C++ (Cpp) ff_generate_wave_table示例

示例#1

文件： af_aphaser.c 项目： TaoheGit/hmi_sdl_android

static int config_output(AVFilterLink *outlink)
{
    AudioPhaserContext *p = outlink->src->priv;
    AVFilterLink *inlink = outlink->src->inputs[0];

    p->delay_buffer_length = p->delay * 0.001 * inlink->sample_rate + 0.5;
    p->delay_buffer = av_calloc(p->delay_buffer_length, sizeof(*p->delay_buffer) * inlink->channels);
    p->modulation_buffer_length = inlink->sample_rate / p->speed + 0.5;
    p->modulation_buffer = av_malloc_array(p->modulation_buffer_length, sizeof(*p->modulation_buffer));

    if (!p->modulation_buffer || !p->delay_buffer)
        return AVERROR(ENOMEM);

    ff_generate_wave_table(p->type, AV_SAMPLE_FMT_S32,
                           p->modulation_buffer, p->modulation_buffer_length,
                           1., p->delay_buffer_length, M_PI / 2.0);

    p->delay_pos = p->modulation_pos = 0;

    switch (inlink->format) {
    case AV_SAMPLE_FMT_DBL:  p->phaser = phaser_dbl;  break;
    case AV_SAMPLE_FMT_DBLP: p->phaser = phaser_dblp; break;
    case AV_SAMPLE_FMT_FLT:  p->phaser = phaser_flt;  break;
    case AV_SAMPLE_FMT_FLTP: p->phaser = phaser_fltp; break;
    case AV_SAMPLE_FMT_S16:  p->phaser = phaser_s16;  break;
    case AV_SAMPLE_FMT_S16P: p->phaser = phaser_s16p; break;
    case AV_SAMPLE_FMT_S32:  p->phaser = phaser_s32;  break;
    case AV_SAMPLE_FMT_S32P: p->phaser = phaser_s32p; break;
    default: av_assert0(0);
    }

    return 0;
}

示例#2

文件： af_flanger.c 项目： 309746069/FFmpeg

static int config_input(AVFilterLink *inlink)
{
    AVFilterContext *ctx = inlink->dst;
    FlangerContext *s = ctx->priv;

    s->max_samples = (s->delay_min + s->delay_depth) * inlink->sample_rate + 2.5;
    s->lfo_length  = inlink->sample_rate / s->speed;
    s->delay_last  = av_calloc(inlink->channels, sizeof(*s->delay_last));
    s->lfo         = av_calloc(s->lfo_length, sizeof(*s->lfo));
    if (!s->lfo || !s->delay_last)
        return AVERROR(ENOMEM);

    ff_generate_wave_table(s->wave_shape, AV_SAMPLE_FMT_FLT, s->lfo, s->lfo_length,
                           floor(s->delay_min * inlink->sample_rate + 0.5),
                           s->max_samples - 2., 3 * M_PI_2);

    return av_samples_alloc_array_and_samples(&s->delay_buffer, NULL,
                                              inlink->channels, s->max_samples,
                                              inlink->format, 0);
}