void avcodec_align_dimensions2(AVCodecContext *s, int *width, int *height,
                               int linesize_align[AV_NUM_DATA_POINTERS])
{
    int i;
    int w_align = 1;
    int h_align = 1;
    AVPixFmtDescriptor const *desc = av_pix_fmt_desc_get(s->pix_fmt);

    if (desc) {
        w_align = 1 << desc->log2_chroma_w;
        h_align = 1 << desc->log2_chroma_h;
    }

    switch (s->pix_fmt) {
    case AV_PIX_FMT_YUV420P:
    case AV_PIX_FMT_YUYV422:
    case AV_PIX_FMT_YVYU422:
    case AV_PIX_FMT_UYVY422:
    case AV_PIX_FMT_YUV422P:
    case AV_PIX_FMT_YUV440P:
    case AV_PIX_FMT_YUV444P:
    case AV_PIX_FMT_GBRP:
    case AV_PIX_FMT_GBRAP:
    case AV_PIX_FMT_GRAY8:
    case AV_PIX_FMT_GRAY16BE:
    case AV_PIX_FMT_GRAY16LE:
    case AV_PIX_FMT_YUVJ420P:
    case AV_PIX_FMT_YUVJ422P:
    case AV_PIX_FMT_YUVJ440P:
    case AV_PIX_FMT_YUVJ444P:
    case AV_PIX_FMT_YUVA420P:
    case AV_PIX_FMT_YUVA422P:
    case AV_PIX_FMT_YUVA444P:
    case AV_PIX_FMT_YUV420P9LE:
    case AV_PIX_FMT_YUV420P9BE:
    case AV_PIX_FMT_YUV420P10LE:
    case AV_PIX_FMT_YUV420P10BE:
    case AV_PIX_FMT_YUV420P12LE:
    case AV_PIX_FMT_YUV420P12BE:
    case AV_PIX_FMT_YUV420P14LE:
    case AV_PIX_FMT_YUV420P14BE:
    case AV_PIX_FMT_YUV420P16LE:
    case AV_PIX_FMT_YUV420P16BE:
    case AV_PIX_FMT_YUVA420P9LE:
    case AV_PIX_FMT_YUVA420P9BE:
    case AV_PIX_FMT_YUVA420P10LE:
    case AV_PIX_FMT_YUVA420P10BE:
    case AV_PIX_FMT_YUVA420P16LE:
    case AV_PIX_FMT_YUVA420P16BE:
    case AV_PIX_FMT_YUV422P9LE:
    case AV_PIX_FMT_YUV422P9BE:
    case AV_PIX_FMT_YUV422P10LE:
    case AV_PIX_FMT_YUV422P10BE:
    case AV_PIX_FMT_YUV422P12LE:
    case AV_PIX_FMT_YUV422P12BE:
    case AV_PIX_FMT_YUV422P14LE:
    case AV_PIX_FMT_YUV422P14BE:
    case AV_PIX_FMT_YUV422P16LE:
    case AV_PIX_FMT_YUV422P16BE:
    case AV_PIX_FMT_YUVA422P9LE:
    case AV_PIX_FMT_YUVA422P9BE:
    case AV_PIX_FMT_YUVA422P10LE:
    case AV_PIX_FMT_YUVA422P10BE:
    case AV_PIX_FMT_YUVA422P16LE:
    case AV_PIX_FMT_YUVA422P16BE:
    case AV_PIX_FMT_YUV440P10LE:
    case AV_PIX_FMT_YUV440P10BE:
    case AV_PIX_FMT_YUV440P12LE:
    case AV_PIX_FMT_YUV440P12BE:
    case AV_PIX_FMT_YUV444P9LE:
    case AV_PIX_FMT_YUV444P9BE:
    case AV_PIX_FMT_YUV444P10LE:
    case AV_PIX_FMT_YUV444P10BE:
    case AV_PIX_FMT_YUV444P12LE:
    case AV_PIX_FMT_YUV444P12BE:
    case AV_PIX_FMT_YUV444P14LE:
    case AV_PIX_FMT_YUV444P14BE:
    case AV_PIX_FMT_YUV444P16LE:
    case AV_PIX_FMT_YUV444P16BE:
    case AV_PIX_FMT_YUVA444P9LE:
    case AV_PIX_FMT_YUVA444P9BE:
    case AV_PIX_FMT_YUVA444P10LE:
    case AV_PIX_FMT_YUVA444P10BE:
    case AV_PIX_FMT_YUVA444P16LE:
    case AV_PIX_FMT_YUVA444P16BE:
    case AV_PIX_FMT_GBRP9LE:
    case AV_PIX_FMT_GBRP9BE:
    case AV_PIX_FMT_GBRP10LE:
    case AV_PIX_FMT_GBRP10BE:
    case AV_PIX_FMT_GBRP12LE:
    case AV_PIX_FMT_GBRP12BE:
    case AV_PIX_FMT_GBRP14LE:
    case AV_PIX_FMT_GBRP14BE:
    case AV_PIX_FMT_GBRP16LE:
    case AV_PIX_FMT_GBRP16BE:
    case AV_PIX_FMT_GBRAP12LE:
    case AV_PIX_FMT_GBRAP12BE:
    case AV_PIX_FMT_GBRAP16LE:
    case AV_PIX_FMT_GBRAP16BE:
        w_align = 16; //FIXME assume 16 pixel per macroblock
        h_align = 16 * 2; // interlaced needs 2 macroblocks height
        break;
    case AV_PIX_FMT_YUV411P:
    case AV_PIX_FMT_YUVJ411P:
    case AV_PIX_FMT_UYYVYY411:
        w_align = 32;
        h_align = 16 * 2;
        break;
    case AV_PIX_FMT_YUV410P:
        if (s->codec_id == AV_CODEC_ID_SVQ1) {
            w_align = 64;
            h_align = 64;
        }
        break;
    case AV_PIX_FMT_RGB555:
        if (s->codec_id == AV_CODEC_ID_RPZA) {
            w_align = 4;
            h_align = 4;
        }
        break;
    case AV_PIX_FMT_PAL8:
    case AV_PIX_FMT_BGR8:
    case AV_PIX_FMT_RGB8:
        if (s->codec_id == AV_CODEC_ID_SMC ||
            s->codec_id == AV_CODEC_ID_CINEPAK) {
            w_align = 4;
            h_align = 4;
        }
        if (s->codec_id == AV_CODEC_ID_JV) {
            w_align = 8;
            h_align = 8;
        }
        break;
    case AV_PIX_FMT_BGR24:
        if ((s->codec_id == AV_CODEC_ID_MSZH) ||
            (s->codec_id == AV_CODEC_ID_ZLIB)) {
            w_align = 4;
            h_align = 4;
        }
        break;
    case AV_PIX_FMT_RGB24:
        if (s->codec_id == AV_CODEC_ID_CINEPAK) {
            w_align = 4;
            h_align = 4;
        }
        break;
    default:
        break;
    }

    if (s->codec_id == AV_CODEC_ID_IFF_ILBM) {
        w_align = FFMAX(w_align, 8);
    }

    *width  = FFALIGN(*width, w_align);
    *height = FFALIGN(*height, h_align);
    if (s->codec_id == AV_CODEC_ID_H264 || s->lowres) {
        // some of the optimized chroma MC reads one line too much
        // which is also done in mpeg decoders with lowres > 0
        *height += 2;

        // H.264 uses edge emulation for out of frame motion vectors, for this
        // it requires a temporary area large enough to hold a 21x21 block,
        // increasing witdth ensure that the temporary area is large enough,
        // the next rounded up width is 32
        *width = FFMAX(*width, 32);
    }

    for (i = 0; i < 4; i++)
        linesize_align[i] = STRIDE_ALIGN;
}
Unknown