void avfilter_filter_samples(AVFilterLink *link, AVFilterBufferRef *samplesref)
{
    void (*filter_samples)(AVFilterLink *, AVFilterBufferRef *);
    AVFilterPad *dst = link->dstpad;
    int i;

    FF_DPRINTF_START(NULL, filter_samples); ff_dlog_link(NULL, link, 1);

    if (!(filter_samples = dst->filter_samples))
        filter_samples = avfilter_default_filter_samples;

    /* prepare to copy the samples if the buffer has insufficient permissions */
    if ((dst->min_perms & samplesref->perms) != dst->min_perms ||
        dst->rej_perms & samplesref->perms) {

        av_log(link->dst, AV_LOG_DEBUG,
               "Copying audio data in avfilter (have perms %x, need %x, reject %x)\n",
               samplesref->perms, link->dstpad->min_perms, link->dstpad->rej_perms);

        link->cur_buf = avfilter_default_get_audio_buffer(link, dst->min_perms,
                                                          samplesref->audio->nb_samples);
        link->cur_buf->pts                = samplesref->pts;
        link->cur_buf->audio->sample_rate = samplesref->audio->sample_rate;

        /* Copy actual data into new samples buffer */
        for (i = 0; samplesref->data[i]; i++)
            memcpy(link->cur_buf->data[i], samplesref->data[i], samplesref->linesize[0]);

        avfilter_unref_buffer(samplesref);
    } else
        link->cur_buf = samplesref;

    filter_samples(link, link->cur_buf);
}