vpx/vpxdec.c

/*
 *  Copyright (c) 2010 The WebM project authors. All Rights Reserved.
 *
 *  Use of this source code is governed by a BSD-style license
 *  that can be found in the LICENSE file in the root of the source
 *  tree. An additional intellectual property rights grant can be found
 *  in the file PATENTS.  All contributing project authors may
 *  be found in the AUTHORS file in the root of the source tree.
 */


/* This is a simple program that reads ivf files and decodes them
 * using the new interface. Decoded frames are output as YV12 raw.
 */
#include <stdio.h>
#include <stdlib.h>
#include <stdarg.h>
#include <string.h>
#include <limits.h>
#if defined(_WIN32)
#include <io.h>
#define snprintf _snprintf
#define isatty   _isatty
#define fileno   _fileno
#else
#include <unistd.h>
#endif
#define VPX_CODEC_DISABLE_COMPAT 1
#include "vpx_config.h"
#include "vpx/vpx_decoder.h"
#include "vpx_ports/vpx_timer.h"
#if CONFIG_VP8_DECODER
#include "vpx/vp8dx.h"
#endif
#if CONFIG_MD5
#include "md5_utils.h"
#endif
#include "tools_common.h"
#include "nestegg/include/nestegg/nestegg.h"

#ifndef PATH_MAX
#define PATH_MAX 256
#endif

static const char *exec_name;

#define VP8_FOURCC (0x00385056)
static const struct
{
    char const *name;
    const vpx_codec_iface_t *iface;
    unsigned int             fourcc;
    unsigned int             fourcc_mask;
} ifaces[] =
{
#if CONFIG_VP8_DECODER
    {"vp8",  &vpx_codec_vp8_dx_algo,   VP8_FOURCC, 0x00FFFFFF},
#endif
};

#include "args.h"
static const arg_def_t codecarg = ARG_DEF(NULL, "codec", 1,
                                  "Codec to use");
static const arg_def_t use_yv12 = ARG_DEF(NULL, "yv12", 0,
                                  "Output raw YV12 frames");
static const arg_def_t use_i420 = ARG_DEF(NULL, "i420", 0,
                                  "Output raw I420 frames");
static const arg_def_t flipuvarg = ARG_DEF(NULL, "flipuv", 0,
                                   "Flip the chroma planes in the output");
static const arg_def_t noblitarg = ARG_DEF(NULL, "noblit", 0,
                                   "Don't process the decoded frames");
static const arg_def_t progressarg = ARG_DEF(NULL, "progress", 0,
                                     "Show progress after each frame decodes");
static const arg_def_t limitarg = ARG_DEF(NULL, "limit", 1,
                                  "Stop decoding after n frames");
static const arg_def_t postprocarg = ARG_DEF(NULL, "postproc", 0,
                                     "Postprocess decoded frames");
static const arg_def_t summaryarg = ARG_DEF(NULL, "summary", 0,
                                    "Show timing summary");
static const arg_def_t outputfile = ARG_DEF("o", "output", 1,
                                    "Output file name pattern (see below)");
static const arg_def_t threadsarg = ARG_DEF("t", "threads", 1,
                                    "Max threads to use");
static const arg_def_t verbosearg = ARG_DEF("v", "verbose", 0,
                                  "Show version string");

#if CONFIG_MD5
static const arg_def_t md5arg = ARG_DEF(NULL, "md5", 0,
                                        "Compute the MD5 sum of the decoded frame");
#endif
static const arg_def_t *all_args[] =
{
    &codecarg, &use_yv12, &use_i420, &flipuvarg, &noblitarg,
    &progressarg, &limitarg, &postprocarg, &summaryarg, &outputfile,
    &threadsarg, &verbosearg,
#if CONFIG_MD5
    &md5arg,
#endif
    NULL
};

#if CONFIG_VP8_DECODER
static const arg_def_t addnoise_level = ARG_DEF(NULL, "noise-level", 1,
                                        "Enable VP8 postproc add noise");
static const arg_def_t deblock = ARG_DEF(NULL, "deblock", 0,
                                 "Enable VP8 deblocking");
static const arg_def_t demacroblock_level = ARG_DEF(NULL, "demacroblock-level", 1,
        "Enable VP8 demacroblocking, w/ level");
static const arg_def_t pp_debug_info = ARG_DEF(NULL, "pp-debug-info", 1,
                                       "Enable VP8 visible debug info");


static const arg_def_t *vp8_pp_args[] =
{
    &addnoise_level, &deblock, &demacroblock_level, &pp_debug_info,
    NULL
};
#endif

static void usage_exit()
{
    int i;

    fprintf(stderr, "Usage: %s <options> filename\n\n"
            "Options:\n", exec_name);
    arg_show_usage(stderr, all_args);
#if CONFIG_VP8_DECODER
    fprintf(stderr, "\nVP8 Postprocessing Options:\n");
    arg_show_usage(stderr, vp8_pp_args);
#endif
    fprintf(stderr,
            "\nOutput File Patterns:\n\n"
            "  The -o argument specifies the name of the file(s) to "
            "write to. If the\n  argument does not include any escape "
            "characters, the output will be\n  written to a single file. "
            "Otherwise, the filename will be calculated by\n  expanding "
            "the following escape characters:\n"
            "\n\t%%w   - Frame width"
            "\n\t%%h   - Frame height"
            "\n\t%%<n> - Frame number, zero padded to <n> places (1..9)"
            "\n\n  Pattern arguments are only supported in conjunction "
            "with the --yv12 and\n  --i420 options. If the -o option is "
            "not specified, the output will be\n  directed to stdout.\n"
            );
    fprintf(stderr, "\nIncluded decoders:\n\n");

    for (i = 0; i < sizeof(ifaces) / sizeof(ifaces[0]); i++)
        fprintf(stderr, "    %-6s - %s\n",
                ifaces[i].name,
                vpx_codec_iface_name(ifaces[i].iface));

    exit(EXIT_FAILURE);
}

void die(const char *fmt, ...)
{
    va_list ap;
    va_start(ap, fmt);
    vfprintf(stderr, fmt, ap);
    fprintf(stderr, "\n");
    usage_exit();
}

static unsigned int mem_get_le16(const void *vmem)
{
    unsigned int  val;
    const unsigned char *mem = (const unsigned char *)vmem;

    val = mem[1] << 8;
    val |= mem[0];
    return val;
}

static unsigned int mem_get_le32(const void *vmem)
{
    unsigned int  val;
    const unsigned char *mem = (const unsigned char *)vmem;

    val = mem[3] << 24;
    val |= mem[2] << 16;
    val |= mem[1] << 8;
    val |= mem[0];
    return val;
}

enum file_kind
{
    RAW_FILE,
    IVF_FILE,
    WEBM_FILE
};

struct input_ctx
{
    enum file_kind  kind;
    FILE           *infile;
    nestegg        *nestegg_ctx;
    nestegg_packet *pkt;
    unsigned int    chunk;
    unsigned int    chunks;
    unsigned int    video_track;
};

#define IVF_FRAME_HDR_SZ (sizeof(uint32_t) + sizeof(uint64_t))
#define RAW_FRAME_HDR_SZ (sizeof(uint32_t))
static int read_frame(struct input_ctx      *input,
                      uint8_t               **buf,
                      size_t                *buf_sz,
                      size_t                *buf_alloc_sz)
{
    char            raw_hdr[IVF_FRAME_HDR_SZ];
    size_t          new_buf_sz;
    FILE           *infile = input->infile;
    enum file_kind  kind = input->kind;
    if(kind == WEBM_FILE)
    {
        if(input->chunk >= input->chunks)
        {
            unsigned int track;

            do
            {
                /* End of this packet, get another. */
                if(input->pkt)
                    nestegg_free_packet(input->pkt);

                if(nestegg_read_packet(input->nestegg_ctx, &input->pkt) <= 0
                   || nestegg_packet_track(input->pkt, &track))
                    return 1;

            } while(track != input->video_track);

            if(nestegg_packet_count(input->pkt, &input->chunks))
                return 1;
            input->chunk = 0;
        }

        if(nestegg_packet_data(input->pkt, input->chunk, buf, buf_sz))
            return 1;
        input->chunk++;

        return 0;
    }
    /* For both the raw and ivf formats, the frame size is the first 4 bytes
     * of the frame header. We just need to special case on the header
     * size.
     */
    else if (fread(raw_hdr, kind==IVF_FILE
                   ? IVF_FRAME_HDR_SZ : RAW_FRAME_HDR_SZ, 1, infile) != 1)
    {
        if (!feof(infile))
            fprintf(stderr, "Failed to read frame size\n");

        new_buf_sz = 0;
    }
    else
    {
        new_buf_sz = mem_get_le32(raw_hdr);

        if (new_buf_sz > 256 * 1024 * 1024)
        {
            fprintf(stderr, "Error: Read invalid frame size (%u)\n",
                    (unsigned int)new_buf_sz);
            new_buf_sz = 0;
        }

        if (kind == RAW_FILE && new_buf_sz > 256 * 1024)
            fprintf(stderr, "Warning: Read invalid frame size (%u)"
                    " - not a raw file?\n", (unsigned int)new_buf_sz);

        if (new_buf_sz > *buf_alloc_sz)
        {
            uint8_t *new_buf = realloc(*buf, 2 * new_buf_sz);

            if (new_buf)
            {
                *buf = new_buf;
                *buf_alloc_sz = 2 * new_buf_sz;
            }
            else
            {
                fprintf(stderr, "Failed to allocate compressed data buffer\n");
                new_buf_sz = 0;
            }
        }
    }

    *buf_sz = new_buf_sz;

    if (*buf_sz)
    {
        if (fread(*buf, 1, *buf_sz, infile) != *buf_sz)
        {
            fprintf(stderr, "Failed to read full frame\n");
            return 1;
        }

        return 0;
    }

    return 1;
}

void *out_open(const char *out_fn, int do_md5)
{
    void *out = NULL;

    if (do_md5)
    {
#if CONFIG_MD5
        MD5Context *md5_ctx = out = malloc(sizeof(MD5Context));
        (void)out_fn;
        MD5Init(md5_ctx);
#endif
    }
    else
    {
        FILE *outfile = out = strcmp("-", out_fn) ? fopen(out_fn, "wb")
                                                  : set_binary_mode(stdout);

        if (!outfile)
        {
            fprintf(stderr, "Failed to output file");
            exit(EXIT_FAILURE);
        }
    }

    return out;
}

void out_put(void *out, const uint8_t *buf, unsigned int len, int do_md5)
{
    if (do_md5)
    {
#if CONFIG_MD5
        MD5Update(out, buf, len);
#endif
    }
    else
    {
        if(fwrite(buf, 1, len, out));
    }
}

void out_close(void *out, const char *out_fn, int do_md5)
{
    if (do_md5)
    {
#if CONFIG_MD5
        uint8_t md5[16];
        int i;

        MD5Final(md5, out);
        free(out);

        for (i = 0; i < 16; i++)
            printf("%02x", md5[i]);

        printf("  %s\n", out_fn);
#endif
    }
    else
    {
        fclose(out);
    }
}

unsigned int file_is_ivf(FILE *infile,
                         unsigned int *fourcc,
                         unsigned int *width,
                         unsigned int *height,
                         unsigned int *fps_den,
                         unsigned int *fps_num)
{
    char raw_hdr[32];
    int is_ivf = 0;

    if (fread(raw_hdr, 1, 32, infile) == 32)
    {
        if (raw_hdr[0] == 'D' && raw_hdr[1] == 'K'
            && raw_hdr[2] == 'I' && raw_hdr[3] == 'F')
        {
            is_ivf = 1;

            if (mem_get_le16(raw_hdr + 4) != 0)
                fprintf(stderr, "Error: Unrecognized IVF version! This file may not"
                        " decode properly.");

            *fourcc = mem_get_le32(raw_hdr + 8);
            *width = mem_get_le16(raw_hdr + 12);
            *height = mem_get_le16(raw_hdr + 14);
            *fps_num = mem_get_le32(raw_hdr + 16);
            *fps_den = mem_get_le32(raw_hdr + 20);

            /* Some versions of vpxenc used 1/(2*fps) for the timebase, so
             * we can guess the framerate using only the timebase in this
             * case. Other files would require reading ahead to guess the
             * timebase, like we do for webm.
             */
            if(*fps_num < 1000)
            {
                /* Correct for the factor of 2 applied to the timebase in the
                 * encoder.
                 */
                if(*fps_num&1)*fps_den<<=1;
                else *fps_num>>=1;
            }
            else
            {
                /* Don't know FPS for sure, and don't have readahead code
                 * (yet?), so just default to 30fps.
                 */
                *fps_num = 30;
                *fps_den = 1;
            }
        }
    }

    if (!is_ivf)
        rewind(infile);

    return is_ivf;
}


unsigned int file_is_raw(FILE *infile,
                         unsigned int *fourcc,
                         unsigned int *width,
                         unsigned int *height,
                         unsigned int *fps_den,
                         unsigned int *fps_num)
{
    unsigned char buf[32];
    int is_raw = 0;
    vpx_codec_stream_info_t si;

    if (fread(buf, 1, 32, infile) == 32)
    {
        int i;

        if(mem_get_le32(buf) < 256 * 1024 * 1024)
            for (i = 0; i < sizeof(ifaces) / sizeof(ifaces[0]); i++)
                if(!vpx_codec_peek_stream_info(ifaces[i].iface,
                                               buf + 4, 32 - 4, &si))
                {
                    is_raw = 1;
                    *fourcc = ifaces[i].fourcc;
                    *width = si.w;
                    *height = si.h;
                    *fps_num = 30;
                    *fps_den = 1;
                    break;
                }
    }

    rewind(infile);
    return is_raw;
}


static int
nestegg_read_cb(void *buffer, size_t length, void *userdata)
{
    FILE *f = userdata;

    if(fread(buffer, 1, length, f) < length)
    {
        if (ferror(f))
            return -1;
        if (feof(f))
            return 0;
    }
    return 1;
}


static int
nestegg_seek_cb(int64_t offset, int whence, void * userdata)
{
    switch(whence) {
        case NESTEGG_SEEK_SET: whence = SEEK_SET; break;
        case NESTEGG_SEEK_CUR: whence = SEEK_CUR; break;
        case NESTEGG_SEEK_END: whence = SEEK_END; break;
    };
    return fseek(userdata, offset, whence)? -1 : 0;
}


static int64_t
nestegg_tell_cb(void * userdata)
{
    return ftell(userdata);
}


static void
nestegg_log_cb(nestegg * context, unsigned int severity, char const * format,
               ...)
{
    va_list ap;

    va_start(ap, format);
    vfprintf(stderr, format, ap);
    fprintf(stderr, "\n");
    va_end(ap);
}


static int
webm_guess_framerate(struct input_ctx *input,
                     unsigned int     *fps_den,
                     unsigned int     *fps_num)
{
    unsigned int i;
    uint64_t     tstamp=0;

    /* Guess the framerate. Read up to 1 second, or 50 video packets,
     * whichever comes first.
     */
    for(i=0; tstamp < 1000000000 && i < 50;)
    {
        nestegg_packet * pkt;
        unsigned int track;

        if(nestegg_read_packet(input->nestegg_ctx, &pkt) <= 0)
            break;

        nestegg_packet_track(pkt, &track);
        if(track == input->video_track)
        {
            nestegg_packet_tstamp(pkt, &tstamp);
            i++;
        }

        nestegg_free_packet(pkt);
    }

    if(nestegg_track_seek(input->nestegg_ctx, input->video_track, 0))
        goto fail;

    *fps_num = (i - 1) * 1000000;
    *fps_den = tstamp / 1000;
    return 0;
fail:
    nestegg_destroy(input->nestegg_ctx);
    input->nestegg_ctx = NULL;
    rewind(input->infile);
    return 1;
}


static int
file_is_webm(struct input_ctx *input,
             unsigned int     *fourcc,
             unsigned int     *width,
             unsigned int     *height,
             unsigned int     *fps_den,
             unsigned int     *fps_num)
{
    unsigned int i, n;
    int          track_type = -1;
    uint64_t     tstamp=0;

    nestegg_io io = {nestegg_read_cb, nestegg_seek_cb, nestegg_tell_cb,
                     input->infile};
    nestegg_video_params params;
    nestegg_packet * pkt;

    if(nestegg_init(&input->nestegg_ctx, io, NULL))
        goto fail;

    if(nestegg_track_count(input->nestegg_ctx, &n))
        goto fail;

    for(i=0; i<n; i++)
    {
        track_type = nestegg_track_type(input->nestegg_ctx, i);

        if(track_type == NESTEGG_TRACK_VIDEO)
            break;
        else if(track_type < 0)
            goto fail;
    }

    if(nestegg_track_codec_id(input->nestegg_ctx, i) != NESTEGG_CODEC_VP8)
    {
        fprintf(stderr, "Not VP8 video, quitting.\n");
        exit(1);
    }

    input->video_track = i;

    if(nestegg_track_video_params(input->nestegg_ctx, i, &params))
        goto fail;

    *fps_den = 0;
    *fps_num = 0;
    *fourcc = VP8_FOURCC;
    *width = params.width;
    *height = params.height;
    return 1;
fail:
    input->nestegg_ctx = NULL;
    rewind(input->infile);
    return 0;
}


void show_progress(int frame_in, int frame_out, unsigned long dx_time)
{
    fprintf(stderr, "%d decoded frames/%d showed frames in %lu us (%.2f fps)\r",
            frame_in, frame_out, dx_time,
            (float)frame_out * 1000000.0 / (float)dx_time);
}


void generate_filename(const char *pattern, char *out, size_t q_len,
                       unsigned int d_w, unsigned int d_h,
                       unsigned int frame_in)
{
    const char *p = pattern;
    char *q = out;

    do
    {
        char *next_pat = strchr(p, '%');

        if(p == next_pat)
        {
            size_t pat_len;

            // parse the pattern
            q[q_len - 1] = '\0';
            switch(p[1])
            {
            case 'w': snprintf(q, q_len - 1, "%d", d_w); break;
            case 'h': snprintf(q, q_len - 1, "%d", d_h); break;
            case '1': snprintf(q, q_len - 1, "%d", frame_in); break;
            case '2': snprintf(q, q_len - 1, "%02d", frame_in); break;
            case '3': snprintf(q, q_len - 1, "%03d", frame_in); break;
            case '4': snprintf(q, q_len - 1, "%04d", frame_in); break;
            case '5': snprintf(q, q_len - 1, "%05d", frame_in); break;
            case '6': snprintf(q, q_len - 1, "%06d", frame_in); break;
            case '7': snprintf(q, q_len - 1, "%07d", frame_in); break;
            case '8': snprintf(q, q_len - 1, "%08d", frame_in); break;
            case '9': snprintf(q, q_len - 1, "%09d", frame_in); break;
            default:
                die("Unrecognized pattern %%%c\n", p[1]);
            }

            pat_len = strlen(q);
            if(pat_len >= q_len - 1)
                die("Output filename too long.\n");
            q += pat_len;
            p += 2;
            q_len -= pat_len;
        }
        else
        {
            size_t copy_len;

            // copy the next segment
            if(!next_pat)
                copy_len = strlen(p);
            else
                copy_len = next_pat - p;

            if(copy_len >= q_len - 1)
                die("Output filename too long.\n");

            memcpy(q, p, copy_len);
            q[copy_len] = '\0';
            q += copy_len;
            p += copy_len;
            q_len -= copy_len;
        }
    } while(*p);
}


int main(int argc, const char **argv_)
{
    vpx_codec_ctx_t          decoder;
    char                  *fn = NULL;
    int                    i;
    uint8_t               *buf = NULL;
    size_t                 buf_sz = 0, buf_alloc_sz = 0;
    FILE                  *infile;
    int                    frame_in = 0, frame_out = 0, flipuv = 0, noblit = 0, do_md5 = 0, progress = 0;
    int                    stop_after = 0, postproc = 0, summary = 0, quiet = 1;
    vpx_codec_iface_t       *iface = NULL;
    unsigned int           fourcc;
    unsigned long          dx_time = 0;
    struct arg               arg;
    char                   **argv, **argi, **argj;
    const char             *outfile_pattern = 0;
    char                    outfile[PATH_MAX];
    int                     single_file;
    int                     use_y4m = 1;
    unsigned int            width;
    unsigned int            height;
    unsigned int            fps_den;
    unsigned int            fps_num;
    void                   *out = NULL;
    vpx_codec_dec_cfg_t     cfg = {0};
#if CONFIG_VP8_DECODER
    vp8_postproc_cfg_t      vp8_pp_cfg = {0};
#endif
    struct input_ctx        input = {0};

    /* Parse command line */
    exec_name = argv_[0];
    argv = argv_dup(argc - 1, argv_ + 1);

    for (argi = argj = argv; (*argj = *argi); argi += arg.argv_step)
    {
        memset(&arg, 0, sizeof(arg));
        arg.argv_step = 1;

        if (arg_match(&arg, &codecarg, argi))
        {
            int j, k = -1;

            for (j = 0; j < sizeof(ifaces) / sizeof(ifaces[0]); j++)
                if (!strcmp(ifaces[j].name, arg.val))
                    k = j;

            if (k >= 0)
                iface = ifaces[k].iface;
            else
                die("Error: Unrecognized argument (%s) to --codec\n",
                    arg.val);
        }
        else if (arg_match(&arg, &outputfile, argi))
            outfile_pattern = arg.val;
        else if (arg_match(&arg, &use_yv12, argi))
        {
            use_y4m = 0;
            flipuv = 1;
        }
        else if (arg_match(&arg, &use_i420, argi))
        {
            use_y4m = 0;
            flipuv = 0;
        }
        else if (arg_match(&arg, &flipuvarg, argi))
            flipuv = 1;
        else if (arg_match(&arg, &noblitarg, argi))
            noblit = 1;
        else if (arg_match(&arg, &progressarg, argi))
            progress = 1;
        else if (arg_match(&arg, &limitarg, argi))
            stop_after = arg_parse_uint(&arg);
        else if (arg_match(&arg, &postprocarg, argi))
            postproc = 1;
        else if (arg_match(&arg, &md5arg, argi))
            do_md5 = 1;
        else if (arg_match(&arg, &summaryarg, argi))
            summary = 1;
        else if (arg_match(&arg, &threadsarg, argi))
            cfg.threads = arg_parse_uint(&arg);
        else if (arg_match(&arg, &verbosearg, argi))
            quiet = 0;

#if CONFIG_VP8_DECODER
        else if (arg_match(&arg, &addnoise_level, argi))
        {
            postproc = 1;
            vp8_pp_cfg.post_proc_flag |= VP8_ADDNOISE;
            vp8_pp_cfg.noise_level = arg_parse_uint(&arg);
        }
        else if (arg_match(&arg, &demacroblock_level, argi))
        {
            postproc = 1;
            vp8_pp_cfg.post_proc_flag |= VP8_DEMACROBLOCK;
            vp8_pp_cfg.deblocking_level = arg_parse_uint(&arg);
        }
        else if (arg_match(&arg, &deblock, argi))
        {
            postproc = 1;
            vp8_pp_cfg.post_proc_flag |= VP8_DEBLOCK;
        }
        else if (arg_match(&arg, &pp_debug_info, argi))
        {
            unsigned int level = arg_parse_uint(&arg);

            postproc = 1;
            vp8_pp_cfg.post_proc_flag &= ~0x7;

            if (level)
                vp8_pp_cfg.post_proc_flag |= level;
        }

#endif
        else
            argj++;
    }

    /* Check for unrecognized options */
    for (argi = argv; *argi; argi++)
        if (argi[0][0] == '-' && strlen(argi[0]) > 1)
            die("Error: Unrecognized option %s\n", *argi);

    /* Handle non-option arguments */
    fn = argv[0];

    if (!fn)
        usage_exit();

    /* Open file */
    infile = strcmp(fn, "-") ? fopen(fn, "rb") : set_binary_mode(stdin);

    if (!infile)
    {
        fprintf(stderr, "Failed to open file '%s'",
                strcmp(fn, "-") ? fn : "stdin");
        return EXIT_FAILURE;
    }

    /* Make sure we don't dump to the terminal, unless forced to with -o - */
    if(!outfile_pattern && isatty(fileno(stdout)) && !do_md5 && !noblit)
    {
        fprintf(stderr,
                "Not dumping raw video to your terminal. Use '-o -' to "
                "override.\n");
        return EXIT_FAILURE;
    }

    input.infile = infile;
    if(file_is_ivf(infile, &fourcc, &width, &height, &fps_den,
                   &fps_num))
        input.kind = IVF_FILE;
    else if(file_is_webm(&input, &fourcc, &width, &height, &fps_den, &fps_num))
        input.kind = WEBM_FILE;
    else if(file_is_raw(infile, &fourcc, &width, &height, &fps_den, &fps_num))
        input.kind = RAW_FILE;
    else
    {
        fprintf(stderr, "Unrecognized input file type.\n");
        return EXIT_FAILURE;
    }

    /* If the output file is not set or doesn't have a sequence number in
     * it, then we only open it once.
     */
    outfile_pattern = outfile_pattern ? outfile_pattern : "-";
    single_file = 1;
    {
        const char *p = outfile_pattern;
        do
        {
            p = strchr(p, '%');
            if(p && p[1] >= '1' && p[1] <= '9')
            {
                // pattern contains sequence number, so it's not unique.
                single_file = 0;
                break;
            }
            if(p)
                p++;
        } while(p);
    }

    if(single_file && !noblit)
    {
        generate_filename(outfile_pattern, outfile, sizeof(outfile)-1,
                          width, height, 0);
        out = out_open(outfile, do_md5);
    }

    if (use_y4m && !noblit)
    {
        char buffer[128];
        if (!single_file)
        {
            fprintf(stderr, "YUV4MPEG2 not supported with output patterns,"
                            " try --i420 or --yv12.\n");
            return EXIT_FAILURE;
        }

        if(input.kind == WEBM_FILE)
            if(webm_guess_framerate(&input, &fps_den, &fps_num))
            {
                fprintf(stderr, "Failed to guess framerate -- error parsing "
                                "webm file?\n");
                return EXIT_FAILURE;
            }


        /*Note: We can't output an aspect ratio here because IVF doesn't
           store one, and neither does VP8.
          That will have to wait until these tools support WebM natively.*/
        sprintf(buffer, "YUV4MPEG2 C%s W%u H%u F%u:%u I%c\n",
                "420jpeg", width, height, fps_num, fps_den, 'p');
        out_put(out, (unsigned char *)buffer, strlen(buffer), do_md5);
    }

    /* Try to determine the codec from the fourcc. */
    for (i = 0; i < sizeof(ifaces) / sizeof(ifaces[0]); i++)
        if ((fourcc & ifaces[i].fourcc_mask) == ifaces[i].fourcc)
        {
            vpx_codec_iface_t  *ivf_iface = ifaces[i].iface;

            if (iface && iface != ivf_iface)
                fprintf(stderr, "Notice -- IVF header indicates codec: %s\n",
                        ifaces[i].name);
            else
                iface = ivf_iface;

            break;
        }

    if (vpx_codec_dec_init(&decoder, iface ? iface :  ifaces[0].iface, &cfg,
                           postproc ? VPX_CODEC_USE_POSTPROC : 0))
    {
        fprintf(stderr, "Failed to initialize decoder: %s\n", vpx_codec_error(&decoder));
        return EXIT_FAILURE;
    }

    if (!quiet)
        fprintf(stderr, "%s\n", decoder.name);

#if CONFIG_VP8_DECODER

    if (vp8_pp_cfg.post_proc_flag
        && vpx_codec_control(&decoder, VP8_SET_POSTPROC, &vp8_pp_cfg))
    {
        fprintf(stderr, "Failed to configure postproc: %s\n", vpx_codec_error(&decoder));
        return EXIT_FAILURE;
    }

#endif

    /* Decode file */
    while (!read_frame(&input, &buf, &buf_sz, &buf_alloc_sz))
    {
        vpx_codec_iter_t  iter = NULL;
        vpx_image_t    *img;
        struct vpx_usec_timer timer;

        vpx_usec_timer_start(&timer);

        if (vpx_codec_decode(&decoder, buf, buf_sz, NULL, 0))
        {
            const char *detail = vpx_codec_error_detail(&decoder);
            fprintf(stderr, "Failed to decode frame: %s\n", vpx_codec_error(&decoder));

            if (detail)
                fprintf(stderr, "  Additional information: %s\n", detail);

            goto fail;
        }

        vpx_usec_timer_mark(&timer);
        dx_time += vpx_usec_timer_elapsed(&timer);

        ++frame_in;

        if ((img = vpx_codec_get_frame(&decoder, &iter)))
            ++frame_out;

        if (progress)
            show_progress(frame_in, frame_out, dx_time);

        if (!noblit)
        {
            if (img)
            {
                unsigned int y;
                char out_fn[PATH_MAX];
                uint8_t *buf;

                if (!single_file)
                {
                    size_t len = sizeof(out_fn)-1;

                    out_fn[len] = '\0';
                    generate_filename(outfile_pattern, out_fn, len-1,
                                      img->d_w, img->d_h, frame_in);
                    out = out_open(out_fn, do_md5);
                }
                else if(use_y4m)
                    out_put(out, (unsigned char *)"FRAME\n", 6, do_md5);

                buf = img->planes[VPX_PLANE_Y];

                for (y = 0; y < img->d_h; y++)
                {
                    out_put(out, buf, img->d_w, do_md5);
                    buf += img->stride[VPX_PLANE_Y];
                }

                buf = img->planes[flipuv?VPX_PLANE_V:VPX_PLANE_U];

                for (y = 0; y < (1 + img->d_h) / 2; y++)
                {
                    out_put(out, buf, (1 + img->d_w) / 2, do_md5);
                    buf += img->stride[VPX_PLANE_U];
                }

                buf = img->planes[flipuv?VPX_PLANE_U:VPX_PLANE_V];

                for (y = 0; y < (1 + img->d_h) / 2; y++)
                {
                    out_put(out, buf, (1 + img->d_w) / 2, do_md5);
                    buf += img->stride[VPX_PLANE_V];
                }

                if (!single_file)
                    out_close(out, out_fn, do_md5);
            }
        }

        if (stop_after && frame_in >= stop_after)
            break;
    }

    if (summary || progress)
    {
        show_progress(frame_in, frame_out, dx_time);
        fprintf(stderr, "\n");
    }

fail:

    if (vpx_codec_destroy(&decoder))
    {
        fprintf(stderr, "Failed to destroy decoder: %s\n", vpx_codec_error(&decoder));
        return EXIT_FAILURE;
    }

    if (single_file && !noblit)
        out_close(out, outfile, do_md5);

    if(input.nestegg_ctx)
        nestegg_destroy(input.nestegg_ctx);
    if(input.kind != WEBM_FILE)
        free(buf);
    fclose(infile);
    free(argv);

    return EXIT_SUCCESS;
}