static av_always_inline int encode_line(FFV1Context *s, int w,
                                        int16_t *sample[3],
                                        int plane_index, int bits)
{
    PlaneContext *const p = &s->plane[plane_index];
    RangeCoder *const c   = &s->c;
    int x;
    int run_index = s->run_index;
    int run_count = 0;
    int run_mode  = 0;

    if (s->ac) {
        if (c->bytestream_end - c->bytestream < w * 35) {
            av_log(s->avctx, AV_LOG_ERROR, "encoded frame too large\n");
            return AVERROR_INVALIDDATA;
        }
    } else {
        if (s->pb.buf_end - s->pb.buf - (put_bits_count(&s->pb) >> 3) < w * 4) {
            av_log(s->avctx, AV_LOG_ERROR, "encoded frame too large\n");
            return AVERROR_INVALIDDATA;
        }
    }

    if (s->slice_coding_mode == 1) {
        for (x = 0; x < w; x++) {
            int i;
            int v = sample[0][x];
            for (i = bits-1; i>=0; i--) {
                uint8_t state = 128;
                put_rac(c, &state, (v>>i) & 1);
            }
        }
        return 0;
    }

    for (x = 0; x < w; x++) {
        int diff, context;

        context = get_context(p, sample[0] + x, sample[1] + x, sample[2] + x);
        diff    = sample[0][x] - predict(sample[0] + x, sample[1] + x);

        if (context < 0) {
            context = -context;
            diff    = -diff;
        }

        diff = fold(diff, bits);

        if (s->ac) {
            if (s->flags & CODEC_FLAG_PASS1) {
                put_symbol_inline(c, p->state[context], diff, 1, s->rc_stat,
                                  s->rc_stat2[p->quant_table_index][context]);
            } else {
                put_symbol_inline(c, p->state[context], diff, 1, NULL, NULL);
            }
        } else {
            if (context == 0)
                run_mode = 1;

            if (run_mode) {
                if (diff) {
                    while (run_count >= 1 << ff_log2_run[run_index]) {
                        run_count -= 1 << ff_log2_run[run_index];
                        run_index++;
                        put_bits(&s->pb, 1, 1);
                    }

                    put_bits(&s->pb, 1 + ff_log2_run[run_index], run_count);
                    if (run_index)
                        run_index--;
                    run_count = 0;
                    run_mode  = 0;
                    if (diff > 0)
                        diff--;
                } else {
                    run_count++;
                }
            }

            av_dlog(s->avctx, "count:%d index:%d, mode:%d, x:%d pos:%d\n",
                    run_count, run_index, run_mode, x,
                    (int)put_bits_count(&s->pb));

            if (run_mode == 0)
                put_vlc_symbol(&s->pb, &p->vlc_state[context], diff, bits);
        }
    }
    if (run_mode) {
        while (run_count >= 1 << ff_log2_run[run_index]) {
            run_count -= 1 << ff_log2_run[run_index];
            run_index++;
            put_bits(&s->pb, 1, 1);
        }

        if (run_count)
            put_bits(&s->pb, 1, 1);
    }
    s->run_index = run_index;

    return 0;
}