static int output_data_internal(MLPDecodeContext *m, unsigned int substr,
                                uint8_t *data, unsigned int *data_size, int is32)
{
    SubStream *s = &m->substream[substr];
    unsigned int i, out_ch = 0;
    int32_t *data_32 = (int32_t*) data;
    int16_t *data_16 = (int16_t*) data;

    if (*data_size < (s->max_channel + 1) * s->blockpos * (is32 ? 4 : 2))
        return -1;

    for (i = 0; i < s->blockpos; i++) {
        for (out_ch = 0; out_ch <= s->max_matrix_channel; out_ch++) {
            int mat_ch = s->ch_assign[out_ch];
            int32_t sample = m->sample_buffer[i][mat_ch]
                          << s->output_shift[mat_ch];
            s->lossless_check_data ^= (sample & 0xffffff) << mat_ch;
            if (is32) *data_32++ = sample << 8;
            else      *data_16++ = sample >> 8;
        }
    }

    *data_size = i * out_ch * (is32 ? 4 : 2);

    return 0;
}