FFmpeg/libavcodec/proresenc.c

/*
 * Apple ProRes encoder
 *
 * Copyright (c) 2012 Konstantin Shishkov
 *
 * This file is part of Libav.
 *
 * Libav is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public
 * License as published by the Free Software Foundation; either
 * version 2.1 of the License, or (at your option) any later version.
 *
 * Libav is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public
 * License along with Libav; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
 */

#include "libavutil/opt.h"
#include "avcodec.h"
#include "put_bits.h"
#include "bytestream.h"
#include "internal.h"
#include "proresdsp.h"
#include "proresdata.h"

#define CFACTOR_Y422 2
#define CFACTOR_Y444 3

#define MAX_MBS_PER_SLICE 8

#define MAX_PLANES 3 // should be increased to 4 when there's PIX_FMT_YUV444AP10

enum {
    PRORES_PROFILE_PROXY = 0,
    PRORES_PROFILE_LT,
    PRORES_PROFILE_STANDARD,
    PRORES_PROFILE_HQ,
};

#define NUM_MB_LIMITS 4
static const int prores_mb_limits[NUM_MB_LIMITS] = {
    1620, // up to 720x576
    2700, // up to 960x720
    6075, // up to 1440x1080
    9216, // up to 2048x1152
};

static const struct prores_profile {
    const char *full_name;
    uint32_t    tag;
    int         min_quant;
    int         max_quant;
    int         br_tab[NUM_MB_LIMITS];
    uint8_t     quant[64];
} prores_profile_info[4] = {
    {
        .full_name = "proxy",
        .tag       = MKTAG('a', 'p', 'c', 'o'),
        .min_quant = 4,
        .max_quant = 8,
        .br_tab    = { 300, 242, 220, 194 },
        .quant     = {
             4,  7,  9, 11, 13, 14, 15, 63,
             7,  7, 11, 12, 14, 15, 63, 63,
             9, 11, 13, 14, 15, 63, 63, 63,
            11, 11, 13, 14, 63, 63, 63, 63,
            11, 13, 14, 63, 63, 63, 63, 63,
            13, 14, 63, 63, 63, 63, 63, 63,
            13, 63, 63, 63, 63, 63, 63, 63,
            63, 63, 63, 63, 63, 63, 63, 63,
        },
    },
    {
        .full_name = "LT",
        .tag       = MKTAG('a', 'p', 'c', 's'),
        .min_quant = 1,
        .max_quant = 9,
        .br_tab    = { 720, 560, 490, 440 },
        .quant     = {
             4,  5,  6,  7,  9, 11, 13, 15,
             5,  5,  7,  8, 11, 13, 15, 17,
             6,  7,  9, 11, 13, 15, 15, 17,
             7,  7,  9, 11, 13, 15, 17, 19,
             7,  9, 11, 13, 14, 16, 19, 23,
             9, 11, 13, 14, 16, 19, 23, 29,
             9, 11, 13, 15, 17, 21, 28, 35,
            11, 13, 16, 17, 21, 28, 35, 41,
        },
    },
    {
        .full_name = "standard",
        .tag       = MKTAG('a', 'p', 'c', 'n'),
        .min_quant = 1,
        .max_quant = 6,
        .br_tab    = { 1050, 808, 710, 632 },
        .quant     = {
             4,  4,  5,  5,  6,  7,  7,  9,
             4,  4,  5,  6,  7,  7,  9,  9,
             5,  5,  6,  7,  7,  9,  9, 10,
             5,  5,  6,  7,  7,  9,  9, 10,
             5,  6,  7,  7,  8,  9, 10, 12,
             6,  7,  7,  8,  9, 10, 12, 15,
             6,  7,  7,  9, 10, 11, 14, 17,
             7,  7,  9, 10, 11, 14, 17, 21,
        },
    },
    {
        .full_name = "high quality",
        .tag       = MKTAG('a', 'p', 'c', 'h'),
        .min_quant = 1,
        .max_quant = 6,
        .br_tab    = { 1566, 1216, 1070, 950 },
        .quant     = {
             4,  4,  4,  4,  4,  4,  4,  4,
             4,  4,  4,  4,  4,  4,  4,  4,
             4,  4,  4,  4,  4,  4,  4,  4,
             4,  4,  4,  4,  4,  4,  4,  5,
             4,  4,  4,  4,  4,  4,  5,  5,
             4,  4,  4,  4,  4,  5,  5,  6,
             4,  4,  4,  4,  5,  5,  6,  7,
             4,  4,  4,  4,  5,  6,  7,  7,
        },
    }
// for 4444 profile bitrate numbers are { 2350, 1828, 1600, 1425 }
};

#define TRELLIS_WIDTH 16
#define SCORE_LIMIT   INT_MAX / 2

struct TrellisNode {
    int prev_node;
    int quant;
    int bits;
    int score;
};

#define MAX_STORED_Q 16

typedef struct ProresContext {
    AVClass *class;
    DECLARE_ALIGNED(16, DCTELEM, blocks)[MAX_PLANES][64 * 4 * MAX_MBS_PER_SLICE];
    DECLARE_ALIGNED(16, uint16_t, emu_buf)[16*16];
    int16_t quants[MAX_STORED_Q][64];
    int16_t custom_q[64];

    ProresDSPContext dsp;
    ScanTable  scantable;

    int mb_width, mb_height;
    int mbs_per_slice;
    int num_chroma_blocks, chroma_factor;
    int slices_width;
    int num_slices;
    int num_planes;
    int bits_per_mb;

    int frame_size;

    int profile;
    const struct prores_profile *profile_info;

    struct TrellisNode *nodes;
    int *slice_q;
} ProresContext;

static void get_slice_data(ProresContext *ctx, const uint16_t *src,
                           int linesize, int x, int y, int w, int h,
                           DCTELEM *blocks,
                           int mbs_per_slice, int blocks_per_mb)
{
    const uint16_t *esrc;
    const int mb_width = 4 * blocks_per_mb;
    int elinesize;
    int i, j, k;

    for (i = 0; i < mbs_per_slice; i++, src += mb_width) {
        if (x >= w) {
            memset(blocks, 0, 64 * (mbs_per_slice - i) * blocks_per_mb
                              * sizeof(*blocks));
            return;
        }
        if (x + mb_width <= w && y + 16 <= h) {
            esrc      = src;
            elinesize = linesize;
        } else {
            int bw, bh, pix;
            const int estride = 16 / sizeof(*ctx->emu_buf);

            esrc      = ctx->emu_buf;
            elinesize = 16;

            bw = FFMIN(w - x, mb_width);
            bh = FFMIN(h - y, 16);

            for (j = 0; j < bh; j++) {
                memcpy(ctx->emu_buf + j * estride, src + j * linesize,
                       bw * sizeof(*src));
                pix = ctx->emu_buf[j * estride + bw - 1];
                for (k = bw; k < mb_width; k++)
                    ctx->emu_buf[j * estride + k] = pix;
            }
            for (; j < 16; j++)
                memcpy(ctx->emu_buf + j * estride,
                       ctx->emu_buf + (bh - 1) * estride,
                       mb_width * sizeof(*ctx->emu_buf));
        }
        ctx->dsp.fdct(esrc, elinesize, blocks);
        blocks += 64;
        if (blocks_per_mb > 2) {
            ctx->dsp.fdct(src + 8, linesize, blocks);
            blocks += 64;
        }
        ctx->dsp.fdct(src + linesize * 4, linesize, blocks);
        blocks += 64;
        if (blocks_per_mb > 2) {
            ctx->dsp.fdct(src + linesize * 4 + 8, linesize, blocks);
            blocks += 64;
        }

        x += mb_width;
    }
}

/**
 * Write an unsigned rice/exp golomb codeword.
 */
static inline void encode_vlc_codeword(PutBitContext *pb, uint8_t codebook, int val)
{
    unsigned int rice_order, exp_order, switch_bits, switch_val;
    int exponent;

    /* number of prefix bits to switch between Rice and expGolomb */
    switch_bits = (codebook & 3) + 1;
    rice_order  =  codebook >> 5;       /* rice code order */
    exp_order   = (codebook >> 2) & 7;  /* exp golomb code order */

    switch_val  = switch_bits << rice_order;

    if (val >= switch_val) {
        val -= switch_val - (1 << exp_order);
        exponent = av_log2(val);

        put_bits(pb, exponent - exp_order + switch_bits, 0);
        put_bits(pb, 1, 1);
        put_bits(pb, exponent, val);
    } else {
        exponent = val >> rice_order;

        if (exponent)
            put_bits(pb, exponent, 0);
        put_bits(pb, 1, 1);
        if (rice_order)
            put_sbits(pb, rice_order, val);
    }
}

#define GET_SIGN(x)  ((x) >> 31)
#define MAKE_CODE(x) (((x) << 1) ^ GET_SIGN(x))

static void encode_dcs(PutBitContext *pb, DCTELEM *blocks,
                       int blocks_per_slice, int scale)
{
    int i;
    int codebook = 3, code, dc, prev_dc, delta, sign, new_sign;

    prev_dc = (blocks[0] - 0x4000) / scale;
    encode_vlc_codeword(pb, FIRST_DC_CB, MAKE_CODE(prev_dc));
    sign     = 0;
    codebook = 3;
    blocks  += 64;

    for (i = 1; i < blocks_per_slice; i++, blocks += 64) {
        dc       = (blocks[0] - 0x4000) / scale;
        delta    = dc - prev_dc;
        new_sign = GET_SIGN(delta);
        delta    = (delta ^ sign) - sign;
        code     = MAKE_CODE(delta);
        encode_vlc_codeword(pb, ff_prores_dc_codebook[codebook], code);
        codebook = (code + (code & 1)) >> 1;
        codebook = FFMIN(codebook, 3);
        sign     = new_sign;
        prev_dc  = dc;
    }
}

static void encode_acs(PutBitContext *pb, DCTELEM *blocks,
                       int blocks_per_slice,
                       int plane_size_factor,
                       const uint8_t *scan, const int16_t *qmat)
{
    int idx, i;
    int run, level, run_cb, lev_cb;
    int max_coeffs, abs_level;

    max_coeffs = blocks_per_slice << 6;
    run_cb     = ff_prores_run_to_cb_index[4];
    lev_cb     = ff_prores_lev_to_cb_index[2];
    run        = 0;

    for (i = 1; i < 64; i++) {
        for (idx = scan[i]; idx < max_coeffs; idx += 64) {
            level = blocks[idx] / qmat[scan[i]];
            if (level) {
                abs_level = FFABS(level);
                encode_vlc_codeword(pb, ff_prores_ac_codebook[run_cb], run);
                encode_vlc_codeword(pb, ff_prores_ac_codebook[lev_cb],
                                    abs_level - 1);
                put_sbits(pb, 1, GET_SIGN(level));

                run_cb = ff_prores_run_to_cb_index[FFMIN(run, 15)];
                lev_cb = ff_prores_lev_to_cb_index[FFMIN(abs_level, 9)];
                run    = 0;
            } else {
                run++;
            }
        }
    }
}

static int encode_slice_plane(ProresContext *ctx, PutBitContext *pb,
                              const uint16_t *src, int linesize,
                              int mbs_per_slice, DCTELEM *blocks,
                              int blocks_per_mb, int plane_size_factor,
                              const int16_t *qmat)
{
    int blocks_per_slice, saved_pos;

    saved_pos = put_bits_count(pb);
    blocks_per_slice = mbs_per_slice * blocks_per_mb;

    encode_dcs(pb, blocks, blocks_per_slice, qmat[0]);
    encode_acs(pb, blocks, blocks_per_slice, plane_size_factor,
               ctx->scantable.permutated, qmat);
    flush_put_bits(pb);

    return (put_bits_count(pb) - saved_pos) >> 3;
}

static int encode_slice(AVCodecContext *avctx, const AVFrame *pic,
                        PutBitContext *pb,
                        int sizes[4], int x, int y, int quant,
                        int mbs_per_slice)
{
    ProresContext *ctx = avctx->priv_data;
    int i, xp, yp;
    int total_size = 0;
    const uint16_t *src;
    int slice_width_factor = av_log2(mbs_per_slice);
    int num_cblocks, pwidth;
    int plane_factor, is_chroma;
    uint16_t *qmat;

    if (quant < MAX_STORED_Q) {
        qmat = ctx->quants[quant];
    } else {
        qmat = ctx->custom_q;
        for (i = 0; i < 64; i++)
            qmat[i] = ctx->profile_info->quant[i] * quant;
    }

    for (i = 0; i < ctx->num_planes; i++) {
        is_chroma    = (i == 1 || i == 2);
        plane_factor = slice_width_factor + 2;
        if (is_chroma)
            plane_factor += ctx->chroma_factor - 3;
        if (!is_chroma || ctx->chroma_factor == CFACTOR_Y444) {
            xp          = x << 4;
            yp          = y << 4;
            num_cblocks = 4;
            pwidth      = avctx->width;
        } else {
            xp          = x << 3;
            yp          = y << 4;
            num_cblocks = 2;
            pwidth      = avctx->width >> 1;
        }
        src = (const uint16_t*)(pic->data[i] + yp * pic->linesize[i]) + xp;

        get_slice_data(ctx, src, pic->linesize[i], xp, yp,
                       pwidth, avctx->height, ctx->blocks[0],
                       mbs_per_slice, num_cblocks);
        sizes[i] = encode_slice_plane(ctx, pb, src, pic->linesize[i],
                                      mbs_per_slice, ctx->blocks[0],
                                      num_cblocks, plane_factor,
                                      qmat);
        total_size += sizes[i];
    }
    return total_size;
}

static inline int estimate_vlc(uint8_t codebook, int val)
{
    unsigned int rice_order, exp_order, switch_bits, switch_val;
    int exponent;

    /* number of prefix bits to switch between Rice and expGolomb */
    switch_bits = (codebook & 3) + 1;
    rice_order  =  codebook >> 5;       /* rice code order */
    exp_order   = (codebook >> 2) & 7;  /* exp golomb code order */

    switch_val  = switch_bits << rice_order;

    if (val >= switch_val) {
        val -= switch_val - (1 << exp_order);
        exponent = av_log2(val);

        return exponent * 2 - exp_order + switch_bits + 1;
    } else {
        return (val >> rice_order) + rice_order + 1;
    }
}

static int estimate_dcs(int *error, DCTELEM *blocks, int blocks_per_slice,
                        int scale)
{
    int i;
    int codebook = 3, code, dc, prev_dc, delta, sign, new_sign;
    int bits;

    prev_dc  = (blocks[0] - 0x4000) / scale;
    bits     = estimate_vlc(FIRST_DC_CB, MAKE_CODE(prev_dc));
    sign     = 0;
    codebook = 3;
    blocks  += 64;
    *error  += FFABS(blocks[0] - 0x4000) % scale;

    for (i = 1; i < blocks_per_slice; i++, blocks += 64) {
        dc       = (blocks[0] - 0x4000) / scale;
        *error  += FFABS(blocks[0] - 0x4000) % scale;
        delta    = dc - prev_dc;
        new_sign = GET_SIGN(delta);
        delta    = (delta ^ sign) - sign;
        code     = MAKE_CODE(delta);
        bits    += estimate_vlc(ff_prores_dc_codebook[codebook], code);
        codebook = (code + (code & 1)) >> 1;
        codebook = FFMIN(codebook, 3);
        sign     = new_sign;
        prev_dc  = dc;
    }

    return bits;
}

static int estimate_acs(int *error, DCTELEM *blocks, int blocks_per_slice,
                        int plane_size_factor,
                        const uint8_t *scan, const int16_t *qmat)
{
    int idx, i;
    int run, level, run_cb, lev_cb;
    int max_coeffs, abs_level;
    int bits = 0;

    max_coeffs = blocks_per_slice << 6;
    run_cb     = ff_prores_run_to_cb_index[4];
    lev_cb     = ff_prores_lev_to_cb_index[2];
    run        = 0;

    for (i = 1; i < 64; i++) {
        for (idx = scan[i]; idx < max_coeffs; idx += 64) {
            level   = blocks[idx] / qmat[scan[i]];
            *error += FFABS(blocks[idx]) % qmat[scan[i]];
            if (level) {
                abs_level = FFABS(level);
                bits += estimate_vlc(ff_prores_ac_codebook[run_cb], run);
                bits += estimate_vlc(ff_prores_ac_codebook[lev_cb],
                                     abs_level - 1) + 1;

                run_cb = ff_prores_run_to_cb_index[FFMIN(run, 15)];
                lev_cb = ff_prores_lev_to_cb_index[FFMIN(abs_level, 9)];
                run    = 0;
            } else {
                run++;
            }
        }
    }

    return bits;
}

static int estimate_slice_plane(ProresContext *ctx, int *error, int plane,
                                const uint16_t *src, int linesize,
                                int mbs_per_slice,
                                int blocks_per_mb, int plane_size_factor,
                                const int16_t *qmat)
{
    int blocks_per_slice;
    int bits;

    blocks_per_slice = mbs_per_slice * blocks_per_mb;

    bits  = estimate_dcs(error, ctx->blocks[plane], blocks_per_slice, qmat[0]);
    bits += estimate_acs(error, ctx->blocks[plane], blocks_per_slice,
                         plane_size_factor, ctx->scantable.permutated, qmat);

    return FFALIGN(bits, 8);
}

static int find_slice_quant(AVCodecContext *avctx, const AVFrame *pic,
                            int trellis_node, int x, int y, int mbs_per_slice)
{
    ProresContext *ctx = avctx->priv_data;
    int i, q, pq, xp, yp;
    const uint16_t *src;
    int slice_width_factor = av_log2(mbs_per_slice);
    int num_cblocks[MAX_PLANES], pwidth;
    int plane_factor[MAX_PLANES], is_chroma[MAX_PLANES];
    const int min_quant = ctx->profile_info->min_quant;
    const int max_quant = ctx->profile_info->max_quant;
    int error, bits, bits_limit;
    int mbs, prev, cur, new_score;
    int slice_bits[TRELLIS_WIDTH], slice_score[TRELLIS_WIDTH];
    int overquant;
    uint16_t *qmat;

    mbs = x + mbs_per_slice;

    for (i = 0; i < ctx->num_planes; i++) {
        is_chroma[i]    = (i == 1 || i == 2);
        plane_factor[i] = slice_width_factor + 2;
        if (is_chroma[i])
            plane_factor[i] += ctx->chroma_factor - 3;
        if (!is_chroma[i] || ctx->chroma_factor == CFACTOR_Y444) {
            xp             = x << 4;
            yp             = y << 4;
            num_cblocks[i] = 4;
            pwidth         = avctx->width;
        } else {
            xp             = x << 3;
            yp             = y << 4;
            num_cblocks[i] = 2;
            pwidth         = avctx->width >> 1;
        }
        src = (const uint16_t*)(pic->data[i] + yp * pic->linesize[i]) + xp;

        get_slice_data(ctx, src, pic->linesize[i], xp, yp,
                       pwidth, avctx->height, ctx->blocks[i],
                       mbs_per_slice, num_cblocks[i]);
    }

    for (q = min_quant; q < max_quant + 2; q++) {
        ctx->nodes[trellis_node + q].prev_node = -1;
        ctx->nodes[trellis_node + q].quant     = q;
    }

    // todo: maybe perform coarser quantising to fit into frame size when needed
    for (q = min_quant; q <= max_quant; q++) {
        bits  = 0;
        error = 0;
        for (i = 0; i < ctx->num_planes; i++) {
            bits += estimate_slice_plane(ctx, &error, i,
                                         src, pic->linesize[i],
                                         mbs_per_slice,
                                         num_cblocks[i], plane_factor[i],
                                         ctx->quants[q]);
        }
        if (bits > 65000 * 8) {
            error = SCORE_LIMIT;
            break;
        }
        slice_bits[q]  = bits;
        slice_score[q] = error;
    }
    if (slice_bits[max_quant] <= ctx->bits_per_mb * mbs_per_slice) {
        slice_bits[max_quant + 1]  = slice_bits[max_quant];
        slice_score[max_quant + 1] = slice_score[max_quant] + 1;
        overquant = max_quant;
    } else {
        for (q = max_quant + 1; q < 128; q++) {
            bits  = 0;
            error = 0;
            if (q < MAX_STORED_Q) {
                qmat = ctx->quants[q];
            } else {
                qmat = ctx->custom_q;
                for (i = 0; i < 64; i++)
                    qmat[i] = ctx->profile_info->quant[i] * q;
            }
            for (i = 0; i < ctx->num_planes; i++) {
                bits += estimate_slice_plane(ctx, &error, i,
                                             src, pic->linesize[i],
                                             mbs_per_slice,
                                             num_cblocks[i], plane_factor[i],
                                             qmat);
            }
            if (bits <= ctx->bits_per_mb * mbs_per_slice)
                break;
        }

        slice_bits[max_quant + 1]  = bits;
        slice_score[max_quant + 1] = error;
        overquant = q;
    }
    ctx->nodes[trellis_node + max_quant + 1].quant = overquant;

    bits_limit = mbs * ctx->bits_per_mb;
    for (pq = min_quant; pq < max_quant + 2; pq++) {
        prev = trellis_node - TRELLIS_WIDTH + pq;

        for (q = min_quant; q < max_quant + 2; q++) {
            cur = trellis_node + q;

            bits  = ctx->nodes[prev].bits + slice_bits[q];
            error = slice_score[q];
            if (bits > bits_limit)
                error = SCORE_LIMIT;

            if (ctx->nodes[prev].score < SCORE_LIMIT && error < SCORE_LIMIT)
                new_score = ctx->nodes[prev].score + error;
            else
                new_score = SCORE_LIMIT;
            if (ctx->nodes[cur].prev_node == -1 ||
                ctx->nodes[cur].score >= new_score) {

                ctx->nodes[cur].bits      = bits;
                ctx->nodes[cur].score     = new_score;
                ctx->nodes[cur].prev_node = prev;
            }
        }
    }

    error = ctx->nodes[trellis_node + min_quant].score;
    pq    = trellis_node + min_quant;
    for (q = min_quant + 1; q < max_quant + 2; q++) {
        if (ctx->nodes[trellis_node + q].score <= error) {
            error = ctx->nodes[trellis_node + q].score;
            pq    = trellis_node + q;
        }
    }

    return pq;
}

static int encode_frame(AVCodecContext *avctx, AVPacket *pkt,
                        const AVFrame *pic, int *got_packet)
{
    ProresContext *ctx = avctx->priv_data;
    uint8_t *orig_buf, *buf, *slice_hdr, *slice_sizes, *tmp;
    uint8_t *picture_size_pos;
    PutBitContext pb;
    int x, y, i, mb, q = 0;
    int sizes[4] = { 0 };
    int slice_hdr_size = 2 + 2 * (ctx->num_planes - 1);
    int frame_size, picture_size, slice_size;
    int mbs_per_slice = ctx->mbs_per_slice;
    int pkt_size, ret;

    *avctx->coded_frame           = *pic;
    avctx->coded_frame->pict_type = AV_PICTURE_TYPE_I;
    avctx->coded_frame->key_frame = 1;

    pkt_size = ctx->frame_size + FF_MIN_BUFFER_SIZE;

    if ((ret = ff_alloc_packet(pkt, pkt_size)) < 0) {
        av_log(avctx, AV_LOG_ERROR, "Error getting output packet.\n");
        return ret;
    }

    orig_buf = pkt->data;

    // frame atom
    orig_buf += 4;                              // frame size
    bytestream_put_be32  (&orig_buf, FRAME_ID); // frame container ID
    buf = orig_buf;

    // frame header
    tmp = buf;
    buf += 2;                                   // frame header size will be stored here
    bytestream_put_be16  (&buf, 0);             // version 1
    bytestream_put_buffer(&buf, "Lavc", 4);     // creator
    bytestream_put_be16  (&buf, avctx->width);
    bytestream_put_be16  (&buf, avctx->height);
    bytestream_put_byte  (&buf, ctx->chroma_factor << 6); // frame flags
    bytestream_put_byte  (&buf, 0);             // reserved
    bytestream_put_byte  (&buf, 0);             // primaries
    bytestream_put_byte  (&buf, 0);             // transfer function
    bytestream_put_byte  (&buf, 6);             // colour matrix - ITU-R BT.601-4
    bytestream_put_byte  (&buf, 0x40);          // source format and alpha information
    bytestream_put_byte  (&buf, 0);             // reserved
    bytestream_put_byte  (&buf, 0x03);          // matrix flags - both matrices are present
    // luma quantisation matrix
    for (i = 0; i < 64; i++)
        bytestream_put_byte(&buf, ctx->profile_info->quant[i]);
    // chroma quantisation matrix
    for (i = 0; i < 64; i++)
        bytestream_put_byte(&buf, ctx->profile_info->quant[i]);
    bytestream_put_be16  (&tmp, buf - orig_buf); // write back frame header size

    // picture header
    picture_size_pos = buf + 1;
    bytestream_put_byte  (&buf, 0x40);          // picture header size (in bits)
    buf += 4;                                   // picture data size will be stored here
    bytestream_put_be16  (&buf, ctx->num_slices); // total number of slices
    bytestream_put_byte  (&buf, av_log2(ctx->mbs_per_slice) << 4); // slice width and height in MBs

    // seek table - will be filled during slice encoding
    slice_sizes = buf;
    buf += ctx->num_slices * 2;

    // slices
    for (y = 0; y < ctx->mb_height; y++) {
        mbs_per_slice = ctx->mbs_per_slice;
        for (x = mb = 0; x < ctx->mb_width; x += mbs_per_slice, mb++) {
            while (ctx->mb_width - x < mbs_per_slice)
                mbs_per_slice >>= 1;
            q = find_slice_quant(avctx, pic, (mb + 1) * TRELLIS_WIDTH, x, y,
                                 mbs_per_slice);
        }

        for (x = ctx->slices_width - 1; x >= 0; x--) {
            ctx->slice_q[x] = ctx->nodes[q].quant;
            q = ctx->nodes[q].prev_node;
        }

        mbs_per_slice = ctx->mbs_per_slice;
        for (x = mb = 0; x < ctx->mb_width; x += mbs_per_slice, mb++) {
            q = ctx->slice_q[mb];

            while (ctx->mb_width - x < mbs_per_slice)
                mbs_per_slice >>= 1;

            bytestream_put_byte(&buf, slice_hdr_size << 3);
            slice_hdr = buf;
            buf += slice_hdr_size - 1;
            init_put_bits(&pb, buf, (pkt_size - (buf - orig_buf)) * 8);
            encode_slice(avctx, pic, &pb, sizes, x, y, q, mbs_per_slice);

            bytestream_put_byte(&slice_hdr, q);
            slice_size = slice_hdr_size + sizes[ctx->num_planes - 1];
            for (i = 0; i < ctx->num_planes - 1; i++) {
                bytestream_put_be16(&slice_hdr, sizes[i]);
                slice_size += sizes[i];
            }
            bytestream_put_be16(&slice_sizes, slice_size);
            buf += slice_size - slice_hdr_size;
        }
    }

    orig_buf -= 8;
    frame_size = buf - orig_buf;
    picture_size = buf - picture_size_pos - 6;
    bytestream_put_be32(&orig_buf, frame_size);
    bytestream_put_be32(&picture_size_pos, picture_size);

    pkt->size   = frame_size;
    pkt->flags |= AV_PKT_FLAG_KEY;
    *got_packet = 1;

    return 0;
}

static av_cold int encode_close(AVCodecContext *avctx)
{
    ProresContext *ctx = avctx->priv_data;

    if (avctx->coded_frame->data[0])
        avctx->release_buffer(avctx, avctx->coded_frame);

    av_freep(&avctx->coded_frame);

    av_freep(&ctx->nodes);
    av_freep(&ctx->slice_q);

    return 0;
}

static av_cold int encode_init(AVCodecContext *avctx)
{
    ProresContext *ctx = avctx->priv_data;
    int mps;
    int i, j;
    int min_quant, max_quant;

    avctx->bits_per_raw_sample = 10;
    avctx->coded_frame = avcodec_alloc_frame();
    if (!avctx->coded_frame)
        return AVERROR(ENOMEM);

    ff_proresdsp_init(&ctx->dsp);
    ff_init_scantable(ctx->dsp.dct_permutation, &ctx->scantable,
                      ff_prores_progressive_scan);

    mps = ctx->mbs_per_slice;
    if (mps & (mps - 1)) {
        av_log(avctx, AV_LOG_ERROR,
               "there should be an integer power of two MBs per slice\n");
        return AVERROR(EINVAL);
    }

    ctx->chroma_factor = avctx->pix_fmt == PIX_FMT_YUV422P10
                         ? CFACTOR_Y422
                         : CFACTOR_Y444;
    ctx->profile_info  = prores_profile_info + ctx->profile;
    ctx->num_planes    = 3;

    ctx->mb_width      = FFALIGN(avctx->width,  16) >> 4;
    ctx->mb_height     = FFALIGN(avctx->height, 16) >> 4;
    ctx->slices_width  = ctx->mb_width / mps;
    ctx->slices_width += av_popcount(ctx->mb_width - ctx->slices_width * mps);
    ctx->num_slices    = ctx->mb_height * ctx->slices_width;

    for (i = 0; i < NUM_MB_LIMITS - 1; i++)
        if (prores_mb_limits[i] >= ctx->mb_width * ctx->mb_height)
            break;
    ctx->bits_per_mb   = ctx->profile_info->br_tab[i];

    ctx->frame_size = ctx->num_slices * (2 + 2 * ctx->num_planes
                                         + (2 * mps * ctx->bits_per_mb) / 8)
                      + 200;

    min_quant = ctx->profile_info->min_quant;
    max_quant = ctx->profile_info->max_quant;
    for (i = min_quant; i < MAX_STORED_Q; i++) {
        for (j = 0; j < 64; j++)
            ctx->quants[i][j] = ctx->profile_info->quant[j] * i;
    }

    avctx->codec_tag   = ctx->profile_info->tag;

    av_log(avctx, AV_LOG_DEBUG, "profile %d, %d slices, %d bits per MB\n",
           ctx->profile, ctx->num_slices, ctx->bits_per_mb);
    av_log(avctx, AV_LOG_DEBUG, "estimated frame size %d\n",
           ctx->frame_size);

    ctx->nodes = av_malloc((ctx->slices_width + 1) * TRELLIS_WIDTH
                           * sizeof(*ctx->nodes));
    if (!ctx->nodes) {
        encode_close(avctx);
        return AVERROR(ENOMEM);
    }
    for (i = min_quant; i < max_quant + 2; i++) {
        ctx->nodes[i].prev_node = -1;
        ctx->nodes[i].bits      = 0;
        ctx->nodes[i].score     = 0;
    }

    ctx->slice_q = av_malloc(ctx->slices_width * sizeof(*ctx->slice_q));
    if (!ctx->slice_q) {
        encode_close(avctx);
        return AVERROR(ENOMEM);
    }

    return 0;
}

#define OFFSET(x) offsetof(ProresContext, x)
#define VE     AV_OPT_FLAG_VIDEO_PARAM | AV_OPT_FLAG_ENCODING_PARAM

static const AVOption options[] = {
    { "mbs_per_slice", "macroblocks per slice", OFFSET(mbs_per_slice),
        AV_OPT_TYPE_INT, { 8 }, 1, MAX_MBS_PER_SLICE, VE },
    { "profile",       NULL, OFFSET(profile), AV_OPT_TYPE_INT,
        { PRORES_PROFILE_STANDARD },
        PRORES_PROFILE_PROXY, PRORES_PROFILE_HQ, VE, "profile" },
    { "proxy",         NULL, 0, AV_OPT_TYPE_CONST, { PRORES_PROFILE_PROXY },
        0, 0, VE, "profile" },
    { "lt",            NULL, 0, AV_OPT_TYPE_CONST, { PRORES_PROFILE_LT },
        0, 0, VE, "profile" },
    { "standard",      NULL, 0, AV_OPT_TYPE_CONST, { PRORES_PROFILE_STANDARD },
        0, 0, VE, "profile" },
    { "hq",            NULL, 0, AV_OPT_TYPE_CONST, { PRORES_PROFILE_HQ },
        0, 0, VE, "profile" },
    { NULL }
};

static const AVClass proresenc_class = {
    .class_name = "ProRes encoder",
    .item_name  = av_default_item_name,
    .option     = options,
    .version    = LIBAVUTIL_VERSION_INT,
};

AVCodec ff_prores_encoder = {
    .name           = "prores",
    .type           = AVMEDIA_TYPE_VIDEO,
    .id             = CODEC_ID_PRORES,
    .priv_data_size = sizeof(ProresContext),
    .init           = encode_init,
    .close          = encode_close,
    .encode2        = encode_frame,
    .long_name      = NULL_IF_CONFIG_SMALL("Apple ProRes (iCodec Pro)"),
    .pix_fmts       = (const enum PixelFormat[]) {
                          PIX_FMT_YUV422P10, PIX_FMT_YUV444P10, PIX_FMT_NONE
                      },
    .priv_class     = &proresenc_class,
};