ffprobe.c

    const char *p;
    char *q;
    size_t size = 1;

    /* precompute size */
    for (p = src; *p; p++, size++) {
        ESCAPE_CHECK_SIZE(src, size, SIZE_MAX-10);
        switch (*p) {
        case '&' : size += strlen("&");  break;
        case '<' : size += strlen("&lt;");   break;
        case '>' : size += strlen("&gt;");   break;
        case '\"': size += strlen("&quot;"); break;
        case '\'': size += strlen("&apos;"); break;
        default: size++;
        }
    }
    ESCAPE_REALLOC_BUF(dst_size, dst, src, size);

#define COPY_STR(str) {      \
        const char *s = str; \
        while (*s)           \
            *q++ = *s++;     \
    }

    p = src;
    q = *dst;
    while (*p) {
        switch (*p) {
        case '&' : COPY_STR("&amp;");  break;
        case '<' : COPY_STR("&lt;");   break;
        case '>' : COPY_STR("&gt;");   break;
        case '\"': COPY_STR("&quot;"); break;
        case '\'': COPY_STR("&apos;"); break;
        default: *q++ = *p;
        }
        p++;
    }
    *q = 0;

    return *dst;
}

static void xml_print_header(WriterContext *wctx)
{
    XMLContext *xml = wctx->priv;
    const char *qual = " xmlns:xsi='http://www.w3.org/2001/XMLSchema-instance' "
        "xmlns:ffprobe='http://www.ffmpeg.org/schema/ffprobe' "
        "xsi:schemaLocation='http://www.ffmpeg.org/schema/ffprobe ffprobe.xsd'";

    printf("<?xml version=\"1.0\" encoding=\"UTF-8\"?>\n");
    printf("<%sffprobe%s>\n",
           xml->fully_qualified ? "ffprobe:" : "",
           xml->fully_qualified ? qual : "");

    xml->indent_level++;
}

static void xml_print_footer(WriterContext *wctx)
{
    XMLContext *xml = wctx->priv;

    xml->indent_level--;
    printf("</%sffprobe>\n", xml->fully_qualified ? "ffprobe:" : "");
}

#define XML_INDENT() printf("%*c", xml->indent_level * 4, ' ')

static void xml_print_chapter_header(WriterContext *wctx, const char *chapter)
{
    XMLContext *xml = wctx->priv;

    if (wctx->nb_chapter)
        printf("\n");
    xml->multiple_entries = !strcmp(chapter, "packets") || !strcmp(chapter, "frames") ||
                            !strcmp(chapter, "packets_and_frames") ||
                            !strcmp(chapter, "streams");

    if (xml->multiple_entries) {
        XML_INDENT(); printf("<%s>\n", chapter);
        xml->indent_level++;
    }
}

static void xml_print_chapter_footer(WriterContext *wctx, const char *chapter)
{
    XMLContext *xml = wctx->priv;

    if (xml->multiple_entries) {
        xml->indent_level--;
        XML_INDENT(); printf("</%s>\n", chapter);
    }
}

static void xml_print_section_header(WriterContext *wctx, const char *section)
{
    XMLContext *xml = wctx->priv;

    XML_INDENT(); printf("<%s ", section);
    xml->within_tag = 1;
}

static void xml_print_section_footer(WriterContext *wctx, const char *section)
{
    XMLContext *xml = wctx->priv;

    if (xml->within_tag)
        printf("/>\n");
    else {
        XML_INDENT(); printf("</%s>\n", section);
    }
}

static void xml_print_str(WriterContext *wctx, const char *key, const char *value)
{
    XMLContext *xml = wctx->priv;

    if (wctx->nb_item)
        printf(" ");
    printf("%s=\"%s\"", key, xml_escape_str(&xml->buf, &xml->buf_size, value, wctx));
}

static void xml_print_int(WriterContext *wctx, const char *key, long long int value)
{
    if (wctx->nb_item)
        printf(" ");
    printf("%s=\"%lld\"", key, value);
}

static void xml_show_tags(WriterContext *wctx, AVDictionary *dict)
{
    XMLContext *xml = wctx->priv;
    AVDictionaryEntry *tag = NULL;
    int is_first = 1;

    xml->indent_level++;
    while ((tag = av_dict_get(dict, "", tag, AV_DICT_IGNORE_SUFFIX))) {
        if (is_first) {
            /* close section tag */
            printf(">\n");
            xml->within_tag = 0;
            is_first = 0;
        }
        XML_INDENT();
        printf("<tag key=\"%s\"",
               xml_escape_str(&xml->buf, &xml->buf_size, tag->key,   wctx));
        printf(" value=\"%s\"/>\n",
               xml_escape_str(&xml->buf, &xml->buf_size, tag->value, wctx));
    }
    xml->indent_level--;
}

static Writer xml_writer = {
    .name                 = "xml",
    .priv_size            = sizeof(XMLContext),
    .init                 = xml_init,
    .uninit               = xml_uninit,
    .print_header         = xml_print_header,
    .print_footer         = xml_print_footer,
    .print_chapter_header = xml_print_chapter_header,
    .print_chapter_footer = xml_print_chapter_footer,
    .print_section_header = xml_print_section_header,
    .print_section_footer = xml_print_section_footer,
    .print_integer        = xml_print_int,
    .print_string         = xml_print_str,
    .show_tags            = xml_show_tags,
    .flags = WRITER_FLAG_PUT_PACKETS_AND_FRAMES_IN_SAME_CHAPTER,
};

static void writer_register_all(void)
{
    static int initialized;

    if (initialized)
        return;
    initialized = 1;

    writer_register(&default_writer);
    writer_register(&compact_writer);
    writer_register(&csv_writer);
    writer_register(&json_writer);
    writer_register(&xml_writer);
}

#define print_fmt(k, f, ...) do {              \
    if (fast_asprintf(&pbuf, f, __VA_ARGS__))  \
        writer_print_string(w, k, pbuf.s, 0);  \
} while (0)

#define print_fmt_opt(k, f, ...) do {          \
    if (fast_asprintf(&pbuf, f, __VA_ARGS__))  \
        writer_print_string(w, k, pbuf.s, 1);  \
} while (0)

#define print_int(k, v)         writer_print_integer(w, k, v)
#define print_str(k, v)         writer_print_string(w, k, v, 0)
#define print_str_opt(k, v)     writer_print_string(w, k, v, 1)
#define print_time(k, v, tb)    writer_print_time(w, k, v, tb)
#define print_ts(k, v)          writer_print_ts(w, k, v)
#define print_val(k, v, u)      writer_print_string(w, k, \
    value_string(val_str, sizeof(val_str), (struct unit_value){.val.i = v, .unit=u}), 0)
#define print_section_header(s) writer_print_section_header(w, s)
#define print_section_footer(s) writer_print_section_footer(w, s)
#define show_tags(metadata)     writer_show_tags(w, metadata)

static void show_packet(WriterContext *w, AVFormatContext *fmt_ctx, AVPacket *pkt, int packet_idx)
{
    char val_str[128];
    AVStream *st = fmt_ctx->streams[pkt->stream_index];
    struct print_buf pbuf = {.s = NULL};
    const char *s;

    print_section_header("packet");
    s = av_get_media_type_string(st->codec->codec_type);
    if (s) print_str    ("codec_type", s);
    else   print_str_opt("codec_type", "unknown");
    print_int("stream_index",     pkt->stream_index);
    print_ts  ("pts",             pkt->pts);
    print_time("pts_time",        pkt->pts, &st->time_base);
    print_ts  ("dts",             pkt->dts);
    print_time("dts_time",        pkt->dts, &st->time_base);
    print_ts  ("duration",        pkt->duration);
    print_time("duration_time",   pkt->duration, &st->time_base);
    print_val("size",             pkt->size, unit_byte_str);
    if (pkt->pos != -1) print_fmt    ("pos", "%"PRId64, pkt->pos);
    else                print_str_opt("pos", "N/A");
    print_fmt("flags", "%c",      pkt->flags & AV_PKT_FLAG_KEY ? 'K' : '_');
    print_section_footer("packet");

    av_free(pbuf.s);
    fflush(stdout);
}

static void show_frame(WriterContext *w, AVFrame *frame, AVStream *stream)
{
    struct print_buf pbuf = {.s = NULL};
    const char *s;

    print_section_header("frame");
    print_str("media_type",             "video");
    print_int("width",                  frame->width);
    print_int("height",                 frame->height);
    s = av_get_pix_fmt_name(frame->format);
    if (s) print_str    ("pix_fmt", s);
    else   print_str_opt("pix_fmt", "unknown");
    if (frame->sample_aspect_ratio.num) {
        print_fmt("sample_aspect_ratio", "%d:%d",
                  frame->sample_aspect_ratio.num,
                  frame->sample_aspect_ratio.den);
    } else {
        print_str_opt("sample_aspect_ratio", "N/A");
    }
    print_fmt("pict_type",              "%c", av_get_picture_type_char(frame->pict_type));
    print_int("coded_picture_number",   frame->coded_picture_number);
    print_int("display_picture_number", frame->display_picture_number);
    print_int("interlaced_frame",       frame->interlaced_frame);
    print_int("top_field_first",        frame->top_field_first);
    print_int("repeat_pict",            frame->repeat_pict);
    print_int("reference",              frame->reference);
    print_int("key_frame",              frame->key_frame);
    print_ts  ("pkt_pts",               frame->pkt_pts);
    print_time("pkt_pts_time",          frame->pkt_pts, &stream->time_base);
    print_ts  ("pkt_dts",               frame->pkt_dts);
    print_time("pkt_dts_time",          frame->pkt_dts, &stream->time_base);
    if (frame->pkt_pos != -1) print_fmt    ("pkt_pos", "%"PRId64, frame->pkt_pos);
    else                      print_str_opt("pkt_pos", "N/A");
    print_section_footer("frame");

    av_free(pbuf.s);
    fflush(stdout);
}

static av_always_inline int get_video_frame(AVFormatContext *fmt_ctx,
                                            AVFrame *frame, AVPacket *pkt)
{
    AVCodecContext *dec_ctx = fmt_ctx->streams[pkt->stream_index]->codec;
    int got_picture = 0;

    if (dec_ctx->codec_id   != CODEC_ID_NONE &&
        dec_ctx->codec_type == AVMEDIA_TYPE_VIDEO)
        avcodec_decode_video2(dec_ctx, frame, &got_picture, pkt);
    return got_picture;
}

static void show_packets(WriterContext *w, AVFormatContext *fmt_ctx)
{
    AVPacket pkt;
    AVFrame frame;
    int i = 0;

    av_init_packet(&pkt);

    while (!av_read_frame(fmt_ctx, &pkt)) {
        if (do_show_packets)
            show_packet(w, fmt_ctx, &pkt, i++);
        if (do_show_frames &&
            get_video_frame(fmt_ctx, &frame, &pkt)) {
            show_frame(w, &frame, fmt_ctx->streams[pkt.stream_index]);
            av_destruct_packet(&pkt);
        }
    }
    av_init_packet(&pkt);
    pkt.data = NULL;
    pkt.size = 0;
    //Flush remaining frames that are cached in the decoder
    for (i = 0; i < fmt_ctx->nb_streams; i++) {
        pkt.stream_index = i;
        while (get_video_frame(fmt_ctx, &frame, &pkt))
            show_frame(w, &frame, fmt_ctx->streams[pkt.stream_index]);
    }
}

static void show_stream(WriterContext *w, AVFormatContext *fmt_ctx, int stream_idx)
{
    AVStream *stream = fmt_ctx->streams[stream_idx];
    AVCodecContext *dec_ctx;
    AVCodec *dec;
    char val_str[128];
    const char *s;
    AVRational display_aspect_ratio;
    struct print_buf pbuf = {.s = NULL};

    print_section_header("stream");

    print_int("index", stream->index);

    if ((dec_ctx = stream->codec)) {
        if ((dec = dec_ctx->codec)) {
            print_str("codec_name",      dec->name);
            print_str("codec_long_name", dec->long_name);
        } else {
            print_str_opt("codec_name",      "unknown");
            print_str_opt("codec_long_name", "unknown");
        }

        s = av_get_media_type_string(dec_ctx->codec_type);
        if (s) print_str    ("codec_type", s);
        else   print_str_opt("codec_type", "unknown");
        print_fmt("codec_time_base", "%d/%d", dec_ctx->time_base.num, dec_ctx->time_base.den);

        /* print AVI/FourCC tag */
        av_get_codec_tag_string(val_str, sizeof(val_str), dec_ctx->codec_tag);
        print_str("codec_tag_string",    val_str);
        print_fmt("codec_tag", "0x%04x", dec_ctx->codec_tag);

        switch (dec_ctx->codec_type) {
        case AVMEDIA_TYPE_VIDEO:
            print_int("width",        dec_ctx->width);
            print_int("height",       dec_ctx->height);
            print_int("has_b_frames", dec_ctx->has_b_frames);
            if (dec_ctx->sample_aspect_ratio.num) {
                print_fmt("sample_aspect_ratio", "%d:%d",
                          dec_ctx->sample_aspect_ratio.num,
                          dec_ctx->sample_aspect_ratio.den);
                av_reduce(&display_aspect_ratio.num, &display_aspect_ratio.den,
                          dec_ctx->width  * dec_ctx->sample_aspect_ratio.num,
                          dec_ctx->height * dec_ctx->sample_aspect_ratio.den,
                          1024*1024);
                print_fmt("display_aspect_ratio", "%d:%d",
                          display_aspect_ratio.num,
                          display_aspect_ratio.den);
            } else {
                print_str_opt("sample_aspect_ratio", "N/A");
                print_str_opt("display_aspect_ratio", "N/A");
            }
            s = av_get_pix_fmt_name(dec_ctx->pix_fmt);
            if (s) print_str    ("pix_fmt", s);
            else   print_str_opt("pix_fmt", "unknown");
            print_int("level",   dec_ctx->level);
            if (dec_ctx->timecode_frame_start >= 0) {
                uint32_t tc = dec_ctx->timecode_frame_start;
                print_fmt("timecode", "%02d:%02d:%02d%c%02d",
                          tc>>19 & 0x1f,              // hours
                          tc>>13 & 0x3f,              // minutes
                          tc>>6  & 0x3f,              // seconds
                          tc     & 1<<24 ? ';' : ':', // drop
                          tc     & 0x3f);             // frames
            } else {
                print_str_opt("timecode", "N/A");
            }
            break;

        case AVMEDIA_TYPE_AUDIO:
            s = av_get_sample_fmt_name(dec_ctx->sample_fmt);
            if (s) print_str    ("sample_fmt", s);
            else   print_str_opt("sample_fmt", "unknown");
            print_val("sample_rate",     dec_ctx->sample_rate, unit_hertz_str);
            print_int("channels",        dec_ctx->channels);
            print_int("bits_per_sample", av_get_bits_per_sample(dec_ctx->codec_id));
            break;
        }
    } else {
        print_str_opt("codec_type", "unknown");
    }
    if (dec_ctx->codec && dec_ctx->codec->priv_class && show_private_data) {
        const AVOption *opt = NULL;
        while (opt = av_opt_next(dec_ctx->priv_data,opt)) {
            uint8_t *str;
            if (opt->flags) continue;
            if (av_opt_get(dec_ctx->priv_data, opt->name, 0, &str) >= 0) {
                print_str(opt->name, str);
                av_free(str);
            }
        }
    }

    if (fmt_ctx->iformat->flags & AVFMT_SHOW_IDS) print_fmt    ("id", "0x%x", stream->id);
    else                                          print_str_opt("id", "N/A");
    print_fmt("r_frame_rate",   "%d/%d", stream->r_frame_rate.num,   stream->r_frame_rate.den);
    print_fmt("avg_frame_rate", "%d/%d", stream->avg_frame_rate.num, stream->avg_frame_rate.den);
    print_fmt("time_base",      "%d/%d", stream->time_base.num,      stream->time_base.den);
    print_time("start_time",    stream->start_time, &stream->time_base);
    print_time("duration",      stream->duration,   &stream->time_base);
    if (stream->nb_frames) print_fmt    ("nb_frames", "%"PRId64, stream->nb_frames);
    else                   print_str_opt("nb_frames", "N/A");
    show_tags(stream->metadata);

    print_section_footer("stream");
    av_free(pbuf.s);
    fflush(stdout);
}

static void show_streams(WriterContext *w, AVFormatContext *fmt_ctx)
{
    int i;
    for (i = 0; i < fmt_ctx->nb_streams; i++)
        show_stream(w, fmt_ctx, i);
}

static void show_format(WriterContext *w, AVFormatContext *fmt_ctx)
{
    char val_str[128];
    int64_t size = avio_size(fmt_ctx->pb);

    print_section_header("format");
    print_str("filename",         fmt_ctx->filename);
    print_int("nb_streams",       fmt_ctx->nb_streams);
    print_str("format_name",      fmt_ctx->iformat->name);
    print_str("format_long_name", fmt_ctx->iformat->long_name);
    print_time("start_time",      fmt_ctx->start_time, &AV_TIME_BASE_Q);
    print_time("duration",        fmt_ctx->duration,   &AV_TIME_BASE_Q);
    if (size >= 0) print_val    ("size", size, unit_byte_str);
    else           print_str_opt("size", "N/A");
    if (fmt_ctx->bit_rate > 0) print_val    ("bit_rate", fmt_ctx->bit_rate, unit_bit_per_second_str);
    else                       print_str_opt("bit_rate", "N/A");
    show_tags(fmt_ctx->metadata);
    print_section_footer("format");
    fflush(stdout);
}

static void show_error(WriterContext *w, int err)
{
    char errbuf[128];
    const char *errbuf_ptr = errbuf;

    if (av_strerror(err, errbuf, sizeof(errbuf)) < 0)
        errbuf_ptr = strerror(AVUNERROR(err));

    writer_print_chapter_header(w, "error");
    print_section_header("error");
    print_int("code", err);
    print_str("string", errbuf_ptr);
    print_section_footer("error");
    writer_print_chapter_footer(w, "error");
}

static int open_input_file(AVFormatContext **fmt_ctx_ptr, const char *filename)
{
    int err, i;
    AVFormatContext *fmt_ctx = NULL;
    AVDictionaryEntry *t;

    if ((err = avformat_open_input(&fmt_ctx, filename, iformat, &format_opts)) < 0) {
        print_error(filename, err);
        return err;
    }
    if ((t = av_dict_get(format_opts, "", NULL, AV_DICT_IGNORE_SUFFIX))) {
        av_log(NULL, AV_LOG_ERROR, "Option %s not found.\n", t->key);
        return AVERROR_OPTION_NOT_FOUND;
    }


    /* fill the streams in the format context */
    if ((err = avformat_find_stream_info(fmt_ctx, NULL)) < 0) {
        print_error(filename, err);
        return err;
    }

    av_dump_format(fmt_ctx, 0, filename, 0);

    /* bind a decoder to each input stream */
    for (i = 0; i < fmt_ctx->nb_streams; i++) {
        AVStream *stream = fmt_ctx->streams[i];
        AVCodec *codec;

        if (!(codec = avcodec_find_decoder(stream->codec->codec_id))) {
            av_log(NULL, AV_LOG_ERROR, "Unsupported codec with id %d for input stream %d\n",
                   stream->codec->codec_id, stream->index);
        } else if (avcodec_open2(stream->codec, codec, NULL) < 0) {
            av_log(NULL, AV_LOG_ERROR, "Error while opening codec for input stream %d\n",
                   stream->index);
        }
    }

    *fmt_ctx_ptr = fmt_ctx;
    return 0;
}

#define PRINT_CHAPTER(name) do {                                        \
    if (do_show_ ## name) {                                             \
        writer_print_chapter_header(wctx, #name);                       \
        show_ ## name (wctx, fmt_ctx);                                  \
        writer_print_chapter_footer(wctx, #name);                       \
    }                                                                   \
} while (0)

static int probe_file(WriterContext *wctx, const char *filename)
{
    AVFormatContext *fmt_ctx;
    int ret, i;

    ret = open_input_file(&fmt_ctx, filename);
    if (ret >= 0) {
        if (do_show_packets || do_show_frames) {
            const char *chapter;
            if (do_show_frames && do_show_packets &&
                wctx->writer->flags & WRITER_FLAG_PUT_PACKETS_AND_FRAMES_IN_SAME_CHAPTER)
                chapter = "packets_and_frames";
            else if (do_show_packets && !do_show_frames)
                chapter = "packets";
            else // (!do_show_packets && do_show_frames)
                chapter = "frames";
            writer_print_chapter_header(wctx, chapter);
            show_packets(wctx, fmt_ctx);
            writer_print_chapter_footer(wctx, chapter);
        }
        PRINT_CHAPTER(streams);
        PRINT_CHAPTER(format);
        for (i = 0; i < fmt_ctx->nb_streams; i++)
            if (fmt_ctx->streams[i]->codec->codec_id != CODEC_ID_NONE)
                avcodec_close(fmt_ctx->streams[i]->codec);
        avformat_close_input(&fmt_ctx);
    }

    return ret;
}

static void show_usage(void)
{
    av_log(NULL, AV_LOG_INFO, "Simple multimedia streams analyzer\n");
    av_log(NULL, AV_LOG_INFO, "usage: %s [OPTIONS] [INPUT_FILE]\n", program_name);
    av_log(NULL, AV_LOG_INFO, "\n");
}

static int opt_format(const char *opt, const char *arg)
{
    iformat = av_find_input_format(arg);
    if (!iformat) {
        av_log(NULL, AV_LOG_ERROR, "Unknown input format: %s\n", arg);
        return AVERROR(EINVAL);
    }
    return 0;
}

static void opt_input_file(void *optctx, const char *arg)
{
    if (input_filename) {
        av_log(NULL, AV_LOG_ERROR, "Argument '%s' provided as input filename, but '%s' was already specified.\n",
               arg, input_filename);
        exit(1);
    }
    if (!strcmp(arg, "-"))
        arg = "pipe:";
    input_filename = arg;
}

static int opt_help(const char *opt, const char *arg)
{
    av_log_set_callback(log_callback_help);
    show_usage();
    show_help_options(options, "Main options:\n", 0, 0);
    printf("\n");

    show_help_children(avformat_get_class(), AV_OPT_FLAG_DECODING_PARAM);

    return 0;
}

static int opt_pretty(const char *opt, const char *arg)
{
    show_value_unit              = 1;
    use_value_prefix             = 1;
    use_byte_value_binary_prefix = 1;
    use_value_sexagesimal_format = 1;
    return 0;
}

static const OptionDef options[] = {
#include "cmdutils_common_opts.h"
    { "f", HAS_ARG, {(void*)opt_format}, "force format", "format" },
    { "unit", OPT_BOOL, {(void*)&show_value_unit}, "show unit of the displayed values" },
    { "prefix", OPT_BOOL, {(void*)&use_value_prefix}, "use SI prefixes for the displayed values" },
    { "byte_binary_prefix", OPT_BOOL, {(void*)&use_byte_value_binary_prefix},
      "use binary prefixes for byte units" },
    { "sexagesimal", OPT_BOOL,  {(void*)&use_value_sexagesimal_format},
      "use sexagesimal format HOURS:MM:SS.MICROSECONDS for time units" },
    { "pretty", 0, {(void*)&opt_pretty},
      "prettify the format of displayed values, make it more human readable" },
    { "print_format", OPT_STRING | HAS_ARG, {(void*)&print_format},
      "set the output printing format (available formats are: default, compact, csv, json, xml)", "format" },
    { "show_error",   OPT_BOOL, {(void*)&do_show_error} ,  "show probing error" },
    { "show_format",  OPT_BOOL, {(void*)&do_show_format} , "show format/container info" },
    { "show_frames",  OPT_BOOL, {(void*)&do_show_frames} , "show frames info" },
    { "show_packets", OPT_BOOL, {(void*)&do_show_packets}, "show packets info" },
    { "show_streams", OPT_BOOL, {(void*)&do_show_streams}, "show streams info" },
    { "show_private_data", OPT_BOOL, {(void*)&show_private_data}, "show private data" },
    { "private",           OPT_BOOL, {(void*)&show_private_data}, "same as show_private_data" },
    { "default", HAS_ARG | OPT_AUDIO | OPT_VIDEO | OPT_EXPERT, {(void*)opt_default}, "generic catch all option", "" },
    { "i", HAS_ARG, {(void *)opt_input_file}, "read specified file", "input_file"},
    { NULL, },
};

int main(int argc, char **argv)
{
    const Writer *w;
    WriterContext *wctx;
    char *buf;
    char *w_name = NULL, *w_args = NULL;
    int ret;

    parse_loglevel(argc, argv, options);
    av_register_all();
    avformat_network_init();
    init_opts();
#if CONFIG_AVDEVICE
    avdevice_register_all();
#endif

    show_banner(argc, argv, options);
    parse_options(NULL, argc, argv, options, opt_input_file);

    writer_register_all();

    if (!print_format)
        print_format = av_strdup("default");
    w_name = av_strtok(print_format, "=", &buf);
    w_args = buf;

    w = writer_get_by_name(w_name);
    if (!w) {
        av_log(NULL, AV_LOG_ERROR, "Unknown output format with name '%s'\n", w_name);
        ret = AVERROR(EINVAL);
        goto end;
    }

    if ((ret = writer_open(&wctx, w, w_args, NULL)) >= 0) {
        writer_print_header(wctx);

        if (!input_filename) {
            show_usage();
            av_log(NULL, AV_LOG_ERROR, "You have to specify one input file.\n");
            av_log(NULL, AV_LOG_ERROR, "Use -h to get full help or, even better, run 'man %s'.\n", program_name);
            ret = AVERROR(EINVAL);
        } else {
            ret = probe_file(wctx, input_filename);
            if (ret < 0 && do_show_error)
                show_error(wctx, ret);
        }

        writer_print_footer(wctx);
        writer_close(&wctx);
    }

end:
    av_freep(&print_format);
    avformat_network_deinit();

    return ret;
}