1/*
2 * Electronic Arts Madcow Video Decoder
3 * Copyright (c) 2007-2009 Peter Ross
4 *
5 * This file is part of Libav.
6 *
7 * Libav 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 * Libav 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 Libav; 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 "dsputil.h"
34#include "aandcttab.h"
35#include "mpeg12.h"
36#include "mpeg12data.h"
37#include "libavutil/imgutils.h"
38
39#define EA_PREAMBLE_SIZE    8
40#define MADk_TAG MKTAG('M', 'A', 'D', 'k')    /* MAD i-frame */
41#define MADm_TAG MKTAG('M', 'A', 'D', 'm')    /* MAD p-frame */
42#define MADe_TAG MKTAG('M', 'A', 'D', 'e')    /* MAD lqp-frame */
43
44typedef struct MadContext {
45    MpegEncContext s;
46    AVFrame frame;
47    AVFrame last_frame;
48    void *bitstream_buf;
49    unsigned int bitstream_buf_size;
50    DECLARE_ALIGNED(16, DCTELEM, block)[64];
51} MadContext;
52
53static void bswap16_buf(uint16_t *dst, const uint16_t *src, int count)
54{
55    int i;
56    for (i=0; i<count; i++)
57        dst[i] = av_bswap16(src[i]);
58}
59
60static av_cold int decode_init(AVCodecContext *avctx)
61{
62    MadContext *t = avctx->priv_data;
63    MpegEncContext *s = &t->s;
64    s->avctx = avctx;
65    avctx->pix_fmt = PIX_FMT_YUV420P;
66    if (avctx->idct_algo == FF_IDCT_AUTO)
67        avctx->idct_algo = FF_IDCT_EA;
68    dsputil_init(&s->dsp, avctx);
69    ff_init_scantable(s->dsp.idct_permutation, &s->intra_scantable, ff_zigzag_direct);
70    ff_mpeg12_init_vlcs();
71    return 0;
72}
73
74static inline void comp(unsigned char *dst, int dst_stride,
75                        unsigned char *src, int src_stride, int add)
76{
77    int j, i;
78    for (j=0; j<8; j++)
79        for (i=0; i<8; i++)
80            dst[j*dst_stride + i] = av_clip_uint8(src[j*src_stride + i] + add);
81}
82
83static inline void comp_block(MadContext *t, int mb_x, int mb_y,
84                              int j, int mv_x, int mv_y, int add)
85{
86    MpegEncContext *s = &t->s;
87    if (j < 4) {
88        comp(t->frame.data[0] + (mb_y*16 + ((j&2)<<2))*t->frame.linesize[0] + mb_x*16 + ((j&1)<<3),
89             t->frame.linesize[0],
90             t->last_frame.data[0] + (mb_y*16 + ((j&2)<<2) + mv_y)*t->last_frame.linesize[0] + mb_x*16 + ((j&1)<<3) + mv_x,
91             t->last_frame.linesize[0], add);
92    } else if (!(s->avctx->flags & CODEC_FLAG_GRAY)) {
93        int index = j - 3;
94        comp(t->frame.data[index] + (mb_y*8)*t->frame.linesize[index] + mb_x * 8,
95             t->frame.linesize[index],
96             t->last_frame.data[index] + (mb_y * 8 + (mv_y/2))*t->last_frame.linesize[index] + mb_x * 8 + (mv_x/2),
97             t->last_frame.linesize[index], add);
98    }
99}
100
101static inline void idct_put(MadContext *t, DCTELEM *block, int mb_x, int mb_y, int j)
102{
103    MpegEncContext *s = &t->s;
104    if (j < 4) {
105        s->dsp.idct_put(
106            t->frame.data[0] + (mb_y*16 + ((j&2)<<2))*t->frame.linesize[0] + mb_x*16 + ((j&1)<<3),
107            t->frame.linesize[0], block);
108    } else if (!(s->avctx->flags & CODEC_FLAG_GRAY)) {
109        int index = j - 3;
110        s->dsp.idct_put(
111            t->frame.data[index] + (mb_y*8)*t->frame.linesize[index] + mb_x*8,
112            t->frame.linesize[index], block);
113    }
114}
115
116static inline void decode_block_intra(MadContext * t, DCTELEM * block)
117{
118    MpegEncContext *s = &t->s;
119    int level, i, j, run;
120    RLTable *rl = &ff_rl_mpeg1;
121    const uint8_t *scantable = s->intra_scantable.permutated;
122    int16_t *quant_matrix = s->intra_matrix;
123
124    block[0] = (128 + get_sbits(&s->gb, 8)) * quant_matrix[0];
125
126    /* The RL decoder is derived from mpeg1_decode_block_intra;
127       Escaped level and run values a decoded differently */
128    i = 0;
129    {
130        OPEN_READER(re, &s->gb);
131        /* now quantify & encode AC coefficients */
132        for (;;) {
133            UPDATE_CACHE(re, &s->gb);
134            GET_RL_VLC(level, run, re, &s->gb, rl->rl_vlc[0], TEX_VLC_BITS, 2, 0);
135
136            if (level == 127) {
137                break;
138            } else if (level != 0) {
139                i += run;
140                j = scantable[i];
141                level = (level*quant_matrix[j]) >> 4;
142                level = (level-1)|1;
143                level = (level ^ SHOW_SBITS(re, &s->gb, 1)) - SHOW_SBITS(re, &s->gb, 1);
144                LAST_SKIP_BITS(re, &s->gb, 1);
145            } else {
146                /* escape */
147                UPDATE_CACHE(re, &s->gb);
148                level = SHOW_SBITS(re, &s->gb, 10); SKIP_BITS(re, &s->gb, 10);
149
150                UPDATE_CACHE(re, &s->gb);
151                run = SHOW_UBITS(re, &s->gb, 6)+1; LAST_SKIP_BITS(re, &s->gb, 6);
152
153                i += run;
154                j = scantable[i];
155                if (level < 0) {
156                    level = -level;
157                    level = (level*quant_matrix[j]) >> 4;
158                    level = (level-1)|1;
159                    level = -level;
160                } else {
161                    level = (level*quant_matrix[j]) >> 4;
162                    level = (level-1)|1;
163                }
164            }
165            if (i > 63) {
166                av_log(s->avctx, AV_LOG_ERROR, "ac-tex damaged at %d %d\n", s->mb_x, s->mb_y);
167                return;
168            }
169
170            block[j] = level;
171        }
172        CLOSE_READER(re, &s->gb);
173    }
174}
175
176static int decode_motion(GetBitContext *gb)
177{
178    int value = 0;
179    if (get_bits1(gb)) {
180        if (get_bits1(gb))
181            value = -17;
182        value += get_bits(gb, 4) + 1;
183    }
184    return value;
185}
186
187static void decode_mb(MadContext *t, int inter)
188{
189    MpegEncContext *s = &t->s;
190    int mv_map = 0;
191    int mv_x, mv_y;
192    int j;
193
194    if (inter) {
195        int v = decode210(&s->gb);
196        if (v < 2) {
197            mv_map = v ? get_bits(&s->gb, 6) : 63;
198            mv_x = decode_motion(&s->gb);
199            mv_y = decode_motion(&s->gb);
200        } else {
201            mv_map = 0;
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            comp_block(t, s->mb_x, s->mb_y, j, mv_x, mv_y, add);
209        } else {
210            s->dsp.clear_block(t->block);
211            decode_block_intra(t, t->block);
212            idct_put(t, t->block, s->mb_x, s->mb_y, j);
213        }
214    }
215}
216
217static void calc_intra_matrix(MadContext *t, int qscale)
218{
219    MpegEncContext *s = &t->s;
220    int i;
221
222    if (s->avctx->idct_algo == FF_IDCT_EA) {
223        s->intra_matrix[0] = (ff_inv_aanscales[0]*ff_mpeg1_default_intra_matrix[0]) >> 11;
224        for (i=1; i<64; i++)
225            s->intra_matrix[i] = (ff_inv_aanscales[i]*ff_mpeg1_default_intra_matrix[i]*qscale + 32) >> 10;
226    } else {
227        s->intra_matrix[0] = ff_mpeg1_default_intra_matrix[0];
228        for (i=1; i<64; i++)
229            s->intra_matrix[i] = (ff_mpeg1_default_intra_matrix[i]*qscale) << 1;
230    }
231}
232
233static int decode_frame(AVCodecContext *avctx,
234                        void *data, int *data_size,
235                        AVPacket *avpkt)
236{
237    const uint8_t *buf = avpkt->data;
238    int buf_size       = avpkt->size;
239    const uint8_t *buf_end = buf+buf_size;
240    MadContext *t     = avctx->priv_data;
241    MpegEncContext *s = &t->s;
242    int chunk_type;
243    int inter;
244
245    if (buf_size < 17) {
246        av_log(avctx, AV_LOG_ERROR, "Input buffer too small\n");
247        *data_size = 0;
248        return -1;
249    }
250
251    chunk_type = AV_RL32(&buf[0]);
252    inter = (chunk_type == MADm_TAG || chunk_type == MADe_TAG);
253    buf += 8;
254
255    av_reduce(&avctx->time_base.num, &avctx->time_base.den,
256              AV_RL16(&buf[6]), 1000, 1<<30);
257
258    s->width  = AV_RL16(&buf[8]);
259    s->height = AV_RL16(&buf[10]);
260    calc_intra_matrix(t, buf[13]);
261    buf += 16;
262
263    if (avctx->width != s->width || avctx->height != s->height) {
264        if (av_image_check_size(s->width, s->height, 0, avctx) < 0)
265            return -1;
266        avcodec_set_dimensions(avctx, s->width, s->height);
267        if (t->frame.data[0])
268            avctx->release_buffer(avctx, &t->frame);
269    }
270
271    t->frame.reference = 1;
272    if (!t->frame.data[0]) {
273        if (avctx->get_buffer(avctx, &t->frame) < 0) {
274            av_log(avctx, AV_LOG_ERROR, "get_buffer() failed\n");
275            return -1;
276        }
277    }
278
279    av_fast_malloc(&t->bitstream_buf, &t->bitstream_buf_size, (buf_end-buf) + FF_INPUT_BUFFER_PADDING_SIZE);
280    if (!t->bitstream_buf)
281        return AVERROR(ENOMEM);
282    bswap16_buf(t->bitstream_buf, (const uint16_t*)buf, (buf_end-buf)/2);
283    init_get_bits(&s->gb, t->bitstream_buf, 8*(buf_end-buf));
284
285    for (s->mb_y=0; s->mb_y < (avctx->height+15)/16; s->mb_y++)
286        for (s->mb_x=0; s->mb_x < (avctx->width +15)/16; s->mb_x++)
287            decode_mb(t, inter);
288
289    *data_size = sizeof(AVFrame);
290    *(AVFrame*)data = t->frame;
291
292    if (chunk_type != MADe_TAG)
293        FFSWAP(AVFrame, t->frame, t->last_frame);
294
295    return buf_size;
296}
297
298static av_cold int decode_end(AVCodecContext *avctx)
299{
300    MadContext *t = avctx->priv_data;
301    if (t->frame.data[0])
302        avctx->release_buffer(avctx, &t->frame);
303    if (t->last_frame.data[0])
304        avctx->release_buffer(avctx, &t->last_frame);
305    av_free(t->bitstream_buf);
306    return 0;
307}
308
309AVCodec ff_eamad_decoder = {
310    .name           = "eamad",
311    .type           = AVMEDIA_TYPE_VIDEO,
312    .id             = CODEC_ID_MAD,
313    .priv_data_size = sizeof(MadContext),
314    .init           = decode_init,
315    .close          = decode_end,
316    .decode         = decode_frame,
317    .capabilities   = CODEC_CAP_DR1,
318    .long_name = NULL_IF_CONFIG_SMALL("Electronic Arts Madcow Video")
319};
320