PeerStreamer

/*

 * Cinepak Video Decoder

 * Copyright (C) 2003 the ffmpeg project

 *

 * 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

 * Cinepak video decoder

 * by Ewald Snel <ewald@rambo.its.tudelft.nl>

 * For more information on the Cinepak algorithm, visit:

 *   http://www.csse.monash.edu.au/~timf/

 * For more information on the quirky data inside Sega FILM/CPK files, visit:

 *   http://wiki.multimedia.cx/index.php?title=Sega_FILM

 */

#include <stdio.h>

#include <stdlib.h>

#include <string.h>

#include "libavutil/intreadwrite.h"

#include "avcodec.h"

typedef struct {

    uint8_t  y0, y1, y2, y3;

    uint8_t  u, v;

} cvid_codebook;

#define MAX_STRIPS      32

typedef struct {

    uint16_t          id;

    uint16_t          x1, y1;

    uint16_t          x2, y2;

    cvid_codebook     v4_codebook[256];

    cvid_codebook     v1_codebook[256];

} cvid_strip;

typedef struct CinepakContext {

    AVCodecContext *avctx;

    AVFrame frame;

    const unsigned char *data;

    int size;

    int width, height;

    int palette_video;

    cvid_strip strips[MAX_STRIPS];

    int sega_film_skip_bytes;

} CinepakContext;

static void cinepak_decode_codebook (cvid_codebook *codebook,

                                     int chunk_id, int size, const uint8_t *data)

{

    const uint8_t *eod = (data + size);

    uint32_t flag, mask;

    int      i, n;

    /* check if this chunk contains 4- or 6-element vectors */

    n    = (chunk_id & 0x04) ? 4 : 6;

    flag = 0;

    mask = 0;

    for (i=0; i < 256; i++) {

        if ((chunk_id & 0x01) && !(mask >>= 1)) {

            if ((data + 4) > eod)

                break;

            flag  = AV_RB32 (data);

            data += 4;

            mask  = 0x80000000;

        }

        if (!(chunk_id & 0x01) || (flag & mask)) {

            if ((data + n) > eod)

                break;

            if (n == 6) {

                codebook[i].y0 = *data++;

                codebook[i].y1 = *data++;

                codebook[i].y2 = *data++;

                codebook[i].y3 = *data++;

                codebook[i].u  = 128 + *data++;

                codebook[i].v  = 128 + *data++;

            } else {

                /* this codebook type indicates either greyscale or

                 * palettized video; if palettized, U & V components will

                 * not be used so it is safe to set them to 128 for the

                 * benefit of greyscale rendering in YUV420P */

                codebook[i].y0 = *data++;

                codebook[i].y1 = *data++;

                codebook[i].y2 = *data++;

                codebook[i].y3 = *data++;

                codebook[i].u  = 128;

                codebook[i].v  = 128;

            }

        }

    }

}

static int cinepak_decode_vectors (CinepakContext *s, cvid_strip *strip,

                                   int chunk_id, int size, const uint8_t *data)

{

    const uint8_t   *eod = (data + size);

    uint32_t         flag, mask;

    cvid_codebook   *codebook;

    unsigned int     x, y;

    uint32_t         iy[4];

    uint32_t         iu[2];

    uint32_t         iv[2];

    flag = 0;

    mask = 0;

    for (y=strip->y1; y < strip->y2; y+=4) {

        iy[0] = strip->x1 + (y * s->frame.linesize[0]);

        iy[1] = iy[0] + s->frame.linesize[0];

        iy[2] = iy[1] + s->frame.linesize[0];

        iy[3] = iy[2] + s->frame.linesize[0];

        iu[0] = (strip->x1/2) + ((y/2) * s->frame.linesize[1]);

        iu[1] = iu[0] + s->frame.linesize[1];

        iv[0] = (strip->x1/2) + ((y/2) * s->frame.linesize[2]);

        iv[1] = iv[0] + s->frame.linesize[2];

        for (x=strip->x1; x < strip->x2; x+=4) {

            if ((chunk_id & 0x01) && !(mask >>= 1)) {

                if ((data + 4) > eod)

                    return -1;

                flag  = AV_RB32 (data);

                data += 4;

                mask  = 0x80000000;

            }

            if (!(chunk_id & 0x01) || (flag & mask)) {

                if (!(chunk_id & 0x02) && !(mask >>= 1)) {

                    if ((data + 4) > eod)

                        return -1;

                    flag  = AV_RB32 (data);

                    data += 4;

                    mask  = 0x80000000;

                }

                if ((chunk_id & 0x02) || (~flag & mask)) {

                    if (data >= eod)

                        return -1;

                    codebook = &strip->v1_codebook[*data++];

                    s->frame.data[0][iy[0] + 0] = codebook->y0;

                    s->frame.data[0][iy[0] + 1] = codebook->y0;

                    s->frame.data[0][iy[1] + 0] = codebook->y0;

                    s->frame.data[0][iy[1] + 1] = codebook->y0;

                    if (!s->palette_video) {

                        s->frame.data[1][iu[0]] = codebook->u;

                        s->frame.data[2][iv[0]] = codebook->v;

                    }

                    s->frame.data[0][iy[0] + 2] = codebook->y1;

                    s->frame.data[0][iy[0] + 3] = codebook->y1;

                    s->frame.data[0][iy[1] + 2] = codebook->y1;

                    s->frame.data[0][iy[1] + 3] = codebook->y1;

                    if (!s->palette_video) {

                        s->frame.data[1][iu[0] + 1] = codebook->u;

                        s->frame.data[2][iv[0] + 1] = codebook->v;

                    }

                    s->frame.data[0][iy[2] + 0] = codebook->y2;

                    s->frame.data[0][iy[2] + 1] = codebook->y2;

                    s->frame.data[0][iy[3] + 0] = codebook->y2;

                    s->frame.data[0][iy[3] + 1] = codebook->y2;

                    if (!s->palette_video) {

                        s->frame.data[1][iu[1]] = codebook->u;

                        s->frame.data[2][iv[1]] = codebook->v;

                    }

                    s->frame.data[0][iy[2] + 2] = codebook->y3;

                    s->frame.data[0][iy[2] + 3] = codebook->y3;

                    s->frame.data[0][iy[3] + 2] = codebook->y3;

                    s->frame.data[0][iy[3] + 3] = codebook->y3;

                    if (!s->palette_video) {

                        s->frame.data[1][iu[1] + 1] = codebook->u;

                        s->frame.data[2][iv[1] + 1] = codebook->v;

                    }

                } else if (flag & mask) {

                    if ((data + 4) > eod)

                        return -1;

                    codebook = &strip->v4_codebook[*data++];

                    s->frame.data[0][iy[0] + 0] = codebook->y0;

                    s->frame.data[0][iy[0] + 1] = codebook->y1;

                    s->frame.data[0][iy[1] + 0] = codebook->y2;

                    s->frame.data[0][iy[1] + 1] = codebook->y3;

                    if (!s->palette_video) {

                        s->frame.data[1][iu[0]] = codebook->u;

                        s->frame.data[2][iv[0]] = codebook->v;

                    }

                    codebook = &strip->v4_codebook[*data++];

                    s->frame.data[0][iy[0] + 2] = codebook->y0;

                    s->frame.data[0][iy[0] + 3] = codebook->y1;

                    s->frame.data[0][iy[1] + 2] = codebook->y2;

                    s->frame.data[0][iy[1] + 3] = codebook->y3;

                    if (!s->palette_video) {

                        s->frame.data[1][iu[0] + 1] = codebook->u;

                        s->frame.data[2][iv[0] + 1] = codebook->v;

                    }

                    codebook = &strip->v4_codebook[*data++];

                    s->frame.data[0][iy[2] + 0] = codebook->y0;

                    s->frame.data[0][iy[2] + 1] = codebook->y1;

                    s->frame.data[0][iy[3] + 0] = codebook->y2;

                    s->frame.data[0][iy[3] + 1] = codebook->y3;

                    if (!s->palette_video) {

                        s->frame.data[1][iu[1]] = codebook->u;

                        s->frame.data[2][iv[1]] = codebook->v;

                    }

                    codebook = &strip->v4_codebook[*data++];

                    s->frame.data[0][iy[2] + 2] = codebook->y0;

                    s->frame.data[0][iy[2] + 3] = codebook->y1;

                    s->frame.data[0][iy[3] + 2] = codebook->y2;

                    s->frame.data[0][iy[3] + 3] = codebook->y3;

                    if (!s->palette_video) {

                        s->frame.data[1][iu[1] + 1] = codebook->u;

                        s->frame.data[2][iv[1] + 1] = codebook->v;

                    }

                }

            }

            iy[0] += 4;  iy[1] += 4;

            iy[2] += 4;  iy[3] += 4;

            iu[0] += 2;  iu[1] += 2;

            iv[0] += 2;  iv[1] += 2;

        }

    }

    return 0;

}

static int cinepak_decode_strip (CinepakContext *s,

                                 cvid_strip *strip, const uint8_t *data, int size)

{

    const uint8_t *eod = (data + size);

    int      chunk_id, chunk_size;

    /* coordinate sanity checks */

    if (strip->x1 >= s->width  || strip->x2 > s->width  ||

        strip->y1 >= s->height || strip->y2 > s->height ||

        strip->x1 >= strip->x2 || strip->y1 >= strip->y2)

        return -1;

    while ((data + 4) <= eod) {

        chunk_id   = data[0];

        chunk_size = AV_RB24 (&data[1]) - 4;

        if(chunk_size < 0)

            return -1;

        data      += 4;

        chunk_size = ((data + chunk_size) > eod) ? (eod - data) : chunk_size;

        switch (chunk_id) {

        case 0x20:

        case 0x21:

        case 0x24:

        case 0x25:

            cinepak_decode_codebook (strip->v4_codebook, chunk_id,

                chunk_size, data);

            break;

        case 0x22:

        case 0x23:

        case 0x26:

        case 0x27:

            cinepak_decode_codebook (strip->v1_codebook, chunk_id,

                chunk_size, data);

            break;

        case 0x30:

        case 0x31:

        case 0x32:

            return cinepak_decode_vectors (s, strip, chunk_id,

                chunk_size, data);

        }

        data += chunk_size;

    }

    return -1;

}

static int cinepak_decode (CinepakContext *s)

{

    const uint8_t  *eod = (s->data + s->size);

    int           i, result, strip_size, frame_flags, num_strips;

    int           y0 = 0;

    int           encoded_buf_size;

    if (s->size < 10)

        return -1;

    frame_flags = s->data[0];

    num_strips  = AV_RB16 (&s->data[8]);

    encoded_buf_size = ((s->data[1] << 16) | AV_RB16 (&s->data[2]));

    /* if this is the first frame, check for deviant Sega FILM data */

    if (s->sega_film_skip_bytes == -1) {

        if (encoded_buf_size != s->size) {

            /* If the encoded frame size differs from the frame size as indicated

             * by the container file, this data likely comes from a Sega FILM/CPK file.

             * If the frame header is followed by the bytes FE 00 00 06 00 00 then

             * this is probably one of the two known files that have 6 extra bytes

             * after the frame header. Else, assume 2 extra bytes. */

            if ((s->data[10] == 0xFE) &&

                (s->data[11] == 0x00) &&

                (s->data[12] == 0x00) &&

                (s->data[13] == 0x06) &&

                (s->data[14] == 0x00) &&

                (s->data[15] == 0x00))

                s->sega_film_skip_bytes = 6;

            else

                s->sega_film_skip_bytes = 2;

        } else

            s->sega_film_skip_bytes = 0;

    }

    s->data += 10 + s->sega_film_skip_bytes;

    if (num_strips > MAX_STRIPS)

        num_strips = MAX_STRIPS;

    for (i=0; i < num_strips; i++) {

        if ((s->data + 12) > eod)

            return -1;

        s->strips[i].id = s->data[0];

        s->strips[i].y1 = y0;

        s->strips[i].x1 = 0;

        s->strips[i].y2 = y0 + AV_RB16 (&s->data[8]);

        s->strips[i].x2 = s->avctx->width;

        strip_size = AV_RB24 (&s->data[1]) - 12;

        s->data   += 12;

        strip_size = ((s->data + strip_size) > eod) ? (eod - s->data) : strip_size;

        if ((i > 0) && !(frame_flags & 0x01)) {

            memcpy (s->strips[i].v4_codebook, s->strips[i-1].v4_codebook,

                sizeof(s->strips[i].v4_codebook));

            memcpy (s->strips[i].v1_codebook, s->strips[i-1].v1_codebook,

                sizeof(s->strips[i].v1_codebook));

        }

        result = cinepak_decode_strip (s, &s->strips[i], s->data, strip_size);

        if (result != 0)

            return result;

        s->data += strip_size;

        y0    = s->strips[i].y2;

    }

    return 0;

}

static av_cold int cinepak_decode_init(AVCodecContext *avctx)

{

    CinepakContext *s = avctx->priv_data;

    s->avctx = avctx;

    s->width = (avctx->width + 3) & ~3;

    s->height = (avctx->height + 3) & ~3;

    s->sega_film_skip_bytes = -1;  /* uninitialized state */

    // check for paletted data

    if ((avctx->palctrl == NULL) || (avctx->bits_per_coded_sample == 40)) {

        s->palette_video = 0;

        avctx->pix_fmt = PIX_FMT_YUV420P;

    } else {

        s->palette_video = 1;

        avctx->pix_fmt = PIX_FMT_PAL8;

    }

    s->frame.data[0] = NULL;

    return 0;

}

static int cinepak_decode_frame(AVCodecContext *avctx,

                                void *data, int *data_size,

                                AVPacket *avpkt)

{

    const uint8_t *buf = avpkt->data;

    int buf_size = avpkt->size;

    CinepakContext *s = avctx->priv_data;

    s->data = buf;

    s->size = buf_size;

    s->frame.reference = 1;

    s->frame.buffer_hints = FF_BUFFER_HINTS_VALID | FF_BUFFER_HINTS_PRESERVE |

                            FF_BUFFER_HINTS_REUSABLE;

    if (avctx->reget_buffer(avctx, &s->frame)) {

        av_log(avctx, AV_LOG_ERROR, "reget_buffer() failed\n");

        return -1;

    }

    cinepak_decode(s);

    if (s->palette_video) {

        memcpy (s->frame.data[1], avctx->palctrl->palette, AVPALETTE_SIZE);

        if (avctx->palctrl->palette_changed) {

            s->frame.palette_has_changed = 1;

            avctx->palctrl->palette_changed = 0;

        } else

            s->frame.palette_has_changed = 0;

    }

    *data_size = sizeof(AVFrame);

    *(AVFrame*)data = s->frame;

    /* report that the buffer was completely consumed */

    return buf_size;

}

static av_cold int cinepak_decode_end(AVCodecContext *avctx)

{

    CinepakContext *s = avctx->priv_data;

    if (s->frame.data[0])

        avctx->release_buffer(avctx, &s->frame);

    return 0;

}

AVCodec ff_cinepak_decoder = {

    "cinepak",

    AVMEDIA_TYPE_VIDEO,

    CODEC_ID_CINEPAK,

    sizeof(CinepakContext),

    cinepak_decode_init,

    NULL,

    cinepak_decode_end,

    cinepak_decode_frame,

    CODEC_CAP_DR1,

    .long_name = NULL_IF_CONFIG_SMALL("Cinepak"),

};