1/*
2 * TechSmith Screen Codec 2 (aka Dora) decoder
3 * Copyright (c) 2012 Konstantin Shishkov
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 Street, Fifth Floor, Boston, MA 02110-1301 USA
20 */
21
22/**
23 * @file
24 * TechSmith Screen Codec 2 decoder
25 */
26
27#include <inttypes.h>
28
29#define BITSTREAM_READER_LE
30#include "avcodec.h"
31#include "get_bits.h"
32#include "bytestream.h"
33#include "internal.h"
34#include "tscc2data.h"
35
36typedef struct TSCC2Context {
37    AVCodecContext *avctx;
38    AVFrame       *pic;
39    int            mb_width, mb_height;
40    uint8_t        *slice_quants;
41    int            quant[2];
42    int            q[2][3];
43    GetBitContext  gb;
44
45    VLC            dc_vlc, nc_vlc[NUM_VLC_SETS], ac_vlc[NUM_VLC_SETS];
46    int            block[16];
47} TSCC2Context;
48
49static av_cold void free_vlcs(TSCC2Context *c)
50{
51    int i;
52
53    ff_free_vlc(&c->dc_vlc);
54    for (i = 0; i < NUM_VLC_SETS; i++) {
55        ff_free_vlc(c->nc_vlc + i);
56        ff_free_vlc(c->ac_vlc + i);
57    }
58}
59
60static av_cold int init_vlcs(TSCC2Context *c)
61{
62    int i, ret;
63
64    ret = ff_init_vlc_sparse(&c->dc_vlc, 9, DC_VLC_COUNT,
65                             tscc2_dc_vlc_bits,  1, 1,
66                             tscc2_dc_vlc_codes, 2, 2,
67                             tscc2_dc_vlc_syms,  2, 2, INIT_VLC_LE);
68    if (ret)
69        return ret;
70
71    for (i = 0; i < NUM_VLC_SETS; i++) {
72        ret = ff_init_vlc_sparse(c->nc_vlc + i, 9, 16,
73                                 tscc2_nc_vlc_bits[i],  1, 1,
74                                 tscc2_nc_vlc_codes[i], 2, 2,
75                                 tscc2_nc_vlc_syms,     1, 1, INIT_VLC_LE);
76        if (ret) {
77            free_vlcs(c);
78            return ret;
79        }
80        ret = ff_init_vlc_sparse(c->ac_vlc + i, 9, tscc2_ac_vlc_sizes[i],
81                                 tscc2_ac_vlc_bits[i],  1, 1,
82                                 tscc2_ac_vlc_codes[i], 2, 2,
83                                 tscc2_ac_vlc_syms[i],  2, 2, INIT_VLC_LE);
84        if (ret) {
85            free_vlcs(c);
86            return ret;
87        }
88    }
89
90    return 0;
91}
92
93#define DEQUANT(val, q) (((q) * (val) + 0x80) >> 8)
94#define DCT1D(d0, d1, d2, d3, s0, s1, s2, s3, OP) \
95    OP(d0, 5 * ((s0) + (s1) + (s2)) + 2 * (s3));  \
96    OP(d1, 5 * ((s0) - (s2) - (s3)) + 2 * (s1));  \
97    OP(d2, 5 * ((s0) - (s2) + (s3)) - 2 * (s1));  \
98    OP(d3, 5 * ((s0) - (s1) + (s2)) - 2 * (s3));  \
99
100#define COL_OP(a, b)  a = (b)
101#define ROW_OP(a, b)  a = ((b) + 0x20) >> 6
102
103static void tscc2_idct4_put(int *in, int q[3], uint8_t *dst, int stride)
104{
105    int i;
106    int tblk[4 * 4];
107    int t0, t1, t2, t3;
108
109    for (i = 0; i < 4; i++) {
110        t0 = DEQUANT(q[0 + (i & 1)], in[0 * 4 + i]);
111        t1 = DEQUANT(q[1 + (i & 1)], in[1 * 4 + i]);
112        t2 = DEQUANT(q[0 + (i & 1)], in[2 * 4 + i]);
113        t3 = DEQUANT(q[1 + (i & 1)], in[3 * 4 + i]);
114        DCT1D(tblk[0 * 4 + i], tblk[1 * 4 + i],
115              tblk[2 * 4 + i], tblk[3 * 4 + i],
116              t0, t1, t2, t3, COL_OP);
117    }
118    for (i = 0; i < 4; i++) {
119        DCT1D(dst[0], dst[1], dst[2], dst[3],
120              tblk[i * 4 + 0], tblk[i * 4 + 1],
121              tblk[i * 4 + 2], tblk[i * 4 + 3], ROW_OP);
122        dst += stride;
123    }
124}
125
126static int tscc2_decode_mb(TSCC2Context *c, int *q, int vlc_set,
127                           uint8_t *dst, int stride, int plane)
128{
129    GetBitContext *gb = &c->gb;
130    int prev_dc, dc, nc, ac, bpos, val;
131    int i, j, k, l;
132
133    if (get_bits1(gb)) {
134        if (get_bits1(gb)) {
135            val = get_bits(gb, 8);
136            for (i = 0; i < 8; i++, dst += stride)
137                memset(dst, val, 16);
138        } else {
139            if (get_bits_left(gb) < 16 * 8 * 8)
140                return AVERROR_INVALIDDATA;
141            for (i = 0; i < 8; i++) {
142                for (j = 0; j < 16; j++)
143                    dst[j] = get_bits(gb, 8);
144                dst += stride;
145            }
146        }
147        return 0;
148    }
149
150    prev_dc = 0;
151    for (j = 0; j < 2; j++) {
152        for (k = 0; k < 4; k++) {
153            if (!(j | k)) {
154                dc = get_bits(gb, 8);
155            } else {
156                dc = get_vlc2(gb, c->dc_vlc.table, 9, 2);
157                if (dc == -1)
158                    return AVERROR_INVALIDDATA;
159                if (dc == 0x100)
160                    dc = get_bits(gb, 8);
161            }
162            dc          = (dc + prev_dc) & 0xFF;
163            prev_dc     = dc;
164            c->block[0] = dc;
165
166            nc = get_vlc2(gb, c->nc_vlc[vlc_set].table, 9, 1);
167            if (nc == -1)
168                return AVERROR_INVALIDDATA;
169
170            bpos = 1;
171            memset(c->block + 1, 0, 15 * sizeof(*c->block));
172            for (l = 0; l < nc; l++) {
173                ac = get_vlc2(gb, c->ac_vlc[vlc_set].table, 9, 2);
174                if (ac == -1)
175                    return AVERROR_INVALIDDATA;
176                if (ac == 0x1000)
177                    ac = get_bits(gb, 12);
178                bpos += ac & 0xF;
179                if (bpos >= 16)
180                    return AVERROR_INVALIDDATA;
181                val = sign_extend(ac >> 4, 8);
182                c->block[tscc2_zigzag[bpos++]] = val;
183            }
184            tscc2_idct4_put(c->block, q, dst + k * 4, stride);
185        }
186        dst += 4 * stride;
187    }
188    return 0;
189}
190
191static int tscc2_decode_slice(TSCC2Context *c, int mb_y,
192                              const uint8_t *buf, int buf_size)
193{
194    int i, mb_x, q, ret;
195    int off;
196
197    if ((ret = init_get_bits8(&c->gb, buf, buf_size)) < 0)
198        return ret;
199
200    for (mb_x = 0; mb_x < c->mb_width; mb_x++) {
201        q = c->slice_quants[mb_x + c->mb_width * mb_y];
202
203        if (q == 0 || q == 3) // skip block
204            continue;
205        for (i = 0; i < 3; i++) {
206            off = mb_x * 16 + mb_y * 8 * c->pic->linesize[i];
207            ret = tscc2_decode_mb(c, c->q[q - 1], c->quant[q - 1] - 2,
208                                  c->pic->data[i] + off, c->pic->linesize[i], i);
209            if (ret)
210                return ret;
211        }
212    }
213
214    return 0;
215}
216
217static int tscc2_decode_frame(AVCodecContext *avctx, void *data,
218                              int *got_frame, AVPacket *avpkt)
219{
220    const uint8_t *buf = avpkt->data;
221    int buf_size = avpkt->size;
222    TSCC2Context *c = avctx->priv_data;
223    GetByteContext gb;
224    uint32_t frame_type, size;
225    int i, val, len, pos = 0;
226    int num_mb = c->mb_width * c->mb_height;
227    int ret;
228
229    bytestream2_init(&gb, buf, buf_size);
230    frame_type = bytestream2_get_byte(&gb);
231    if (frame_type > 1) {
232        av_log(avctx, AV_LOG_ERROR, "Incorrect frame type %"PRIu32"\n",
233               frame_type);
234        return AVERROR_INVALIDDATA;
235    }
236
237    if ((ret = ff_reget_buffer(avctx, c->pic)) < 0) {
238        return ret;
239    }
240
241    if (frame_type == 0) {
242        *got_frame      = 1;
243        if ((ret = av_frame_ref(data, c->pic)) < 0)
244            return ret;
245
246        return buf_size;
247    }
248
249    if (bytestream2_get_bytes_left(&gb) < 4) {
250        av_log(avctx, AV_LOG_ERROR, "Frame is too short\n");
251        return AVERROR_INVALIDDATA;
252    }
253
254    c->quant[0] = bytestream2_get_byte(&gb);
255    c->quant[1] = bytestream2_get_byte(&gb);
256    if (c->quant[0] < 2 || c->quant[0] > NUM_VLC_SETS + 1 ||
257        c->quant[1] < 2 || c->quant[1] > NUM_VLC_SETS + 1) {
258        av_log(avctx, AV_LOG_ERROR, "Invalid quantisers %d / %d\n",
259               c->quant[0], c->quant[1]);
260        return AVERROR_INVALIDDATA;
261    }
262
263    for (i = 0; i < 3; i++) {
264        c->q[0][i] = tscc2_quants[c->quant[0] - 2][i];
265        c->q[1][i] = tscc2_quants[c->quant[1] - 2][i];
266    }
267
268    bytestream2_skip(&gb, 1);
269
270    size = bytestream2_get_le32(&gb);
271    if (size > bytestream2_get_bytes_left(&gb)) {
272        av_log(avctx, AV_LOG_ERROR, "Slice properties chunk is too large\n");
273        return AVERROR_INVALIDDATA;
274    }
275
276    for (i = 0; i < size; i++) {
277        val   = bytestream2_get_byte(&gb);
278        len   = val & 0x3F;
279        val >>= 6;
280        if (pos + len > num_mb) {
281            av_log(avctx, AV_LOG_ERROR, "Too many slice properties\n");
282            return AVERROR_INVALIDDATA;
283        }
284        memset(c->slice_quants + pos, val, len);
285        pos += len;
286    }
287    if (pos < num_mb) {
288        av_log(avctx, AV_LOG_ERROR, "Too few slice properties (%d / %d)\n",
289               pos, num_mb);
290        return AVERROR_INVALIDDATA;
291    }
292
293    for (i = 0; i < c->mb_height; i++) {
294        size = bytestream2_peek_byte(&gb);
295        if (size & 1) {
296            size = bytestream2_get_byte(&gb) - 1;
297        } else {
298            size = bytestream2_get_le32(&gb) >> 1;
299        }
300        if (!size) {
301            int skip_row = 1, j, off = i * c->mb_width;
302            for (j = 0; j < c->mb_width; j++) {
303                if (c->slice_quants[off + j] == 1 ||
304                    c->slice_quants[off + j] == 2) {
305                    skip_row = 0;
306                    break;
307                }
308            }
309            if (!skip_row) {
310                av_log(avctx, AV_LOG_ERROR, "Non-skip row with zero size\n");
311                return AVERROR_INVALIDDATA;
312            }
313        }
314        if (bytestream2_get_bytes_left(&gb) < size) {
315            av_log(avctx, AV_LOG_ERROR, "Invalid slice size (%"PRIu32"/%u)\n",
316                   size, bytestream2_get_bytes_left(&gb));
317            return AVERROR_INVALIDDATA;
318        }
319        ret = tscc2_decode_slice(c, i, buf + bytestream2_tell(&gb), size);
320        if (ret) {
321            av_log(avctx, AV_LOG_ERROR, "Error decoding slice %d\n", i);
322            return ret;
323        }
324        bytestream2_skip(&gb, size);
325    }
326
327    *got_frame      = 1;
328    if ((ret = av_frame_ref(data, c->pic)) < 0)
329        return ret;
330
331    /* always report that the buffer was completely consumed */
332    return buf_size;
333}
334
335static av_cold int tscc2_decode_end(AVCodecContext *avctx)
336{
337    TSCC2Context * const c = avctx->priv_data;
338
339    av_frame_free(&c->pic);
340    av_freep(&c->slice_quants);
341    free_vlcs(c);
342
343    return 0;
344}
345
346static av_cold int tscc2_decode_init(AVCodecContext *avctx)
347{
348    TSCC2Context * const c = avctx->priv_data;
349    int ret;
350
351    c->avctx = avctx;
352
353    avctx->pix_fmt = AV_PIX_FMT_YUV444P;
354
355    if ((ret = init_vlcs(c)) < 0) {
356        av_log(avctx, AV_LOG_ERROR, "Cannot initialise VLCs\n");
357        return ret;
358    }
359
360    c->mb_width     = FFALIGN(avctx->width,  16) >> 4;
361    c->mb_height    = FFALIGN(avctx->height,  8) >> 3;
362    c->slice_quants = av_malloc(c->mb_width * c->mb_height);
363    if (!c->slice_quants) {
364        av_log(avctx, AV_LOG_ERROR, "Cannot allocate slice information\n");
365        free_vlcs(c);
366        return AVERROR(ENOMEM);
367    }
368
369    c->pic = av_frame_alloc();
370    if (!c->pic) {
371        tscc2_decode_end(avctx);
372        return AVERROR(ENOMEM);
373    }
374
375    return 0;
376}
377
378AVCodec ff_tscc2_decoder = {
379    .name           = "tscc2",
380    .long_name      = NULL_IF_CONFIG_SMALL("TechSmith Screen Codec 2"),
381    .type           = AVMEDIA_TYPE_VIDEO,
382    .id             = AV_CODEC_ID_TSCC2,
383    .priv_data_size = sizeof(TSCC2Context),
384    .init           = tscc2_decode_init,
385    .close          = tscc2_decode_end,
386    .decode         = tscc2_decode_frame,
387    .capabilities   = CODEC_CAP_DR1,
388};
389