static int rate_control(AVCodecContext *avctx, void *arg) { SliceArgs *slice_dat = arg; VC2EncContext *s = slice_dat->ctx; const int sx = slice_dat->x; const int sy = slice_dat->y; int quant_buf[2], bits_buf[2], quant = s->q_start, range = s->q_start/3; const int64_t top = slice_dat->bits_ceil; const double percent = s->tolerance; const double bottom = top - top*(percent/100.0f); int bits = count_hq_slice(s, sx, sy, quant); range -= range & 1; /* Make it an even number */ while ((bits > top) || (bits < bottom)) { range *= bits > top ? +1 : -1; quant = av_clip(quant + range, 0, s->q_ceil); bits = count_hq_slice(s, sx, sy, quant); range = av_clip(range/2, 1, s->q_ceil); if (quant_buf[1] == quant) { quant = bits_buf[0] < bits ? quant_buf[0] : quant; bits = bits_buf[0] < bits ? bits_buf[0] : bits; break; } quant_buf[1] = quant_buf[0]; quant_buf[0] = quant; bits_buf[1] = bits_buf[0]; bits_buf[0] = bits; } slice_dat->quant_idx = av_clip(quant, 0, s->q_ceil); slice_dat->bytes = FFALIGN((bits >> 3), s->size_scaler) + 4 + s->prefix_bytes; return 0; }