
     * properly escape it within [] in that case. */
    memset(&hints, 0, sizeof(hints));
    hints.ai_flags = AI_NUMERICHOST;
    if (!getaddrinfo(hostname, NULL, &hints, &ai)) {
        if (ai->ai_family == AF_INET6) {
            av_strlcat(str, "[", size);
            av_strlcat(str, hostname, size);
            av_strlcat(str, "]", size);
        } else {
            av_strlcat(str, hostname, size);
        }
        freeaddrinfo(ai);
    } else
#endif
        /* Not an IPv6 address, just output the plain string. */
        av_strlcat(str, hostname, size);

    if (port >= 0)
        av_strlcatf(str, size, ":%d", port);
    if (fmt) {
        va_list vl;
        int len = strlen(str);

        va_start(vl, fmt);
        vsnprintf(str + len, size > len ? size - len : 0, fmt, vl);
        va_end(vl);
    }
    return strlen(str);
}

int ff_write_chained(AVFormatContext *dst, int dst_stream, AVPacket *pkt,
                     AVFormatContext *src)
{
    AVPacket local_pkt;

    local_pkt = *pkt;
    local_pkt.stream_index = dst_stream;
    if (pkt->pts != AV_NOPTS_VALUE)
        local_pkt.pts = av_rescale_q(pkt->pts,
                                     src->streams[pkt->stream_index]->time_base,
                                     dst->streams[dst_stream]->time_base);
    if (pkt->dts != AV_NOPTS_VALUE)
        local_pkt.dts = av_rescale_q(pkt->dts,
                                     src->streams[pkt->stream_index]->time_base,
                                     dst->streams[dst_stream]->time_base);
    return av_write_frame(dst, &local_pkt);
}

void ff_parse_key_value(const char *str, ff_parse_key_val_cb callback_get_buf,
                        void *context)
{
    const char *ptr = str;

    /* Parse key=value pairs. */
    for (;;) {
        const char *key;
        char *dest = NULL, *dest_end;
        int key_len, dest_len = 0;

        /* Skip whitespace and potential commas. */
        while (*ptr && (isspace(*ptr) || *ptr == ','))
            ptr++;
        if (!*ptr)
            break;

        key = ptr;

        if (!(ptr = strchr(key, '=')))
            break;
        ptr++;
        key_len = ptr - key;

        callback_get_buf(context, key, key_len, &dest, &dest_len);
        dest_end = dest + dest_len - 1;

        if (*ptr == '\"') {
            ptr++;
            while (*ptr && *ptr != '\"') {
                if (*ptr == '\\') {
                    if (!ptr[1])
                        break;
                    if (dest && dest < dest_end)
                        *dest++ = ptr[1];
                    ptr += 2;
                } else {
                    if (dest && dest < dest_end)
                        *dest++ = *ptr;
                    ptr++;
                }
            }
            if (*ptr == '\"')
                ptr++;
        } else {
            for (; *ptr && !(isspace(*ptr) || *ptr == ','); ptr++)
                if (dest && dest < dest_end)
                    *dest++ = *ptr;
        }
        if (dest)
            *dest = 0;
    }
}

int ff_find_stream_index(AVFormatContext *s, int id)
{
    int i;
    for (i = 0; i < s->nb_streams; i++) {
        if (s->streams[i]->id == id)
            return i;
    }
    return -1;
}