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  1. /*
  2.  * Sony PlayStation MDEC (Motion DECoder)
  3.  * Copyright (c) 2003 Michael Niedermayer
  4.  *
  5.  * based upon code from Sebastian Jedruszkiewicz <elf@frogger.rules.pl>
  6.  *
  7.  * This file is part of FFmpeg.
  8.  *
  9.  * FFmpeg is free software; you can redistribute it and/or
  10.  * modify it under the terms of the GNU Lesser General Public
  11.  * License as published by the Free Software Foundation; either
  12.  * version 2.1 of the License, or (at your option) any later version.
  13.  *
  14.  * FFmpeg is distributed in the hope that it will be useful,
  15.  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  16.  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  17.  * Lesser General Public License for more details.
  18.  *
  19.  * You should have received a copy of the GNU Lesser General Public
  20.  * License along with FFmpeg; if not, write to the Free Software
  21.  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
  22.  */
  23.  
  24. /**
  25.  * @file
  26.  * Sony PlayStation MDEC (Motion DECoder)
  27.  * This is very similar to intra-only MPEG-1.
  28.  */
  29.  
  30. #include "avcodec.h"
  31. #include "mpegvideo.h"
  32. #include "mpeg12.h"
  33. #include "thread.h"
  34.  
  35. typedef struct MDECContext {
  36.     AVCodecContext *avctx;
  37.     DSPContext dsp;
  38.     ThreadFrame frame;
  39.     GetBitContext gb;
  40.     ScanTable scantable;
  41.     int version;
  42.     int qscale;
  43.     int last_dc[3];
  44.     int mb_width;
  45.     int mb_height;
  46.     int mb_x, mb_y;
  47.     DECLARE_ALIGNED(16, int16_t, block)[6][64];
  48.     uint8_t *bitstream_buffer;
  49.     unsigned int bitstream_buffer_size;
  50.     int block_last_index[6];
  51. } MDECContext;
  52.  
  53. //very similar to MPEG-1
  54. static inline int mdec_decode_block_intra(MDECContext *a, int16_t *block, int n)
  55. {
  56.     int level, diff, i, j, run;
  57.     int component;
  58.     RLTable *rl = &ff_rl_mpeg1;
  59.     uint8_t * const scantable = a->scantable.permutated;
  60.     const uint16_t *quant_matrix = ff_mpeg1_default_intra_matrix;
  61.     const int qscale = a->qscale;
  62.  
  63.     /* DC coefficient */
  64.     if (a->version == 2) {
  65.         block[0] = 2 * get_sbits(&a->gb, 10) + 1024;
  66.     } else {
  67.         component = (n <= 3 ? 0 : n - 4 + 1);
  68.         diff = decode_dc(&a->gb, component);
  69.         if (diff >= 0xffff)
  70.             return AVERROR_INVALIDDATA;
  71.         a->last_dc[component] += diff;
  72.         block[0] = a->last_dc[component] << 3;
  73.     }
  74.  
  75.     i = 0;
  76.     {
  77.         OPEN_READER(re, &a->gb);
  78.         /* now quantify & encode AC coefficients */
  79.         for (;;) {
  80.             UPDATE_CACHE(re, &a->gb);
  81.             GET_RL_VLC(level, run, re, &a->gb, rl->rl_vlc[0], TEX_VLC_BITS, 2, 0);
  82.  
  83.             if (level == 127) {
  84.                 break;
  85.             } else if (level != 0) {
  86.                 i    += run;
  87.                 j     = scantable[i];
  88.                 level = (level * qscale * quant_matrix[j]) >> 3;
  89.                 level = (level ^ SHOW_SBITS(re, &a->gb, 1)) - SHOW_SBITS(re, &a->gb, 1);
  90.                 LAST_SKIP_BITS(re, &a->gb, 1);
  91.             } else {
  92.                 /* escape */
  93.                 run = SHOW_UBITS(re, &a->gb, 6)+1; LAST_SKIP_BITS(re, &a->gb, 6);
  94.                 UPDATE_CACHE(re, &a->gb);
  95.                 level = SHOW_SBITS(re, &a->gb, 10); SKIP_BITS(re, &a->gb, 10);
  96.                 i    += run;
  97.                 j     = scantable[i];
  98.                 if (level < 0) {
  99.                     level = -level;
  100.                     level = (level * qscale * quant_matrix[j]) >> 3;
  101.                     level = (level - 1) | 1;
  102.                     level = -level;
  103.                 } else {
  104.                     level = (level * qscale * quant_matrix[j]) >> 3;
  105.                     level = (level - 1) | 1;
  106.                 }
  107.             }
  108.             if (i > 63) {
  109.                 av_log(a->avctx, AV_LOG_ERROR, "ac-tex damaged at %d %d\n", a->mb_x, a->mb_y);
  110.                 return AVERROR_INVALIDDATA;
  111.             }
  112.  
  113.             block[j] = level;
  114.         }
  115.         CLOSE_READER(re, &a->gb);
  116.     }
  117.     a->block_last_index[n] = i;
  118.     return 0;
  119. }
  120.  
  121. static inline int decode_mb(MDECContext *a, int16_t block[6][64])
  122. {
  123.     int i, ret;
  124.     static const int block_index[6] = { 5, 4, 0, 1, 2, 3 };
  125.  
  126.     a->dsp.clear_blocks(block[0]);
  127.  
  128.     for (i = 0; i < 6; i++) {
  129.         if ((ret = mdec_decode_block_intra(a, block[block_index[i]],
  130.                                            block_index[i])) < 0)
  131.             return ret;
  132.         if (get_bits_left(&a->gb) < 0)
  133.             return AVERROR_INVALIDDATA;
  134.     }
  135.     return 0;
  136. }
  137.  
  138. static inline void idct_put(MDECContext *a, AVFrame *frame, int mb_x, int mb_y)
  139. {
  140.     int16_t (*block)[64] = a->block;
  141.     int linesize = frame->linesize[0];
  142.  
  143.     uint8_t *dest_y  = frame->data[0] + (mb_y * 16* linesize              ) + mb_x * 16;
  144.     uint8_t *dest_cb = frame->data[1] + (mb_y * 8 * frame->linesize[1]) + mb_x * 8;
  145.     uint8_t *dest_cr = frame->data[2] + (mb_y * 8 * frame->linesize[2]) + mb_x * 8;
  146.  
  147.     a->dsp.idct_put(dest_y,                    linesize, block[0]);
  148.     a->dsp.idct_put(dest_y                + 8, linesize, block[1]);
  149.     a->dsp.idct_put(dest_y + 8 * linesize,     linesize, block[2]);
  150.     a->dsp.idct_put(dest_y + 8 * linesize + 8, linesize, block[3]);
  151.  
  152.     if (!(a->avctx->flags & CODEC_FLAG_GRAY)) {
  153.         a->dsp.idct_put(dest_cb, frame->linesize[1], block[4]);
  154.         a->dsp.idct_put(dest_cr, frame->linesize[2], block[5]);
  155.     }
  156. }
  157.  
  158. static int decode_frame(AVCodecContext *avctx,
  159.                         void *data, int *got_frame,
  160.                         AVPacket *avpkt)
  161. {
  162.     MDECContext * const a = avctx->priv_data;
  163.     const uint8_t *buf    = avpkt->data;
  164.     int buf_size          = avpkt->size;
  165.     ThreadFrame frame     = { .f = data };
  166.     int i, ret;
  167.  
  168.     if ((ret = ff_thread_get_buffer(avctx, &frame, 0)) < 0)
  169.         return ret;
  170.     frame.f->pict_type = AV_PICTURE_TYPE_I;
  171.     frame.f->key_frame = 1;
  172.  
  173.     av_fast_malloc(&a->bitstream_buffer, &a->bitstream_buffer_size, buf_size + FF_INPUT_BUFFER_PADDING_SIZE);
  174.     if (!a->bitstream_buffer)
  175.         return AVERROR(ENOMEM);
  176.     for (i = 0; i < buf_size; i += 2) {
  177.         a->bitstream_buffer[i]     = buf[i + 1];
  178.         a->bitstream_buffer[i + 1] = buf[i];
  179.     }
  180.     if ((ret = init_get_bits8(&a->gb, a->bitstream_buffer, buf_size)) < 0)
  181.         return ret;
  182.  
  183.     /* skip over 4 preamble bytes in stream (typically 0xXX 0xXX 0x00 0x38) */
  184.     skip_bits(&a->gb, 32);
  185.  
  186.     a->qscale  = get_bits(&a->gb, 16);
  187.     a->version = get_bits(&a->gb, 16);
  188.  
  189.     a->last_dc[0] = a->last_dc[1] = a->last_dc[2] = 128;
  190.  
  191.     for (a->mb_x = 0; a->mb_x < a->mb_width; a->mb_x++) {
  192.         for (a->mb_y = 0; a->mb_y < a->mb_height; a->mb_y++) {
  193.             if ((ret = decode_mb(a, a->block)) < 0)
  194.                 return ret;
  195.  
  196.             idct_put(a, frame.f, a->mb_x, a->mb_y);
  197.         }
  198.     }
  199.  
  200.     *got_frame = 1;
  201.  
  202.     return (get_bits_count(&a->gb) + 31) / 32 * 4;
  203. }
  204.  
  205. static av_cold int decode_init(AVCodecContext *avctx)
  206. {
  207.     MDECContext * const a = avctx->priv_data;
  208.  
  209.     a->mb_width  = (avctx->coded_width  + 15) / 16;
  210.     a->mb_height = (avctx->coded_height + 15) / 16;
  211.  
  212.     a->avctx           = avctx;
  213.  
  214.     ff_dsputil_init(&a->dsp, avctx);
  215.     ff_mpeg12_init_vlcs();
  216.     ff_init_scantable(a->dsp.idct_permutation, &a->scantable, ff_zigzag_direct);
  217.  
  218.     if (avctx->idct_algo == FF_IDCT_AUTO)
  219.         avctx->idct_algo = FF_IDCT_SIMPLE;
  220.     avctx->pix_fmt  = AV_PIX_FMT_YUVJ420P;
  221.  
  222.     return 0;
  223. }
  224.  
  225. static av_cold int decode_init_thread_copy(AVCodecContext *avctx)
  226. {
  227.     MDECContext * const a = avctx->priv_data;
  228.  
  229.     a->avctx           = avctx;
  230.  
  231.     return 0;
  232. }
  233.  
  234. static av_cold int decode_end(AVCodecContext *avctx)
  235. {
  236.     MDECContext * const a = avctx->priv_data;
  237.  
  238.     av_freep(&a->bitstream_buffer);
  239.     a->bitstream_buffer_size = 0;
  240.  
  241.     return 0;
  242. }
  243.  
  244. AVCodec ff_mdec_decoder = {
  245.     .name             = "mdec",
  246.     .long_name        = NULL_IF_CONFIG_SMALL("Sony PlayStation MDEC (Motion DECoder)"),
  247.     .type             = AVMEDIA_TYPE_VIDEO,
  248.     .id               = AV_CODEC_ID_MDEC,
  249.     .priv_data_size   = sizeof(MDECContext),
  250.     .init             = decode_init,
  251.     .close            = decode_end,
  252.     .decode           = decode_frame,
  253.     .capabilities     = CODEC_CAP_DR1 | CODEC_CAP_FRAME_THREADS,
  254.     .init_thread_copy = ONLY_IF_THREADS_ENABLED(decode_init_thread_copy)
  255. };
  256.