path: root/libavcodec/dvenc.c

/*
 * DV encoder
 * Copyright (c) 2003 Roman Shaposhnik
 *
 * 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
 */

/**
 * @file
 * DV encoder
 */

#include "config.h"

#include "libavutil/attributes.h"
#include "libavutil/pixdesc.h"

#include "avcodec.h"
#include "dv.h"
#include "dv_profile_internal.h"
#include "dv_tablegen.h"
#include "fdctdsp.h"
#include "internal.h"
#include "me_cmp.h"
#include "pixblockdsp.h"
#include "put_bits.h"

static av_cold int dvvideo_encode_init(AVCodecContext *avctx)
{
    DVVideoContext *s = avctx->priv_data;
    FDCTDSPContext fdsp;
    MECmpContext mecc;
    PixblockDSPContext pdsp;
    int ret;

    s->sys = av_dv_codec_profile(avctx->width, avctx->height, avctx->pix_fmt);
    if (!s->sys) {
        av_log(avctx, AV_LOG_ERROR, "Found no DV profile for %ix%i %s video. "
                                    "Valid DV profiles are:\n",
               avctx->width, avctx->height, av_get_pix_fmt_name(avctx->pix_fmt));
        ff_dv_print_profiles(avctx, AV_LOG_ERROR);
        return AVERROR(EINVAL);
    }
    ret = ff_dv_init_dynamic_tables(s, s->sys);
    if (ret < 0) {
        av_log(avctx, AV_LOG_ERROR, "Error initializing work tables.\n");
        return ret;
    }

    dv_vlc_map_tableinit();

    ff_fdctdsp_init(&fdsp, avctx);
    ff_me_cmp_init(&mecc, avctx);
    ff_pixblockdsp_init(&pdsp, avctx);
    ff_set_cmp(&mecc, mecc.ildct_cmp, avctx->ildct_cmp);

    s->get_pixels = pdsp.get_pixels;
    s->ildct_cmp  = mecc.ildct_cmp[5];

    s->fdct[0]    = fdsp.fdct;
    s->fdct[1]    = fdsp.fdct248;

    return ff_dvvideo_init(avctx);
}

/* bit budget for AC only in 5 MBs */
static const int vs_total_ac_bits = (100 * 4 + 68 * 2) * 5;
static const int mb_area_start[5] = { 1, 6, 21, 43, 64 };

#if CONFIG_SMALL
/* Convert run and level (where level != 0) pair into VLC, returning bit size */
static av_always_inline int dv_rl2vlc(int run, int level, int sign,
                                      uint32_t *vlc)
{
    int size;
    if (run < DV_VLC_MAP_RUN_SIZE && level < DV_VLC_MAP_LEV_SIZE) {
        *vlc = dv_vlc_map[run][level].vlc | sign;
        size = dv_vlc_map[run][level].size;
    } else {
        if (level < DV_VLC_MAP_LEV_SIZE) {
            *vlc = dv_vlc_map[0][level].vlc | sign;
            size = dv_vlc_map[0][level].size;
        } else {
            *vlc = 0xfe00 | (level << 1) | sign;
            size = 16;
        }
        if (run) {
            *vlc |= ((run < 16) ? dv_vlc_map[run - 1][0].vlc :
                     (0x1f80 | (run - 1))) << size;
            size +=  (run < 16) ? dv_vlc_map[run - 1][0].size : 13;
        }
    }

    return size;
}

static av_always_inline int dv_rl2vlc_size(int run, int level)
{
    int size;

    if (run < DV_VLC_MAP_RUN_SIZE && level < DV_VLC_MAP_LEV_SIZE) {
        size = dv_vlc_map[run][level].size;
    } else {
        size = (level < DV_VLC_MAP_LEV_SIZE) ? dv_vlc_map[0][level].size : 16;
        if (run)
            size += (run < 16) ? dv_vlc_map[run - 1][0].size : 13;
    }
    return size;
}
#else
static av_always_inline int dv_rl2vlc(int run, int l, int sign, uint32_t *vlc)
{
    *vlc = dv_vlc_map[run][l].vlc | sign;
    return dv_vlc_map[run][l].size;
}

static av_always_inline int dv_rl2vlc_size(int run, int l)
{
    return dv_vlc_map[run][l].size;
}
#endif

typedef struct EncBlockInfo {
    int      area_q[4];
    int      bit_size[4];
    int      prev[5];
    int      cur_ac;
    int      cno;
    int      dct_mode;
    int16_t  mb[64];
    uint8_t  next[64];
    uint8_t  sign[64];
    uint8_t  partial_bit_count;
    uint32_t partial_bit_buffer; /* we can't use uint16_t here */
} EncBlockInfo;

static av_always_inline PutBitContext *dv_encode_ac(EncBlockInfo *bi,
                                                    PutBitContext *pb_pool,
                                                    PutBitContext *pb_end)
{
    int prev, bits_left;
    PutBitContext *pb = pb_pool;
    int size          = bi->partial_bit_count;
    uint32_t vlc      = bi->partial_bit_buffer;

    bi->partial_bit_count  =
    bi->partial_bit_buffer = 0;
    for (;;) {
        /* Find suitable storage space */
        for (; size > (bits_left = put_bits_left(pb)); pb++) {
            if (bits_left) {
                size -= bits_left;
                put_bits(pb, bits_left, vlc >> size);
                vlc = vlc & ((1 << size) - 1);
            }
            if (pb + 1 >= pb_end) {
                bi->partial_bit_count  = size;
                bi->partial_bit_buffer = vlc;
                return pb;
            }
        }

        /* Store VLC */
        put_bits(pb, size, vlc);

        if (bi->cur_ac >= 64)
            break;

        /* Construct the next VLC */
        prev       = bi->cur_ac;
        bi->cur_ac = bi->next[prev];
        if (bi->cur_ac < 64) {
            size = dv_rl2vlc(bi->cur_ac - prev - 1, bi->mb[bi->cur_ac],
                             bi->sign[bi->cur_ac], &vlc);
        } else {
            size = 4;
            vlc  = 6; /* End Of Block stamp */
        }
    }
    return pb;
}

static av_always_inline int dv_guess_dct_mode(DVVideoContext *s, uint8_t *data,
                                              int linesize)
{
    if (s->avctx->flags & CODEC_FLAG_INTERLACED_DCT) {
        int ps = s->ildct_cmp(NULL, data, NULL, linesize, 8) - 400;
        if (ps > 0) {
            int is = s->ildct_cmp(NULL, data,            NULL, linesize << 1, 4) +
                     s->ildct_cmp(NULL, data + linesize, NULL, linesize << 1, 4);
            return ps > is;
        }
    }

    return 0;
}

static const int dv_weight_bits = 18;
static const int dv_weight_88[64] = {
    131072, 257107, 257107, 242189, 252167, 242189, 235923, 237536,
    237536, 235923, 229376, 231390, 223754, 231390, 229376, 222935,
    224969, 217965, 217965, 224969, 222935, 200636, 218652, 211916,
    212325, 211916, 218652, 200636, 188995, 196781, 205965, 206433,
    206433, 205965, 196781, 188995, 185364, 185364, 200636, 200704,
    200636, 185364, 185364, 174609, 180568, 195068, 195068, 180568,
    174609, 170091, 175557, 189591, 175557, 170091, 165371, 170627,
    170627, 165371, 160727, 153560, 160727, 144651, 144651, 136258,
};
static const int dv_weight_248[64] = {
    131072, 242189, 257107, 237536, 229376, 200636, 242189, 223754,
    224969, 196781, 262144, 242189, 229376, 200636, 257107, 237536,
    211916, 185364, 235923, 217965, 229376, 211916, 206433, 180568,
    242189, 223754, 224969, 196781, 211916, 185364, 235923, 217965,
    200704, 175557, 222935, 205965, 200636, 185364, 195068, 170627,
    229376, 211916, 206433, 180568, 200704, 175557, 222935, 205965,
    175557, 153560, 188995, 174609, 165371, 144651, 200636, 185364,
    195068, 170627, 175557, 153560, 188995, 174609, 165371, 144651,
};

static av_always_inline int dv_init_enc_block(EncBlockInfo *bi, uint8_t *data,
                                              int linesize, DVVideoContext *s,
                                              int bias)
{
    const int *weight;
    const uint8_t *zigzag_scan;
    LOCAL_ALIGNED_16(int16_t, blk, [64]);
    int i, area;
    /* We offer two different methods for class number assignment: the
     * method suggested in SMPTE 314M Table 22, and an improved
     * method. The SMPTE method is very conservative; it assigns class
     * 3 (i.e. severe quantization) to any block where the largest AC
     * component is greater than 36. Libav's DV encoder tracks AC bit
     * consumption precisely, so there is no need to bias most blocks
     * towards strongly lossy compression. Instead, we assign class 2
     * to most blocks, and use class 3 only when strictly necessary
     * (for blocks whose largest AC component exceeds 255). */

#if 0 /* SMPTE spec method */
    static const int classes[] = { 12, 24, 36, 0xffff };
#else /* improved Libav method */
    static const int classes[] = { -1, -1, 255, 0xffff };
#endif
    int max  = classes[0];
    int prev = 0;

    assert((((int) blk) & 15) == 0);

    bi->area_q[0]          =
    bi->area_q[1]          =
    bi->area_q[2]          =
    bi->area_q[3]          = 0;
    bi->partial_bit_count  = 0;
    bi->partial_bit_buffer = 0;
    bi->cur_ac             = 0;
    if (data) {
        bi->dct_mode = dv_guess_dct_mode(s, data, linesize);
        s->get_pixels(blk, data, linesize);
        s->fdct[bi->dct_mode](blk);
    } else {
        /* We rely on the fact that encoding all zeros leads to an immediate
         * EOB, which is precisely what the spec calls for in the "dummy"
         * blocks. */
        memset(blk, 0, 64 * sizeof(*blk));
        bi->dct_mode = 0;
    }
    bi->mb[0] = blk[0];

    zigzag_scan = bi->dct_mode ? ff_dv_zigzag248_direct : ff_zigzag_direct;
    weight      = bi->dct_mode ? dv_weight_248 : dv_weight_88;

    for (area = 0; area < 4; area++) {
        bi->prev[area]     = prev;
        bi->bit_size[area] = 1; // 4 areas 4 bits for EOB :)
        for (i = mb_area_start[area]; i < mb_area_start[area + 1]; i++) {
            int level = blk[zigzag_scan[i]];

            if (level + 15 > 30U) {
                bi->sign[i] = (level >> 31) & 1;
                /* Weight it and and shift down into range, adding for rounding.
                 * The extra division by a factor of 2^4 reverses the 8x
                 * expansion of the DCT AND the 2x doubling of the weights. */
                level     = (FFABS(level) * weight[i] + (1 << (dv_weight_bits + 3))) >>
                            (dv_weight_bits + 4);
                bi->mb[i] = level;
                if (level > max)
                    max = level;
                bi->bit_size[area] += dv_rl2vlc_size(i - prev - 1, level);
                bi->next[prev]      = i;
                prev                = i;
            }
        }
    }
    bi->next[prev] = i;
    for (bi->cno = 0; max > classes[bi->cno]; bi->cno++)
        ;

    bi->cno += bias;

    if (bi->cno >= 3) {
        bi->cno = 3;
        prev    = 0;
        i       = bi->next[prev];
        for (area = 0; area < 4; area++) {
            bi->prev[area]     = prev;
            bi->bit_size[area] = 1; // 4 areas 4 bits for EOB :)
            for (; i < mb_area_start[area + 1]; i = bi->next[i]) {
                bi->mb[i] >>= 1;

                if (bi->mb[i]) {
                    bi->bit_size[area] += dv_rl2vlc_size(i - prev - 1, bi->mb[i]);
                    bi->next[prev]      = i;
                    prev                = i;
                }
            }
        }
        bi->next[prev] = i;
    }

    return bi->bit_size[0] + bi->bit_size[1] +
           bi->bit_size[2] + bi->bit_size[3];
}

static inline void dv_guess_qnos(EncBlockInfo *blks, int *qnos)
{
    int size[5];
    int i, j, k, a, prev, a2;
    EncBlockInfo *b;

    size[0] =
    size[1] =
    size[2] =
    size[3] =
    size[4] = 1 << 24;
    do {
        b = blks;
        for (i = 0; i < 5; i++) {
            if (!qnos[i])
                continue;

            qnos[i]--;
            size[i] = 0;
            for (j = 0; j < 6; j++, b++) {
                for (a = 0; a < 4; a++) {
                    if (b->area_q[a] != ff_dv_quant_shifts[qnos[i] + ff_dv_quant_offset[b->cno]][a]) {
                        b->bit_size[a] = 1; // 4 areas 4 bits for EOB :)
                        b->area_q[a]++;
                        prev = b->prev[a];
                        assert(b->next[prev] >= mb_area_start[a + 1] || b->mb[prev]);
                        for (k = b->next[prev]; k < mb_area_start[a + 1]; k = b->next[k]) {
                            b->mb[k] >>= 1;
                            if (b->mb[k]) {
                                b->bit_size[a] += dv_rl2vlc_size(k - prev - 1, b->mb[k]);
                                prev            = k;
                            } else {
                                if (b->next[k] >= mb_area_start[a + 1] && b->next[k] < 64) {
                                    for (a2 = a + 1; b->next[k] >= mb_area_start[a2 + 1]; a2++)
                                        b->prev[a2] = prev;
                                    assert(a2 < 4);
                                    assert(b->mb[b->next[k]]);
                                    b->bit_size[a2] += dv_rl2vlc_size(b->next[k] - prev - 1, b->mb[b->next[k]]) -
                                                       dv_rl2vlc_size(b->next[k] - k    - 1, b->mb[b->next[k]]);
                                    assert(b->prev[a2] == k && (a2 + 1 >= 4 || b->prev[a2 + 1] != k));
                                    b->prev[a2] = prev;
                                }
                                b->next[prev] = b->next[k];
                            }
                        }
                        b->prev[a + 1] = prev;
                    }
                    size[i] += b->bit_size[a];
                }
            }
            if (vs_total_ac_bits >= size[0] + size[1] + size[2] + size[3] + size[4])
                return;
        }
    } while (qnos[0] | qnos[1] | qnos[2] | qnos[3] | qnos[4]);

    for (a = 2; a == 2 || vs_total_ac_bits < size[0]; a += a) {
        b       = blks;
        size[0] = 5 * 6 * 4; // EOB
        for (j = 0; j < 6 * 5; j++, b++) {
            prev = b->prev[0];
            for (k = b->next[prev]; k < 64; k = b->next[k]) {
                if (b->mb[k] < a && b->mb[k] > -a) {
                    b->next[prev] = b->next[k];
                } else {
                    size[0] += dv_rl2vlc_size(k - prev - 1, b->mb[k]);
                    prev     = k;
                }
            }
        }
    }
}

static int dv_encode_video_segment(AVCodecContext *avctx, void *arg)
{
    DVVideoContext *s = avctx->priv_data;
    DVwork_chunk *work_chunk = arg;
    int mb_index, i, j;
    int mb_x, mb_y, c_offset, linesize, y_stride;
    uint8_t *y_ptr;
    uint8_t *dif;
    LOCAL_ALIGNED_8(uint8_t, scratch, [128]);
    EncBlockInfo enc_blks[5 * DV_MAX_BPM];
    PutBitContext pbs[5 * DV_MAX_BPM];
    PutBitContext *pb;
    EncBlockInfo *enc_blk;
    int vs_bit_size = 0;
    int qnos[5] = { 15, 15, 15, 15, 15 }; /* No quantization */
    int *qnosp = &qnos[0];

    dif     = &s->buf[work_chunk->buf_offset * 80];
    enc_blk = &enc_blks[0];
    for (mb_index = 0; mb_index < 5; mb_index++) {
        dv_calculate_mb_xy(s, work_chunk, mb_index, &mb_x, &mb_y);

        /* initializing luminance blocks */
        if ((s->sys->pix_fmt == AV_PIX_FMT_YUV420P)                      ||
            (s->sys->pix_fmt == AV_PIX_FMT_YUV411P && mb_x >= (704 / 8)) ||
            (s->sys->height >= 720 && mb_y != 134)) {
            y_stride = s->frame->linesize[0] << 3;
        } else {
            y_stride = 16;
        }
        y_ptr    = s->frame->data[0] +
                   ((mb_y * s->frame->linesize[0] + mb_x) << 3);
        linesize = s->frame->linesize[0];

        if (s->sys->video_stype == 4) { /* SD 422 */
            vs_bit_size +=
                dv_init_enc_block(enc_blk + 0, y_ptr,                linesize, s, 0) +
                dv_init_enc_block(enc_blk + 1, NULL,                 linesize, s, 0) +
                dv_init_enc_block(enc_blk + 2, y_ptr + 8,            linesize, s, 0) +
                dv_init_enc_block(enc_blk + 3, NULL,                 linesize, s, 0);
        } else {
            vs_bit_size +=
                dv_init_enc_block(enc_blk + 0, y_ptr,                linesize, s, 0) +
                dv_init_enc_block(enc_blk + 1, y_ptr + 8,            linesize, s, 0) +
                dv_init_enc_block(enc_blk + 2, y_ptr +     y_stride, linesize, s, 0) +
                dv_init_enc_block(enc_blk + 3, y_ptr + 8 + y_stride, linesize, s, 0);
        }
        enc_blk += 4;

        /* initializing chrominance blocks */
        c_offset = (((mb_y >>  (s->sys->pix_fmt == AV_PIX_FMT_YUV420P)) * s->frame->linesize[1] +
                     (mb_x >> ((s->sys->pix_fmt == AV_PIX_FMT_YUV411P) ? 2 : 1))) << 3);
        for (j = 2; j; j--) {
            uint8_t *c_ptr = s->frame->data[j] + c_offset;
            linesize = s->frame->linesize[j];
            y_stride = (mb_y == 134) ? 8 : (s->frame->linesize[j] << 3);
            if (s->sys->pix_fmt == AV_PIX_FMT_YUV411P && mb_x >= (704 / 8)) {
                uint8_t *d;
                uint8_t *b = scratch;
                for (i = 0; i < 8; i++) {
                    d      = c_ptr + (linesize << 3);
                    b[0]   = c_ptr[0];
                    b[1]   = c_ptr[1];
                    b[2]   = c_ptr[2];
                    b[3]   = c_ptr[3];
                    b[4]   = d[0];
                    b[5]   = d[1];
                    b[6]   = d[2];
                    b[7]   = d[3];
                    c_ptr += linesize;
                    b     += 16;
                }
                c_ptr    = scratch;
                linesize = 16;
            }

            vs_bit_size += dv_init_enc_block(enc_blk++, c_ptr, linesize, s, 1);
            if (s->sys->bpm == 8)
                vs_bit_size += dv_init_enc_block(enc_blk++, c_ptr + y_stride,
                                                 linesize, s, 1);
        }
    }

    if (vs_total_ac_bits < vs_bit_size)
        dv_guess_qnos(&enc_blks[0], qnosp);

    /* DIF encoding process */
    for (j = 0; j < 5 * s->sys->bpm;) {
        int start_mb = j;

        dif[3] = *qnosp++;
        dif   += 4;

        /* First pass over individual cells only */
        for (i = 0; i < s->sys->bpm; i++, j++) {
            int sz = s->sys->block_sizes[i] >> 3;

            init_put_bits(&pbs[j], dif, sz);
            put_sbits(&pbs[j], 9, ((enc_blks[j].mb[0] >> 3) - 1024 + 2) >> 2);
            put_bits(&pbs[j], 1, enc_blks[j].dct_mode);
            put_bits(&pbs[j], 2, enc_blks[j].cno);

            dv_encode_ac(&enc_blks[j], &pbs[j], &pbs[j + 1]);
            dif += sz;
        }

        /* Second pass over each MB space */
        pb = &pbs[start_mb];
        for (i = 0; i < s->sys->bpm; i++)
            if (enc_blks[start_mb + i].partial_bit_count)
                pb = dv_encode_ac(&enc_blks[start_mb + i], pb,
                                  &pbs[start_mb + s->sys->bpm]);
    }

    /* Third and final pass over the whole video segment space */
    pb = &pbs[0];
    for (j = 0; j < 5 * s->sys->bpm; j++) {
        if (enc_blks[j].partial_bit_count)
            pb = dv_encode_ac(&enc_blks[j], pb, &pbs[s->sys->bpm * 5]);
        if (enc_blks[j].partial_bit_count)
            av_log(avctx, AV_LOG_ERROR, "ac bitstream overflow\n");
    }

    for (j = 0; j < 5 * s->sys->bpm; j++) {
        int pos;
        int size = pbs[j].size_in_bits >> 3;
        flush_put_bits(&pbs[j]);
        pos = put_bits_count(&pbs[j]) >> 3;
        if (pos > size) {
            av_log(avctx, AV_LOG_ERROR,
                   "bitstream written beyond buffer size\n");
            return -1;
        }
        memset(pbs[j].buf + pos, 0xff, size - pos);
    }

    return 0;
}

static inline int dv_write_pack(enum dv_pack_type pack_id, DVVideoContext *c,
                                uint8_t *buf)
{
    /*
     * Here's what SMPTE314M says about these two:
     *    (page 6) APTn, AP1n, AP2n, AP3n: These data shall be identical
     *             as track application IDs (APTn = 001, AP1n =
     *             001, AP2n = 001, AP3n = 001), if the source signal
     *             comes from a digital VCR. If the signal source is
     *             unknown, all bits for these data shall be set to 1.
     *    (page 12) STYPE: STYPE defines a signal type of video signal
     *                     00000b = 4:1:1 compression
     *                     00100b = 4:2:2 compression
     *                     XXXXXX = Reserved
     * Now, I've got two problems with these statements:
     *   1. it looks like APT == 111b should be a safe bet, but it isn't.
     *      It seems that for PAL as defined in IEC 61834 we have to set
     *      APT to 000 and for SMPTE314M to 001.
     *   2. It is not at all clear what STYPE is used for 4:2:0 PAL
     *      compression scheme (if any).
     */
    int apt = (c->sys->pix_fmt == AV_PIX_FMT_YUV420P ? 0 : 1);

    uint8_t aspect = 0;
    if ((int) (av_q2d(c->avctx->sample_aspect_ratio) *
               c->avctx->width / c->avctx->height * 10) >= 17) /* 16:9 */
        aspect = 0x02;

    buf[0] = (uint8_t) pack_id;
    switch (pack_id) {
    case dv_header525: /* I can't imagine why these two weren't defined as real */
    case dv_header625: /* packs in SMPTE314M -- they definitely look like ones */
        buf[1] =  0xf8       | /* reserved -- always 1 */
                 (apt & 0x07); /* APT: Track application ID */
        buf[2] = (0    << 7) | /* TF1: audio data is 0 - valid; 1 - invalid */
                 (0x0f << 3) | /* reserved -- always 1 */
                 (apt & 0x07); /* AP1: Audio application ID */
        buf[3] = (0    << 7) | /* TF2: video data is 0 - valid; 1 - invalid */
                 (0x0f << 3) | /* reserved -- always 1 */
                 (apt & 0x07); /* AP2: Video application ID */
        buf[4] = (0    << 7) | /* TF3: subcode(SSYB) is 0 - valid; 1 - invalid */
                 (0x0f << 3) | /* reserved -- always 1 */
                 (apt & 0x07); /* AP3: Subcode application ID */
        break;
    case dv_video_source:
        buf[1] = 0xff;         /* reserved -- always 1 */
        buf[2] = (1 << 7) |    /* B/W: 0 - b/w, 1 - color */
                 (1 << 6) |    /* following CLF is valid - 0, invalid - 1 */
                 (3 << 4) |    /* CLF: color frames ID (see ITU-R BT.470-4) */
                 0xf;          /* reserved -- always 1 */
        buf[3] = (3 << 6)           | /* reserved -- always 1 */
                 (c->sys->dsf << 5) | /*  system: 60fields/50fields */
                 c->sys->video_stype; /* signal type video compression */
        buf[4] = 0xff;         /* VISC: 0xff -- no information */
        break;
    case dv_video_control:
        buf[1] = (0 << 6) |    /* Copy generation management (CGMS) 0 -- free */
                 0x3f;         /* reserved -- always 1 */
        buf[2] = 0xc8 |        /* reserved -- always b11001xxx */
                 aspect;
        buf[3] = (1 << 7) |    /* frame/field flag 1 -- frame, 0 -- field */
                 (1 << 6) |    /* first/second field flag 0 -- field 2, 1 -- field 1 */
                 (1 << 5) |    /* frame change flag 0 -- same picture as before, 1 -- different */
                 (1 << 4) |    /* 1 - interlaced, 0 - noninterlaced */
                 0xc;          /* reserved -- always b1100 */
        buf[4] = 0xff;         /* reserved -- always 1 */
        break;
    default:
        buf[1] =
        buf[2] =
        buf[3] =
        buf[4] = 0xff;
    }
    return 5;
}

static inline int dv_write_dif_id(enum dv_section_type t, uint8_t chan_num,
                                  uint8_t seq_num, uint8_t dif_num,
                                  uint8_t *buf)
{
    buf[0] = (uint8_t) t;      /* Section type */
    buf[1] = (seq_num  << 4) | /* DIF seq number 0-9 for 525/60; 0-11 for 625/50 */
             (chan_num << 3) | /* FSC: for 50Mb/s 0 - first channel; 1 - second */
             7;                /* reserved -- always 1 */
    buf[2] = dif_num;          /* DIF block number Video: 0-134, Audio: 0-8 */
    return 3;
}

static inline int dv_write_ssyb_id(uint8_t syb_num, uint8_t fr, uint8_t *buf)
{
    if (syb_num == 0 || syb_num == 6) {
        buf[0] = (fr << 7) | /* FR ID 1 - first half of each channel; 0 - second */
                 (0  << 4) | /* AP3 (Subcode application ID) */
                 0x0f;       /* reserved -- always 1 */
    } else if (syb_num == 11) {
        buf[0] = (fr << 7) | /* FR ID 1 - first half of each channel; 0 - second */
                 0x7f;       /* reserved -- always 1 */
    } else {
        buf[0] = (fr << 7) | /* FR ID 1 - first half of each channel; 0 - second */
                 (0  << 4) | /* APT (Track application ID) */
                 0x0f;       /* reserved -- always 1 */
    }
    buf[1] = 0xf0 |            /* reserved -- always 1 */
             (syb_num & 0x0f); /* SSYB number 0 - 11   */
    buf[2] = 0xff;             /* reserved -- always 1 */
    return 3;
}

static void dv_format_frame(DVVideoContext *c, uint8_t *buf)
{
    int chan, i, j, k;

    for (chan = 0; chan < c->sys->n_difchan; chan++) {
        for (i = 0; i < c->sys->difseg_size; i++) {
            memset(buf, 0xff, 80 * 6); /* first 6 DIF blocks are for control data */

            /* DV header: 1DIF */
            buf += dv_write_dif_id(dv_sect_header, chan, i, 0, buf);
            buf += dv_write_pack((c->sys->dsf ? dv_header625 : dv_header525),
                                 c, buf);
            buf += 72; /* unused bytes */

            /* DV subcode: 2DIFs */
            for (j = 0; j < 2; j++) {
                buf += dv_write_dif_id(dv_sect_subcode, chan, i, j, buf);
                for (k = 0; k < 6; k++)
                    buf += dv_write_ssyb_id(k, (i < c->sys->difseg_size / 2), buf) + 5;
                buf += 29; /* unused bytes */
            }

            /* DV VAUX: 3DIFS */
            for (j = 0; j < 3; j++) {
                buf += dv_write_dif_id(dv_sect_vaux, chan, i, j, buf);
                buf += dv_write_pack(dv_video_source,  c, buf);
                buf += dv_write_pack(dv_video_control, c, buf);
                buf += 7 * 5;
                buf += dv_write_pack(dv_video_source,  c, buf);
                buf += dv_write_pack(dv_video_control, c, buf);
                buf += 4 * 5 + 2; /* unused bytes */
            }

            /* DV Audio/Video: 135 Video DIFs + 9 Audio DIFs */
            for (j = 0; j < 135; j++) {
                if (j % 15 == 0) {
                    memset(buf, 0xff, 80);
                    buf += dv_write_dif_id(dv_sect_audio, chan, i, j / 15, buf);
                    buf += 77; /* audio control & shuffled PCM audio */
                }
                buf += dv_write_dif_id(dv_sect_video, chan, i, j, buf);
                buf += 77; /* 1 video macroblock: 1 bytes control
                            * 4 * 14 bytes Y 8x8 data
                            * 10 bytes Cr 8x8 data
                            * 10 bytes Cb 8x8 data */
            }
        }
    }
}

static int dvvideo_encode_frame(AVCodecContext *c, AVPacket *pkt,
                                const AVFrame *frame, int *got_packet)
{
    DVVideoContext *s = c->priv_data;
    int ret;

    if ((ret = ff_alloc_packet(pkt, s->sys->frame_size)) < 0) {
        av_log(c, AV_LOG_ERROR, "Error getting output packet.\n");
        return ret;
    }

    c->pix_fmt                = s->sys->pix_fmt;
    s->frame                  = frame;
    c->coded_frame->key_frame = 1;
    c->coded_frame->pict_type = AV_PICTURE_TYPE_I;

    s->buf = pkt->data;
    c->execute(c, dv_encode_video_segment, s->work_chunks, NULL,
               dv_work_pool_size(s->sys), sizeof(DVwork_chunk));

    emms_c();

    dv_format_frame(s, pkt->data);

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

    return 0;
}

AVCodec ff_dvvideo_encoder = {
    .name           = "dvvideo",
    .long_name      = NULL_IF_CONFIG_SMALL("DV (Digital Video)"),
    .type           = AVMEDIA_TYPE_VIDEO,
    .id             = AV_CODEC_ID_DVVIDEO,
    .priv_data_size = sizeof(DVVideoContext),
    .init           = dvvideo_encode_init,
    .encode2        = dvvideo_encode_frame,
    .capabilities   = CODEC_CAP_SLICE_THREADS,
    .pix_fmts       = (const enum AVPixelFormat[]) {
        AV_PIX_FMT_YUV411P, AV_PIX_FMT_YUV422P,
        AV_PIX_FMT_YUV420P, AV_PIX_FMT_NONE
    },
};