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  1. /*
  2.  * Electronic Arts Madcow Video Decoder
  3.  * Copyright (c) 2007-2009 Peter Ross
  4.  *
  5.  * This file is part of FFmpeg.
  6.  *
  7.  * FFmpeg is free software; you can redistribute it and/or
  8.  * modify it under the terms of the GNU Lesser General Public
  9.  * License as published by the Free Software Foundation; either
  10.  * version 2.1 of the License, or (at your option) any later version.
  11.  *
  12.  * FFmpeg is distributed in the hope that it will be useful,
  13.  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  14.  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  15.  * Lesser General Public License for more details.
  16.  *
  17.  * You should have received a copy of the GNU Lesser General Public
  18.  * License along with FFmpeg; if not, write to the Free Software
  19.  * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
  20.  */
  21.  
  22. /**
  23.  * @file
  24.  * Electronic Arts Madcow Video Decoder
  25.  * @author Peter Ross <pross@xvid.org>
  26.  *
  27.  * @see technical details at
  28.  * http://wiki.multimedia.cx/index.php?title=Electronic_Arts_MAD
  29.  */
  30.  
  31. #include "avcodec.h"
  32. #include "get_bits.h"
  33. #include "aandcttab.h"
  34. #include "eaidct.h"
  35. #include "internal.h"
  36. #include "mpeg12.h"
  37. #include "mpeg12data.h"
  38. #include "libavutil/imgutils.h"
  39.  
  40. #define EA_PREAMBLE_SIZE    8
  41. #define MADk_TAG MKTAG('M', 'A', 'D', 'k')    /* MAD i-frame */
  42. #define MADm_TAG MKTAG('M', 'A', 'D', 'm')    /* MAD p-frame */
  43. #define MADe_TAG MKTAG('M', 'A', 'D', 'e')    /* MAD lqp-frame */
  44.  
  45. typedef struct MadContext {
  46.     AVCodecContext *avctx;
  47.     DSPContext dsp;
  48.     AVFrame last_frame;
  49.     GetBitContext gb;
  50.     void *bitstream_buf;
  51.     unsigned int bitstream_buf_size;
  52.     DECLARE_ALIGNED(16, int16_t, block)[64];
  53.     ScanTable scantable;
  54.     uint16_t quant_matrix[64];
  55.     int mb_x;
  56.     int mb_y;
  57. } MadContext;
  58.  
  59. static av_cold int decode_init(AVCodecContext *avctx)
  60. {
  61.     MadContext *s = avctx->priv_data;
  62.     s->avctx = avctx;
  63.     avctx->pix_fmt = AV_PIX_FMT_YUV420P;
  64.     ff_dsputil_init(&s->dsp, avctx);
  65.     ff_init_scantable_permutation(s->dsp.idct_permutation, FF_NO_IDCT_PERM);
  66.     ff_init_scantable(s->dsp.idct_permutation, &s->scantable, ff_zigzag_direct);
  67.     ff_mpeg12_init_vlcs();
  68.     return 0;
  69. }
  70.  
  71. static inline void comp(unsigned char *dst, int dst_stride,
  72.                         unsigned char *src, int src_stride, int add)
  73. {
  74.     int j, i;
  75.     for (j=0; j<8; j++)
  76.         for (i=0; i<8; i++)
  77.             dst[j*dst_stride + i] = av_clip_uint8(src[j*src_stride + i] + add);
  78. }
  79.  
  80. static inline void comp_block(MadContext *t, AVFrame *frame,
  81.                               int mb_x, int mb_y,
  82.                               int j, int mv_x, int mv_y, int add)
  83. {
  84.     if (j < 4) {
  85.         unsigned offset = (mb_y*16 + ((j&2)<<2) + mv_y)*t->last_frame.linesize[0] + mb_x*16 + ((j&1)<<3) + mv_x;
  86.         if (offset >= (t->avctx->height - 7) * t->last_frame.linesize[0] - 7)
  87.             return;
  88.         comp(frame->data[0] + (mb_y*16 + ((j&2)<<2))*frame->linesize[0] + mb_x*16 + ((j&1)<<3),
  89.              frame->linesize[0],
  90.              t->last_frame.data[0] + offset,
  91.              t->last_frame.linesize[0], add);
  92.     } else if (!(t->avctx->flags & CODEC_FLAG_GRAY)) {
  93.         int index = j - 3;
  94.         unsigned offset = (mb_y * 8 + (mv_y/2))*t->last_frame.linesize[index] + mb_x * 8 + (mv_x/2);
  95.         if (offset >= (t->avctx->height/2 - 7) * t->last_frame.linesize[index] - 7)
  96.             return;
  97.         comp(frame->data[index] + (mb_y*8)*frame->linesize[index] + mb_x * 8,
  98.              frame->linesize[index],
  99.              t->last_frame.data[index] + offset,
  100.              t->last_frame.linesize[index], add);
  101.     }
  102. }
  103.  
  104. static inline void idct_put(MadContext *t, AVFrame *frame, int16_t *block,
  105.                             int mb_x, int mb_y, int j)
  106. {
  107.     if (j < 4) {
  108.         ff_ea_idct_put_c(
  109.             frame->data[0] + (mb_y*16 + ((j&2)<<2))*frame->linesize[0] + mb_x*16 + ((j&1)<<3),
  110.             frame->linesize[0], block);
  111.     } else if (!(t->avctx->flags & CODEC_FLAG_GRAY)) {
  112.         int index = j - 3;
  113.         ff_ea_idct_put_c(
  114.             frame->data[index] + (mb_y*8)*frame->linesize[index] + mb_x*8,
  115.             frame->linesize[index], block);
  116.     }
  117. }
  118.  
  119. static inline int decode_block_intra(MadContext *s, int16_t * block)
  120. {
  121.     int level, i, j, run;
  122.     RLTable *rl = &ff_rl_mpeg1;
  123.     const uint8_t *scantable = s->scantable.permutated;
  124.     int16_t *quant_matrix = s->quant_matrix;
  125.  
  126.     block[0] = (128 + get_sbits(&s->gb, 8)) * quant_matrix[0];
  127.  
  128.     /* The RL decoder is derived from mpeg1_decode_block_intra;
  129.        Escaped level and run values a decoded differently */
  130.     i = 0;
  131.     {
  132.         OPEN_READER(re, &s->gb);
  133.         /* now quantify & encode AC coefficients */
  134.         for (;;) {
  135.             UPDATE_CACHE(re, &s->gb);
  136.             GET_RL_VLC(level, run, re, &s->gb, rl->rl_vlc[0], TEX_VLC_BITS, 2, 0);
  137.  
  138.             if (level == 127) {
  139.                 break;
  140.             } else if (level != 0) {
  141.                 i += run;
  142.                 j = scantable[i];
  143.                 level = (level*quant_matrix[j]) >> 4;
  144.                 level = (level-1)|1;
  145.                 level = (level ^ SHOW_SBITS(re, &s->gb, 1)) - SHOW_SBITS(re, &s->gb, 1);
  146.                 LAST_SKIP_BITS(re, &s->gb, 1);
  147.             } else {
  148.                 /* escape */
  149.                 UPDATE_CACHE(re, &s->gb);
  150.                 level = SHOW_SBITS(re, &s->gb, 10); SKIP_BITS(re, &s->gb, 10);
  151.  
  152.                 UPDATE_CACHE(re, &s->gb);
  153.                 run = SHOW_UBITS(re, &s->gb, 6)+1; LAST_SKIP_BITS(re, &s->gb, 6);
  154.  
  155.                 i += run;
  156.                 j = scantable[i];
  157.                 if (level < 0) {
  158.                     level = -level;
  159.                     level = (level*quant_matrix[j]) >> 4;
  160.                     level = (level-1)|1;
  161.                     level = -level;
  162.                 } else {
  163.                     level = (level*quant_matrix[j]) >> 4;
  164.                     level = (level-1)|1;
  165.                 }
  166.             }
  167.             if (i > 63) {
  168.                 av_log(s->avctx, AV_LOG_ERROR, "ac-tex damaged at %d %d\n", s->mb_x, s->mb_y);
  169.                 return -1;
  170.             }
  171.  
  172.             block[j] = level;
  173.         }
  174.         CLOSE_READER(re, &s->gb);
  175.     }
  176.     return 0;
  177. }
  178.  
  179. static int decode_motion(GetBitContext *gb)
  180. {
  181.     int value = 0;
  182.     if (get_bits1(gb)) {
  183.         if (get_bits1(gb))
  184.             value = -17;
  185.         value += get_bits(gb, 4) + 1;
  186.     }
  187.     return value;
  188. }
  189.  
  190. static int decode_mb(MadContext *s, AVFrame *frame, int inter)
  191. {
  192.     int mv_map = 0;
  193.     int mv_x, mv_y;
  194.     int j;
  195.  
  196.     if (inter) {
  197.         int v = decode210(&s->gb);
  198.         if (v < 2) {
  199.             mv_map = v ? get_bits(&s->gb, 6) : 63;
  200.             mv_x = decode_motion(&s->gb);
  201.             mv_y = decode_motion(&s->gb);
  202.         }
  203.     }
  204.  
  205.     for (j=0; j<6; j++) {
  206.         if (mv_map & (1<<j)) {  // mv_x and mv_y are guarded by mv_map
  207.             int add = 2*decode_motion(&s->gb);
  208.             if (s->last_frame.data[0])
  209.                 comp_block(s, frame, s->mb_x, s->mb_y, j, mv_x, mv_y, add);
  210.         } else {
  211.             s->dsp.clear_block(s->block);
  212.             if(decode_block_intra(s, s->block) < 0)
  213.                 return -1;
  214.             idct_put(s, frame, s->block, s->mb_x, s->mb_y, j);
  215.         }
  216.     }
  217.     return 0;
  218. }
  219.  
  220. static void calc_quant_matrix(MadContext *s, int qscale)
  221. {
  222.     int i;
  223.  
  224.     s->quant_matrix[0] = (ff_inv_aanscales[0]*ff_mpeg1_default_intra_matrix[0]) >> 11;
  225.     for (i=1; i<64; i++)
  226.         s->quant_matrix[i] = (ff_inv_aanscales[i]*ff_mpeg1_default_intra_matrix[i]*qscale + 32) >> 10;
  227. }
  228.  
  229. static int decode_frame(AVCodecContext *avctx,
  230.                         void *data, int *got_frame,
  231.                         AVPacket *avpkt)
  232. {
  233.     const uint8_t *buf = avpkt->data;
  234.     int buf_size       = avpkt->size;
  235.     const uint8_t *buf_end = buf+buf_size;
  236.     MadContext *s     = avctx->priv_data;
  237.     AVFrame *frame    = data;
  238.     int width, height;
  239.     int chunk_type;
  240.     int inter, ret;
  241.  
  242.     if (buf_size < 26) {
  243.         av_log(avctx, AV_LOG_ERROR, "Input buffer too small\n");
  244.         *got_frame = 0;
  245.         return AVERROR_INVALIDDATA;
  246.     }
  247.  
  248.     chunk_type = AV_RL32(&buf[0]);
  249.     inter = (chunk_type == MADm_TAG || chunk_type == MADe_TAG);
  250.     buf += 8;
  251.  
  252.     av_reduce(&avctx->time_base.num, &avctx->time_base.den,
  253.               AV_RL16(&buf[6]), 1000, 1<<30);
  254.  
  255.     width  = AV_RL16(&buf[8]);
  256.     height = AV_RL16(&buf[10]);
  257.     calc_quant_matrix(s, buf[13]);
  258.     buf += 16;
  259.  
  260.     if (width < 16 || height < 16) {
  261.         av_log(avctx, AV_LOG_ERROR, "Dimensions too small\n");
  262.         return AVERROR_INVALIDDATA;
  263.     }
  264.  
  265.     if (avctx->width != width || avctx->height != height) {
  266.         if((width * height)/2048*7 > buf_end-buf)
  267.             return AVERROR_INVALIDDATA;
  268.         if ((ret = av_image_check_size(width, height, 0, avctx)) < 0)
  269.             return ret;
  270.         avcodec_set_dimensions(avctx, width, height);
  271.         av_frame_unref(&s->last_frame);
  272.     }
  273.  
  274.     if ((ret = ff_get_buffer(avctx, frame, AV_GET_BUFFER_FLAG_REF)) < 0)
  275.         return ret;
  276.  
  277.     if (inter && !s->last_frame.data[0]) {
  278.         av_log(avctx, AV_LOG_WARNING, "Missing reference frame.\n");
  279.         ret = ff_get_buffer(avctx, &s->last_frame, AV_GET_BUFFER_FLAG_REF);
  280.         if (ret < 0)
  281.             return ret;
  282.         memset(s->last_frame.data[0], 0, s->last_frame.height *
  283.                s->last_frame.linesize[0]);
  284.         memset(s->last_frame.data[1], 0x80, s->last_frame.height / 2 *
  285.                s->last_frame.linesize[1]);
  286.         memset(s->last_frame.data[2], 0x80, s->last_frame.height / 2 *
  287.                s->last_frame.linesize[2]);
  288.     }
  289.  
  290.     av_fast_padded_malloc(&s->bitstream_buf, &s->bitstream_buf_size,
  291.                           buf_end - buf);
  292.     if (!s->bitstream_buf)
  293.         return AVERROR(ENOMEM);
  294.     s->dsp.bswap16_buf(s->bitstream_buf, (const uint16_t*)buf, (buf_end-buf)/2);
  295.     memset((uint8_t*)s->bitstream_buf + (buf_end-buf), 0, FF_INPUT_BUFFER_PADDING_SIZE);
  296.     init_get_bits(&s->gb, s->bitstream_buf, 8*(buf_end-buf));
  297.  
  298.     for (s->mb_y=0; s->mb_y < (avctx->height+15)/16; s->mb_y++)
  299.         for (s->mb_x=0; s->mb_x < (avctx->width +15)/16; s->mb_x++)
  300.             if(decode_mb(s, frame, inter) < 0)
  301.                 return AVERROR_INVALIDDATA;
  302.  
  303.     *got_frame = 1;
  304.  
  305.     if (chunk_type != MADe_TAG) {
  306.         av_frame_unref(&s->last_frame);
  307.         if ((ret = av_frame_ref(&s->last_frame, frame)) < 0)
  308.             return ret;
  309.     }
  310.  
  311.     return buf_size;
  312. }
  313.  
  314. static av_cold int decode_end(AVCodecContext *avctx)
  315. {
  316.     MadContext *t = avctx->priv_data;
  317.     av_frame_unref(&t->last_frame);
  318.     av_free(t->bitstream_buf);
  319.     return 0;
  320. }
  321.  
  322. AVCodec ff_eamad_decoder = {
  323.     .name           = "eamad",
  324.     .long_name      = NULL_IF_CONFIG_SMALL("Electronic Arts Madcow Video"),
  325.     .type           = AVMEDIA_TYPE_VIDEO,
  326.     .id             = AV_CODEC_ID_MAD,
  327.     .priv_data_size = sizeof(MadContext),
  328.     .init           = decode_init,
  329.     .close          = decode_end,
  330.     .decode         = decode_frame,
  331.     .capabilities   = CODEC_CAP_DR1,
  332. };
  333.