Function encode_slice

libavcodec/ffv1enc.c:1563–1684

static int encode_slice(AVCodecContext *c, void *arg)
{
    FFV1SliceContext *sc = arg;
    FFV1Context *f   = c->priv_data;
    int width        = sc->slice_width;
    int height       = sc->slice_height;
    int x            = sc->slice_x;
    int y            = sc->slice_y;
    const AVFrame *const p = f->cur_enc_frame;
    const int ps     = av_pix_fmt_desc_get(c->pix_fmt)->comp[0].step;
    int ret;
    RangeCoder c_bak = sc->c;
    const int chroma_width  = AV_CEIL_RSHIFT(width,  f->chroma_h_shift);
    const int chroma_height = AV_CEIL_RSHIFT(height, f->chroma_v_shift);
    const uint8_t *planes[4] = {p->data[0] + ps*x + y*p->linesize[0],
                                p->data[1] ? p->data[1] + ps*x + y*p->linesize[1] : NULL,
                                p->data[2] ? p->data[2] + ps*x + y*p->linesize[2] : NULL,
                                p->data[3] ? p->data[3] + ps*x + y*p->linesize[3] : NULL};
    int ac = f->ac;

    sc->slice_coding_mode = 0;
    if (f->version > 3 && f->colorspace == 1) {
        choose_rct_params(f, sc, planes, p->linesize, width, height);
    } else {
        sc->slice_rct_by_coef = 1;
        sc->slice_rct_ry_coef = 1;
    }

retry:
    if (f->key_frame)
        ff_ffv1_clear_slice_state(f, sc);
    if (f->version > 2) {
        encode_slice_header(f, sc);
    }

    if (sc->remap) {
      //Both the 16bit and 32bit remap do exactly the same thing but with 16bits we can
      //Implement this using a "histogram" while for 32bit that would be gb sized, thus a more
      //complex implementation sorting pairs is used.
      if (f->bits_per_raw_sample != 32) {
        if (f->colorspace == 0 && c->pix_fmt != AV_PIX_FMT_YA8 && c->pix_fmt != AV_PIX_FMT_YAF16) {
            const int cx            = x >> f->chroma_h_shift;
            const int cy            = y >> f->chroma_v_shift;

            //TODO decide on the order for the encoded remaps and loads. with golomb rice it
            // easier to have all range coded ones together, otherwise it may be nicer to handle each plane as a whole?

            load_plane(f, sc, p->data[0] + ps*x + y*p->linesize[0], width, height, p->linesize[0], 0, 1);

            if (f->chroma_planes) {
                load_plane(f, sc, p->data[1] + ps*cx+cy*p->linesize[1], chroma_width, chroma_height, p->linesize[1], 1, 1);
                load_plane(f, sc, p->data[2] + ps*cx+cy*p->linesize[2], chroma_width, chroma_height, p->linesize[2], 2, 1);
            }
            if (f->transparency)
                load_plane(f, sc, p->data[3] + ps*x + y*p->linesize[3], width, height, p->linesize[3], 3, 1);
        } else if (c->pix_fmt == AV_PIX_FMT_YA8 || c->pix_fmt == AV_PIX_FMT_YAF16) {
            load_plane(f, sc, p->data[0] +           ps*x + y*p->linesize[0], width, height, p->linesize[0], 0, 2);
            load_plane(f, sc, p->data[0] + (ps>>1) + ps*x + y*p->linesize[0], width, height, p->linesize[0], 1, 2);