rcc->buffer_index -= frame_size;
if (rcc->buffer_index < 0) {
av_log(s->avctx, AV_LOG_ERROR, "rc buffer underflow\n");
+ if (frame_size > max_rate && s->qscale == s->avctx->qmax) {
+ av_log(s->avctx, AV_LOG_ERROR, "max bitrate possibly too small or try trellis with large lmax or increase qmax\n");
+ }
rcc->buffer_index = 0;
}