cmdutils.c

    par = strchr(topic, '=');
    if (par)
        *par++ = 0;

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

    av_freep(&topic);
    return 0;
}

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

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

    return yesno;
}

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

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

    fclose(f);
    return ret;
}

void init_pts_correction(PtsCorrectionContext *ctx)
{
    ctx->num_faulty_pts = ctx->num_faulty_dts = 0;
    ctx->last_pts = ctx->last_dts = INT64_MIN;
}

int64_t guess_correct_pts(PtsCorrectionContext *ctx, int64_t reordered_pts,
                          int64_t dts)
{
    int64_t pts = AV_NOPTS_VALUE;

    if (dts != AV_NOPTS_VALUE) {
        ctx->num_faulty_dts += dts <= ctx->last_dts;
        ctx->last_dts = dts;
    }
    if (reordered_pts != AV_NOPTS_VALUE) {
        ctx->num_faulty_pts += reordered_pts <= ctx->last_pts;
        ctx->last_pts = reordered_pts;
    }
    if ((ctx->num_faulty_pts<=ctx->num_faulty_dts || dts == AV_NOPTS_VALUE)
        && reordered_pts != AV_NOPTS_VALUE)
        pts = reordered_pts;
    else
        pts = dts;

    return pts;
}

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

    if (is_path) {
        av_strlcpy(filename, preset_name, filename_size);
        f = fopen(filename, "r");
    } else {
        for (i = 0; i < 3 && !f; i++) {
            if (!base[i])
                continue;
            snprintf(filename, filename_size, "%s%s/%s.avpreset", base[i],
                     i != 1 ? "" : "/.avconv", preset_name);
            f = fopen(filename, "r");
            if (!f && codec_name) {
                snprintf(filename, filename_size,
                         "%s%s/%s-%s.avpreset",
                         base[i], i != 1 ? "" : "/.avconv", codec_name,
                         preset_name);
                f = fopen(filename, "r");
            }
        }
    }

    return f;
}

int check_stream_specifier(AVFormatContext *s, AVStream *st, const char *spec)
{
    if (*spec <= '9' && *spec >= '0') /* opt:index */
        return strtol(spec, NULL, 0) == st->index;
    else if (*spec == 'v' || *spec == 'a' || *spec == 's' || *spec == 'd' ||
             *spec == 't') { /* opt:[vasdt] */
        enum AVMediaType type;

        switch (*spec++) {
        case 'v': type = AVMEDIA_TYPE_VIDEO;      break;
        case 'a': type = AVMEDIA_TYPE_AUDIO;      break;
        case 's': type = AVMEDIA_TYPE_SUBTITLE;   break;
        case 'd': type = AVMEDIA_TYPE_DATA;       break;
        case 't': type = AVMEDIA_TYPE_ATTACHMENT; break;
        default:  av_assert0(0);
        }
        if (type != st->codec->codec_type)
            return 0;
        if (*spec++ == ':') { /* possibly followed by :index */
            int i, index = strtol(spec, NULL, 0);
            for (i = 0; i < s->nb_streams; i++)
                if (s->streams[i]->codec->codec_type == type && index-- == 0)
                   return i == st->index;
            return 0;
        }
        return 1;
    } else if (*spec == 'p' && *(spec + 1) == ':') {
        int prog_id, i, j;
        char *endptr;
        spec += 2;
        prog_id = strtol(spec, &endptr, 0);
        for (i = 0; i < s->nb_programs; i++) {
            if (s->programs[i]->id != prog_id)
                continue;

            if (*endptr++ == ':') {
                int stream_idx = strtol(endptr, NULL, 0);
                return stream_idx >= 0 &&
                    stream_idx < s->programs[i]->nb_stream_indexes &&
                    st->index == s->programs[i]->stream_index[stream_idx];
            }

            for (j = 0; j < s->programs[i]->nb_stream_indexes; j++)
                if (st->index == s->programs[i]->stream_index[j])
                    return 1;
        }
        return 0;
    } else if (!*spec) /* empty specifier, matches everything */
        return 1;

    av_log(s, AV_LOG_ERROR, "Invalid stream specifier: %s.\n", spec);
    return AVERROR(EINVAL);
}

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

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

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

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

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

        if (av_opt_find(&cc, t->key, NULL, flags, AV_OPT_SEARCH_FAKE_OBJ) ||
            (codec && codec->priv_class &&
             av_opt_find(&codec->priv_class, t->key, NULL, flags,
                         AV_OPT_SEARCH_FAKE_OBJ)))
            av_dict_set(&ret, t->key, t->value, 0);
        else if (t->key[0] == prefix &&
                 av_opt_find(&cc, t->key + 1, NULL, flags,
                             AV_OPT_SEARCH_FAKE_OBJ))
            av_dict_set(&ret, t->key + 1, t->value, 0);

        if (p)
            *p = ':';
    }
    return ret;
}

AVDictionary **setup_find_stream_info_opts(AVFormatContext *s,
                                           AVDictionary *codec_opts)
{
    int i;
    AVDictionary **opts;

    if (!s->nb_streams)
        return NULL;
    opts = av_mallocz(s->nb_streams * sizeof(*opts));
    if (!opts) {
        av_log(NULL, AV_LOG_ERROR,
               "Could not alloc memory for stream options.\n");
        return NULL;
    }
    for (i = 0; i < s->nb_streams; i++)
        opts[i] = filter_codec_opts(codec_opts, s->streams[i]->codec->codec_id,
                                    s, s->streams[i], NULL);
    return opts;
}

void *grow_array(void *array, int elem_size, int *size, int new_size)
{
    if (new_size >= INT_MAX / elem_size) {
        av_log(NULL, AV_LOG_ERROR, "Array too big.\n");
        exit(1);
    }
    if (*size < new_size) {
        uint8_t *tmp = av_realloc(array, new_size*elem_size);
        if (!tmp) {
            av_log(NULL, AV_LOG_ERROR, "Could not alloc buffer.\n");
            exit(1);
        }
        memset(tmp + *size*elem_size, 0, (new_size-*size) * elem_size);
        *size = new_size;
        return tmp;
    }
    return array;
}

static int alloc_buffer(FrameBuffer **pool, 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);

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

    avcodec_align_dimensions(s, &w, &h);
    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->data[i] = buf->base[i];
        else if (buf->base[i])
            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->pool    = pool;

    *pbuf = buf;
    return 0;
}

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

    if (!*pool && (ret = alloc_buffer(pool, s, pool)) < 0)
        return ret;

    buf              = *pool;
    *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(pool, s, &buf)) < 0)
            return ret;
    }
    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 unref_buffer(FrameBuffer *buf)
{
    FrameBuffer **pool = buf->pool;

    av_assert0(buf->refcount);
    buf->refcount--;
    if (!buf->refcount) {
        buf->next = *pool;
        *pool = buf;
    }
}

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

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

    unref_buffer(buf);
}

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

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