stl->unitsize = (g_slist_length(sdi->channels) + 7) / 8;
stl->prev_sample = g_malloc0(stl->unitsize);
stl->pre_trigger_size = stl->unitsize * pre_trigger_samples;
stl->unitsize = (g_slist_length(sdi->channels) + 7) / 8;
stl->prev_sample = g_malloc0(stl->unitsize);
stl->pre_trigger_size = stl->unitsize * pre_trigger_samples;
stl->pre_trigger_head = stl->pre_trigger_buffer;
if (stl->pre_trigger_size > 0 && !stl->pre_trigger_buffer) {
stl->pre_trigger_head = stl->pre_trigger_buffer;
if (stl->pre_trigger_size > 0 && !stl->pre_trigger_buffer) {