cmdutils.c

    int lim = parse_number_or_die(opt, arg, OPT_INT64, 0, INT_MAX);
    struct rlimit rl = { lim, lim + 1 };
    if (setrlimit(RLIMIT_CPU, &rl))
        perror("setrlimit");
#else
    av_log(NULL, AV_LOG_WARNING, "-%s not implemented on this OS\n", opt);
#endif
    return 0;
}

void print_error(const char *filename, int err)
{
    char errbuf[128];
    const char *errbuf_ptr = errbuf;

    if (av_strerror(err, errbuf, sizeof(errbuf)) < 0)
        errbuf_ptr = strerror(AVUNERROR(err));
    av_log(NULL, AV_LOG_ERROR, "%s: %s\n", filename, errbuf_ptr);
}

static int warned_cfg = 0;

#define INDENT        1
#define SHOW_VERSION  2
#define SHOW_CONFIG   4
#define SHOW_COPYRIGHT 8

#define PRINT_LIB_INFO(libname, LIBNAME, flags, level)                  \
    if (CONFIG_##LIBNAME) {                                             \
        const char *indent = flags & INDENT? "  " : "";                 \
        if (flags & SHOW_VERSION) {                                     \
            unsigned int version = libname##_version();                 \
            av_log(NULL, level,                                         \
                   "%slib%-11s %2d.%3d.%3d / %2d.%3d.%3d\n",            \
                   indent, #libname,                                    \
                   LIB##LIBNAME##_VERSION_MAJOR,                        \
                   LIB##LIBNAME##_VERSION_MINOR,                        \
                   LIB##LIBNAME##_VERSION_MICRO,                        \
                   version >> 16, version >> 8 & 0xff, version & 0xff); \
        }                                                               \
        if (flags & SHOW_CONFIG) {                                      \
            const char *cfg = libname##_configuration();                \
            if (strcmp(FFMPEG_CONFIGURATION, cfg)) {                    \
                if (!warned_cfg) {                                      \
                    av_log(NULL, level,                                 \
                            "%sWARNING: library configuration mismatch\n", \
                            indent);                                    \
                    warned_cfg = 1;                                     \
                }                                                       \
                av_log(NULL, level, "%s%-11s configuration: %s\n",      \
                        indent, #libname, cfg);                         \
            }                                                           \
        }                                                               \
    }                                                                   \

static void print_all_libs_info(int flags, int level)
{
    PRINT_LIB_INFO(avutil,   AVUTIL,   flags, level);
    PRINT_LIB_INFO(avcodec,  AVCODEC,  flags, level);
    PRINT_LIB_INFO(avformat, AVFORMAT, flags, level);
    PRINT_LIB_INFO(avdevice, AVDEVICE, flags, level);
    PRINT_LIB_INFO(avfilter, AVFILTER, flags, level);
    PRINT_LIB_INFO(avresample, AVRESAMPLE, flags, level);
    PRINT_LIB_INFO(swscale,  SWSCALE,  flags, level);
    PRINT_LIB_INFO(swresample,SWRESAMPLE,  flags, level);
    PRINT_LIB_INFO(postproc, POSTPROC, flags, level);
}

static void print_program_info(int flags, int level)
{
    const char *indent = flags & INDENT? "  " : "";

    av_log(NULL, level, "%s version " FFMPEG_VERSION, program_name);
    if (flags & SHOW_COPYRIGHT)
        av_log(NULL, level, " Copyright (c) %d-%d the FFmpeg developers",
               program_birth_year, CONFIG_THIS_YEAR);
    av_log(NULL, level, "\n");
    av_log(NULL, level, "%sbuilt on %s %s with %s\n",
           indent, __DATE__, __TIME__, CC_IDENT);

    av_log(NULL, level, "%sconfiguration: " FFMPEG_CONFIGURATION "\n", indent);
}

static void print_buildconf(int flags, int level)
{
    const char *indent = flags & INDENT ? "  " : "";
    char str[] = { FFMPEG_CONFIGURATION };
    char *conflist, *remove_tilde, *splitconf;

    // Change all the ' --' strings to '~--' so that
    // they can be identified as tokens.
    while ((conflist = strstr(str, " --")) != NULL) {
        strncpy(conflist, "~--", 3);
    }

    // Compensate for the weirdness this would cause
    // when passing 'pkg-config --static'.
    while ((remove_tilde = strstr(str, "pkg-config~")) != NULL) {
        strncpy(remove_tilde, "pkg-config ", 11);
    }

    splitconf = strtok(str, "~");
    av_log(NULL, level, "\n%sconfiguration:\n", indent);
    while (splitconf != NULL) {
        av_log(NULL, level, "%s%s%s\n", indent, indent, splitconf);
        splitconf = strtok(NULL, "~");
    }
}

void show_banner(int argc, char **argv, const OptionDef *options)
{
    int idx = locate_option(argc, argv, options, "version");
    if (hide_banner || idx)
        return;

    print_program_info (INDENT|SHOW_COPYRIGHT, AV_LOG_INFO);
    print_all_libs_info(INDENT|SHOW_CONFIG,  AV_LOG_INFO);
    print_all_libs_info(INDENT|SHOW_VERSION, AV_LOG_INFO);
}

int show_version(void *optctx, const char *opt, const char *arg)
{
    av_log_set_callback(log_callback_help);
    print_program_info (SHOW_COPYRIGHT, AV_LOG_INFO);
    print_all_libs_info(SHOW_VERSION, AV_LOG_INFO);

    return 0;
}

int show_buildconf(void *optctx, const char *opt, const char *arg)
{
    av_log_set_callback(log_callback_help);
    print_buildconf      (INDENT|0, AV_LOG_INFO);

    return 0;
}

int show_license(void *optctx, const char *opt, const char *arg)
{
#if CONFIG_NONFREE
    printf(
    "This version of %s has nonfree parts compiled in.\n"
    "Therefore it is not legally redistributable.\n",
    program_name );
#elif CONFIG_GPLV3
    printf(
    "%s is free software; you can redistribute it and/or modify\n"
    "it under the terms of the GNU General Public License as published by\n"
    "the Free Software Foundation; either version 3 of the License, or\n"
    "(at your option) any later version.\n"
    "\n"
    "%s is distributed in the hope that it will be useful,\n"
    "but WITHOUT ANY WARRANTY; without even the implied warranty of\n"
    "MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the\n"
    "GNU General Public License for more details.\n"
    "\n"
    "You should have received a copy of the GNU General Public License\n"
    "along with %s.  If not, see <http://www.gnu.org/licenses/>.\n",
    program_name, program_name, program_name );
#elif CONFIG_GPL
    printf(
    "%s is free software; you can redistribute it and/or modify\n"
    "it under the terms of the GNU General Public License as published by\n"
    "the Free Software Foundation; either version 2 of the License, or\n"
    "(at your option) any later version.\n"
    "\n"
    "%s is distributed in the hope that it will be useful,\n"
    "but WITHOUT ANY WARRANTY; without even the implied warranty of\n"
    "MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the\n"
    "GNU General Public License for more details.\n"
    "\n"
    "You should have received a copy of the GNU General Public License\n"
    "along with %s; if not, write to the Free Software\n"
    "Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA\n",
    program_name, program_name, program_name );
#elif CONFIG_LGPLV3
    printf(
    "%s is free software; you can redistribute it and/or modify\n"
    "it under the terms of the GNU Lesser General Public License as published by\n"
    "the Free Software Foundation; either version 3 of the License, or\n"
    "(at your option) any later version.\n"
    "\n"
    "%s is distributed in the hope that it will be useful,\n"
    "but WITHOUT ANY WARRANTY; without even the implied warranty of\n"
    "MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the\n"
    "GNU Lesser General Public License for more details.\n"
    "\n"
    "You should have received a copy of the GNU Lesser General Public License\n"
    "along with %s.  If not, see <http://www.gnu.org/licenses/>.\n",
    program_name, program_name, program_name );
#else
    printf(
    "%s is free software; you can redistribute it and/or\n"
    "modify it under the terms of the GNU Lesser General Public\n"
    "License as published by the Free Software Foundation; either\n"
    "version 2.1 of the License, or (at your option) any later version.\n"
    "\n"
    "%s is distributed in the hope that it will be useful,\n"
    "but WITHOUT ANY WARRANTY; without even the implied warranty of\n"
    "MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU\n"
    "Lesser General Public License for more details.\n"
    "\n"
    "You should have received a copy of the GNU Lesser General Public\n"
    "License along with %s; if not, write to the Free Software\n"
    "Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA\n",
    program_name, program_name, program_name );
#endif

    return 0;
}

static int is_device(const AVClass *avclass)
{
    if (!avclass)
        return 0;
    return avclass->category == AV_CLASS_CATEGORY_DEVICE_VIDEO_OUTPUT ||
           avclass->category == AV_CLASS_CATEGORY_DEVICE_VIDEO_INPUT ||
           avclass->category == AV_CLASS_CATEGORY_DEVICE_AUDIO_OUTPUT ||
           avclass->category == AV_CLASS_CATEGORY_DEVICE_AUDIO_INPUT ||
           avclass->category == AV_CLASS_CATEGORY_DEVICE_OUTPUT ||
           avclass->category == AV_CLASS_CATEGORY_DEVICE_INPUT;
}

static int show_formats_devices(void *optctx, const char *opt, const char *arg, int device_only)
{
    AVInputFormat *ifmt  = NULL;
    AVOutputFormat *ofmt = NULL;
    const char *last_name;
    int is_dev;

    printf("%s\n"
           " D. = Demuxing supported\n"
           " .E = Muxing supported\n"
           " --\n", device_only ? "Devices:" : "File formats:");
    last_name = "000";
    for (;;) {
        int decode = 0;
        int encode = 0;
        const char *name      = NULL;
        const char *long_name = NULL;

        while ((ofmt = av_oformat_next(ofmt))) {
            is_dev = is_device(ofmt->priv_class);
            if (!is_dev && device_only)
                continue;
            if ((!name || strcmp(ofmt->name, name) < 0) &&
                strcmp(ofmt->name, last_name) > 0) {
                name      = ofmt->name;
                long_name = ofmt->long_name;
                encode    = 1;
            }
        }
        while ((ifmt = av_iformat_next(ifmt))) {
            is_dev = is_device(ifmt->priv_class);
            if (!is_dev && device_only)
                continue;
            if ((!name || strcmp(ifmt->name, name) < 0) &&
                strcmp(ifmt->name, last_name) > 0) {
                name      = ifmt->name;
                long_name = ifmt->long_name;
                encode    = 0;
            }
            if (name && strcmp(ifmt->name, name) == 0)
                decode = 1;
        }
        if (!name)
            break;
        last_name = name;

        printf(" %s%s %-15s %s\n",
               decode ? "D" : " ",
               encode ? "E" : " ",
               name,
            long_name ? long_name:" ");
    }
    return 0;
}

int show_formats(void *optctx, const char *opt, const char *arg)
{
    return show_formats_devices(optctx, opt, arg, 0);
}

int show_devices(void *optctx, const char *opt, const char *arg)
{
    return show_formats_devices(optctx, opt, arg, 1);
}

#define PRINT_CODEC_SUPPORTED(codec, field, type, list_name, term, get_name) \
    if (codec->field) {                                                      \
        const type *p = codec->field;                                        \
                                                                             \
        printf("    Supported " list_name ":");                              \
        while (*p != term) {                                                 \
            get_name(*p);                                                    \
            printf(" %s", name);                                             \
            p++;                                                             \
        }                                                                    \
        printf("\n");                                                        \
    }                                                                        \

static void print_codec(const AVCodec *c)
{
    int encoder = av_codec_is_encoder(c);

    printf("%s %s [%s]:\n", encoder ? "Encoder" : "Decoder", c->name,
           c->long_name ? c->long_name : "");

    if (c->type == AVMEDIA_TYPE_VIDEO ||
        c->type == AVMEDIA_TYPE_AUDIO) {
        printf("    Threading capabilities: ");
        switch (c->capabilities & (CODEC_CAP_FRAME_THREADS |
                                   CODEC_CAP_SLICE_THREADS)) {
        case CODEC_CAP_FRAME_THREADS |
             CODEC_CAP_SLICE_THREADS: printf("frame and slice"); break;
        case CODEC_CAP_FRAME_THREADS: printf("frame");           break;
        case CODEC_CAP_SLICE_THREADS: printf("slice");           break;
        default:                      printf("no");              break;
        }
        printf("\n");
    }

    if (c->supported_framerates) {
        const AVRational *fps = c->supported_framerates;

        printf("    Supported framerates:");
        while (fps->num) {
            printf(" %d/%d", fps->num, fps->den);
            fps++;
        }
        printf("\n");
    }
    PRINT_CODEC_SUPPORTED(c, pix_fmts, enum AVPixelFormat, "pixel formats",
                          AV_PIX_FMT_NONE, GET_PIX_FMT_NAME);
    PRINT_CODEC_SUPPORTED(c, supported_samplerates, int, "sample rates", 0,
                          GET_SAMPLE_RATE_NAME);
    PRINT_CODEC_SUPPORTED(c, sample_fmts, enum AVSampleFormat, "sample formats",
                          AV_SAMPLE_FMT_NONE, GET_SAMPLE_FMT_NAME);
    PRINT_CODEC_SUPPORTED(c, channel_layouts, uint64_t, "channel layouts",
                          0, GET_CH_LAYOUT_DESC);

    if (c->priv_class) {
        show_help_children(c->priv_class,
                           AV_OPT_FLAG_ENCODING_PARAM |
                           AV_OPT_FLAG_DECODING_PARAM);
    }
}

static char get_media_type_char(enum AVMediaType type)
{
    switch (type) {
        case AVMEDIA_TYPE_VIDEO:    return 'V';
        case AVMEDIA_TYPE_AUDIO:    return 'A';
        case AVMEDIA_TYPE_DATA:     return 'D';
        case AVMEDIA_TYPE_SUBTITLE: return 'S';
        case AVMEDIA_TYPE_ATTACHMENT:return 'T';
        default:                    return '?';
    }
}

static const AVCodec *next_codec_for_id(enum AVCodecID id, const AVCodec *prev,
                                        int encoder)
{
    while ((prev = av_codec_next(prev))) {
        if (prev->id == id &&
            (encoder ? av_codec_is_encoder(prev) : av_codec_is_decoder(prev)))
            return prev;
    }
    return NULL;
}

static int compare_codec_desc(const void *a, const void *b)
{
    const AVCodecDescriptor * const *da = a;
    const AVCodecDescriptor * const *db = b;

    return (*da)->type != (*db)->type ? (*da)->type - (*db)->type :
           strcmp((*da)->name, (*db)->name);
}

static unsigned get_codecs_sorted(const AVCodecDescriptor ***rcodecs)
{
    const AVCodecDescriptor *desc = NULL;
    const AVCodecDescriptor **codecs;
    unsigned nb_codecs = 0, i = 0;

    while ((desc = avcodec_descriptor_next(desc)))
        nb_codecs++;
    if (!(codecs = av_calloc(nb_codecs, sizeof(*codecs)))) {
        av_log(NULL, AV_LOG_ERROR, "Out of memory\n");
        exit_program(1);
    }
    desc = NULL;
    while ((desc = avcodec_descriptor_next(desc)))
        codecs[i++] = desc;
    av_assert0(i == nb_codecs);
    qsort(codecs, nb_codecs, sizeof(*codecs), compare_codec_desc);
    *rcodecs = codecs;
    return nb_codecs;
}

static void print_codecs_for_id(enum AVCodecID id, int encoder)
{
    const AVCodec *codec = NULL;

    printf(" (%s: ", encoder ? "encoders" : "decoders");

    while ((codec = next_codec_for_id(id, codec, encoder)))
        printf("%s ", codec->name);

    printf(")");
}

int show_codecs(void *optctx, const char *opt, const char *arg)
{
    const AVCodecDescriptor **codecs;
    unsigned i, nb_codecs = get_codecs_sorted(&codecs);

    printf("Codecs:\n"
           " D..... = Decoding supported\n"
           " .E.... = Encoding supported\n"
           " ..V... = Video codec\n"
           " ..A... = Audio codec\n"
           " ..S... = Subtitle codec\n"
           " ...I.. = Intra frame-only codec\n"
           " ....L. = Lossy compression\n"
           " .....S = Lossless compression\n"
           " -------\n");
    for (i = 0; i < nb_codecs; i++) {
        const AVCodecDescriptor *desc = codecs[i];
        const AVCodec *codec = NULL;

        if (strstr(desc->name, "_deprecated"))
            continue;

        printf(" ");
        printf(avcodec_find_decoder(desc->id) ? "D" : ".");
        printf(avcodec_find_encoder(desc->id) ? "E" : ".");

        printf("%c", get_media_type_char(desc->type));
        printf((desc->props & AV_CODEC_PROP_INTRA_ONLY) ? "I" : ".");
        printf((desc->props & AV_CODEC_PROP_LOSSY)      ? "L" : ".");
        printf((desc->props & AV_CODEC_PROP_LOSSLESS)   ? "S" : ".");

        printf(" %-20s %s", desc->name, desc->long_name ? desc->long_name : "");

        /* print decoders/encoders when there's more than one or their
         * names are different from codec name */
        while ((codec = next_codec_for_id(desc->id, codec, 0))) {
            if (strcmp(codec->name, desc->name)) {
                print_codecs_for_id(desc->id, 0);
                break;
            }
        }
        codec = NULL;
        while ((codec = next_codec_for_id(desc->id, codec, 1))) {
            if (strcmp(codec->name, desc->name)) {
                print_codecs_for_id(desc->id, 1);
                break;
            }
        }

        printf("\n");
    }
    av_free(codecs);
    return 0;
}

static void print_codecs(int encoder)
{
    const AVCodecDescriptor **codecs;
    unsigned i, nb_codecs = get_codecs_sorted(&codecs);

    printf("%s:\n"
           " V..... = Video\n"
           " A..... = Audio\n"
           " S..... = Subtitle\n"
           " .F.... = Frame-level multithreading\n"
           " ..S... = Slice-level multithreading\n"
           " ...X.. = Codec is experimental\n"
           " ....B. = Supports draw_horiz_band\n"
           " .....D = Supports direct rendering method 1\n"
           " ------\n",
           encoder ? "Encoders" : "Decoders");
    for (i = 0; i < nb_codecs; i++) {
        const AVCodecDescriptor *desc = codecs[i];
        const AVCodec *codec = NULL;

        while ((codec = next_codec_for_id(desc->id, codec, encoder))) {
            printf(" %c", get_media_type_char(desc->type));
            printf((codec->capabilities & CODEC_CAP_FRAME_THREADS) ? "F" : ".");
            printf((codec->capabilities & CODEC_CAP_SLICE_THREADS) ? "S" : ".");
            printf((codec->capabilities & CODEC_CAP_EXPERIMENTAL)  ? "X" : ".");
            printf((codec->capabilities & CODEC_CAP_DRAW_HORIZ_BAND)?"B" : ".");
            printf((codec->capabilities & CODEC_CAP_DR1)           ? "D" : ".");

            printf(" %-20s %s", codec->name, codec->long_name ? codec->long_name : "");
            if (strcmp(codec->name, desc->name))
                printf(" (codec %s)", desc->name);

            printf("\n");
        }
    }
    av_free(codecs);
}

int show_decoders(void *optctx, const char *opt, const char *arg)
{
    print_codecs(0);
    return 0;
}

int show_encoders(void *optctx, const char *opt, const char *arg)
{
    print_codecs(1);
    return 0;
}

int show_bsfs(void *optctx, const char *opt, const char *arg)
{
    AVBitStreamFilter *bsf = NULL;

    printf("Bitstream filters:\n");
    while ((bsf = av_bitstream_filter_next(bsf)))
        printf("%s\n", bsf->name);
    printf("\n");
    return 0;
}

int show_protocols(void *optctx, const char *opt, const char *arg)
{
    void *opaque = NULL;
    const char *name;

    printf("Supported file protocols:\n"
           "Input:\n");
    while ((name = avio_enum_protocols(&opaque, 0)))
        printf("%s\n", name);
    printf("Output:\n");
    while ((name = avio_enum_protocols(&opaque, 1)))
        printf("%s\n", name);
    return 0;
}

int show_filters(void *optctx, const char *opt, const char *arg)
{
#if CONFIG_AVFILTER
    const AVFilter *filter = NULL;
    char descr[64], *descr_cur;
    int i, j;
    const AVFilterPad *pad;

    printf("Filters:\n"
           "  T.. = Timeline support\n"
           "  .S. = Slice threading\n"
           "  ..C = Commmand support\n"
           "  A = Audio input/output\n"
           "  V = Video input/output\n"
           "  N = Dynamic number and/or type of input/output\n"
           "  | = Source or sink filter\n");
    while ((filter = avfilter_next(filter))) {
        descr_cur = descr;
        for (i = 0; i < 2; i++) {
            if (i) {
                *(descr_cur++) = '-';
                *(descr_cur++) = '>';
            }
            pad = i ? filter->outputs : filter->inputs;
            for (j = 0; pad && pad[j].name; j++) {
                if (descr_cur >= descr + sizeof(descr) - 4)
                    break;
                *(descr_cur++) = get_media_type_char(pad[j].type);
            }
            if (!j)
                *(descr_cur++) = ((!i && (filter->flags & AVFILTER_FLAG_DYNAMIC_INPUTS)) ||
                                  ( i && (filter->flags & AVFILTER_FLAG_DYNAMIC_OUTPUTS))) ? 'N' : '|';
        }
        *descr_cur = 0;
        printf(" %c%c%c %-16s %-10s %s\n",
               filter->flags & AVFILTER_FLAG_SUPPORT_TIMELINE ? 'T' : '.',
               filter->flags & AVFILTER_FLAG_SLICE_THREADS    ? 'S' : '.',
               filter->process_command                        ? 'C' : '.',
               filter->name, descr, filter->description);
    }
#else
    printf("No filters available: libavfilter disabled\n");
#endif
    return 0;
}

int show_colors(void *optctx, const char *opt, const char *arg)
{
    const char *name;
    const uint8_t *rgb;
    int i;

    printf("%-32s #RRGGBB\n", "name");

    for (i = 0; name = av_get_known_color_name(i, &rgb); i++)
        printf("%-32s #%02x%02x%02x\n", name, rgb[0], rgb[1], rgb[2]);

    return 0;
}

int show_pix_fmts(void *optctx, const char *opt, const char *arg)
{
    const AVPixFmtDescriptor *pix_desc = NULL;

    printf("Pixel formats:\n"
           "I.... = Supported Input  format for conversion\n"
           ".O... = Supported Output format for conversion\n"
           "..H.. = Hardware accelerated format\n"
           "...P. = Paletted format\n"
           "....B = Bitstream format\n"
           "FLAGS NAME            NB_COMPONENTS BITS_PER_PIXEL\n"
           "-----\n");

#if !CONFIG_SWSCALE
#   define sws_isSupportedInput(x)  0
#   define sws_isSupportedOutput(x) 0
#endif

    while ((pix_desc = av_pix_fmt_desc_next(pix_desc))) {
        enum AVPixelFormat pix_fmt = av_pix_fmt_desc_get_id(pix_desc);
        printf("%c%c%c%c%c %-16s       %d            %2d\n",
               sws_isSupportedInput (pix_fmt)              ? 'I' : '.',
               sws_isSupportedOutput(pix_fmt)              ? 'O' : '.',
               pix_desc->flags & AV_PIX_FMT_FLAG_HWACCEL   ? 'H' : '.',
               pix_desc->flags & AV_PIX_FMT_FLAG_PAL       ? 'P' : '.',
               pix_desc->flags & AV_PIX_FMT_FLAG_BITSTREAM ? 'B' : '.',
               pix_desc->name,
               pix_desc->nb_components,
               av_get_bits_per_pixel(pix_desc));
    }
    return 0;
}

int show_layouts(void *optctx, const char *opt, const char *arg)
{
    int i = 0;
    uint64_t layout, j;
    const char *name, *descr;

    printf("Individual channels:\n"
           "NAME           DESCRIPTION\n");
    for (i = 0; i < 63; i++) {
        name = av_get_channel_name((uint64_t)1 << i);
        if (!name)
            continue;
        descr = av_get_channel_description((uint64_t)1 << i);
        printf("%-14s %s\n", name, descr);
    }
    printf("\nStandard channel layouts:\n"
           "NAME           DECOMPOSITION\n");
    for (i = 0; !av_get_standard_channel_layout(i, &layout, &name); i++) {
        if (name) {
            printf("%-14s ", name);
            for (j = 1; j; j <<= 1)
                if ((layout & j))
                    printf("%s%s", (layout & (j - 1)) ? "+" : "", av_get_channel_name(j));
            printf("\n");
        }
    }
    return 0;
}

int show_sample_fmts(void *optctx, const char *opt, const char *arg)
{
    int i;
    char fmt_str[128];
    for (i = -1; i < AV_SAMPLE_FMT_NB; i++)
        printf("%s\n", av_get_sample_fmt_string(fmt_str, sizeof(fmt_str), i));
    return 0;
}

static void show_help_codec(const char *name, int encoder)
{
    const AVCodecDescriptor *desc;
    const AVCodec *codec;

    if (!name) {
        av_log(NULL, AV_LOG_ERROR, "No codec name specified.\n");
        return;
    }

    codec = encoder ? avcodec_find_encoder_by_name(name) :
                      avcodec_find_decoder_by_name(name);

    if (codec)
        print_codec(codec);
    else if ((desc = avcodec_descriptor_get_by_name(name))) {
        int printed = 0;

        while ((codec = next_codec_for_id(desc->id, codec, encoder))) {
            printed = 1;
            print_codec(codec);
        }

        if (!printed) {
            av_log(NULL, AV_LOG_ERROR, "Codec '%s' is known to FFmpeg, "
                   "but no %s for it are available. FFmpeg might need to be "
                   "recompiled with additional external libraries.\n",
                   name, encoder ? "encoders" : "decoders");
        }
    } else {
        av_log(NULL, AV_LOG_ERROR, "Codec '%s' is not recognized by FFmpeg.\n",
               name);
    }
}

static void show_help_demuxer(const char *name)
{
    const AVInputFormat *fmt = av_find_input_format(name);

    if (!fmt) {
        av_log(NULL, AV_LOG_ERROR, "Unknown format '%s'.\n", name);
        return;
    }

    printf("Demuxer %s [%s]:\n", fmt->name, fmt->long_name);

    if (fmt->extensions)
        printf("    Common extensions: %s.\n", fmt->extensions);

    if (fmt->priv_class)
        show_help_children(fmt->priv_class, AV_OPT_FLAG_DECODING_PARAM);
}

static void show_help_muxer(const char *name)
{
    const AVCodecDescriptor *desc;
    const AVOutputFormat *fmt = av_guess_format(name, NULL, NULL);

    if (!fmt) {
        av_log(NULL, AV_LOG_ERROR, "Unknown format '%s'.\n", name);
        return;
    }

    printf("Muxer %s [%s]:\n", fmt->name, fmt->long_name);

    if (fmt->extensions)
        printf("    Common extensions: %s.\n", fmt->extensions);
    if (fmt->mime_type)
        printf("    Mime type: %s.\n", fmt->mime_type);
    if (fmt->video_codec != AV_CODEC_ID_NONE &&
        (desc = avcodec_descriptor_get(fmt->video_codec))) {
        printf("    Default video codec: %s.\n", desc->name);
    }
    if (fmt->audio_codec != AV_CODEC_ID_NONE &&
        (desc = avcodec_descriptor_get(fmt->audio_codec))) {
        printf("    Default audio codec: %s.\n", desc->name);
    }
    if (fmt->subtitle_codec != AV_CODEC_ID_NONE &&
        (desc = avcodec_descriptor_get(fmt->subtitle_codec))) {
        printf("    Default subtitle codec: %s.\n", desc->name);
    }

    if (fmt->priv_class)
        show_help_children(fmt->priv_class, AV_OPT_FLAG_ENCODING_PARAM);
}

#if CONFIG_AVFILTER
static void show_help_filter(const char *name)
{
#if CONFIG_AVFILTER
    const AVFilter *f = avfilter_get_by_name(name);
    int i, count;

    if (!name) {
        av_log(NULL, AV_LOG_ERROR, "No filter name specified.\n");
        return;
    } else if (!f) {
        av_log(NULL, AV_LOG_ERROR, "Unknown filter '%s'.\n", name);
        return;
    }

    printf("Filter %s\n", f->name);
    if (f->description)
        printf("  %s\n", f->description);

    if (f->flags & AVFILTER_FLAG_SLICE_THREADS)
        printf("    slice threading supported\n");

    printf("    Inputs:\n");
    count = avfilter_pad_count(f->inputs);
    for (i = 0; i < count; i++) {
        printf("       #%d: %s (%s)\n", i, avfilter_pad_get_name(f->inputs, i),
               media_type_string(avfilter_pad_get_type(f->inputs, i)));
    }
    if (f->flags & AVFILTER_FLAG_DYNAMIC_INPUTS)
        printf("        dynamic (depending on the options)\n");
    else if (!count)
        printf("        none (source filter)\n");

    printf("    Outputs:\n");
    count = avfilter_pad_count(f->outputs);
    for (i = 0; i < count; i++) {
        printf("       #%d: %s (%s)\n", i, avfilter_pad_get_name(f->outputs, i),
               media_type_string(avfilter_pad_get_type(f->outputs, i)));
    }
    if (f->flags & AVFILTER_FLAG_DYNAMIC_OUTPUTS)
        printf("        dynamic (depending on the options)\n");
    else if (!count)
        printf("        none (sink filter)\n");

    if (f->priv_class)
        show_help_children(f->priv_class, AV_OPT_FLAG_VIDEO_PARAM | AV_OPT_FLAG_FILTERING_PARAM |
                                          AV_OPT_FLAG_AUDIO_PARAM);
    if (f->flags & AVFILTER_FLAG_SUPPORT_TIMELINE)
        printf("This filter has support for timeline through the 'enable' option.\n");
#else
    av_log(NULL, AV_LOG_ERROR, "Build without libavfilter; "
           "can not to satisfy request\n");
#endif
}
#endif

int show_help(void *optctx, const char *opt, const char *arg)
{
    char *topic, *par;
    av_log_set_callback(log_callback_help);

    topic = av_strdup(arg ? arg : "");
    par = strchr(topic, '=');
    if (par)
        *par++ = 0;

    if (!*topic) {
        show_help_default(topic, par);
    } else if (!strcmp(topic, "decoder")) {
        show_help_codec(par, 0);
    } else if (!strcmp(topic, "encoder")) {
        show_help_codec(par, 1);
    } else if (!strcmp(topic, "demuxer")) {
        show_help_demuxer(par);
    } else if (!strcmp(topic, "muxer")) {
        show_help_muxer(par);
#if CONFIG_AVFILTER
    } else if (!strcmp(topic, "filter")) {
        show_help_filter(par);
#endif
    } else {
        show_help_default(topic, par);
    }

    av_freep(&topic);
    return 0;
}

int read_yesno(void)
{
    int c = getchar();
    int yesno = (av_toupper(c) == 'Y');

    while (c != '\n' && c != EOF)
        c = getchar();

    return yesno;
}

int cmdutils_read_file(const char *filename, char **bufptr, size_t *size)
{
    int ret;
    FILE *f = av_fopen_utf8(filename, "rb");

    if (!f) {
        ret = AVERROR(errno);
        av_log(NULL, AV_LOG_ERROR, "Cannot read file '%s': %s\n", filename,
               strerror(errno));
        return ret;
    }
    fseek(f, 0, SEEK_END);
    *size = ftell(f);
    fseek(f, 0, SEEK_SET);
    if (*size == (size_t)-1) {
        ret = AVERROR(errno);
        av_log(NULL, AV_LOG_ERROR, "IO error: %s\n", strerror(errno));
        fclose(f);
        return ret;
    }
    *bufptr = av_malloc(*size + 1);
    if (!*bufptr) {
        av_log(NULL, AV_LOG_ERROR, "Could not allocate file buffer\n");
        fclose(f);
        return AVERROR(ENOMEM);
    }
    ret = fread(*bufptr, 1, *size, f);
    if (ret < *size) {
        av_free(*bufptr);
        if (ferror(f)) {
            ret = AVERROR(errno);
            av_log(NULL, AV_LOG_ERROR, "Error while reading file '%s': %s\n",
                   filename, strerror(errno));
        } else
            ret = AVERROR_EOF;
    } else {
        ret = 0;
        (*bufptr)[(*size)++] = '\0';
    }

    fclose(f);
    return ret;
}

FILE *get_preset_file(char *filename, size_t filename_size,
                      const char *preset_name, int is_path,
                      const char *codec_name)
{
    FILE *f = NULL;
    int i;
    const char *base[3] = { getenv("FFMPEG_DATADIR"),
                            getenv("HOME"),
                            FFMPEG_DATADIR, };

    if (is_path) {
        av_strlcpy(filename, preset_name, filename_size);
        f = fopen(filename, "r");
    } else {
#ifdef _WIN32
        char datadir[MAX_PATH], *ls;
        base[2] = NULL;

        if (GetModuleFileNameA(GetModuleHandleA(NULL), datadir, sizeof(datadir) - 1))
        {
            for (ls = datadir; ls < datadir + strlen(datadir); ls++)
                if (*ls == '\\') *ls = '/';

            if (ls = strrchr(datadir, '/'))
            {
                *ls = 0;
                strncat(datadir, "/ffpresets",  sizeof(datadir) - 1 - strlen(datadir));
                base[2] = datadir;
            }
        }
#endif
        for (i = 0; i < 3 && !f; i++) {
            if (!base[i])
                continue;
            snprintf(filename, filename_size, "%s%s/%s.ffpreset", base[i],
                     i != 1 ? "" : "/.ffmpeg", preset_name);
            f = fopen(filename, "r");
            if (!f && codec_name) {
                snprintf(filename, filename_size,
                         "%s%s/%s-%s.ffpreset",
                         base[i], i != 1 ? "" : "/.ffmpeg", codec_name,
                         preset_name);
                f = fopen(filename, "r");
            }
        }
    }

    return f;
}

int check_stream_specifier(AVFormatContext *s, AVStream *st, const char *spec)
{
    int ret = avformat_match_stream_specifier(s, st, spec);
    if (ret < 0)
        av_log(s, AV_LOG_ERROR, "Invalid stream specifier: %s.\n", spec);
    return ret;
}

AVDictionary *filter_codec_opts(AVDictionary *opts, enum AVCodecID codec_id,
                                AVFormatContext *s, AVStream *st, AVCodec *codec)
{
    AVDictionary    *ret = NULL;
    AVDictionaryEntry *t = NULL;
    int            flags = s->oformat ? AV_OPT_FLAG_ENCODING_PARAM
                                      : AV_OPT_FLAG_DECODING_PARAM;
    char          prefix = 0;
    const AVClass    *cc = avcodec_get_class();

    if (!codec)
        codec            = s->oformat ? avcodec_find_encoder(codec_id)
                                      : avcodec_find_decoder(codec_id);

    switch (st->codec->codec_type) {
    case AVMEDIA_TYPE_VIDEO:
        prefix  = 'v';
        flags  |= AV_OPT_FLAG_VIDEO_PARAM;
        break;
    case AVMEDIA_TYPE_AUDIO:
        prefix  = 'a';
        flags  |= AV_OPT_FLAG_AUDIO_PARAM;
        break;
    case AVMEDIA_TYPE_SUBTITLE:
        prefix  = 's';
        flags  |= AV_OPT_FLAG_SUBTITLE_PARAM;
        break;
    }

    while (t = av_dict_get(opts, "", t, AV_DICT_IGNORE_SUFFIX)) {
        char *p = strchr(t->key, ':');

        /* check stream specification in opt name */
        if (p)
            switch (check_stream_specifier(s, st, p + 1)) {
            case  1: *p = 0; break;
            case  0:         continue;
            default:         exit_program(1);