1/*
2 * Electronic Arts TGV Video Decoder
3 * Copyright (c) 2007-2008 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 TGV Video Decoder
25 * by Peter Ross (pross@xvid.org)
26 *
27 * Technical details here:
28 * http://wiki.multimedia.cx/index.php?title=Electronic_Arts_TGV
29 */
30
31#include "avcodec.h"
32#define ALT_BITSTREAM_READER_LE
33#include "get_bits.h"
34#include "libavutil/lzo.h"
35
36#define EA_PREAMBLE_SIZE    8
37#define kVGT_TAG MKTAG('k', 'V', 'G', 'T')
38
39typedef struct TgvContext {
40    AVCodecContext *avctx;
41    AVFrame frame;
42    AVFrame last_frame;
43    int width,height;
44    unsigned int palette[AVPALETTE_COUNT];
45
46    int (*mv_codebook)[2];
47    unsigned char (*block_codebook)[16];
48    int num_mvs;           ///< current length of mv_codebook
49    int num_blocks_packed; ///< current length of block_codebook
50} TgvContext;
51
52static av_cold int tgv_decode_init(AVCodecContext *avctx){
53    TgvContext *s = avctx->priv_data;
54    s->avctx = avctx;
55    avctx->time_base = (AVRational){1, 15};
56    avctx->pix_fmt = PIX_FMT_PAL8;
57    return 0;
58}
59
60/**
61 * Unpack buffer
62 * @return 0 on success, -1 on critical buffer underflow
63 */
64static int unpack(const uint8_t *src, const uint8_t *src_end, unsigned char *dst, int width, int height) {
65    unsigned char *dst_end = dst + width*height;
66    int size, size1, size2, av_uninit(offset), run;
67    unsigned char *dst_start = dst;
68
69    if (src[0] & 0x01)
70        src += 5;
71    else
72        src += 2;
73
74    if (src+3>src_end)
75        return -1;
76    size = AV_RB24(src);
77    src += 3;
78
79    while(size>0 && src<src_end) {
80
81        /* determine size1 and size2 */
82        size1 = (src[0] & 3);
83        if ( src[0] & 0x80 ) {  // 1
84            if (src[0] & 0x40 ) {  // 11
85                if ( src[0] & 0x20 ) {  // 111
86                    if ( src[0] < 0xFC )  // !(111111)
87                        size1 = (((src[0] & 31) + 1) << 2);
88                    src++;
89                    size2 = 0;
90                } else {  // 110
91                    offset = ((src[0] & 0x10) << 12) + AV_RB16(&src[1]) + 1;
92                    size2 = ((src[0] & 0xC) << 6) + src[3] + 5;
93                    src += 4;
94                }
95            } else {  // 10
96                size1 = ( ( src[1] & 0xC0) >> 6 );
97                offset = (AV_RB16(&src[1]) & 0x3FFF) + 1;
98                size2 = (src[0] & 0x3F) + 4;
99                src += 3;
100            }
101        } else {  // 0
102            offset = ((src[0] & 0x60) << 3) + src[1] + 1;
103            size2 = ((src[0] & 0x1C) >> 2) + 3;
104            src += 2;
105        }
106
107
108        /* fetch strip from src */
109        if (size1>src_end-src)
110            break;
111
112        if (size1>0) {
113            size -= size1;
114            run = FFMIN(size1, dst_end-dst);
115            memcpy(dst, src, run);
116            dst += run;
117            src += run;
118        }
119
120        if (size2>0) {
121            if (dst-dst_start<offset)
122                return 0;
123            size -= size2;
124            run = FFMIN(size2, dst_end-dst);
125            av_memcpy_backptr(dst, offset, run);
126            dst += run;
127        }
128    }
129
130    return 0;
131}
132
133/**
134 * Decode inter-frame
135 * @return 0 on success, -1 on critical buffer underflow
136 */
137static int tgv_decode_inter(TgvContext * s, const uint8_t *buf, const uint8_t *buf_end){
138    unsigned char *frame0_end = s->last_frame.data[0] + s->avctx->width*s->last_frame.linesize[0];
139    int num_mvs;
140    int num_blocks_raw;
141    int num_blocks_packed;
142    int vector_bits;
143    int i,j,x,y;
144    GetBitContext gb;
145    int mvbits;
146    const unsigned char *blocks_raw;
147
148    if(buf+12>buf_end)
149        return -1;
150
151    num_mvs           = AV_RL16(&buf[0]);
152    num_blocks_raw    = AV_RL16(&buf[2]);
153    num_blocks_packed = AV_RL16(&buf[4]);
154    vector_bits       = AV_RL16(&buf[6]);
155    buf += 12;
156
157    /* allocate codebook buffers as neccessary */
158    if (num_mvs > s->num_mvs) {
159        s->mv_codebook = av_realloc(s->mv_codebook, num_mvs*2*sizeof(int));
160        s->num_mvs = num_mvs;
161    }
162
163    if (num_blocks_packed > s->num_blocks_packed) {
164        s->block_codebook = av_realloc(s->block_codebook, num_blocks_packed*16*sizeof(unsigned char));
165        s->num_blocks_packed = num_blocks_packed;
166    }
167
168    /* read motion vectors */
169    mvbits = (num_mvs*2*10+31) & ~31;
170
171    if (buf+(mvbits>>3)+16*num_blocks_raw+8*num_blocks_packed>buf_end)
172        return -1;
173
174    init_get_bits(&gb, buf, mvbits);
175    for (i=0; i<num_mvs; i++) {
176        s->mv_codebook[i][0] = get_sbits(&gb, 10);
177        s->mv_codebook[i][1] = get_sbits(&gb, 10);
178    }
179    buf += mvbits>>3;
180
181    /* note ptr to uncompressed blocks */
182    blocks_raw = buf;
183    buf += num_blocks_raw*16;
184
185    /* read compressed blocks */
186    init_get_bits(&gb, buf, (buf_end-buf)<<3);
187    for (i=0; i<num_blocks_packed; i++) {
188        int tmp[4];
189        for(j=0; j<4; j++)
190            tmp[j] = get_bits(&gb, 8);
191        for(j=0; j<16; j++)
192            s->block_codebook[i][15-j] = tmp[get_bits(&gb, 2)];
193    }
194
195    if (get_bits_left(&gb) < vector_bits *
196        (s->avctx->height/4) * (s->avctx->width/4))
197        return -1;
198
199    /* read vectors and build frame */
200    for(y=0; y<s->avctx->height/4; y++)
201    for(x=0; x<s->avctx->width/4; x++) {
202        unsigned int vector = get_bits(&gb, vector_bits);
203        const unsigned char *src;
204        int src_stride;
205
206        if (vector < num_mvs) {
207            src = s->last_frame.data[0] +
208                  (y*4 + s->mv_codebook[vector][1])*s->last_frame.linesize[0] +
209                   x*4 + s->mv_codebook[vector][0];
210            src_stride = s->last_frame.linesize[0];
211            if (src+3*src_stride+3>=frame0_end)
212                continue;
213        }else{
214            int offset = vector - num_mvs;
215            if (offset<num_blocks_raw)
216                src = blocks_raw + 16*offset;
217            else if (offset-num_blocks_raw<num_blocks_packed)
218                src = s->block_codebook[offset-num_blocks_raw];
219            else
220                continue;
221            src_stride = 4;
222        }
223
224        for(j=0; j<4; j++)
225        for(i=0; i<4; i++)
226            s->frame.data[0][ (y*4+j)*s->frame.linesize[0] + (x*4+i)  ] =
227               src[j*src_stride + i];
228    }
229
230    return 0;
231}
232
233/** release AVFrame buffers if allocated */
234static void cond_release_buffer(AVFrame *pic)
235{
236    if (pic->data[0]) {
237        av_freep(&pic->data[0]);
238        av_free(pic->data[1]);
239    }
240}
241
242static int tgv_decode_frame(AVCodecContext *avctx,
243                            void *data, int *data_size,
244                            AVPacket *avpkt)
245{
246    const uint8_t *buf = avpkt->data;
247    int buf_size = avpkt->size;
248    TgvContext *s = avctx->priv_data;
249    const uint8_t *buf_end = buf + buf_size;
250    int chunk_type;
251
252    chunk_type = AV_RL32(&buf[0]);
253    buf += EA_PREAMBLE_SIZE;
254
255    if (chunk_type==kVGT_TAG) {
256        int pal_count, i;
257        if(buf+12>buf_end) {
258            av_log(avctx, AV_LOG_WARNING, "truncated header\n");
259            return -1;
260        }
261
262        s->width  = AV_RL16(&buf[0]);
263        s->height = AV_RL16(&buf[2]);
264        if (s->avctx->width!=s->width || s->avctx->height!=s->height) {
265            avcodec_set_dimensions(s->avctx, s->width, s->height);
266            cond_release_buffer(&s->frame);
267            cond_release_buffer(&s->last_frame);
268        }
269
270        pal_count = AV_RL16(&buf[6]);
271        buf += 12;
272        for(i=0; i<pal_count && i<AVPALETTE_COUNT && buf+2<buf_end; i++) {
273            s->palette[i] = AV_RB24(buf);
274            buf += 3;
275        }
276    }
277
278    if (avcodec_check_dimensions(avctx, s->width, s->height))
279        return -1;
280
281    /* shuffle */
282    FFSWAP(AVFrame, s->frame, s->last_frame);
283    if (!s->frame.data[0]) {
284        s->frame.reference = 1;
285        s->frame.buffer_hints = FF_BUFFER_HINTS_VALID;
286        s->frame.linesize[0] = s->width;
287
288        /* allocate additional 12 bytes to accomodate av_memcpy_backptr() OUTBUF_PADDED optimisation */
289        s->frame.data[0] = av_malloc(s->width*s->height + 12);
290        if (!s->frame.data[0])
291            return AVERROR(ENOMEM);
292        s->frame.data[1] = av_malloc(AVPALETTE_SIZE);
293        if (!s->frame.data[1]) {
294            av_freep(&s->frame.data[0]);
295            return AVERROR(ENOMEM);
296        }
297    }
298    memcpy(s->frame.data[1], s->palette, AVPALETTE_SIZE);
299
300    if(chunk_type==kVGT_TAG) {
301        s->frame.key_frame = 1;
302        s->frame.pict_type = FF_I_TYPE;
303        if (unpack(buf, buf_end, s->frame.data[0], s->avctx->width, s->avctx->height)<0) {
304            av_log(avctx, AV_LOG_WARNING, "truncated intra frame\n");
305            return -1;
306        }
307    }else{
308        if (!s->last_frame.data[0]) {
309            av_log(avctx, AV_LOG_WARNING, "inter frame without corresponding intra frame\n");
310            return buf_size;
311        }
312        s->frame.key_frame = 0;
313        s->frame.pict_type = FF_P_TYPE;
314        if (tgv_decode_inter(s, buf, buf_end)<0) {
315            av_log(avctx, AV_LOG_WARNING, "truncated inter frame\n");
316            return -1;
317        }
318    }
319
320    *data_size = sizeof(AVFrame);
321    *(AVFrame*)data = s->frame;
322
323    return buf_size;
324}
325
326static av_cold int tgv_decode_end(AVCodecContext *avctx)
327{
328    TgvContext *s = avctx->priv_data;
329    cond_release_buffer(&s->frame);
330    cond_release_buffer(&s->last_frame);
331    av_free(s->mv_codebook);
332    av_free(s->block_codebook);
333    return 0;
334}
335
336AVCodec eatgv_decoder = {
337    "eatgv",
338    AVMEDIA_TYPE_VIDEO,
339    CODEC_ID_TGV,
340    sizeof(TgvContext),
341    tgv_decode_init,
342    NULL,
343    tgv_decode_end,
344    tgv_decode_frame,
345    .long_name = NULL_IF_CONFIG_SMALL("Electronic Arts TGV video"),
346};
347