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1
/*
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 * Copyright (C) 2005  Ole Andr? Vadla Ravn?s <oleavr@gmail.com>
3
 * Copyright (C) 2008  Ramiro Polla <ramiro@lisha.ufsc.br>
4
 *
5
 * This file is part of FFmpeg.
6
 *
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 * FFmpeg is free software; you can redistribute it and/or
8
 * modify it under the terms of the GNU Lesser General Public
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 * License as published by the Free Software Foundation; either
10
 * version 2.1 of the License, or (at your option) any later version.
11
 *
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 * FFmpeg is distributed in the hope that it will be useful,
13
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
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 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
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 * Lesser General Public License for more details.
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 *
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 * You should have received a copy of the GNU Lesser General Public
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 * License along with FFmpeg; if not, write to the Free Software
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 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
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 */
21

    
22
#include <stdlib.h>
23
#include <string.h>
24
#include <stdint.h>
25

    
26
#include "avcodec.h"
27
#include "bitstream.h"
28
#include "dsputil.h"
29

    
30
#define MIMIC_HEADER_SIZE   20
31

    
32
typedef struct {
33
    AVCodecContext *avctx;
34

    
35
    int             num_vblocks[3];
36
    int             num_hblocks[3];
37

    
38
    uint8_t        *swap_buf;
39
    int             swap_buf_size;
40

    
41
    int             cur_index;
42
    int             prev_index;
43

    
44
    AVFrame         buf_ptrs    [16];
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    AVPicture       flipped_ptrs[16];
46

    
47
    DECLARE_ALIGNED_16(DCTELEM, dct_block[64]);
48

    
49
    GetBitContext   gb;
50
    ScanTable       scantable;
51
    DSPContext      dsp;
52
    VLC             vlc;
53
} MimicContext;
54

    
55
static const uint32_t huffcodes[] = {
56
    0x0000000a, 0x00000000, 0x00000000, 0x00000000, 0x00000000, 0x00000000,
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    0x00000000, 0x00000000, 0x00000000, 0x00000000, 0x00000000, 0x00000000,
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    0x00000000, 0x00000000, 0x00000000, 0x00000000, 0x00000000, 0x0000000b,
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    0x0000001b, 0x00000038, 0x00000078, 0x00000079, 0x0000007a, 0x000000f9,
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    0x000000fa, 0x000003fb, 0x000007f8, 0x000007f9, 0x000007fa, 0x000007fb,
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    0x00000ff8, 0x00000ff9, 0x00000001, 0x00000039, 0x0000007b, 0x000000fb,
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    0x000001f8, 0x000001f9, 0x00000ffa, 0x00000ffb, 0x00001ff8, 0x00001ff9,
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    0x00001ffa, 0x00001ffb, 0x00003ff8, 0x00003ff9, 0x00003ffa, 0x00000000,
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    0x00000004, 0x0000003a, 0x000001fa, 0x00003ffb, 0x00007ff8, 0x00007ff9,
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    0x00007ffa, 0x00007ffb, 0x0000fff8, 0x0000fff9, 0x0000fffa, 0x0000fffb,
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    0x0001fff8, 0x0001fff9, 0x0001fffa, 0x00000000, 0x0000000c, 0x000000f8,
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    0x000001fb, 0x0001fffb, 0x0003fff8, 0x0003fff9, 0x0003fffa, 0x0003fffb,
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    0x0007fff8, 0x0007fff9, 0x0007fffa, 0x0007fffb, 0x000ffff8, 0x000ffff9,
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    0x000ffffa, 0x00000000, 0x0000001a, 0x000003f8, 0x000ffffb, 0x001ffff8,
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    0x001ffff9, 0x001ffffa, 0x001ffffb, 0x003ffff8, 0x003ffff9, 0x003ffffa,
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    0x003ffffb, 0x007ffff8, 0x007ffff9, 0x007ffffa, 0x007ffffb, 0x00000000,
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    0x0000003b, 0x000003f9, 0x00fffff8, 0x00fffff9, 0x00fffffa, 0x00fffffb,
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    0x01fffff8, 0x01fffff9, 0x01fffffa, 0x01fffffb, 0x03fffff8, 0x03fffff9,
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    0x03fffffa, 0x03fffffb, 0x07fffff8, 0x00000000, 0x000003fa, 0x07fffff9,
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    0x07fffffa, 0x07fffffb, 0x0ffffff8, 0x0ffffff9, 0x0ffffffa, 0x0ffffffb,
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    0x1ffffff8, 0x1ffffff9, 0x1ffffffa, 0x1ffffffb, 0x3ffffff8, 0x3ffffff9,
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    0x3ffffffa,
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};
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static const uint8_t huffbits[] = {
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     4,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,
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     0,  0,  0,  0,  2,  4,  5,  6,  7,  7,  7,  8,
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     8, 10, 11, 11, 11, 11, 12, 12,  2,  6,  7,  8,
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     9,  9, 12, 12, 13, 13, 13, 13, 14, 14, 14,  0,
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     3,  6,  9, 14, 15, 15, 15, 15, 16, 16, 16, 16,
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    17, 17, 17,  0,  4,  8,  9, 17, 18, 18, 18, 18,
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    19, 19, 19, 19, 20, 20, 20,  0,  5, 10, 20, 21,
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    21, 21, 21, 22, 22, 22, 22, 23, 23, 23, 23,  0,
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     6, 10, 24, 24, 24, 24, 25, 25, 25, 25, 26, 26,
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    26, 26, 27,  0, 10, 27, 27, 27, 28, 28, 28, 28,
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    29, 29, 29, 29, 30, 30, 30,
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};
93

    
94
static const uint8_t col_zag[64] = {
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     0,  8,  1,  2,  9, 16, 24, 17,
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    10,  3,  4, 11, 18, 25, 32, 40,
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    33, 26, 19, 12,  5,  6, 13, 20,
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    27, 34, 41, 48, 56, 49, 42, 35,
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    28, 21, 14,  7, 15, 22, 29, 36,
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    43, 50, 57, 58, 51, 44, 37, 30,
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    23, 31, 38, 45, 52, 59, 39, 46,
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    53, 60, 61, 54, 47, 55, 62, 63
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};
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static av_cold int mimic_decode_init(AVCodecContext *avctx)
106
{
107
    MimicContext *ctx = avctx->priv_data;
108

    
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    ctx->prev_index = 0;
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    ctx->cur_index = 15;
111

    
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    if(init_vlc(&ctx->vlc, 8, sizeof(huffbits)/sizeof(huffbits[0]),
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                 huffbits, 1, 1, huffcodes, 4, 4, 0)) {
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        av_log(avctx, AV_LOG_ERROR, "error initializing vlc table\n");
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        return -1;
116
    }
117
    dsputil_init(&ctx->dsp, avctx);
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    ff_init_scantable(ctx->dsp.idct_permutation, &ctx->scantable, col_zag);
119

    
120
    return 0;
121
}
122

    
123
const static int8_t vlcdec_lookup[9][64] = {
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    {    0, },
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    {   -1,   1, },
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    {   -3,   3,   -2,   2, },
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    {   -7,   7,   -6,   6,   -5,   5,   -4,   4, },
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    {  -15,  15,  -14,  14,  -13,  13,  -12,  12,
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       -11,  11,  -10,  10,   -9,   9,   -8,   8, },
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    {  -31,  31,  -30,  30,  -29,  29,  -28,  28,
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       -27,  27,  -26,  26,  -25,  25,  -24,  24,
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       -23,  23,  -22,  22,  -21,  21,  -20,  20,
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       -19,  19,  -18,  18,  -17,  17,  -16,  16, },
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    {  -63,  63,  -62,  62,  -61,  61,  -60,  60,
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       -59,  59,  -58,  58,  -57,  57,  -56,  56,
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       -55,  55,  -54,  54,  -53,  53,  -52,  52,
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       -51,  51,  -50,  50,  -49,  49,  -48,  48,
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       -47,  47,  -46,  46,  -45,  45,  -44,  44,
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       -43,  43,  -42,  42,  -41,  41,  -40,  40,
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       -39,  39,  -38,  38,  -37,  37,  -36,  36,
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       -35,  35,  -34,  34,  -33,  33,  -32,  32, },
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    { -127, 127, -126, 126, -125, 125, -124, 124,
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      -123, 123, -122, 122, -121, 121, -120, 120,
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      -119, 119, -118, 118, -117, 117, -116, 116,
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      -115, 115, -114, 114, -113, 113, -112, 112,
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      -111, 111, -110, 110, -109, 109, -108, 108,
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      -107, 107, -106, 106, -105, 105, -104, 104,
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      -103, 103, -102, 102, -101, 101, -100, 100,
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       -99,  99,  -98,  98,  -97,  97,  -96,  96, },
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    {  -95,  95,  -94,  94,  -93,  93,  -92,  92,
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       -91,  91,  -90,  90,  -89,  89,  -88,  88,
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       -87,  87,  -86,  86,  -85,  85,  -84,  84,
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       -83,  83,  -82,  82,  -81,  81,  -80,  80,
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       -79,  79,  -78,  78,  -77,  77,  -76,  76,
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       -75,  75,  -74,  74,  -73,  73,  -72,  72,
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       -71,  71,  -70,  70,  -69,  69,  -68,  68,
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       -67,  67,  -66,  66,  -65,  65,  -64,  64, },
158
};
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160
static int vlc_decode_block(MimicContext *ctx, DCTELEM *block, int num_coeffs,
161
                            int qscale)
162
{
163
    unsigned int pos;
164

    
165
    memset(block, 0, 64 * sizeof(DCTELEM));
166

    
167
    block[0] = get_bits(&ctx->gb, 8) << 3;
168

    
169
    for(pos = 1; pos < num_coeffs; pos++) {
170
        uint32_t vlc, num_bits;
171
        int value;
172
        int coeff;
173

    
174
        vlc = get_vlc2(&ctx->gb, ctx->vlc.table, ctx->vlc.bits, 4);
175
        if(!vlc) /* end-of-block code */
176
            return 1;
177
        if(vlc == -1)
178
            return 0;
179

    
180
        /* pos_add and num_bits are coded in the vlc code */
181
        pos +=     vlc&15; // pos_add
182
        num_bits = vlc>>4; // num_bits
183

    
184
        if(pos >= 64)
185
            return 0;
186

    
187
        value = get_bits(&ctx->gb, num_bits);
188

    
189
        /* FFmpeg's IDCT behaves somewhat different from the original code, so
190
         * a factor of 4 was added to the input */
191

    
192
        coeff = vlcdec_lookup[num_bits][value];
193
        if(pos<3)
194
            coeff <<= 4;
195
        else /* TODO Use >> 10 instead of / 1001 */
196
            coeff = (coeff * qscale) / 1001;
197

    
198
        block[ctx->scantable.permutated[pos]] = coeff;
199
    }
200

    
201
    return 1;
202
}
203

    
204
static int decode(MimicContext *ctx, int quality, int num_coeffs,
205
                  int is_iframe)
206
{
207
    int y, x, plane;
208

    
209
    for(plane = 0; plane < 3; plane++) {
210
        const int is_chroma = !!plane;
211
        const int qscale = av_clip(10000-quality,is_chroma?1000:2000,10000)<<2;
212
        const int stride = ctx->flipped_ptrs[ctx->cur_index].linesize[plane];
213
        const uint8_t *src = ctx->flipped_ptrs[ctx->prev_index].data[plane];
214
        uint8_t       *dst = ctx->flipped_ptrs[ctx->cur_index ].data[plane];
215

    
216
        for(y = 0 ; y < ctx->num_vblocks[plane] ; y++) {
217
            for(x = 0; x < ctx->num_hblocks[plane]; x++) {
218

    
219
                /* Check for a change condition in the current block.
220
                 * - iframes always change.
221
                 * - Luma plane changes on get_bits1 == 0
222
                 * - Chroma planes change on get_bits1 == 1 */
223
                if(is_iframe || get_bits1(&ctx->gb) == is_chroma) {
224

    
225
                    /* Luma planes may use a backreference from the 15 last
226
                     * frames preceding the previous. (get_bits1 == 1)
227
                     * Chroma planes don't use backreferences. */
228
                    if(is_chroma || is_iframe || !get_bits1(&ctx->gb)) {
229

    
230
                        if(!vlc_decode_block(ctx, ctx->dct_block,
231
                                             num_coeffs, qscale))
232
                            return 0;
233
                        ctx->dsp.idct_put(dst, stride, ctx->dct_block);
234
                    } else {
235
                        unsigned int backref = get_bits(&ctx->gb, 4);
236
                        int index = (ctx->cur_index+backref)&15;
237
                        uint8_t *p = ctx->flipped_ptrs[index].data[0];
238

    
239
                        if(p) {
240
                            p += src -
241
                                ctx->flipped_ptrs[ctx->prev_index].data[plane];
242
                            ctx->dsp.put_pixels_tab[1][0](dst, p, stride, 8);
243
                        } else {
244
                            av_log(ctx->avctx, AV_LOG_ERROR,
245
                                     "No such backreference! Buggy sample.\n");
246
                        }
247
                    }
248
                } else {
249
                    ctx->dsp.put_pixels_tab[1][0](dst, src, stride, 8);
250
                }
251
                src += 8;
252
                dst += 8;
253
            }
254
            src += (stride - ctx->num_hblocks[plane])<<3;
255
            dst += (stride - ctx->num_hblocks[plane])<<3;
256
        }
257
    }
258

    
259
    return 1;
260
}
261

    
262
/**
263
 * Flip the buffer upside-down and put it in the YVU order to match the
264
 * way Mimic encodes frames.
265
 */
266
static void prepare_avpic(MimicContext *ctx, AVPicture *dst, AVPicture *src)
267
{
268
    int i;
269
    dst->data[0] = src->data[0]+( ctx->avctx->height    -1)*src->linesize[0];
270
    dst->data[1] = src->data[2]+((ctx->avctx->height>>1)-1)*src->linesize[2];
271
    dst->data[2] = src->data[1]+((ctx->avctx->height>>1)-1)*src->linesize[1];
272
    for(i = 0 ; i < 3 ; i++)
273
        dst->linesize[i] = -src->linesize[i];
274
}
275

    
276
static int mimic_decode_frame(AVCodecContext *avctx, void *data,
277
                              int *data_size, const uint8_t *buf, int buf_size)
278
{
279
    MimicContext *ctx = avctx->priv_data;
280
    int is_pframe;
281
    int width, height;
282
    int quality, num_coeffs;
283
    int swap_buf_size = buf_size - MIMIC_HEADER_SIZE;
284

    
285
    /*
286
     * Header structure:
287
     *  uint16_t    I_dont_remember;
288
     *  uint16_t    quality;
289
     *  uint16_t    width;
290
     *  uint16_t    height;
291
     *  uint32_t    some_constant;
292
     *  uint32_t    is_pframe;
293
     *  uint32_t    num_coeffs;
294
     */
295

    
296
    if(buf_size < MIMIC_HEADER_SIZE) {
297
        av_log(avctx, AV_LOG_ERROR, "insufficient data\n");
298
        return -1;
299
    }
300

    
301
    width  = AV_RL16(buf + 4);
302
    height = AV_RL16(buf + 6);
303

    
304
    if(!ctx->avctx) {
305
        int i;
306

    
307
        if(!(width == 160 && height == 120) &&
308
           !(width == 320 && height == 240)) {
309
            av_log(avctx, AV_LOG_ERROR, "invalid width/height!\n");
310
            return -1;
311
        }
312

    
313
        ctx->avctx     = avctx;
314
        avctx->width   = width;
315
        avctx->height  = height;
316
        avctx->pix_fmt = PIX_FMT_YUV420P;
317
        for(i = 0 ; i < 3 ; i++) {
318
            ctx->num_vblocks[i] = -((-height) >> (3 + !!i));
319
            ctx->num_hblocks[i] =     width   >> (3 + !!i) ;
320
        }
321
    } else if(width != ctx->avctx->width || height != ctx->avctx->height) {
322
        av_log(avctx, AV_LOG_ERROR, "resolution changing is not supported\n");
323
        return -1;
324
    }
325

    
326
    quality    = AV_RL16(buf + 2);
327
    is_pframe  = AV_RL32(buf + 12);
328
    num_coeffs = buf[16];
329

    
330
    if(is_pframe && !ctx->buf_ptrs[ctx->prev_index].data[0]) {
331
        av_log(avctx, AV_LOG_ERROR, "decoding must start with keyframe\n");
332
        return -1;
333
    }
334

    
335
    ctx->buf_ptrs[ctx->cur_index].reference = 1;
336
    if(avctx->get_buffer(avctx, &ctx->buf_ptrs[ctx->cur_index])) {
337
        av_log(avctx, AV_LOG_ERROR, "get_buffer() failed\n");
338
        return -1;
339
    }
340

    
341
    prepare_avpic(ctx, &ctx->flipped_ptrs[ctx->cur_index],
342
                  (AVPicture*) &ctx->buf_ptrs[ctx->cur_index]);
343

    
344
    ctx->swap_buf = av_fast_realloc(ctx->swap_buf, &ctx->swap_buf_size,
345
                                 swap_buf_size + FF_INPUT_BUFFER_PADDING_SIZE);
346
    if(!ctx->swap_buf)
347
        return AVERROR_NOMEM;
348

    
349
    ctx->dsp.bswap_buf((uint32_t*)ctx->swap_buf,
350
                        (const uint32_t*) (buf + MIMIC_HEADER_SIZE),
351
                        swap_buf_size>>2);
352
    init_get_bits(&ctx->gb, ctx->swap_buf, swap_buf_size << 3);
353

    
354
    if(!decode(ctx, quality, num_coeffs, !is_pframe)) {
355
        avctx->release_buffer(avctx, &ctx->buf_ptrs[ctx->cur_index]);
356
        return -1;
357
    }
358

    
359
    ctx->buf_ptrs[ctx->cur_index].pict_type = is_pframe ? FF_P_TYPE:FF_I_TYPE;
360
    *(AVFrame*)data = ctx->buf_ptrs[ctx->cur_index];
361
    *data_size = sizeof(AVFrame);
362

    
363
    ctx->prev_index = ctx->cur_index;
364
    ctx->cur_index--;
365
    ctx->cur_index &= 15;
366

    
367
    /* Only release frames that aren't used for backreferences anymore */
368
    if(ctx->buf_ptrs[ctx->cur_index].data[0])
369
        avctx->release_buffer(avctx, &ctx->buf_ptrs[ctx->cur_index]);
370

    
371
    return buf_size;
372
}
373

    
374
static av_cold int mimic_decode_end(AVCodecContext *avctx)
375
{
376
    MimicContext *ctx = avctx->priv_data;
377
    int i;
378

    
379
    av_free(ctx->swap_buf);
380
    for(i = 0; i < 16; i++)
381
        if(ctx->buf_ptrs[i].data[0])
382
            avctx->release_buffer(avctx, &ctx->buf_ptrs[i]);
383
    free_vlc(&ctx->vlc);
384

    
385
    return 0;
386
}
387

    
388
AVCodec mimic_decoder = {
389
    "mimic",
390
    CODEC_TYPE_VIDEO,
391
    CODEC_ID_MIMIC,
392
    sizeof(MimicContext),
393
    mimic_decode_init,
394
    NULL,
395
    mimic_decode_end,
396
    mimic_decode_frame,
397
    CODEC_CAP_DR1,
398
};