ffmpeg_opt.c

/*
 * ffmpeg option parsing
 *
 * This file is part of FFmpeg.
 *
 * FFmpeg is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public
 * License as published by the Free Software Foundation; either
 * version 2.1 of the License, or (at your option) any later version.
 *
 * FFmpeg is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public
 * License along with FFmpeg; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
 */

#include <stdint.h>

#include "ffmpeg.h"
#include "cmdutils.h"

#include "libavformat/avformat.h"

#include "libavcodec/avcodec.h"

#include "libavfilter/avfilter.h"

#include "libavutil/avassert.h"
#include "libavutil/avstring.h"
#include "libavutil/avutil.h"
#include "libavutil/channel_layout.h"
#include "libavutil/intreadwrite.h"
#include "libavutil/fifo.h"
#include "libavutil/mathematics.h"
#include "libavutil/opt.h"
#include "libavutil/parseutils.h"
#include "libavutil/pixdesc.h"
#include "libavutil/pixfmt.h"

#define MATCH_PER_STREAM_OPT(name, type, outvar, fmtctx, st)\
{\
    int i, ret;\
    for (i = 0; i < o->nb_ ## name; i++) {\
        char *spec = o->name[i].specifier;\
        if ((ret = check_stream_specifier(fmtctx, st, spec)) > 0)\
            outvar = o->name[i].u.type;\
        else if (ret < 0)\
            exit_program(1);\
    }\
}

#define MATCH_PER_TYPE_OPT(name, type, outvar, fmtctx, mediatype)\
{\
    int i;\
    for (i = 0; i < o->nb_ ## name; i++) {\
        char *spec = o->name[i].specifier;\
        if (!strcmp(spec, mediatype))\
            outvar = o->name[i].u.type;\
    }\
}

const HWAccel hwaccels[] = {
#if HAVE_VDPAU_X11
    { "vdpau", vdpau_init, HWACCEL_VDPAU, AV_PIX_FMT_VDPAU },
#endif
#if HAVE_DXVA2_LIB
    { "dxva2", dxva2_init, HWACCEL_DXVA2, AV_PIX_FMT_DXVA2_VLD },
#endif
#if CONFIG_VDA
    { "vda",   vda_init,   HWACCEL_VDA,   AV_PIX_FMT_VDA },
#endif
    { 0 },
};

char *vstats_filename;

float audio_drift_threshold = 0.1;
float dts_delta_threshold   = 10;
float dts_error_threshold   = 3600*30;

int audio_volume      = 256;
int audio_sync_method = 0;
int video_sync_method = VSYNC_AUTO;
int do_deinterlace    = 0;
int do_benchmark      = 0;
int do_benchmark_all  = 0;
int do_hex_dump       = 0;
int do_pkt_dump       = 0;
int copy_ts           = 0;
int copy_tb           = -1;
int debug_ts          = 0;
int exit_on_error     = 0;
int print_stats       = -1;
int qp_hist           = 0;
int stdin_interaction = 1;
int frame_bits_per_raw_sample = 0;
float max_error_rate  = 2.0/3;


static int intra_only         = 0;
static int file_overwrite     = 0;
static int no_file_overwrite  = 0;
static int intra_dc_precision = 8;
static int do_psnr            = 0;
static int input_sync;
static int override_ffserver  = 0;

static void uninit_options(OptionsContext *o)
{
    const OptionDef *po = options;
    int i;

    /* all OPT_SPEC and OPT_STRING can be freed in generic way */
    while (po->name) {
        void *dst = (uint8_t*)o + po->u.off;

        if (po->flags & OPT_SPEC) {
            SpecifierOpt **so = dst;
            int i, *count = (int*)(so + 1);
            for (i = 0; i < *count; i++) {
                av_freep(&(*so)[i].specifier);
                if (po->flags & OPT_STRING)
                    av_freep(&(*so)[i].u.str);
            }
            av_freep(so);
            *count = 0;
        } else if (po->flags & OPT_OFFSET && po->flags & OPT_STRING)
            av_freep(dst);
        po++;
    }

    for (i = 0; i < o->nb_stream_maps; i++)
        av_freep(&o->stream_maps[i].linklabel);
    av_freep(&o->stream_maps);
    av_freep(&o->audio_channel_maps);
    av_freep(&o->streamid_map);
    av_freep(&o->attachments);
}

static void init_options(OptionsContext *o)
{
    memset(o, 0, sizeof(*o));

    o->stop_time = INT64_MAX;
    o->mux_max_delay  = 0.7;
    o->start_time     = AV_NOPTS_VALUE;
    o->recording_time = INT64_MAX;
    o->limit_filesize = UINT64_MAX;
    o->chapters_input_file = INT_MAX;
    o->accurate_seek  = 1;
}

/* return a copy of the input with the stream specifiers removed from the keys */
static AVDictionary *strip_specifiers(AVDictionary *dict)
{
    AVDictionaryEntry *e = NULL;
    AVDictionary    *ret = NULL;

    while ((e = av_dict_get(dict, "", e, AV_DICT_IGNORE_SUFFIX))) {
        char *p = strchr(e->key, ':');

        if (p)
            *p = 0;
        av_dict_set(&ret, e->key, e->value, 0);
        if (p)
            *p = ':';
    }
    return ret;
}

static int opt_sameq(void *optctx, const char *opt, const char *arg)
{
    av_log(NULL, AV_LOG_ERROR, "Option '%s' was removed. "
           "If you are looking for an option to preserve the quality (which is not "
           "what -%s was for), use -qscale 0 or an equivalent quality factor option.\n",
           opt, opt);
    return AVERROR(EINVAL);
}

static int opt_video_channel(void *optctx, const char *opt, const char *arg)
{
    av_log(NULL, AV_LOG_WARNING, "This option is deprecated, use -channel.\n");
    return opt_default(optctx, "channel", arg);
}

static int opt_video_standard(void *optctx, const char *opt, const char *arg)
{
    av_log(NULL, AV_LOG_WARNING, "This option is deprecated, use -standard.\n");
    return opt_default(optctx, "standard", arg);
}

static int opt_audio_codec(void *optctx, const char *opt, const char *arg)
{
    OptionsContext *o = optctx;
    return parse_option(o, "codec:a", arg, options);
}

static int opt_video_codec(void *optctx, const char *opt, const char *arg)
{
    OptionsContext *o = optctx;
    return parse_option(o, "codec:v", arg, options);
}

static int opt_subtitle_codec(void *optctx, const char *opt, const char *arg)
{
    OptionsContext *o = optctx;
    return parse_option(o, "codec:s", arg, options);
}

static int opt_data_codec(void *optctx, const char *opt, const char *arg)
{
    OptionsContext *o = optctx;
    return parse_option(o, "codec:d", arg, options);
}

static int opt_map(void *optctx, const char *opt, const char *arg)
{
    OptionsContext *o = optctx;
    StreamMap *m = NULL;
    int i, negative = 0, file_idx;
    int sync_file_idx = -1, sync_stream_idx = 0;
    char *p, *sync;
    char *map;

    if (*arg == '-') {
        negative = 1;
        arg++;
    }
    map = av_strdup(arg);

    /* parse sync stream first, just pick first matching stream */
    if (sync = strchr(map, ',')) {
        *sync = 0;
        sync_file_idx = strtol(sync + 1, &sync, 0);
        if (sync_file_idx >= nb_input_files || sync_file_idx < 0) {
            av_log(NULL, AV_LOG_FATAL, "Invalid sync file index: %d.\n", sync_file_idx);
            exit_program(1);
        }
        if (*sync)
            sync++;
        for (i = 0; i < input_files[sync_file_idx]->nb_streams; i++)
            if (check_stream_specifier(input_files[sync_file_idx]->ctx,
                                       input_files[sync_file_idx]->ctx->streams[i], sync) == 1) {
                sync_stream_idx = i;
                break;
            }
        if (i == input_files[sync_file_idx]->nb_streams) {
            av_log(NULL, AV_LOG_FATAL, "Sync stream specification in map %s does not "
                                       "match any streams.\n", arg);
            exit_program(1);
        }
    }


    if (map[0] == '[') {
        /* this mapping refers to lavfi output */
        const char *c = map + 1;
        GROW_ARRAY(o->stream_maps, o->nb_stream_maps);
        m = &o->stream_maps[o->nb_stream_maps - 1];
        m->linklabel = av_get_token(&c, "]");
        if (!m->linklabel) {
            av_log(NULL, AV_LOG_ERROR, "Invalid output link label: %s.\n", map);
            exit_program(1);
        }
    } else {
        file_idx = strtol(map, &p, 0);
        if (file_idx >= nb_input_files || file_idx < 0) {
            av_log(NULL, AV_LOG_FATAL, "Invalid input file index: %d.\n", file_idx);
            exit_program(1);
        }
        if (negative)
            /* disable some already defined maps */
            for (i = 0; i < o->nb_stream_maps; i++) {
                m = &o->stream_maps[i];
                if (file_idx == m->file_index &&
                    check_stream_specifier(input_files[m->file_index]->ctx,
                                           input_files[m->file_index]->ctx->streams[m->stream_index],
                                           *p == ':' ? p + 1 : p) > 0)
                    m->disabled = 1;
            }
        else
            for (i = 0; i < input_files[file_idx]->nb_streams; i++) {
                if (check_stream_specifier(input_files[file_idx]->ctx, input_files[file_idx]->ctx->streams[i],
                            *p == ':' ? p + 1 : p) <= 0)
                    continue;
                GROW_ARRAY(o->stream_maps, o->nb_stream_maps);
                m = &o->stream_maps[o->nb_stream_maps - 1];

                m->file_index   = file_idx;
                m->stream_index = i;

                if (sync_file_idx >= 0) {
                    m->sync_file_index   = sync_file_idx;
                    m->sync_stream_index = sync_stream_idx;
                } else {
                    m->sync_file_index   = file_idx;
                    m->sync_stream_index = i;
                }
            }
    }

    if (!m) {
        av_log(NULL, AV_LOG_FATAL, "Stream map '%s' matches no streams.\n", arg);
        exit_program(1);
    }

    av_freep(&map);
    return 0;
}

static int opt_attach(void *optctx, const char *opt, const char *arg)
{
    OptionsContext *o = optctx;
    GROW_ARRAY(o->attachments, o->nb_attachments);
    o->attachments[o->nb_attachments - 1] = arg;
    return 0;
}

static int opt_map_channel(void *optctx, const char *opt, const char *arg)
{
    OptionsContext *o = optctx;
    int n;
    AVStream *st;
    AudioChannelMap *m;

    GROW_ARRAY(o->audio_channel_maps, o->nb_audio_channel_maps);
    m = &o->audio_channel_maps[o->nb_audio_channel_maps - 1];

    /* muted channel syntax */
    n = sscanf(arg, "%d:%d.%d", &m->channel_idx, &m->ofile_idx, &m->ostream_idx);
    if ((n == 1 || n == 3) && m->channel_idx == -1) {
        m->file_idx = m->stream_idx = -1;
        if (n == 1)
            m->ofile_idx = m->ostream_idx = -1;
        return 0;
    }

    /* normal syntax */
    n = sscanf(arg, "%d.%d.%d:%d.%d",
               &m->file_idx,  &m->stream_idx, &m->channel_idx,
               &m->ofile_idx, &m->ostream_idx);

    if (n != 3 && n != 5) {
        av_log(NULL, AV_LOG_FATAL, "Syntax error, mapchan usage: "
               "[file.stream.channel|-1][:syncfile:syncstream]\n");
        exit_program(1);
    }

    if (n != 5) // only file.stream.channel specified
        m->ofile_idx = m->ostream_idx = -1;

    /* check input */
    if (m->file_idx < 0 || m->file_idx >= nb_input_files) {
        av_log(NULL, AV_LOG_FATAL, "mapchan: invalid input file index: %d\n",
               m->file_idx);
        exit_program(1);
    }
    if (m->stream_idx < 0 ||
        m->stream_idx >= input_files[m->file_idx]->nb_streams) {
        av_log(NULL, AV_LOG_FATAL, "mapchan: invalid input file stream index #%d.%d\n",
               m->file_idx, m->stream_idx);
        exit_program(1);
    }
    st = input_files[m->file_idx]->ctx->streams[m->stream_idx];
    if (st->codec->codec_type != AVMEDIA_TYPE_AUDIO) {
        av_log(NULL, AV_LOG_FATAL, "mapchan: stream #%d.%d is not an audio stream.\n",
               m->file_idx, m->stream_idx);
        exit_program(1);
    }
    if (m->channel_idx < 0 || m->channel_idx >= st->codec->channels) {
        av_log(NULL, AV_LOG_FATAL, "mapchan: invalid audio channel #%d.%d.%d\n",
               m->file_idx, m->stream_idx, m->channel_idx);
        exit_program(1);
    }
    return 0;
}

/**
 * Parse a metadata specifier passed as 'arg' parameter.
 * @param arg  metadata string to parse
 * @param type metadata type is written here -- g(lobal)/s(tream)/c(hapter)/p(rogram)
 * @param index for type c/p, chapter/program index is written here
 * @param stream_spec for type s, the stream specifier is written here
 */
static void parse_meta_type(char *arg, char *type, int *index, const char **stream_spec)
{
    if (*arg) {
        *type = *arg;
        switch (*arg) {
        case 'g':
            break;
        case 's':
            if (*(++arg) && *arg != ':') {
                av_log(NULL, AV_LOG_FATAL, "Invalid metadata specifier %s.\n", arg);
                exit_program(1);
            }
            *stream_spec = *arg == ':' ? arg + 1 : "";
            break;
        case 'c':
        case 'p':
            if (*(++arg) == ':')
                *index = strtol(++arg, NULL, 0);
            break;
        default:
            av_log(NULL, AV_LOG_FATAL, "Invalid metadata type %c.\n", *arg);
            exit_program(1);
        }
    } else
        *type = 'g';
}

static int copy_metadata(char *outspec, char *inspec, AVFormatContext *oc, AVFormatContext *ic, OptionsContext *o)
{
    AVDictionary **meta_in = NULL;
    AVDictionary **meta_out = NULL;
    int i, ret = 0;
    char type_in, type_out;
    const char *istream_spec = NULL, *ostream_spec = NULL;
    int idx_in = 0, idx_out = 0;

    parse_meta_type(inspec,  &type_in,  &idx_in,  &istream_spec);
    parse_meta_type(outspec, &type_out, &idx_out, &ostream_spec);

    if (!ic) {
        if (type_out == 'g' || !*outspec)
            o->metadata_global_manual = 1;
        if (type_out == 's' || !*outspec)
            o->metadata_streams_manual = 1;
        if (type_out == 'c' || !*outspec)
            o->metadata_chapters_manual = 1;
        return 0;
    }

    if (type_in == 'g' || type_out == 'g')
        o->metadata_global_manual = 1;
    if (type_in == 's' || type_out == 's')
        o->metadata_streams_manual = 1;
    if (type_in == 'c' || type_out == 'c')
        o->metadata_chapters_manual = 1;

    /* ic is NULL when just disabling automatic mappings */
    if (!ic)
        return 0;

#define METADATA_CHECK_INDEX(index, nb_elems, desc)\
    if ((index) < 0 || (index) >= (nb_elems)) {\
        av_log(NULL, AV_LOG_FATAL, "Invalid %s index %d while processing metadata maps.\n",\
                (desc), (index));\
        exit_program(1);\
    }

#define SET_DICT(type, meta, context, index)\
        switch (type) {\
        case 'g':\
            meta = &context->metadata;\
            break;\
        case 'c':\
            METADATA_CHECK_INDEX(index, context->nb_chapters, "chapter")\
            meta = &context->chapters[index]->metadata;\
            break;\
        case 'p':\
            METADATA_CHECK_INDEX(index, context->nb_programs, "program")\
            meta = &context->programs[index]->metadata;\
            break;\
        case 's':\
            break; /* handled separately below */ \
        default: av_assert0(0);\
        }\

    SET_DICT(type_in, meta_in, ic, idx_in);
    SET_DICT(type_out, meta_out, oc, idx_out);

    /* for input streams choose first matching stream */
    if (type_in == 's') {
        for (i = 0; i < ic->nb_streams; i++) {
            if ((ret = check_stream_specifier(ic, ic->streams[i], istream_spec)) > 0) {
                meta_in = &ic->streams[i]->metadata;
                break;
            } else if (ret < 0)
                exit_program(1);
        }
        if (!meta_in) {
            av_log(NULL, AV_LOG_FATAL, "Stream specifier %s does not match  any streams.\n", istream_spec);
            exit_program(1);
        }
    }

    if (type_out == 's') {
        for (i = 0; i < oc->nb_streams; i++) {
            if ((ret = check_stream_specifier(oc, oc->streams[i], ostream_spec)) > 0) {
                meta_out = &oc->streams[i]->metadata;
                av_dict_copy(meta_out, *meta_in, AV_DICT_DONT_OVERWRITE);
            } else if (ret < 0)
                exit_program(1);
        }
    } else
        av_dict_copy(meta_out, *meta_in, AV_DICT_DONT_OVERWRITE);

    return 0;
}

static int opt_recording_timestamp(void *optctx, const char *opt, const char *arg)
{
    OptionsContext *o = optctx;
    char buf[128];
    int64_t recording_timestamp = parse_time_or_die(opt, arg, 0) / 1E6;
    struct tm time = *gmtime((time_t*)&recording_timestamp);
    strftime(buf, sizeof(buf), "creation_time=%FT%T%z", &time);
    parse_option(o, "metadata", buf, options);

    av_log(NULL, AV_LOG_WARNING, "%s is deprecated, set the 'creation_time' metadata "
                                 "tag instead.\n", opt);
    return 0;
}

static AVCodec *find_codec_or_die(const char *name, enum AVMediaType type, int encoder)
{
    const AVCodecDescriptor *desc;
    const char *codec_string = encoder ? "encoder" : "decoder";
    AVCodec *codec;

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

    if (!codec && (desc = avcodec_descriptor_get_by_name(name))) {
        codec = encoder ? avcodec_find_encoder(desc->id) :
                          avcodec_find_decoder(desc->id);
        if (codec)
            av_log(NULL, AV_LOG_VERBOSE, "Matched %s '%s' for codec '%s'.\n",
                   codec_string, codec->name, desc->name);
    }

    if (!codec) {
        av_log(NULL, AV_LOG_FATAL, "Unknown %s '%s'\n", codec_string, name);
        exit_program(1);
    }
    if (codec->type != type) {
        av_log(NULL, AV_LOG_FATAL, "Invalid %s type '%s'\n", codec_string, name);
        exit_program(1);
    }
    return codec;
}

static AVCodec *choose_decoder(OptionsContext *o, AVFormatContext *s, AVStream *st)
{
    char *codec_name = NULL;

    MATCH_PER_STREAM_OPT(codec_names, str, codec_name, s, st);
    if (codec_name) {
        AVCodec *codec = find_codec_or_die(codec_name, st->codec->codec_type, 0);
        st->codec->codec_id = codec->id;
        return codec;
    } else
        return avcodec_find_decoder(st->codec->codec_id);
}

/* Add all the streams from the given input file to the global
 * list of input streams. */
static void add_input_streams(OptionsContext *o, AVFormatContext *ic)
{
    int i, ret;

    for (i = 0; i < ic->nb_streams; i++) {
        AVStream *st = ic->streams[i];
        AVCodecContext *dec = st->codec;
        InputStream *ist = av_mallocz(sizeof(*ist));
        char *framerate = NULL, *hwaccel = NULL, *hwaccel_device = NULL;
        char *codec_tag = NULL;
        char *next;
        char *discard_str = NULL;
        const AVOption *discard_opt = av_opt_find(dec, "skip_frame", NULL, 0, 0);

        if (!ist)
            exit_program(1);

        GROW_ARRAY(input_streams, nb_input_streams);
        input_streams[nb_input_streams - 1] = ist;

        ist->st = st;
        ist->file_index = nb_input_files;
        ist->discard = 1;
        st->discard  = AVDISCARD_ALL;

        ist->ts_scale = 1.0;
        MATCH_PER_STREAM_OPT(ts_scale, dbl, ist->ts_scale, ic, st);

        MATCH_PER_STREAM_OPT(codec_tags, str, codec_tag, ic, st);
        if (codec_tag) {
            uint32_t tag = strtol(codec_tag, &next, 0);
            if (*next)
                tag = AV_RL32(codec_tag);
            st->codec->codec_tag = tag;
        }

        ist->dec = choose_decoder(o, ic, st);
        ist->decoder_opts = filter_codec_opts(o->g->codec_opts, ist->st->codec->codec_id, ic, st, ist->dec);

        ist->reinit_filters = -1;
        MATCH_PER_STREAM_OPT(reinit_filters, i, ist->reinit_filters, ic, st);

        MATCH_PER_STREAM_OPT(discard, str, discard_str, ic, st);
        ist->user_set_discard = AVDISCARD_NONE;
        if (discard_str && av_opt_eval_int(dec, discard_opt, discard_str, &ist->user_set_discard) < 0) {
            av_log(NULL, AV_LOG_ERROR, "Error parsing discard %s.\n",
                    discard_str);
            exit_program(1);
        }

        ist->filter_in_rescale_delta_last = AV_NOPTS_VALUE;

        ist->dec_ctx = avcodec_alloc_context3(ist->dec);
        if (!ist->dec_ctx) {
            av_log(NULL, AV_LOG_ERROR, "Error allocating the decoder context.\n");
            exit_program(1);
        }

        ret = avcodec_copy_context(ist->dec_ctx, dec);
        if (ret < 0) {
            av_log(NULL, AV_LOG_ERROR, "Error initializing the decoder context.\n");
            exit_program(1);
        }

        switch (dec->codec_type) {
        case AVMEDIA_TYPE_VIDEO:
            if(!ist->dec)
                ist->dec = avcodec_find_decoder(dec->codec_id);
            if (av_codec_get_lowres(dec)) {
                dec->flags |= CODEC_FLAG_EMU_EDGE;
            }

            ist->resample_height  = ist->dec_ctx->height;
            ist->resample_width   = ist->dec_ctx->width;
            ist->resample_pix_fmt = ist->dec_ctx->pix_fmt;

            MATCH_PER_STREAM_OPT(frame_rates, str, framerate, ic, st);
            if (framerate && av_parse_video_rate(&ist->framerate,
                                                 framerate) < 0) {
                av_log(NULL, AV_LOG_ERROR, "Error parsing framerate %s.\n",
                       framerate);
                exit_program(1);
            }

            ist->top_field_first = -1;
            MATCH_PER_STREAM_OPT(top_field_first, i, ist->top_field_first, ic, st);

            MATCH_PER_STREAM_OPT(hwaccels, str, hwaccel, ic, st);
            if (hwaccel) {
                if (!strcmp(hwaccel, "none"))
                    ist->hwaccel_id = HWACCEL_NONE;
                else if (!strcmp(hwaccel, "auto"))
                    ist->hwaccel_id = HWACCEL_AUTO;
                else {
                    int i;
                    for (i = 0; hwaccels[i].name; i++) {
                        if (!strcmp(hwaccels[i].name, hwaccel)) {
                            ist->hwaccel_id = hwaccels[i].id;
                            break;
                        }
                    }

                    if (!ist->hwaccel_id) {
                        av_log(NULL, AV_LOG_FATAL, "Unrecognized hwaccel: %s.\n",
                               hwaccel);
                        av_log(NULL, AV_LOG_FATAL, "Supported hwaccels: ");
                        for (i = 0; hwaccels[i].name; i++)
                            av_log(NULL, AV_LOG_FATAL, "%s ", hwaccels[i].name);
                        av_log(NULL, AV_LOG_FATAL, "\n");
                        exit_program(1);
                    }
                }
            }

            MATCH_PER_STREAM_OPT(hwaccel_devices, str, hwaccel_device, ic, st);
            if (hwaccel_device) {
                ist->hwaccel_device = av_strdup(hwaccel_device);
                if (!ist->hwaccel_device)
                    exit_program(1);
            }
            ist->hwaccel_pix_fmt = AV_PIX_FMT_NONE;

            break;
        case AVMEDIA_TYPE_AUDIO:
            ist->guess_layout_max = INT_MAX;
            MATCH_PER_STREAM_OPT(guess_layout_max, i, ist->guess_layout_max, ic, st);
            guess_input_channel_layout(ist);

            ist->resample_sample_fmt     = ist->dec_ctx->sample_fmt;
            ist->resample_sample_rate    = ist->dec_ctx->sample_rate;
            ist->resample_channels       = ist->dec_ctx->channels;
            ist->resample_channel_layout = ist->dec_ctx->channel_layout;

            break;
        case AVMEDIA_TYPE_DATA:
        case AVMEDIA_TYPE_SUBTITLE: {
            char *canvas_size = NULL;
            if(!ist->dec)
                ist->dec = avcodec_find_decoder(dec->codec_id);
            MATCH_PER_STREAM_OPT(fix_sub_duration, i, ist->fix_sub_duration, ic, st);
            MATCH_PER_STREAM_OPT(canvas_sizes, str, canvas_size, ic, st);
            if (canvas_size &&
                av_parse_video_size(&dec->width, &dec->height, canvas_size) < 0) {
                av_log(NULL, AV_LOG_FATAL, "Invalid canvas size: %s.\n", canvas_size);
                exit_program(1);
            }
            break;
        }
        case AVMEDIA_TYPE_ATTACHMENT:
        case AVMEDIA_TYPE_UNKNOWN:
            break;
        default:
            abort();
        }
    }
}

static void assert_file_overwrite(const char *filename)
{
    if (file_overwrite && no_file_overwrite) {
        fprintf(stderr, "Error, both -y and -n supplied. Exiting.\n");
        exit_program(1);
    }

    if (!file_overwrite) {
        const char *proto_name = avio_find_protocol_name(filename);
        if (proto_name && !strcmp(proto_name, "file") && avio_check(filename, 0) == 0) {
            if (stdin_interaction && !no_file_overwrite) {
                fprintf(stderr,"File '%s' already exists. Overwrite ? [y/N] ", filename);
                fflush(stderr);
                term_exit();
                signal(SIGINT, SIG_DFL);
                if (!read_yesno()) {
                    av_log(NULL, AV_LOG_FATAL, "Not overwriting - exiting\n");
                    exit_program(1);
                }
                term_init();
            }
            else {
                av_log(NULL, AV_LOG_FATAL, "File '%s' already exists. Exiting.\n", filename);
                exit_program(1);
            }
        }
    }
}

static void dump_attachment(AVStream *st, const char *filename)
{
    int ret;
    AVIOContext *out = NULL;
    AVDictionaryEntry *e;

    if (!st->codec->extradata_size) {
        av_log(NULL, AV_LOG_WARNING, "No extradata to dump in stream #%d:%d.\n",
               nb_input_files - 1, st->index);
        return;
    }
    if (!*filename && (e = av_dict_get(st->metadata, "filename", NULL, 0)))
        filename = e->value;
    if (!*filename) {
        av_log(NULL, AV_LOG_FATAL, "No filename specified and no 'filename' tag"
               "in stream #%d:%d.\n", nb_input_files - 1, st->index);
        exit_program(1);
    }

    assert_file_overwrite(filename);

    if ((ret = avio_open2(&out, filename, AVIO_FLAG_WRITE, &int_cb, NULL)) < 0) {
        av_log(NULL, AV_LOG_FATAL, "Could not open file %s for writing.\n",
               filename);
        exit_program(1);
    }

    avio_write(out, st->codec->extradata, st->codec->extradata_size);
    avio_flush(out);
    avio_close(out);
}

static int open_input_file(OptionsContext *o, const char *filename)
{
    InputFile *f;
    AVFormatContext *ic;
    AVInputFormat *file_iformat = NULL;
    int err, i, ret;
    int64_t timestamp;
    uint8_t buf[128];
    AVDictionary **opts;
    AVDictionary *unused_opts = NULL;
    AVDictionaryEntry *e = NULL;
    int orig_nb_streams;                     // number of streams before avformat_find_stream_info
    char *   video_codec_name = NULL;
    char *   audio_codec_name = NULL;
    char *subtitle_codec_name = NULL;

    if (o->format) {
        if (!(file_iformat = av_find_input_format(o->format))) {
            av_log(NULL, AV_LOG_FATAL, "Unknown input format: '%s'\n", o->format);
            exit_program(1);
        }
    }

    if (!strcmp(filename, "-"))
        filename = "pipe:";

    stdin_interaction &= strncmp(filename, "pipe:", 5) &&
                         strcmp(filename, "/dev/stdin");

    /* get default parameters from command line */
    ic = avformat_alloc_context();
    if (!ic) {
        print_error(filename, AVERROR(ENOMEM));
        exit_program(1);
    }
    if (o->nb_audio_sample_rate) {
        snprintf(buf, sizeof(buf), "%d", o->audio_sample_rate[o->nb_audio_sample_rate - 1].u.i);
        av_dict_set(&o->g->format_opts, "sample_rate", buf, 0);
    }
    if (o->nb_audio_channels) {
        /* because we set audio_channels based on both the "ac" and
         * "channel_layout" options, we need to check that the specified
         * demuxer actually has the "channels" option before setting it */
        if (file_iformat && file_iformat->priv_class &&
            av_opt_find(&file_iformat->priv_class, "channels", NULL, 0,
                        AV_OPT_SEARCH_FAKE_OBJ)) {
            snprintf(buf, sizeof(buf), "%d",
                     o->audio_channels[o->nb_audio_channels - 1].u.i);
            av_dict_set(&o->g->format_opts, "channels", buf, 0);
        }
    }
    if (o->nb_frame_rates) {
        /* set the format-level framerate option;
         * this is important for video grabbers, e.g. x11 */
        if (file_iformat && file_iformat->priv_class &&
            av_opt_find(&file_iformat->priv_class, "framerate", NULL, 0,
                        AV_OPT_SEARCH_FAKE_OBJ)) {
            av_dict_set(&o->g->format_opts, "framerate",
                        o->frame_rates[o->nb_frame_rates - 1].u.str, 0);
        }
    }
    if (o->nb_frame_sizes) {
        av_dict_set(&o->g->format_opts, "video_size", o->frame_sizes[o->nb_frame_sizes - 1].u.str, 0);
    }
    if (o->nb_frame_pix_fmts)
        av_dict_set(&o->g->format_opts, "pixel_format", o->frame_pix_fmts[o->nb_frame_pix_fmts - 1].u.str, 0);

    MATCH_PER_TYPE_OPT(codec_names, str,    video_codec_name, ic, "v");
    MATCH_PER_TYPE_OPT(codec_names, str,    audio_codec_name, ic, "a");
    MATCH_PER_TYPE_OPT(codec_names, str, subtitle_codec_name, ic, "s");

    ic->video_codec_id   = video_codec_name ?
        find_codec_or_die(video_codec_name   , AVMEDIA_TYPE_VIDEO   , 0)->id : AV_CODEC_ID_NONE;
    ic->audio_codec_id   = audio_codec_name ?
        find_codec_or_die(audio_codec_name   , AVMEDIA_TYPE_AUDIO   , 0)->id : AV_CODEC_ID_NONE;
    ic->subtitle_codec_id= subtitle_codec_name ?
        find_codec_or_die(subtitle_codec_name, AVMEDIA_TYPE_SUBTITLE, 0)->id : AV_CODEC_ID_NONE;

    if (video_codec_name)
        av_format_set_video_codec   (ic, find_codec_or_die(video_codec_name   , AVMEDIA_TYPE_VIDEO   , 0));
    if (audio_codec_name)
        av_format_set_audio_codec   (ic, find_codec_or_die(audio_codec_name   , AVMEDIA_TYPE_AUDIO   , 0));
    if (subtitle_codec_name)
        av_format_set_subtitle_codec(ic, find_codec_or_die(subtitle_codec_name, AVMEDIA_TYPE_SUBTITLE, 0));

    ic->flags |= AVFMT_FLAG_NONBLOCK;
    ic->interrupt_callback = int_cb;

    /* open the input file with generic avformat function */
    err = avformat_open_input(&ic, filename, file_iformat, &o->g->format_opts);
    if (err < 0) {
        print_error(filename, err);
        exit_program(1);
    }
    assert_avoptions(o->g->format_opts);

    /* apply forced codec ids */
    for (i = 0; i < ic->nb_streams; i++)
        choose_decoder(o, ic, ic->streams[i]);

    /* Set AVCodecContext options for avformat_find_stream_info */
    opts = setup_find_stream_info_opts(ic, o->g->codec_opts);
    orig_nb_streams = ic->nb_streams;

    /* If not enough info to get the stream parameters, we decode the
       first frames to get it. (used in mpeg case for example) */
    ret = avformat_find_stream_info(ic, opts);
    if (ret < 0) {
        av_log(NULL, AV_LOG_FATAL, "%s: could not find codec parameters\n", filename);
        avformat_close_input(&ic);
        exit_program(1);
    }

    timestamp = (o->start_time == AV_NOPTS_VALUE) ? 0 : o->start_time;
    /* add the stream start time */
    if (ic->start_time != AV_NOPTS_VALUE)
        timestamp += ic->start_time;

    /* if seeking requested, we execute it */
    if (o->start_time != AV_NOPTS_VALUE) {
        ret = avformat_seek_file(ic, -1, INT64_MIN, timestamp, timestamp, 0);
        if (ret < 0) {
            av_log(NULL, AV_LOG_WARNING, "%s: could not seek to position %0.3f\n",
                   filename, (double)timestamp / AV_TIME_BASE);
        }
    }

    /* update the current parameters so that they match the one of the input stream */
    add_input_streams(o, ic);

    /* dump the file content */
    av_dump_format(ic, nb_input_files, filename, 0);

    GROW_ARRAY(input_files, nb_input_files);
    f = av_mallocz(sizeof(*f));
    if (!f)
        exit_program(1);
    input_files[nb_input_files - 1] = f;

    f->ctx        = ic;
    f->ist_index  = nb_input_streams - ic->nb_streams;
    f->start_time = o->start_time;
    f->recording_time = o->recording_time;
    f->input_ts_offset = o->input_ts_offset;
    f->ts_offset  = o->input_ts_offset - (copy_ts ? 0 : timestamp);
    f->nb_streams = ic->nb_streams;
    f->rate_emu   = o->rate_emu;
    f->accurate_seek = o->accurate_seek;

    /* check if all codec options have been used */
    unused_opts = strip_specifiers(o->g->codec_opts);
    for (i = f->ist_index; i < nb_input_streams; i++) {
        e = NULL;
        while ((e = av_dict_get(input_streams[i]->decoder_opts, "", e,
                                AV_DICT_IGNORE_SUFFIX)))
            av_dict_set(&unused_opts, e->key, NULL, 0);
    }

    e = NULL;
    while ((e = av_dict_get(unused_opts, "", e, AV_DICT_IGNORE_SUFFIX))) {
        const AVClass *class = avcodec_get_class();
        const AVOption *option = av_opt_find(&class, e->key, NULL, 0,
                                             AV_OPT_SEARCH_CHILDREN | AV_OPT_SEARCH_FAKE_OBJ);
        const AVClass *fclass = avformat_get_class();
        const AVOption *foption = av_opt_find(&fclass, e->key, NULL, 0,
                                             AV_OPT_SEARCH_CHILDREN | AV_OPT_SEARCH_FAKE_OBJ);
        if (!option || foption)
            continue;


        if (!(option->flags & AV_OPT_FLAG_DECODING_PARAM)) {
            av_log(NULL, AV_LOG_ERROR, "Codec AVOption %s (%s) specified for "
                   "input file #%d (%s) is not a decoding option.\n", e->key,
                   option->help ? option->help : "", nb_input_files - 1,
                   filename);
            exit_program(1);
        }

        av_log(NULL, AV_LOG_WARNING, "Codec AVOption %s (%s) specified for "
               "input file #%d (%s) has not been used for any stream. The most "
               "likely reason is either wrong type (e.g. a video option with "
               "no video streams) or that it is a private option of some decoder "
               "which was not actually used for any stream.\n", e->key,
               option->help ? option->help : "", nb_input_files - 1, filename);
    }
    av_dict_free(&unused_opts);

    for (i = 0; i < o->nb_dump_attachment; i++) {
        int j;

        for (j = 0; j < ic->nb_streams; j++) {
            AVStream *st = ic->streams[j];

            if (check_stream_specifier(ic, st, o->dump_attachment[i].specifier) == 1)
                dump_attachment(st, o->dump_attachment[i].u.str);
        }
    }

    for (i = 0; i < orig_nb_streams; i++)
        av_dict_free(&opts[i]);
    av_freep(&opts);

    return 0;
}

static uint8_t *get_line(AVIOContext *s)
{
    AVIOContext *line;
    uint8_t *buf;
    char c;

    if (avio_open_dyn_buf(&line) < 0) {
        av_log(NULL, AV_LOG_FATAL, "Could not alloc buffer for reading preset.\n");
        exit_program(1);
    }

    while ((c = avio_r8(s)) && c != '\n')
        avio_w8(line, c);
    avio_w8(line, 0);