Hi crews,

Yes, it's no mistake! What you see is just another code implementing
ProRes decoder.

Now I'm going to explain that confusion.
Writing a ProRes compatible decoder began as team project in 2010.
During this period, I created an internal documentation on the coding
algorithm (entropy coding, slicing and inverse transform); a part of
this doc has been published at

http://wiki.multimedia.cx/index.php?title=Apple_ProRes&action=history

already in 2010 (see my nickname "Maxpol" for a proof), but not to much
to avoid an implementation by someone else.

Later I wrote a working decoder. Due to the lack for interlaced frames
it was incomplete, but it could handle the most of samples available.

Further I shared my docs and code with another developer, whose name I
don't want to mention here. He wrote his own code, heavily based on my work.

The team suffered from poor communication and political intrigues...

A few days ago that other developer has submitted his decoder
anonymously. I feel that the code, containing a significant part of my
work, was released without proper credit.

Therefore I decided to post my code as well (without any parts written
by the other guy though). Hereby I claim copyright on several parts of
the ProRes decoder (vlc, headers and slice decoding), because due to my
hard work it has reached its final form.

My code may be of particular interest because of:
- compatible license (LGPL)
- a full description of the codec (especially its headers and encoding
algorithms) I'm going to make publicitly available soon
- maintainership by a real person instead of an anonymous one

Therefore I let you, crews, to make a final decision about all that...

Best regards
Maxim Poliakovski

/*
 * Apple ProRes compatible decoder
 *
 * Copyright (c) 2010-2011 Maxim Poliakovski
 *
 * This file is part of FFmpeg.
 *
 * FFmpeg 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.
 *
 * FFmpeg 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 FFmpeg; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
 */

/**
 * @file libavcodec/proresdec.c
 * This is a decoder for Apple ProRes 422 SD/HQ/LT/Proxy and ProRes 4444.
 * It is used for storing and editing high definition video data in Apple's Final Cut Pro.
 * For a detailed description click here: http://wiki.multimedia.cx/index.php?title=Apple_ProRes
 */

#define A32_BITSTREAM_READER // some ProRes vlc codes require up to 28 bits to be read at once

#include "avcodec.h"
#include "get_bits.h"
#include "dsputil.h"
#include "libavutil/mathematics.h"

#define	BITS_PER_SAMPLE	10 ///< output precision of that decoder
#define BIAS (1 << (BITS_PER_SAMPLE - 1)) ///< bias value for converting signed pixels into unsigned ones
#define CLIP_MIN (1 << (BITS_PER_SAMPLE - 8)) ///< minimum value for clipping resulting pixels
#define CLIP_MAX (1 << BITS_PER_SAMPLE) - CLIP_MIN - 1 ///< maximum value for clipping resulting pixels


typedef struct {
    DSPContext dsp;
    AVFrame    picture;
    ScanTable  scantable;
    int        scantable_type;  ///< -1 = uninitialized, 0 = progressive, 1/2 = interlaced

    int        frame_type;      ///< 0 = progressive, 1 = top-field first, 2 = bottom-field first
    int        pic_format;      ///< 2 = 422, 3 = 444
    uint8_t    qmat_luma[64];   ///< dequantization matrix for luma
    uint8_t    qmat_chroma[64]; ///< dequantization matrix for chroma
    int        qmat_changed;    ///< 1 - global quantization matrices changed
    int        prev_slice_sf;   ///< scalefactor of the previous decoded slice
    DECLARE_ALIGNED(16, int16_t, qmat_luma_scaled[64]);
    DECLARE_ALIGNED(16, int16_t, qmat_chroma_scaled[64]);
    int        total_slices;    ///< total number of slices in a picture
    const uint8_t **slice_data_index; ///< array of pointers to the data of each slice
    int        chroma_factor;
    int        mb_chroma_factor;
    int        num_chroma_blocks; ///< number of chrominance blocks in a macroblock
    int        num_x_slices;
    int        num_y_slices;
    int        slice_width_factor;
    int        slice_height_factor;
    int        num_x_mbs;
    int        num_y_mbs;
} ProresContext;


static const uint8_t progressive_scan[64] = {
     0,  1,  8,  9,  2,  3, 10, 11,
    16, 17, 24, 25, 18, 19, 26, 27,
     4,  5, 12, 20, 13,  6,  7, 14,
    21, 28, 29, 22, 15, 23, 30, 31,
    32, 33, 40, 48, 41, 34, 35, 42,
    49, 56, 57, 50, 43, 36, 37, 44,
    51, 58, 59, 52, 45, 38, 39, 46,
    53, 60, 61, 54, 47, 55, 62, 63
};

static const uint8_t interlaced_scan[64] = {
     0,  8,  1,  9, 16, 24, 17, 25,
     2, 10,  3, 11, 18, 26, 19, 27,
    32, 40, 33, 34, 41, 48, 56, 49,
    42, 35, 43, 50, 57, 58, 51, 59,
     4, 12,  5,  6, 13, 20, 28, 21,
    14,  7, 15, 22, 29, 36, 44, 37,
    30, 23, 31, 38, 45, 52, 60, 53,
    46, 39, 47, 54, 61, 62, 55, 63
};


/**
 *  ProRes decoder initializations.
 */
static av_cold int decode_init(AVCodecContext * avctx)
{
    ProresContext *ctx = avctx->priv_data;

    ctx->total_slices = 0;
    ctx->slice_data_index = 0;

    avctx->pix_fmt = PIX_FMT_YUV422P10; // set default pixel format

    avctx->bits_per_raw_sample = BITS_PER_SAMPLE;
    dsputil_init(&ctx->dsp, avctx);

    avctx->coded_frame = &ctx->picture;
    avcodec_get_frame_defaults(&ctx->picture);
    ctx->picture.type = AV_PICTURE_TYPE_I;
    ctx->picture.key_frame = 1;

    ctx->scantable_type = -1;   // set scantable type to uninitialized
    memset(ctx->qmat_luma, 4, 64);
    memset(ctx->qmat_chroma, 4, 64);
    ctx->prev_slice_sf = 0;

    return 0;
}


/**
 *  Parse frame header.
 */
static int decode_frame_header(ProresContext * ctx, const uint8_t * buf,
                               const int data_size, AVCodecContext * avctx)
{
    int hdr_size, version, width, height, flags;
    const uint8_t *ptr;

    hdr_size = AV_RB16(buf);
    if (hdr_size > data_size) {
        av_log(avctx, AV_LOG_ERROR, "frame data too short!\n");
        return -1;
    }

    version = AV_RB16(buf + 2);
    if (version >= 2) {
        av_log(avctx, AV_LOG_ERROR, "unsupported header version: %d\n",
               version);
        return -1;
    }

    width = AV_RB16(buf + 8);
    height = AV_RB16(buf + 10);
    if (width != avctx->width || height != avctx->height) {
        av_log(avctx, AV_LOG_ERROR,
               "picture dimension changed! Old: %d x %d, new: %d x %d\n",
               avctx->width, avctx->height, width, height);
        return -1;
    }

    ctx->frame_type = (buf[12] >> 2) & 3;
    if (ctx->frame_type > 2) {
        av_log(avctx, AV_LOG_ERROR, "unsupported frame type: %d!\n",
               ctx->frame_type);
        return -1;
    }

    ctx->chroma_factor = (buf[12] >> 6) & 3;
    ctx->mb_chroma_factor = ctx->chroma_factor + 2;
    ctx->num_chroma_blocks = (1 << ctx->chroma_factor) >> 1;
    switch (ctx->chroma_factor) {
    case 2:
        avctx->pix_fmt = PIX_FMT_YUV422P10;
        break;
    case 3:
        avctx->pix_fmt = PIX_FMT_YUV444P10;
        break;
    default:
        av_log(avctx, AV_LOG_ERROR, "unsupported picture format: %d!\n",
               ctx->pic_format);
        return -1;
    }

    if (ctx->scantable_type != ctx->frame_type) {
        if (!ctx->frame_type)
            ff_init_scantable(ctx->dsp.idct_permutation, &ctx->scantable,
                              progressive_scan);
        else
            ff_init_scantable(ctx->dsp.idct_permutation, &ctx->scantable,
                              interlaced_scan);
        ctx->scantable_type = ctx->frame_type;
    }

    if (ctx->frame_type) {      /* if interlaced */
        ctx->picture.interlaced_frame = 1;
        ctx->picture.top_field_first = ctx->frame_type & 1;
    }

    ctx->qmat_changed = 0;
    ptr = buf + 20;
    flags = buf[19];
    if (flags & 2) {
        if (memcmp(ctx->qmat_luma, ptr, 64)) {
            memcpy(ctx->qmat_luma, ptr, 64);
            ctx->qmat_changed = 1;
        }
        ptr += 64;
    } else {
        memset(ctx->qmat_luma, 4, 64);
        ctx->qmat_changed = 1;
    }

    if (flags & 1) {
        if (memcmp(ctx->qmat_chroma, ptr, 64)) {
            memcpy(ctx->qmat_chroma, ptr, 64);
            ctx->qmat_changed = 1;
        }
    } else {
        memset(ctx->qmat_chroma, 4, 64);
        ctx->qmat_changed = 1;
    }

    return hdr_size;
}


/**
 *  Parse picture header.
 */
static int decode_picture_header(ProresContext * ctx, const uint8_t * buf,
                                 const int data_size, AVCodecContext * avctx)
{
    int   i, hdr_size, pic_data_size, num_slices;
    int   slice_width_factor, slice_height_factor;
    int   remainder, num_x_slices;
    const uint8_t *data_ptr, *index_ptr;

    hdr_size = data_size > 0 ? buf[0] >> 3 : 0;
    if (hdr_size < 8 || hdr_size > data_size) {
        av_log(avctx, AV_LOG_ERROR, "picture header too short!\n");
        return -1;
    }

    pic_data_size = AV_RB32(buf + 1);
    if (pic_data_size > data_size) {
        av_log(avctx, AV_LOG_ERROR, "picture data too short!\n");
        return -1;
    }

    slice_width_factor  = buf[7] >> 4;
    slice_height_factor = buf[7] & 0xF;
    if (slice_width_factor > 3 || slice_height_factor) {
        av_log(avctx, AV_LOG_ERROR,
               "unsupported slice dimension: %d x %d!\n",
               1 << slice_width_factor, 1 << slice_height_factor);
        return -1;
    }

    ctx->slice_width_factor  = slice_width_factor;
    ctx->slice_height_factor = slice_height_factor;

    ctx->num_x_mbs = (avctx->width + 15) >> 4;
    ctx->num_y_mbs =
        (avctx->height + 15) >> (4 + ctx->picture.interlaced_frame);

    remainder    = ctx->num_x_mbs & ((1 << slice_width_factor) - 1);
    num_x_slices = (ctx->num_x_mbs >> slice_width_factor) + (remainder & 1) +
                   ((remainder >> 1) & 1) + ((remainder >> 2) & 1);

    num_slices = num_x_slices * ctx->num_y_mbs;
    if (num_slices != AV_RB16(buf + 5)) {
        av_log(avctx, AV_LOG_ERROR, "invalid number of slices!\n");
        return -1;
    }

    if (ctx->total_slices != num_slices) {
        av_freep(&ctx->slice_data_index);
        ctx->slice_data_index =
            av_malloc((num_slices + 1) * sizeof(uint8_t *));
        if (!ctx->slice_data_index)
            return AVERROR(ENOMEM);
        ctx->total_slices = num_slices;
    }

    if (hdr_size + num_slices * 2 > data_size) {
        av_log(avctx, AV_LOG_ERROR, "slice table too short!\n");
        return -1;
    }

    /* parse slice table allowing quick access to the slice data */
    index_ptr = buf + hdr_size;
    data_ptr = index_ptr + num_slices * 2;

    for (i = 0; i < num_slices; i++) {
        ctx->slice_data_index[i] = data_ptr;
        data_ptr += AV_RB16(index_ptr + i * 2);
    }
    ctx->slice_data_index[i] = data_ptr;

    if (data_ptr > buf + data_size) {
        av_log(avctx, AV_LOG_ERROR, "out of slice data!\n");
        return -1;
    }

    return pic_data_size;
}


/**
 *  Read an unsigned rice/exp golomb codeword.
 */
static inline int decode_vlc_codeword(GetBitContext * gb, uint8_t codebook)
{
    unsigned int rice_order, exp_order, switch_bits;
    unsigned int buf, code;
    int log, prefix_len, len;

    OPEN_READER(re, gb);
    UPDATE_CACHE(re, gb);
    buf = GET_CACHE(re, gb);

    /* 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 */

    log = __builtin_clz(buf); /* count prefix bits (zeroes) */

    if (log < switch_bits) { /* ok, we got a rice code */
        if (!rice_order) {
            /* shortcut for faster decoding of rice codes without remainder */
            code = log;
            LAST_SKIP_BITS(re, gb, log + 1);
        } else {
            prefix_len = log + 1;
            code = (log << rice_order) + NEG_USR32((buf << prefix_len), rice_order);
            LAST_SKIP_BITS(re, gb, prefix_len + rice_order);
        }
    } else { /* otherwise we got a exp golomb code */
        len  = (log << 1) - switch_bits + exp_order + 1;
        code = NEG_USR32(buf, len) - (1 << exp_order) +
               (switch_bits << rice_order);
        LAST_SKIP_BITS(re, gb, len);
    }

    CLOSE_READER(re, gb);

    return code;
}

#define	LSB2SIGN(x) (-((x) & 1))
#define TOSIGNED(x) (((x) >> 1) ^ LSB2SIGN(x))

#define FIRST_DC_CB 0xB8 // rice_order = 5, exp_golomb_order = 6, switch_bits = 0

static uint8_t dc_codebook[4] = {
     0x4, // rice_order = 0, exp_golomb_order = 1, switch_bits = 0
    0x28, // rice_order = 1, exp_golomb_order = 2, switch_bits = 0
    0x4D, // rice_order = 2, exp_golomb_order = 3, switch_bits = 1
    0x70  // rice_order = 3, exp_golomb_order = 4, switch_bits = 0
};


/**
 *  Decode DC coefficients for all blocks in a slice.
 */
static inline void decode_dc_coeffs(GetBitContext * gb, DCTELEM *out,
                                    int nblocks)
{
    DCTELEM prev_dc;
    int     i, sign;
    int16_t delta;
    unsigned int code;

    code = decode_vlc_codeword(gb, FIRST_DC_CB);
    out[0] = prev_dc = TOSIGNED(code);

    out += 64; /* move to the DC coeff of the next block */

    delta = 3;

    for (i = 1; i < nblocks; i++, out += 64) {
        code = decode_vlc_codeword(gb, dc_codebook[FFMIN(FFABS(delta), 3)]);
        if (code < 0)
            return;

        sign = -(((delta >> 15) & 1) ^ (code & 1));
        delta = (((code + 1) >> 1) ^ sign) - sign;
        prev_dc += delta;
        out[0] = prev_dc;
    }
}


static uint8_t ac_codebook[7] = {
     0x4, // rice_order = 0, exp_golomb_order = 1, switch_bits = 0
    0x28, // rice_order = 1, exp_golomb_order = 2, switch_bits = 0
    0x4C, // rice_order = 2, exp_golomb_order = 3, switch_bits = 0
     0x5, // rice_order = 0, exp_golomb_order = 1, switch_bits = 1
    0x29, // rice_order = 1, exp_golomb_order = 2, switch_bits = 1
     0x6, // rice_order = 0, exp_golomb_order = 1, switch_bits = 2
     0xA, // rice_order = 0, exp_golomb_order = 2, switch_bits = 2
};

/**
    Lookup tables for adaptive switching between codebooks
    according with previous run/level value.
 */
static uint8_t run_to_cb_index[16] =
    { 5, 5, 3, 3, 0, 4, 4, 4, 4, 1, 1, 1, 1, 1, 1, 2 };

static uint8_t lev_to_cb_index[10] = { 0, 6, 3, 5, 0, 1, 1, 1, 1, 2 };


/**
 *  Decode AC coefficients for all blocks in a slice.
 */
static inline void decode_ac_coeffs(GetBitContext * gb, DCTELEM * out,
                                    int blocks_per_slice,
                                    int plane_size_factor,
                                    const uint8_t * scan)
{
    int pos, block_mask, run, level, sign, run_cb_index, lev_cb_index;
    int max_coeffs, bits_left;

    /* set initial prediction values */
    run = 4;
    level = 2;

    max_coeffs = blocks_per_slice << 6;
    block_mask = blocks_per_slice - 1;

    for (pos = blocks_per_slice - 1; pos < max_coeffs;) {
        run_cb_index = run_to_cb_index[FFMIN(run, 15)];
        lev_cb_index = lev_to_cb_index[FFMIN(level, 9)];

        bits_left = get_bits_left(gb);
        if (bits_left <= 8 && !show_bits(gb, bits_left))
            return;

        run = decode_vlc_codeword(gb, ac_codebook[run_cb_index]);

        bits_left = get_bits_left(gb);
        if (bits_left <= 8 && !show_bits(gb, bits_left))
            return;

        level = decode_vlc_codeword(gb, ac_codebook[lev_cb_index]) + 1;

        pos += run + 1;
        if (pos >= max_coeffs)
            break;

        sign = get_sbits(gb, 1);
        out[((pos & block_mask) << 6) + scan[pos >> plane_size_factor]] =
            (level ^ sign) - sign;
    }
}


#define CLIP_AND_BIAS(x) (av_clip((x) + BIAS, CLIP_MIN, CLIP_MAX))

/**
 *  Add bias value, clamp and output pixels of a slice
 */
static void put_pixels(const DCTELEM * in, uint16_t * out, int stride,
                       int mbs_per_slice, int blocks_per_mb)
{
    int mb, x, y, src_offset, dst_offset;
    const DCTELEM *src1, *src2;
    uint16_t *dst1, *dst2;

    src1 = in;
    src2 = in + (blocks_per_mb << 5);
    dst1 = out;
    dst2 = out + (stride << 3);

    for (mb = 0; mb < mbs_per_slice; mb++) {
        for (y = 0, dst_offset = 0; y < 8; y++, dst_offset += stride) {
            for (x = 0; x < 8; x++) {
                src_offset = (y << 3) + x;

                dst1[dst_offset + x] = CLIP_AND_BIAS(src1[src_offset]);
                dst2[dst_offset + x] = CLIP_AND_BIAS(src2[src_offset]);

                if (blocks_per_mb > 2) {
                    dst1[dst_offset + x + 8] =
                        CLIP_AND_BIAS(src1[src_offset + 64]);
                    dst2[dst_offset + x + 8] =
                        CLIP_AND_BIAS(src2[src_offset + 64]);
                }
            }
        }

        src1 += blocks_per_mb << 6;
        src2 += blocks_per_mb << 6;
        dst1 += blocks_per_mb << 2;
        dst2 += blocks_per_mb << 2;
    }
}


/**
 *  Decode a slice plane (luma or chroma).
 */
static void decode_slice_plane(ProresContext * ctx, const uint8_t * buf,
                               int data_size, uint16_t * out_ptr,
                               int linesize, int mbs_per_slice,
                               int blocks_per_mb, int plane_size_factor,
                               const int16_t * qmat)
{
    GetBitContext gb;
    DECLARE_ALIGNED(16, DCTELEM, blocks[8 * 4 * 64]);
    DCTELEM *block_ptr;
    int i, blk_num, blocks_per_slice;

    blocks_per_slice = mbs_per_slice * blocks_per_mb;

    memset(blocks, 0, sizeof(blocks));

    init_get_bits(&gb, buf, data_size << 3);

    decode_dc_coeffs(&gb, blocks, blocks_per_slice);

    decode_ac_coeffs(&gb, blocks, blocks_per_slice,
                     plane_size_factor, ctx->scantable.permutated);

    /* inverse quantization, inverse transform and output */
    block_ptr = blocks;

    for (blk_num = 0; blk_num < blocks_per_slice;
         blk_num++, block_ptr += 64) {
        /* TODO: the correct solution shoud be (block_ptr[i] * qmat[i]) >> 1
           and the input of the inverse transform should be scaled by 2
           in order to avoid rounding errors.
           Due to the fact the existing FFmpeg transforms are incompatible with that
           input I temporally introduced the coarse solution below...
         */
        for (i = 0; i < 64; i++)
            block_ptr[i] = (block_ptr[i] * qmat[i]) >> 2;

        ctx->dsp.idct(block_ptr);
    }

    put_pixels(blocks, out_ptr, linesize >> 1, mbs_per_slice,
               blocks_per_mb);
}


/**
 *  Decode a slice.
 */
static int decode_slice(ProresContext * ctx, int pic_num, int slice_num,
                        int mb_x_pos, int mb_y_pos, int mbs_per_slice,
                        AVCodecContext * avctx)
{
    const uint8_t *buf;
    uint8_t *y_data, *u_data, *v_data;
    AVFrame *pic = avctx->coded_frame;
    int i, sf, blocks_per_slice, slice_width_factor;
    int slice_data_size, hdr_size, y_data_size, u_data_size, v_data_size;
    int y_linesize, u_linesize, v_linesize;

    buf = ctx->slice_data_index[slice_num];
    slice_data_size = ctx->slice_data_index[slice_num + 1] - buf;

    slice_width_factor = av_log2(mbs_per_slice);

    y_data = pic->data[0];
    u_data = pic->data[1];
    v_data = pic->data[2];
    y_linesize = pic->linesize[0];
    u_linesize = pic->linesize[1];
    v_linesize = pic->linesize[2];

    if (pic->interlaced_frame) {
        if (!(pic_num ^ pic->top_field_first)) {
            y_data += y_linesize;
            u_data += u_linesize;
            v_data += v_linesize;
        }
        y_linesize <<= 1;
        u_linesize <<= 1;
        v_linesize <<= 1;
    }

    if (slice_data_size < 6) {
        av_log(avctx, AV_LOG_ERROR, "slice data too short!\n");
        return -1;
    }

    /* parse slice header */
    hdr_size = buf[0] >> 3;
    y_data_size = AV_RB16(buf + 2);
    u_data_size = AV_RB16(buf + 4);
    v_data_size = slice_data_size - y_data_size - u_data_size - hdr_size;

    if (v_data_size < 0 || hdr_size < 6) {
        av_log(avctx, AV_LOG_ERROR, "invalid data sizes!\n");
        return -1;
    }

    sf = av_clip(buf[1], 1, 224);
    sf = sf > 128 ? (sf - 96) << 2 : sf;

    /* scale quantization matrixes according with slice's scale factor */
    /* TODO: this can be SIMD-optimized alot */
    if (ctx->qmat_changed || sf != ctx->prev_slice_sf) {
        ctx->prev_slice_sf = sf;
        for (i = 0; i < 64; i++) {
            ctx->qmat_luma_scaled[i] = ctx->qmat_luma[i] * sf;
            ctx->qmat_chroma_scaled[i] = ctx->qmat_chroma[i] * sf;
        }
    }

    /* decode luma plane */
    decode_slice_plane(ctx, buf + hdr_size, y_data_size,
                       (uint16_t *) (y_data + (mb_y_pos << 4) * y_linesize +
                                     (mb_x_pos << 5)), y_linesize,
                       mbs_per_slice, 4, slice_width_factor + 2,
                       ctx->qmat_luma_scaled);

    /* decode U chroma plane */
    decode_slice_plane(ctx, buf + hdr_size + y_data_size, u_data_size,
                       (uint16_t *) (u_data + (mb_y_pos << 4) * u_linesize +
                                     (mb_x_pos << ctx->mb_chroma_factor)),
                       u_linesize, mbs_per_slice, ctx->num_chroma_blocks,
                       slice_width_factor + ctx->chroma_factor - 1,
                       ctx->qmat_chroma_scaled);

    /* decode V chroma plane */
    decode_slice_plane(ctx, buf + hdr_size + y_data_size + u_data_size,
                       v_data_size,
                       (uint16_t *) (v_data + (mb_y_pos << 4) * v_linesize +
                                     (mb_x_pos << ctx->mb_chroma_factor)),
                       v_linesize, mbs_per_slice, ctx->num_chroma_blocks,
                       slice_width_factor + ctx->chroma_factor - 1,
                       ctx->qmat_chroma_scaled);

    return 0;
}


/**
 *  decode a picture
 */
static int decode_picture(ProresContext * ctx, int pic_num,
                          AVCodecContext * avctx)
{
    int slice_num, slice_width, x_pos, y_pos;

    slice_num = 0;

    for (y_pos = 0; y_pos < ctx->num_y_mbs; y_pos++) {
        slice_width = 1 << ctx->slice_width_factor;

        for (x_pos = 0; x_pos < ctx->num_x_mbs && slice_width;
             x_pos += slice_width) {
            while (ctx->num_x_mbs - x_pos < slice_width)
                slice_width >>= 1;

            if (decode_slice
                (ctx, pic_num, slice_num, x_pos, y_pos, slice_width,
                 avctx) < 0)
                return -1;

            slice_num++;
        }
    }

    return 0;
}


#define FRAME_ID MKBETAG('i', 'c', 'p', 'f')
#define MOVE_DATA_PTR(nbytes) buf += (nbytes); buf_size -= (nbytes)

/**
 *  main decoder function
 */
static int decode_frame(AVCodecContext * avctx, void *data, int *data_size,
                        AVPacket * avpkt)
{
    ProresContext *ctx = avctx->priv_data;
    AVFrame *picture = avctx->coded_frame;
    const uint8_t *buf = avpkt->data;
    int buf_size = avpkt->size;
    int frame_hdr_size, pic_num, pic_data_size;

    /* check frame atom container */
    if (buf_size < 28 || buf_size < AV_RB32(buf) ||
        AV_RB32(buf + 4) != FRAME_ID) {
        av_log(avctx, AV_LOG_ERROR, "invalid frame\n");
        return -1;
    }

    MOVE_DATA_PTR(8);

    frame_hdr_size = decode_frame_header(ctx, buf, buf_size, avctx);
    if (frame_hdr_size < 0)
        return -1;

    MOVE_DATA_PTR(frame_hdr_size);

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

    picture->reference = 0;
    if (avctx->get_buffer(avctx, picture) < 0)
        return -1;

    for (pic_num = 0; ctx->picture.interlaced_frame - pic_num + 1;
         pic_num++) {
        pic_data_size = decode_picture_header(ctx, buf, buf_size, avctx);
        if (pic_data_size < 0)
            return -1;

        if (decode_picture(ctx, pic_num, avctx))
            return -1;

        MOVE_DATA_PTR(pic_data_size);
    }

    *data_size = sizeof(AVPicture);
    *(AVFrame *) data = *avctx->coded_frame;

    return avpkt->size;
}


/**
 *  Decoder close function.
 */
static av_cold int decode_close(AVCodecContext * avctx)
{
    ProresContext *ctx = avctx->priv_data;

    if (ctx->picture.data[0])
        avctx->release_buffer(avctx, &ctx->picture);

    av_freep(&ctx->slice_data_index);

    return 0;
}


AVCodec ff_prores_decoder = {
    .name           = "ProRes",
    .type           = AVMEDIA_TYPE_VIDEO,
    .id             = CODEC_ID_PRORES,
    .priv_data_size = sizeof(ProresContext),
    .init           = decode_init,
    .close          = decode_close,
    .decode         = decode_frame,
    .capabilities   = CODEC_CAP_DR1,
    .long_name = NULL_IF_CONFIG_SMALL("Apple ProRes (iCodec Pro)")
};
_______________________________________________
libav-devel mailing list
[email protected]
https://lists.libav.org/mailman/listinfo/libav-devel

Reply via email to