+ if (s->num_channels < 0) {
+ av_log(avctx, AV_LOG_ERROR, "invalid number of channels %d\n", s->num_channels);
+ return AVERROR_INVALIDDATA;
+ } else if (s->num_channels > WMAPRO_MAX_CHANNELS) {
+ av_log_ask_for_sample(avctx, "unsupported number of channels\n");
+ return AVERROR_PATCHWELCOME;
+ }
+
+ /** init previous block len */
+ for (i = 0; i < s->num_channels; i++)
+ s->channel[i].prev_block_len = s->samples_per_frame;
+