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 * by Peter Ross <pross@xvid.org>
26 *
27 * Technical details here:
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
38#define EA_PREAMBLE_SIZE    8
39#define MADk_TAG MKTAG('M', 'A', 'D', 'k')    /* MAD i-frame */
40#define MADm_TAG MKTAG('M', 'A', 'D', 'm')    /* MAD p-frame */
41#define MADe_TAG MKTAG('M', 'A', 'D', 'e')    /* MAD lqp-frame */
42
43typedef struct MadContext {
44    MpegEncContext s;
45    AVFrame frame;
46    AVFrame last_frame;
47    void *bitstream_buf;
48    unsigned int bitstream_buf_size;
49    DECLARE_ALIGNED(16, DCTELEM, block)[64];
50} MadContext;
51
52static void bswap16_buf(uint16_t *dst, const uint16_t *src, int count)
53{
54    int i;
55    for (i=0; i<count; i++)
56        dst[i] = bswap_16(src[i]);
57}
58
59static av_cold int decode_init(AVCodecContext *avctx)
60{
61    MadContext *t = avctx->priv_data;
62    MpegEncContext *s = &t->s;
63    s->avctx = avctx;
64    avctx->pix_fmt = PIX_FMT_YUV420P;
65    if (avctx->idct_algo == FF_IDCT_AUTO)
66        avctx->idct_algo = FF_IDCT_EA;
67    dsputil_init(&s->dsp, avctx);
68    ff_init_scantable(s->dsp.idct_permutation, &s->intra_scantable, ff_zigzag_direct);
69    ff_mpeg12_init_vlcs();
70    return 0;
71}
72
73static inline void comp(unsigned char *dst, int dst_stride,
74                        unsigned char *src, int src_stride, int add)
75{
76    int j, i;
77    for (j=0; j<8; j++)
78        for (i=0; i<8; i++)
79            dst[j*dst_stride + i] = av_clip_uint8(src[j*src_stride + i] + add);
80}
81
82static inline void comp_block(MadContext *t, int mb_x, int mb_y,
83                              int j, int mv_x, int mv_y, int add)
84{
85    MpegEncContext *s = &t->s;
86    if (j < 4) {
87        comp(t->frame.data[0] + (mb_y*16 + ((j&2)<<2))*t->frame.linesize[0] + mb_x*16 + ((j&1)<<3),
88             t->frame.linesize[0],
89             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,
90             t->last_frame.linesize[0], add);
91    } else if (!(s->avctx->flags & CODEC_FLAG_GRAY)) {
92        int index = j - 3;
93        comp(t->frame.data[index] + (mb_y*8)*t->frame.linesize[index] + mb_x * 8,
94             t->frame.linesize[index],
95             t->last_frame.data[index] + (mb_y * 8 + (mv_y/2))*t->last_frame.linesize[index] + mb_x * 8 + (mv_x/2),
96             t->last_frame.linesize[index], add);
97    }
98}
99
100static inline void idct_put(MadContext *t, DCTELEM *block, int mb_x, int mb_y, int j)
101{
102    MpegEncContext *s = &t->s;
103    if (j < 4) {
104        s->dsp.idct_put(
105            t->frame.data[0] + (mb_y*16 + ((j&2)<<2))*t->frame.linesize[0] + mb_x*16 + ((j&1)<<3),
106            t->frame.linesize[0], block);
107    } else if (!(s->avctx->flags & CODEC_FLAG_GRAY)) {
108        int index = j - 3;
109        s->dsp.idct_put(
110            t->frame.data[index] + (mb_y*8)*t->frame.linesize[index] + mb_x*8,
111            t->frame.linesize[index], block);
112    }
113}
114
115static inline void decode_block_intra(MadContext * t, DCTELEM * block)
116{
117    MpegEncContext *s = &t->s;
118    int level, i, j, run;
119    RLTable *rl = &ff_rl_mpeg1;
120    const uint8_t *scantable = s->intra_scantable.permutated;
121    int16_t *quant_matrix = s->intra_matrix;
122
123    block[0] = (128 + get_sbits(&s->gb, 8)) * quant_matrix[0];
124
125    /* The RL decoder is derived from mpeg1_decode_block_intra;
126       Escaped level and run values a decoded differently */
127    i = 0;
128    {
129        OPEN_READER(re, &s->gb);
130        /* now quantify & encode AC coefficients */
131        for (;;) {
132            UPDATE_CACHE(re, &s->gb);
133            GET_RL_VLC(level, run, re, &s->gb, rl->rl_vlc[0], TEX_VLC_BITS, 2, 0);
134
135            if (level == 127) {
136                break;
137            } else if (level != 0) {
138                i += run;
139                j = scantable[i];
140                level = (level*quant_matrix[j]) >> 4;
141                level = (level-1)|1;
142                level = (level ^ SHOW_SBITS(re, &s->gb, 1)) - SHOW_SBITS(re, &s->gb, 1);
143                LAST_SKIP_BITS(re, &s->gb, 1);
144            } else {
145                /* escape */
146                UPDATE_CACHE(re, &s->gb);
147                level = SHOW_SBITS(re, &s->gb, 10); SKIP_BITS(re, &s->gb, 10);
148
149                UPDATE_CACHE(re, &s->gb);
150                run = SHOW_UBITS(re, &s->gb, 6)+1; LAST_SKIP_BITS(re, &s->gb, 6);
151
152                i += run;
153                j = scantable[i];
154                if (level < 0) {
155                    level = -level;
156                    level = (level*quant_matrix[j]) >> 4;
157                    level = (level-1)|1;
158                    level = -level;
159                } else {
160                    level = (level*quant_matrix[j]) >> 4;
161                    level = (level-1)|1;
162                }
163            }
164            if (i > 63) {
165                av_log(s->avctx, AV_LOG_ERROR, "ac-tex damaged at %d %d\n", s->mb_x, s->mb_y);
166                return;
167            }
168
169            block[j] = level;
170        }
171        CLOSE_READER(re, &s->gb);
172    }
173}
174
175static int decode_motion(GetBitContext *gb)
176{
177    int value = 0;
178    if (get_bits1(gb)) {
179        if (get_bits1(gb))
180            value = -17;
181        value += get_bits(gb, 4) + 1;
182    }
183    return value;
184}
185
186static void decode_mb(MadContext *t, int inter)
187{
188    MpegEncContext *s = &t->s;
189    int mv_map = 0;
190    int mv_x, mv_y;
191    int j;
192
193    if (inter) {
194        int v = decode210(&s->gb);
195        if (v < 2) {
196            mv_map = v ? get_bits(&s->gb, 6) : 63;
197            mv_x = decode_motion(&s->gb);
198            mv_y = decode_motion(&s->gb);
199        } else {
200            mv_map = 0;
201        }
202    }
203
204    for (j=0; j<6; j++) {
205        if (mv_map & (1<<j)) {  // mv_x and mv_y are guarded by mv_map
206            int add = 2*decode_motion(&s->gb);
207            comp_block(t, s->mb_x, s->mb_y, j, mv_x, mv_y, add);
208        } else {
209            s->dsp.clear_block(t->block);
210            decode_block_intra(t, t->block);
211            idct_put(t, t->block, s->mb_x, s->mb_y, j);
212        }
213    }
214}
215
216static void calc_intra_matrix(MadContext *t, int qscale)
217{
218    MpegEncContext *s = &t->s;
219    int i;
220
221    if (s->avctx->idct_algo == FF_IDCT_EA) {
222        s->intra_matrix[0] = (ff_inv_aanscales[0]*ff_mpeg1_default_intra_matrix[0]) >> 11;
223        for (i=1; i<64; i++)
224            s->intra_matrix[i] = (ff_inv_aanscales[i]*ff_mpeg1_default_intra_matrix[i]*qscale + 32) >> 10;
225    } else {
226        s->intra_matrix[0] = ff_mpeg1_default_intra_matrix[0];
227        for (i=1; i<64; i++)
228            s->intra_matrix[i] = (ff_mpeg1_default_intra_matrix[i]*qscale) << 1;
229    }
230}
231
232static int decode_frame(AVCodecContext *avctx,
233                        void *data, int *data_size,
234                        AVPacket *avpkt)
235{
236    const uint8_t *buf = avpkt->data;
237    int buf_size       = avpkt->size;
238    const uint8_t *buf_end = buf+buf_size;
239    MadContext *t     = avctx->priv_data;
240    MpegEncContext *s = &t->s;
241    int chunk_type;
242    int inter;
243
244    if (buf_size < 17) {
245        av_log(avctx, AV_LOG_ERROR, "Input buffer too small\n");
246        *data_size = 0;
247        return -1;
248    }
249
250    chunk_type = AV_RL32(&buf[0]);
251    inter = (chunk_type == MADm_TAG || chunk_type == MADe_TAG);
252    buf += 8;
253
254    av_reduce(&avctx->time_base.num, &avctx->time_base.den,
255              AV_RL16(&buf[6]), 1000, 1<<30);
256
257    s->width  = AV_RL16(&buf[8]);
258    s->height = AV_RL16(&buf[10]);
259    calc_intra_matrix(t, buf[13]);
260    buf += 16;
261
262    if (avctx->width != s->width || avctx->height != s->height) {
263        if (avcodec_check_dimensions(avctx, s->width, s->height) < 0)
264            return -1;
265        avcodec_set_dimensions(avctx, s->width, s->height);
266        if (t->frame.data[0])
267            avctx->release_buffer(avctx, &t->frame);
268    }
269
270    t->frame.reference = 1;
271    if (!t->frame.data[0]) {
272        if (avctx->get_buffer(avctx, &t->frame) < 0) {
273            av_log(avctx, AV_LOG_ERROR, "get_buffer() failed\n");
274            return -1;
275        }
276    }
277
278    av_fast_malloc(&t->bitstream_buf, &t->bitstream_buf_size, (buf_end-buf) + FF_INPUT_BUFFER_PADDING_SIZE);
279    if (!t->bitstream_buf)
280        return AVERROR(ENOMEM);
281    bswap16_buf(t->bitstream_buf, (const uint16_t*)buf, (buf_end-buf)/2);
282    init_get_bits(&s->gb, t->bitstream_buf, 8*(buf_end-buf));
283
284    for (s->mb_y=0; s->mb_y < (avctx->height+15)/16; s->mb_y++)
285        for (s->mb_x=0; s->mb_x < (avctx->width +15)/16; s->mb_x++)
286            decode_mb(t, inter);
287
288    *data_size = sizeof(AVFrame);
289    *(AVFrame*)data = t->frame;
290
291    if (chunk_type != MADe_TAG)
292        FFSWAP(AVFrame, t->frame, t->last_frame);
293
294    return buf_size;
295}
296
297static av_cold int decode_end(AVCodecContext *avctx)
298{
299    MadContext *t = avctx->priv_data;
300    if (t->frame.data[0])
301        avctx->release_buffer(avctx, &t->frame);
302    if (t->last_frame.data[0])
303        avctx->release_buffer(avctx, &t->last_frame);
304    av_free(t->bitstream_buf);
305    return 0;
306}
307
308AVCodec eamad_decoder = {
309    "eamad",
310    AVMEDIA_TYPE_VIDEO,
311    CODEC_ID_MAD,
312    sizeof(MadContext),
313    decode_init,
314    NULL,
315    decode_end,
316    decode_frame,
317    CODEC_CAP_DR1,
318    .long_name = NULL_IF_CONFIG_SMALL("Electronic Arts Madcow Video")
319};
320