static inline int available_samples(AVFrame *out)
{
    int bytes_per_sample = av_get_bytes_per_sample(out->format);
    int samples = out->linesize[0] / bytes_per_sample;

    if (av_sample_fmt_is_planar(out->format)) {
        return samples;
    } else {
        int channels = av_get_channel_layout_nb_channels(out->channel_layout);
        return samples / channels;
    }
}