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 "libavfilter/avfiltergraph.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(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;\
    }\
}
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;


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

void reset_options(OptionsContext *o, int is_input)
{
    const OptionDef *po = options;
    OptionsContext bak= *o;
    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);

    memset(o, 0, sizeof(*o));

    if (is_input) {
        o->recording_time = bak.recording_time;
        if (o->recording_time != INT64_MAX)
            av_log(NULL, AV_LOG_WARNING,
                   "-t is not an input option, keeping it for the next output;"
                   " consider fixing your command line.\n");
    } else
    o->recording_time = INT64_MAX;
    o->mux_max_delay  = 0.7;
    o->limit_filesize = UINT64_MAX;
    o->chapters_input_file = INT_MAX;

    uninit_opts();
    init_opts();
}


static int opt_frame_crop(void *optctx, const char *opt, const char *arg)
{
    av_log(NULL, AV_LOG_FATAL, "Option '%s' has been removed, use the crop filter instead\n", opt);
    return AVERROR(EINVAL);
}

static int opt_pad(void *optctx, const char *opt, const char *arg)
{
    av_log(NULL, AV_LOG_FATAL, "Option '%s' has been removed, use the pad filter instead\n", opt);
    return -1;
}

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(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(1);
        }
    }


    if (map[0] == '[') {
        /* this mapping refers to lavfi output */
        const char *c = map + 1;
        o->stream_maps = grow_array(o->stream_maps, sizeof(*o->stream_maps),
                                    &o->nb_stream_maps, o->nb_stream_maps + 1);
        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(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(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;
                o->stream_maps = grow_array(o->stream_maps, sizeof(*o->stream_maps),
                                            &o->nb_stream_maps, o->nb_stream_maps + 1);
                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(1);
    }

    av_freep(&map);
    return 0;
}

static int opt_attach(void *optctx, const char *opt, const char *arg)
{
    OptionsContext *o = optctx;
    o->attachments = grow_array(o->attachments, sizeof(*o->attachments),
                                &o->nb_attachments, o->nb_attachments + 1);
    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;

    o->audio_channel_maps =
        grow_array(o->audio_channel_maps, sizeof(*o->audio_channel_maps),
                   &o->nb_audio_channel_maps, o->nb_audio_channel_maps + 1);
    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(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(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(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(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(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(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(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(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(1);
        }
        if (!meta_in) {
            av_log(NULL, AV_LOG_FATAL, "Stream specifier %s does not match  any streams.\n", istream_spec);
            exit(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(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(1);
    }
    if (codec->type != type) {
        av_log(NULL, AV_LOG_FATAL, "Invalid %s type '%s'\n", codec_string, name);
        exit(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;
    char *next, *codec_tag = NULL;

    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;

        if (!ist)
            exit(1);

        input_streams = grow_array(input_streams, sizeof(*input_streams), &nb_input_streams, nb_input_streams + 1);
        input_streams[nb_input_streams - 1] = ist;

        ist->st = st;
        ist->file_index = nb_input_files;
        ist->discard = 1;
        st->discard  = AVDISCARD_ALL;
        ist->opts = filter_codec_opts(codec_opts, ist->st->codec->codec_id, ic, st, choose_decoder(o, ic, st));

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

        ist->filter_in_rescale_delta_last = AV_NOPTS_VALUE;

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

            ist->resample_height  = dec->height;
            ist->resample_width   = dec->width;
            ist->resample_pix_fmt = dec->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(1);
            }

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

            break;
        case AVMEDIA_TYPE_AUDIO:
            guess_input_channel_layout(ist);

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

            break;
        case AVMEDIA_TYPE_DATA:
        case AVMEDIA_TYPE_SUBTITLE:
            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);
            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) &&
        (strchr(filename, ':') == NULL || filename[1] == ':' ||
         av_strstart(filename, "file:", NULL))) {
        if (avio_check(filename, 0) == 0) {
            if (stdin_interaction && (!no_file_overwrite || 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(1);
                }
                term_init();
            }
            else {
                av_log(NULL, AV_LOG_FATAL, "File '%s' already exists. Exiting.\n", filename);
                exit(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(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(1);
    }

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

static int opt_input_file(void *optctx, const char *opt, const char *filename)
{
    OptionsContext *o = optctx;
    AVFormatContext *ic;
    AVInputFormat *file_iformat = NULL;
    int err, i, ret;
    int64_t timestamp;
    uint8_t buf[128];
    AVDictionary **opts;
    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(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(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(&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(&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(&format_opts, "framerate",
                        o->frame_rates[o->nb_frame_rates - 1].u.str, 0);
        }
    }
    if (o->nb_frame_sizes) {
        av_dict_set(&format_opts, "video_size", o->frame_sizes[o->nb_frame_sizes - 1].u.str, 0);
    }
    if (o->nb_frame_pix_fmts)
        av_dict_set(&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;
    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, &format_opts);
    if (err < 0) {
        print_error(filename, err);
        exit(1);
    }
    assert_avoptions(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, 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(1);
    }

    timestamp = 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 != 0) {
        ret = av_seek_frame(ic, -1, timestamp, AVSEEK_FLAG_BACKWARD);
        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);

    input_files = grow_array(input_files, sizeof(*input_files), &nb_input_files, nb_input_files + 1);
    if (!(input_files[nb_input_files - 1] = av_mallocz(sizeof(*input_files[0]))))
        exit(1);

    input_files[nb_input_files - 1]->ctx        = ic;
    input_files[nb_input_files - 1]->ist_index  = nb_input_streams - ic->nb_streams;
    input_files[nb_input_files - 1]->ts_offset  = o->input_ts_offset - (copy_ts ? 0 : timestamp);
    input_files[nb_input_files - 1]->nb_streams = ic->nb_streams;
    input_files[nb_input_files - 1]->rate_emu   = o->rate_emu;

    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);

    reset_options(o, 1);
    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(1);
    }

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

    return buf;
}

static int get_preset_file_2(const char *preset_name, const char *codec_name, AVIOContext **s)
{
    int i, ret = 1;
    char filename[1000];
    const char *base[3] = { getenv("AVCONV_DATADIR"),
                            getenv("HOME"),
                            AVCONV_DATADIR,
                            };

    for (i = 0; i < FF_ARRAY_ELEMS(base) && ret; i++) {
        if (!base[i])
            continue;
        if (codec_name) {
            snprintf(filename, sizeof(filename), "%s%s/%s-%s.avpreset", base[i],
                     i != 1 ? "" : "/.avconv", codec_name, preset_name);
            ret = avio_open2(s, filename, AVIO_FLAG_READ, &int_cb, NULL);
        }
        if (ret) {
            snprintf(filename, sizeof(filename), "%s%s/%s.avpreset", base[i],
                     i != 1 ? "" : "/.avconv", preset_name);
            ret = avio_open2(s, filename, AVIO_FLAG_READ, &int_cb, NULL);
        }
    }
    return ret;
}

static void choose_encoder(OptionsContext *o, AVFormatContext *s, OutputStream *ost)
{
    char *codec_name = NULL;

    MATCH_PER_STREAM_OPT(codec_names, str, codec_name, s, ost->st);
    if (!codec_name) {
        ost->st->codec->codec_id = av_guess_codec(s->oformat, NULL, s->filename,
                                                  NULL, ost->st->codec->codec_type);
        ost->enc = avcodec_find_encoder(ost->st->codec->codec_id);
    } else if (!strcmp(codec_name, "copy"))
        ost->stream_copy = 1;
    else {
        ost->enc = find_codec_or_die(codec_name, ost->st->codec->codec_type, 1);
        ost->st->codec->codec_id = ost->enc->id;
    }
}

static OutputStream *new_output_stream(OptionsContext *o, AVFormatContext *oc, enum AVMediaType type, int source_index)
{
    OutputStream *ost;
    AVStream *st = avformat_new_stream(oc, NULL);
    int idx      = oc->nb_streams - 1, ret = 0;
    char *bsf = NULL, *next, *codec_tag = NULL;
    AVBitStreamFilterContext *bsfc, *bsfc_prev = NULL;
    double qscale = -1;

    if (!st) {
        av_log(NULL, AV_LOG_FATAL, "Could not alloc stream.\n");
        exit(1);
    }

    if (oc->nb_streams - 1 < o->nb_streamid_map)
        st->id = o->streamid_map[oc->nb_streams - 1];

    output_streams = grow_array(output_streams, sizeof(*output_streams), &nb_output_streams,
                                nb_output_streams + 1);
    if (!(ost = av_mallocz(sizeof(*ost))))
        exit(1);
    output_streams[nb_output_streams - 1] = ost;

    ost->file_index = nb_output_files;
    ost->index      = idx;
    ost->st         = st;
    st->codec->codec_type = type;
    choose_encoder(o, oc, ost);
    if (ost->enc) {
        AVIOContext *s = NULL;
        char *buf = NULL, *arg = NULL, *preset = NULL;

        ost->opts  = filter_codec_opts(codec_opts, ost->enc->id, oc, st, ost->enc);

        MATCH_PER_STREAM_OPT(presets, str, preset, oc, st);
        if (preset && (!(ret = get_preset_file_2(preset, ost->enc->name, &s)))) {
            do  {
                buf = get_line(s);
                if (!buf[0] || buf[0] == '#') {
                    av_free(buf);
                    continue;
                }
                if (!(arg = strchr(buf, '='))) {
                    av_log(NULL, AV_LOG_FATAL, "Invalid line found in the preset file.\n");
                    exit(1);
                }
                *arg++ = 0;
                av_dict_set(&ost->opts, buf, arg, AV_DICT_DONT_OVERWRITE);
                av_free(buf);
            } while (!s->eof_reached);
            avio_close(s);
        }
        if (ret) {
            av_log(NULL, AV_LOG_FATAL,
                   "Preset %s specified for stream %d:%d, but could not be opened.\n",
                   preset, ost->file_index, ost->index);
            exit(1);
        }
    }

    avcodec_get_context_defaults3(st->codec, ost->enc);
    st->codec->codec_type = type; // XXX hack, avcodec_get_context_defaults2() sets type to unknown for stream copy

    ost->max_frames = INT64_MAX;
    MATCH_PER_STREAM_OPT(max_frames, i64, ost->max_frames, oc, st);

    ost->copy_prior_start = -1;
    MATCH_PER_STREAM_OPT(copy_prior_start, i, ost->copy_prior_start, oc ,st);

    MATCH_PER_STREAM_OPT(bitstream_filters, str, bsf, oc, st);
    while (bsf) {
        if (next = strchr(bsf, ','))
            *next++ = 0;
        if (!(bsfc = av_bitstream_filter_init(bsf))) {
            av_log(NULL, AV_LOG_FATAL, "Unknown bitstream filter %s\n", bsf);
            exit(1);
        }
        if (bsfc_prev)
            bsfc_prev->next = bsfc;
        else
            ost->bitstream_filters = bsfc;

        bsfc_prev = bsfc;
        bsf       = next;
    }

    MATCH_PER_STREAM_OPT(codec_tags, str, codec_tag, oc, st);