ffmpeg.c

/*
 * Copyright (c) 2000-2003 Fabrice Bellard
 *
 * 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
 */

/**
 * @file
 * multimedia converter based on the FFmpeg libraries
 */

#include "config.h"
#include <ctype.h>
#include <string.h>
#include <math.h>
#include <stdlib.h>
#include <errno.h>
#include <signal.h>
#include <limits.h>
#include <unistd.h>
#include "libavformat/avformat.h"
#include "libavdevice/avdevice.h"
#include "libswscale/swscale.h"
#include "libavutil/opt.h"
#include "libavutil/audioconvert.h"
#include "libavutil/parseutils.h"
#include "libavutil/samplefmt.h"
#include "libavutil/colorspace.h"
#include "libavutil/fifo.h"
#include "libavutil/intreadwrite.h"
#include "libavutil/dict.h"
#include "libavutil/mathematics.h"
#include "libavutil/pixdesc.h"
#include "libavutil/avstring.h"
#include "libavutil/libm.h"
#include "libavutil/imgutils.h"
#include "libavutil/timestamp.h"
#include "libavformat/os_support.h"
#include "libswresample/swresample.h"

#include "libavformat/ffm.h" // not public API

# include "libavfilter/avcodec.h"
# include "libavfilter/avfilter.h"
# include "libavfilter/avfiltergraph.h"
# include "libavfilter/buffersink.h"
# include "libavfilter/buffersrc.h"

#if HAVE_SYS_RESOURCE_H
#include <sys/types.h>
#include <sys/time.h>
#include <sys/resource.h>
#elif HAVE_GETPROCESSTIMES
#include <windows.h>
#endif
#if HAVE_GETPROCESSMEMORYINFO
#include <windows.h>
#include <psapi.h>
#endif

#if HAVE_SYS_SELECT_H
#include <sys/select.h>
#endif

#if HAVE_TERMIOS_H
#include <fcntl.h>
#include <sys/ioctl.h>
#include <sys/time.h>
#include <termios.h>
#elif HAVE_KBHIT
#include <conio.h>
#endif
#include <time.h>

#include "cmdutils.h"

#include "libavutil/avassert.h"

#define VSYNC_AUTO       -1
#define VSYNC_PASSTHROUGH 0
#define VSYNC_CFR         1
#define VSYNC_VFR         2
#define VSYNC_DROP        0xff

const char program_name[] = "ffmpeg";
const int program_birth_year = 2000;

/* select an input stream for an output stream */
typedef struct StreamMap {
    int disabled;           /** 1 is this mapping is disabled by a negative map */
    int file_index;
    int stream_index;
    int sync_file_index;
    int sync_stream_index;
    char *linklabel;       /** name of an output link, for mapping lavfi outputs */
} StreamMap;

typedef struct {
    int  file_idx,  stream_idx,  channel_idx; // input
    int ofile_idx, ostream_idx;               // output
} AudioChannelMap;

static const OptionDef options[];

#define MAX_STREAMS 1024    /* arbitrary sanity check value */

static int frame_bits_per_raw_sample = 0;
static int video_discard = 0;
static int same_quant = 0;
static int do_deinterlace = 0;
static int intra_dc_precision = 8;
static int qp_hist = 0;
static int intra_only = 0;
static const char *video_codec_name    = NULL;
static const char *audio_codec_name    = NULL;
static const char *subtitle_codec_name = NULL;

static int file_overwrite = 0;
static int no_file_overwrite = 0;
static int do_benchmark = 0;
static int do_benchmark_all = 0;
static int do_hex_dump = 0;
static int do_pkt_dump = 0;
static int do_psnr = 0;
static int do_pass = 0;
static const char *pass_logfilename_prefix;
static int video_sync_method = VSYNC_AUTO;
static int audio_sync_method = 0;
static float audio_drift_threshold = 0.1;
static int copy_ts = 0;
static int copy_tb = -1;
static int opt_shortest = 0;
static char *vstats_filename;
static FILE *vstats_file;

static int audio_volume = 256;

static int exit_on_error = 0;
static int using_stdin = 0;
static int run_as_daemon  = 0;
static volatile int received_nb_signals = 0;
static int64_t video_size = 0;
static int64_t audio_size = 0;
static int64_t extra_size = 0;
static int nb_frames_dup = 0;
static int nb_frames_drop = 0;
static int input_sync;

static float dts_delta_threshold = 10;
static float dts_error_threshold = 3600*30;

static int print_stats = 1;
static int debug_ts = 0;
static int current_time;

static uint8_t *audio_buf;
static unsigned int allocated_audio_buf_size;
static uint8_t *async_buf;
static unsigned int allocated_async_buf_size;

#define DEFAULT_PASS_LOGFILENAME_PREFIX "ffmpeg2pass"

typedef struct InputFilter {
    AVFilterContext    *filter;
    struct InputStream *ist;
    struct FilterGraph *graph;
} InputFilter;

typedef struct OutputFilter {
    AVFilterContext     *filter;
    struct OutputStream *ost;
    struct FilterGraph  *graph;

    /* temporary storage until stream maps are processed */
    AVFilterInOut       *out_tmp;
} OutputFilter;

typedef struct FilterGraph {
    int            index;
    const char    *graph_desc;

    AVFilterGraph *graph;

    InputFilter   **inputs;
    int          nb_inputs;
    OutputFilter **outputs;
    int         nb_outputs;
} FilterGraph;

typedef struct FrameBuffer {
    uint8_t *base[4];
    uint8_t *data[4];
    int  linesize[4];

    int h, w;
    enum PixelFormat pix_fmt;

    int refcount;
    struct InputStream *ist;
    struct FrameBuffer *next;
} FrameBuffer;

typedef struct InputStream {
    int file_index;
    AVStream *st;
    int discard;             /* true if stream data should be discarded */
    int decoding_needed;     /* true if the packets must be decoded in 'raw_fifo' */
    AVCodec *dec;
    AVFrame *decoded_frame;

    int64_t       start;     /* time when read started */
    /* predicted dts of the next packet read for this stream or (when there are
     * several frames in a packet) of the next frame in current packet */
    int64_t       next_dts;
    /* dts of the last packet read for this stream */
    int64_t       dts;

    int64_t       next_pts;  ///< synthetic pts for the next decode frame
    int64_t       pts;       ///< current pts of the decoded frame
    double ts_scale;
    int is_start;            /* is 1 at the start and after a discontinuity */
    int saw_first_ts;
    int showed_multi_packet_warning;
    AVDictionary *opts;

    int resample_height;
    int resample_width;
    int resample_pix_fmt;

    /* a pool of free buffers for decoded data */
    FrameBuffer *buffer_pool;
    int dr1;

    /* decoded data from this stream goes into all those filters
     * currently video only */
    InputFilter **filters;
    int        nb_filters;
} InputStream;

typedef struct InputFile {
    AVFormatContext *ctx;
    int eof_reached;      /* true if eof reached */
    int ist_index;        /* index of first stream in input_streams */
    int buffer_size;      /* current total buffer size */
    int64_t ts_offset;
    int nb_streams;       /* number of stream that ffmpeg is aware of; may be different
                             from ctx.nb_streams if new streams appear during av_read_frame() */
    int rate_emu;
} InputFile;

typedef struct OutputStream {
    int file_index;          /* file index */
    int index;               /* stream index in the output file */
    int source_index;        /* InputStream index */
    AVStream *st;            /* stream in the output file */
    int encoding_needed;     /* true if encoding needed for this stream */
    int frame_number;
    /* input pts and corresponding output pts
       for A/V sync */
    struct InputStream *sync_ist; /* input stream to sync against */
    int64_t sync_opts;       /* output frame counter, could be changed to some true timestamp */ // FIXME look at frame_number
    AVBitStreamFilterContext *bitstream_filters;
    AVCodec *enc;
    int64_t max_frames;
    AVFrame *output_frame;
    AVFrame *filtered_frame;

    /* video only */
    AVRational frame_rate;
    int force_fps;
    int top_field_first;

    float frame_aspect_ratio;
    float last_quality;

    /* forced key frames */
    int64_t *forced_kf_pts;
    int forced_kf_count;
    int forced_kf_index;

    /* audio only */
    int audio_resample;
    int audio_channels_map[SWR_CH_MAX];  ///< list of the channels id to pick from the source stream
    int audio_channels_mapped;           ///< number of channels in audio_channels_map
    int resample_sample_fmt;
    int resample_channels;
    uint64_t resample_channel_layout;
    int resample_sample_rate;
    float rematrix_volume;
    AVFifoBuffer *fifo;     /* for compression: one audio fifo per codec */
    FILE *logfile;

    SwrContext *swr;

    OutputFilter *filter;
    char *avfilter;

    int64_t sws_flags;
    int64_t swr_dither_method;
    double swr_dither_scale;
    AVDictionary *opts;
    int is_past_recording_time;
    int stream_copy;
    const char *attachment_filename;
    int copy_initial_nonkeyframes;

    enum PixelFormat pix_fmts[2];
} OutputStream;


#if HAVE_TERMIOS_H

/* init terminal so that we can grab keys */
static struct termios oldtty;
static int restore_tty;
#endif

typedef struct OutputFile {
    AVFormatContext *ctx;
    AVDictionary *opts;
    int ost_index;       /* index of the first stream in output_streams */
    int64_t recording_time; /* desired length of the resulting file in microseconds */
    int64_t start_time;     /* start time in microseconds */
    uint64_t limit_filesize; /* filesize limit expressed in bytes */
} OutputFile;

static InputStream **input_streams = NULL;
static int        nb_input_streams = 0;
static InputFile   **input_files   = NULL;
static int        nb_input_files   = 0;

static OutputStream **output_streams = NULL;
static int         nb_output_streams = 0;
static OutputFile   **output_files   = NULL;
static int         nb_output_files   = 0;

static FilterGraph **filtergraphs;
int               nb_filtergraphs;

typedef struct OptionsContext {
    /* input/output options */
    int64_t start_time;
    const char *format;

    SpecifierOpt *codec_names;
    int        nb_codec_names;
    SpecifierOpt *audio_channels;
    int        nb_audio_channels;
    SpecifierOpt *audio_sample_rate;
    int        nb_audio_sample_rate;
    SpecifierOpt *rematrix_volume;
    int        nb_rematrix_volume;
    SpecifierOpt *frame_rates;
    int        nb_frame_rates;
    SpecifierOpt *frame_sizes;
    int        nb_frame_sizes;
    SpecifierOpt *frame_pix_fmts;
    int        nb_frame_pix_fmts;

    /* input options */
    int64_t input_ts_offset;
    int rate_emu;

    SpecifierOpt *ts_scale;
    int        nb_ts_scale;
    SpecifierOpt *dump_attachment;
    int        nb_dump_attachment;

    /* output options */
    StreamMap *stream_maps;
    int     nb_stream_maps;
    AudioChannelMap *audio_channel_maps; ///< one info entry per -map_channel
    int           nb_audio_channel_maps; ///< number of (valid) -map_channel settings
    int metadata_global_manual;
    int metadata_streams_manual;
    int metadata_chapters_manual;
    const char **attachments;
    int       nb_attachments;

    int chapters_input_file;

    int64_t recording_time;
    uint64_t limit_filesize;
    float mux_preload;
    float mux_max_delay;

    int video_disable;
    int audio_disable;
    int subtitle_disable;
    int data_disable;

    /* indexed by output file stream index */
    int   *streamid_map;
    int nb_streamid_map;

    SpecifierOpt *metadata;
    int        nb_metadata;
    SpecifierOpt *max_frames;
    int        nb_max_frames;
    SpecifierOpt *bitstream_filters;
    int        nb_bitstream_filters;
    SpecifierOpt *codec_tags;
    int        nb_codec_tags;
    SpecifierOpt *sample_fmts;
    int        nb_sample_fmts;
    SpecifierOpt *qscale;
    int        nb_qscale;
    SpecifierOpt *forced_key_frames;
    int        nb_forced_key_frames;
    SpecifierOpt *force_fps;
    int        nb_force_fps;
    SpecifierOpt *frame_aspect_ratios;
    int        nb_frame_aspect_ratios;
    SpecifierOpt *rc_overrides;
    int        nb_rc_overrides;
    SpecifierOpt *intra_matrices;
    int        nb_intra_matrices;
    SpecifierOpt *inter_matrices;
    int        nb_inter_matrices;
    SpecifierOpt *top_field_first;
    int        nb_top_field_first;
    SpecifierOpt *metadata_map;
    int        nb_metadata_map;
    SpecifierOpt *presets;
    int        nb_presets;
    SpecifierOpt *copy_initial_nonkeyframes;
    int        nb_copy_initial_nonkeyframes;
    SpecifierOpt *filters;
    int        nb_filters;
} OptionsContext;

#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);\
    }\
}

static int64_t getutime(void)
{
#if HAVE_GETRUSAGE
    struct rusage rusage;

    getrusage(RUSAGE_SELF, &rusage);
    return (rusage.ru_utime.tv_sec * 1000000LL) + rusage.ru_utime.tv_usec;
#elif HAVE_GETPROCESSTIMES
    HANDLE proc;
    FILETIME c, e, k, u;
    proc = GetCurrentProcess();
    GetProcessTimes(proc, &c, &e, &k, &u);
    return ((int64_t) u.dwHighDateTime << 32 | u.dwLowDateTime) / 10;
#else
    return av_gettime();
#endif
}

static void update_benchmark(const char *fmt, ...)
{
    if (do_benchmark_all) {
        int64_t t = getutime();
        va_list va;
        char buf[1024];

        if (fmt) {
            va_start(va, fmt);
            vsnprintf(buf, sizeof(buf), fmt, va);
            va_end(va);
            printf("bench: %8"PRIu64" %s \n", t - current_time, buf);
        }
        current_time = t;
    }
}

static 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;
    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 alloc_buffer(InputStream *ist, AVCodecContext *s, FrameBuffer **pbuf)
{
    FrameBuffer  *buf = av_mallocz(sizeof(*buf));
    int i, ret;
    const int pixel_size = av_pix_fmt_descriptors[s->pix_fmt].comp[0].step_minus1+1;
    int h_chroma_shift, v_chroma_shift;
    int edge = 32; // XXX should be avcodec_get_edge_width(), but that fails on svq1
    int w = s->width, h = s->height;

    if (!buf)
        return AVERROR(ENOMEM);

    avcodec_align_dimensions(s, &w, &h);

    if (!(s->flags & CODEC_FLAG_EMU_EDGE)) {
        w += 2*edge;
        h += 2*edge;
    }

    if ((ret = av_image_alloc(buf->base, buf->linesize, w, h,
                              s->pix_fmt, 32)) < 0) {
        av_freep(&buf);
        return ret;
    }
    /* XXX this shouldn't be needed, but some tests break without this line
     * those decoders are buggy and need to be fixed.
     * the following tests fail:
     * cdgraphics, ansi, aasc, fraps-v1, qtrle-1bit
     */
    memset(buf->base[0], 128, ret);

    avcodec_get_chroma_sub_sample(s->pix_fmt, &h_chroma_shift, &v_chroma_shift);
    for (i = 0; i < FF_ARRAY_ELEMS(buf->data); i++) {
        const int h_shift = i==0 ? 0 : h_chroma_shift;
        const int v_shift = i==0 ? 0 : v_chroma_shift;
        if ((s->flags & CODEC_FLAG_EMU_EDGE) || !buf->linesize[1] || !buf->base[i])
            buf->data[i] = buf->base[i];
        else
            buf->data[i] = buf->base[i] +
                           FFALIGN((buf->linesize[i]*edge >> v_shift) +
                                   (pixel_size*edge >> h_shift), 32);
    }
    buf->w       = s->width;
    buf->h       = s->height;
    buf->pix_fmt = s->pix_fmt;
    buf->ist     = ist;

    *pbuf = buf;
    return 0;
}

static void free_buffer_pool(InputStream *ist)
{
    FrameBuffer *buf = ist->buffer_pool;
    while (buf) {
        ist->buffer_pool = buf->next;
        av_freep(&buf->base[0]);
        av_free(buf);
        buf = ist->buffer_pool;
    }
}

static void unref_buffer(InputStream *ist, FrameBuffer *buf)
{
    av_assert0(buf->refcount > 0);
    buf->refcount--;
    if (!buf->refcount) {
        FrameBuffer *tmp;
        for(tmp= ist->buffer_pool; tmp; tmp= tmp->next)
            av_assert1(tmp != buf);
        buf->next = ist->buffer_pool;
        ist->buffer_pool = buf;
    }
}

static int codec_get_buffer(AVCodecContext *s, AVFrame *frame)
{
    InputStream *ist = s->opaque;
    FrameBuffer *buf;
    int ret, i;

    if(av_image_check_size(s->width, s->height, 0, s) || s->pix_fmt<0)
        return -1;

    if (!ist->buffer_pool && (ret = alloc_buffer(ist, s, &ist->buffer_pool)) < 0)
        return ret;

    buf              = ist->buffer_pool;
    ist->buffer_pool = buf->next;
    buf->next        = NULL;
    if (buf->w != s->width || buf->h != s->height || buf->pix_fmt != s->pix_fmt) {
        av_freep(&buf->base[0]);
        av_free(buf);
        if ((ret = alloc_buffer(ist, s, &buf)) < 0)
            return ret;
    }
    av_assert0(!buf->refcount);
    buf->refcount++;

    frame->opaque        = buf;
    frame->type          = FF_BUFFER_TYPE_USER;
    frame->extended_data = frame->data;
    frame->pkt_pts       = s->pkt ? s->pkt->pts : AV_NOPTS_VALUE;
    frame->width         = buf->w;
    frame->height        = buf->h;
    frame->format        = buf->pix_fmt;
    frame->sample_aspect_ratio = s->sample_aspect_ratio;

    for (i = 0; i < FF_ARRAY_ELEMS(buf->data); i++) {
        frame->base[i]     = buf->base[i];  // XXX h264.c uses base though it shouldn't
        frame->data[i]     = buf->data[i];
        frame->linesize[i] = buf->linesize[i];
    }

    return 0;
}

static void codec_release_buffer(AVCodecContext *s, AVFrame *frame)
{
    InputStream *ist = s->opaque;
    FrameBuffer *buf = frame->opaque;
    int i;

    if(frame->type!=FF_BUFFER_TYPE_USER)
        return avcodec_default_release_buffer(s, frame);

    for (i = 0; i < FF_ARRAY_ELEMS(frame->data); i++)
        frame->data[i] = NULL;

    unref_buffer(ist, buf);
}

static void filter_release_buffer(AVFilterBuffer *fb)
{
    FrameBuffer *buf = fb->priv;
    av_free(fb);
    unref_buffer(buf->ist, buf);
}

static enum PixelFormat choose_pixel_fmt(AVStream *st, AVCodec *codec, enum PixelFormat target)
{
    if (codec && codec->pix_fmts) {
        const enum PixelFormat *p = codec->pix_fmts;
        int has_alpha= av_pix_fmt_descriptors[target].nb_components % 2 == 0;
        enum PixelFormat best= PIX_FMT_NONE;
        if (st->codec->strict_std_compliance <= FF_COMPLIANCE_UNOFFICIAL) {
            if (st->codec->codec_id == CODEC_ID_MJPEG) {
                p = (const enum PixelFormat[]) { PIX_FMT_YUVJ420P, PIX_FMT_YUVJ422P, PIX_FMT_YUV420P, PIX_FMT_YUV422P, PIX_FMT_NONE };
            } else if (st->codec->codec_id == CODEC_ID_LJPEG) {
                p = (const enum PixelFormat[]) { PIX_FMT_YUVJ420P, PIX_FMT_YUVJ422P, PIX_FMT_YUVJ444P, PIX_FMT_YUV420P,
                                                 PIX_FMT_YUV422P, PIX_FMT_YUV444P, PIX_FMT_BGRA, PIX_FMT_NONE };
            }
        }
        for (; *p != PIX_FMT_NONE; p++) {
            best= avcodec_find_best_pix_fmt2(best, *p, target, has_alpha, NULL);
            if (*p == target)
                break;
        }
        if (*p == PIX_FMT_NONE) {
            if (target != PIX_FMT_NONE)
                av_log(NULL, AV_LOG_WARNING,
                       "Incompatible pixel format '%s' for codec '%s', auto-selecting format '%s'\n",
                       av_pix_fmt_descriptors[target].name,
                       codec->name,
                       av_pix_fmt_descriptors[best].name);
            return best;
        }
    }
    return target;
}

static char *choose_pixel_fmts(OutputStream *ost)
{
    if (ost->st->codec->pix_fmt != PIX_FMT_NONE) {
        return av_strdup(av_get_pix_fmt_name(choose_pixel_fmt(ost->st, ost->enc, ost->st->codec->pix_fmt)));
    } else if (ost->enc->pix_fmts) {
        const enum PixelFormat *p;
        AVIOContext *s = NULL;
        uint8_t *ret;
        int len;

        if (avio_open_dyn_buf(&s) < 0)
            exit_program(1);

        p = ost->enc->pix_fmts;
        if (ost->st->codec->strict_std_compliance <= FF_COMPLIANCE_UNOFFICIAL) {
            if (ost->st->codec->codec_id == CODEC_ID_MJPEG) {
                p = (const enum PixelFormat[]) { PIX_FMT_YUVJ420P, PIX_FMT_YUVJ422P, PIX_FMT_YUV420P, PIX_FMT_YUV422P, PIX_FMT_NONE };
            } else if (ost->st->codec->codec_id == CODEC_ID_LJPEG) {
                p = (const enum PixelFormat[]) { PIX_FMT_YUVJ420P, PIX_FMT_YUVJ422P, PIX_FMT_YUVJ444P, PIX_FMT_YUV420P,
                                                    PIX_FMT_YUV422P, PIX_FMT_YUV444P, PIX_FMT_BGRA, PIX_FMT_NONE };
            }
        }

        for (; *p != PIX_FMT_NONE; p++)
            avio_printf(s, "%s:", av_get_pix_fmt_name(*p));
        len = avio_close_dyn_buf(s, &ret);
        ret[len - 1] = 0;
        return ret;
    } else
        return NULL;
}

static int configure_video_filters(FilterGraph *fg)
{
    InputStream  *ist = fg->inputs[0]->ist;
    OutputStream *ost = fg->outputs[0]->ost;
    AVFilterContext *in_filter, *out_filter, *filter;
    AVCodecContext *codec = ost->st->codec;
    AVBufferSinkParams *buffersink_params = av_buffersink_params_alloc();
    char *pix_fmts;
    AVRational sample_aspect_ratio;
    char args[255];
    int ret;

    avfilter_graph_free(&fg->graph);
    fg->graph = avfilter_graph_alloc();
    if (!fg->graph)
        return AVERROR(ENOMEM);

    if (ist->st->sample_aspect_ratio.num) {
        sample_aspect_ratio = ist->st->sample_aspect_ratio;
    } else
        sample_aspect_ratio = ist->st->codec->sample_aspect_ratio;

    snprintf(args, 255, "%d:%d:%d:%d:%d:%d:%d:flags=%d", ist->st->codec->width,
             ist->st->codec->height, ist->st->codec->pix_fmt, 1, AV_TIME_BASE,
             sample_aspect_ratio.num, sample_aspect_ratio.den, SWS_BILINEAR + ((ist->st->codec->flags&CODEC_FLAG_BITEXACT) ? SWS_BITEXACT:0));

    ret = avfilter_graph_create_filter(&fg->inputs[0]->filter,
                                       avfilter_get_by_name("buffer"),
                                       "src", args, NULL, fg->graph);
    if (ret < 0)
        return ret;

#if FF_API_OLD_VSINK_API
    ret = avfilter_graph_create_filter(&fg->outputs[0]->filter,
                                       avfilter_get_by_name("buffersink"),
                                       "out", NULL, NULL, fg->graph);
#else
    ret = avfilter_graph_create_filter(&fg->outputs[0]->filter,
                                       avfilter_get_by_name("buffersink"),
                                       "out", NULL, buffersink_params, fg->graph);
#endif
    av_freep(&buffersink_params);

    if (ret < 0)
        return ret;
    in_filter  = fg->inputs[0]->filter;
    out_filter = fg->outputs[0]->filter;

    if (codec->width || codec->height) {
        snprintf(args, 255, "%d:%d:flags=0x%X",
                 codec->width,
                 codec->height,
                 (unsigned)ost->sws_flags);
        if ((ret = avfilter_graph_create_filter(&filter, avfilter_get_by_name("scale"),
                                                NULL, args, NULL, fg->graph)) < 0)
            return ret;
        if ((ret = avfilter_link(in_filter, 0, filter, 0)) < 0)
            return ret;
        in_filter = filter;
    }

    if ((pix_fmts = choose_pixel_fmts(ost))) {
        if ((ret = avfilter_graph_create_filter(&filter,
                                                avfilter_get_by_name("format"),
                                                "format", pix_fmts, NULL,
                                                fg->graph)) < 0)
            return ret;
        if ((ret = avfilter_link(filter, 0, out_filter, 0)) < 0)
            return ret;

        out_filter = filter;
        av_freep(&pix_fmts);
    }

    snprintf(args, sizeof(args), "flags=0x%X", (unsigned)ost->sws_flags);
    fg->graph->scale_sws_opts = av_strdup(args);

    if (ost->avfilter) {
        AVFilterInOut *outputs = avfilter_inout_alloc();
        AVFilterInOut *inputs  = avfilter_inout_alloc();

        outputs->name    = av_strdup("in");
        outputs->filter_ctx = in_filter;
        outputs->pad_idx = 0;
        outputs->next    = NULL;

        inputs->name    = av_strdup("out");
        inputs->filter_ctx = out_filter;
        inputs->pad_idx = 0;
        inputs->next    = NULL;

        if ((ret = avfilter_graph_parse(fg->graph, ost->avfilter, &inputs, &outputs, NULL)) < 0)
            return ret;
        av_freep(&ost->avfilter);
    } else {
        if ((ret = avfilter_link(in_filter, 0, out_filter, 0)) < 0)
            return ret;
    }

    if ((ret = avfilter_graph_config(fg->graph, NULL)) < 0)
        return ret;

    ost->filter = fg->outputs[0];

    return 0;
}

static FilterGraph *init_simple_filtergraph(InputStream *ist, OutputStream *ost)
{
    FilterGraph *fg = av_mallocz(sizeof(*fg));

    if (!fg)
        exit_program(1);
    fg->index = nb_filtergraphs;

    fg->outputs = grow_array(fg->outputs, sizeof(*fg->outputs), &fg->nb_outputs,
                             fg->nb_outputs + 1);
    if (!(fg->outputs[0] = av_mallocz(sizeof(*fg->outputs[0]))))
        exit_program(1);
    fg->outputs[0]->ost   = ost;
    fg->outputs[0]->graph = fg;

    fg->inputs = grow_array(fg->inputs, sizeof(*fg->inputs), &fg->nb_inputs,
                            fg->nb_inputs + 1);
    if (!(fg->inputs[0] = av_mallocz(sizeof(*fg->inputs[0]))))
        exit_program(1);
    fg->inputs[0]->ist   = ist;
    fg->inputs[0]->graph = fg;

    ist->filters = grow_array(ist->filters, sizeof(*ist->filters),
                              &ist->nb_filters, ist->nb_filters + 1);
    ist->filters[ist->nb_filters - 1] = fg->inputs[0];

    filtergraphs = grow_array(filtergraphs, sizeof(*filtergraphs),
                              &nb_filtergraphs, nb_filtergraphs + 1);
    filtergraphs[nb_filtergraphs - 1] = fg;

    return fg;
}

static void init_input_filter(FilterGraph *fg, AVFilterInOut *in)
{
    InputStream *ist;
    enum AVMediaType type = in->filter_ctx->input_pads[in->pad_idx].type;
    int i;

    // TODO: support other filter types
    if (type != AVMEDIA_TYPE_VIDEO) {
        av_log(NULL, AV_LOG_FATAL, "Only video filters supported currently.\n");
        exit_program(1);
    }

    if (in->name) {
        AVFormatContext *s;
        AVStream       *st = NULL;
        char *p;
        int file_idx = strtol(in->name, &p, 0);

        if (file_idx < 0 || file_idx >= nb_input_files) {
            av_log(NULL, AV_LOG_FATAL, "Invalid file index %d in filtergraph description %s.\n",
                   file_idx, fg->graph_desc);
            exit_program(1);
        }
        s = input_files[file_idx]->ctx;

        for (i = 0; i < s->nb_streams; i++) {
            if (s->streams[i]->codec->codec_type != type)
                continue;
            if (check_stream_specifier(s, s->streams[i], *p == ':' ? p + 1 : p) == 1) {
                st = s->streams[i];
                break;
            }
        }
        if (!st) {
            av_log(NULL, AV_LOG_FATAL, "Stream specifier '%s' in filtergraph description %s "
                   "matches no streams.\n", p, fg->graph_desc);
            exit_program(1);
        }
        ist = input_streams[input_files[file_idx]->ist_index + st->index];
    } else {
        /* find the first unused stream of corresponding type */
        for (i = 0; i < nb_input_streams; i++) {
            ist = input_streams[i];
            if (ist->st->codec->codec_type == type && ist->discard)
                break;
        }
        if (i == nb_input_streams) {
            av_log(NULL, AV_LOG_FATAL, "Cannot find a matching stream for "
                   "unlabeled input pad %d on filter %s", in->pad_idx,
                   in->filter_ctx->name);
            exit_program(1);
        }
    }
    ist->discard         = 0;
    ist->decoding_needed = 1;
    ist->st->discard = AVDISCARD_NONE;

    fg->inputs = grow_array(fg->inputs, sizeof(*fg->inputs),
                            &fg->nb_inputs, fg->nb_inputs + 1);
    if (!(fg->inputs[fg->nb_inputs - 1] = av_mallocz(sizeof(*fg->inputs[0]))))
        exit_program(1);
    fg->inputs[fg->nb_inputs - 1]->ist   = ist;
    fg->inputs[fg->nb_inputs - 1]->graph = fg;

    ist->filters = grow_array(ist->filters, sizeof(*ist->filters),
                              &ist->nb_filters, ist->nb_filters + 1);
    ist->filters[ist->nb_filters - 1] = fg->inputs[fg->nb_inputs - 1];
}

static int configure_output_filter(FilterGraph *fg, OutputFilter *ofilter, AVFilterInOut *out)
{
    char *pix_fmts;
    AVCodecContext *codec = ofilter->ost->st->codec;
    AVFilterContext *last_filter = out->filter_ctx;
    int pad_idx = out->pad_idx;
    int ret;
    AVBufferSinkParams *buffersink_params = av_buffersink_params_alloc();

#if FF_API_OLD_VSINK_API
    ret = avfilter_graph_create_filter(&ofilter->filter,
                                       avfilter_get_by_name("buffersink"),
                                       "out", NULL, NULL, fg->graph);
#else
    ret = avfilter_graph_create_filter(&ofilter->filter,
                                       avfilter_get_by_name("buffersink"),
                                       "out", NULL, buffersink_params, fg->graph);
#endif
    av_freep(&buffersink_params);

    if (ret < 0)
        return ret;

    if (codec->width || codec->height) {
        char args[255];
        AVFilterContext *filter;

        snprintf(args, sizeof(args), "%d:%d:flags=0x%X",
                 codec->width,
                 codec->height,
                 (unsigned)ofilter->ost->sws_flags);
        if ((ret = avfilter_graph_create_filter(&filter, avfilter_get_by_name("scale"),
                                                NULL, args, NULL, fg->graph)) < 0)
            return ret;
        if ((ret = avfilter_link(last_filter, pad_idx, filter, 0)) < 0)
            return ret;

        last_filter = filter;
        pad_idx = 0;
    }

    if ((pix_fmts = choose_pixel_fmts(ofilter->ost))) {
        AVFilterContext *filter;
        if ((ret = avfilter_graph_create_filter(&filter,
                                                avfilter_get_by_name("format"),
                                                "format", pix_fmts, NULL,
                                                fg->graph)) < 0)
            return ret;
        if ((ret = avfilter_link(last_filter, pad_idx, filter, 0)) < 0)
            return ret;

        last_filter = filter;
        pad_idx     = 0;