2 * TechSmith Screen Codec 2 (aka Dora) decoder
3 * Copyright (c) 2012 Konstantin Shishkov
5 * This file is part of FFmpeg.
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.
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.
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
24 * TechSmith Screen Codec 2 decoder
29 #define BITSTREAM_READER_LE
31 #include "bytestream.h"
35 #include "tscc2data.h"
37 typedef struct TSCC2Context {
38 AVCodecContext *avctx;
40 int mb_width, mb_height;
41 uint8_t *slice_quants;
46 VLC dc_vlc, nc_vlc[NUM_VLC_SETS], ac_vlc[NUM_VLC_SETS];
50 static av_cold void free_vlcs(TSCC2Context *c)
54 ff_free_vlc(&c->dc_vlc);
55 for (i = 0; i < NUM_VLC_SETS; i++) {
56 ff_free_vlc(c->nc_vlc + i);
57 ff_free_vlc(c->ac_vlc + i);
61 static av_cold int init_vlcs(TSCC2Context *c)
65 ret = ff_init_vlc_sparse(&c->dc_vlc, 9, DC_VLC_COUNT,
66 tscc2_dc_vlc_bits, 1, 1,
67 tscc2_dc_vlc_codes, 2, 2,
68 tscc2_dc_vlc_syms, 2, 2, INIT_VLC_LE);
72 for (i = 0; i < NUM_VLC_SETS; i++) {
73 ret = ff_init_vlc_sparse(c->nc_vlc + i, 9, 16,
74 tscc2_nc_vlc_bits[i], 1, 1,
75 tscc2_nc_vlc_codes[i], 2, 2,
76 tscc2_nc_vlc_syms, 1, 1, INIT_VLC_LE);
79 ret = ff_init_vlc_sparse(c->ac_vlc + i, 9, tscc2_ac_vlc_sizes[i],
80 tscc2_ac_vlc_bits[i], 1, 1,
81 tscc2_ac_vlc_codes[i], 2, 2,
82 tscc2_ac_vlc_syms[i], 2, 2, INIT_VLC_LE);
90 #define DEQUANT(val, q) (((q) * (val) + 0x80) >> 8)
91 #define DCT1D(d0, d1, d2, d3, s0, s1, s2, s3, OP) \
92 OP(d0, 5 * ((s0) + (s1) + (s2)) + 2 * (s3)); \
93 OP(d1, 5 * ((s0) - (s2) - (s3)) + 2 * (s1)); \
94 OP(d2, 5 * ((s0) - (s2) + (s3)) - 2 * (s1)); \
95 OP(d3, 5 * ((s0) - (s1) + (s2)) - 2 * (s3)); \
97 #define COL_OP(a, b) a = (b)
98 #define ROW_OP(a, b) a = ((b) + 0x20) >> 6
100 static void tscc2_idct4_put(int *in, int q[3], uint8_t *dst, int stride)
106 for (i = 0; i < 4; i++) {
107 t0 = DEQUANT(q[0 + (i & 1)], in[0 * 4 + i]);
108 t1 = DEQUANT(q[1 + (i & 1)], in[1 * 4 + i]);
109 t2 = DEQUANT(q[0 + (i & 1)], in[2 * 4 + i]);
110 t3 = DEQUANT(q[1 + (i & 1)], in[3 * 4 + i]);
111 DCT1D(tblk[0 * 4 + i], tblk[1 * 4 + i],
112 tblk[2 * 4 + i], tblk[3 * 4 + i],
113 t0, t1, t2, t3, COL_OP);
115 for (i = 0; i < 4; i++) {
116 DCT1D(dst[0], dst[1], dst[2], dst[3],
117 tblk[i * 4 + 0], tblk[i * 4 + 1],
118 tblk[i * 4 + 2], tblk[i * 4 + 3], ROW_OP);
123 static int tscc2_decode_mb(TSCC2Context *c, int *q, int vlc_set,
124 uint8_t *dst, int stride, int plane)
126 GetBitContext *gb = &c->gb;
127 int prev_dc, dc, nc, ac, bpos, val;
132 val = get_bits(gb, 8);
133 for (i = 0; i < 8; i++, dst += stride)
134 memset(dst, val, 16);
136 if (get_bits_left(gb) < 16 * 8 * 8)
137 return AVERROR_INVALIDDATA;
138 for (i = 0; i < 8; i++) {
139 for (j = 0; j < 16; j++)
140 dst[j] = get_bits(gb, 8);
148 for (j = 0; j < 2; j++) {
149 for (k = 0; k < 4; k++) {
151 dc = get_bits(gb, 8);
153 dc = get_vlc2(gb, c->dc_vlc.table, 9, 2);
155 return AVERROR_INVALIDDATA;
157 dc = get_bits(gb, 8);
159 dc = (dc + prev_dc) & 0xFF;
163 nc = get_vlc2(gb, c->nc_vlc[vlc_set].table, 9, 1);
165 return AVERROR_INVALIDDATA;
168 memset(c->block + 1, 0, 15 * sizeof(*c->block));
169 for (l = 0; l < nc; l++) {
170 ac = get_vlc2(gb, c->ac_vlc[vlc_set].table, 9, 2);
172 return AVERROR_INVALIDDATA;
174 ac = get_bits(gb, 12);
177 return AVERROR_INVALIDDATA;
178 val = sign_extend(ac >> 4, 8);
179 c->block[ff_zigzag_scan[bpos++]] = val;
181 tscc2_idct4_put(c->block, q, dst + k * 4, stride);
188 static int tscc2_decode_slice(TSCC2Context *c, int mb_y,
189 const uint8_t *buf, int buf_size)
194 if ((ret = init_get_bits8(&c->gb, buf, buf_size)) < 0)
197 for (mb_x = 0; mb_x < c->mb_width; mb_x++) {
198 q = c->slice_quants[mb_x + c->mb_width * mb_y];
200 if (q == 0 || q == 3) // skip block
202 for (i = 0; i < 3; i++) {
203 off = mb_x * 16 + mb_y * 8 * c->pic->linesize[i];
204 ret = tscc2_decode_mb(c, c->q[q - 1], c->quant[q - 1] - 2,
205 c->pic->data[i] + off, c->pic->linesize[i], i);
214 static int tscc2_decode_frame(AVCodecContext *avctx, void *data,
215 int *got_frame, AVPacket *avpkt)
217 const uint8_t *buf = avpkt->data;
218 int buf_size = avpkt->size;
219 TSCC2Context *c = avctx->priv_data;
221 uint32_t frame_type, size;
222 int i, val, len, pos = 0;
223 int num_mb = c->mb_width * c->mb_height;
226 bytestream2_init(&gb, buf, buf_size);
227 frame_type = bytestream2_get_byte(&gb);
228 if (frame_type > 1) {
229 av_log(avctx, AV_LOG_ERROR, "Incorrect frame type %"PRIu32"\n",
231 return AVERROR_INVALIDDATA;
234 if (frame_type == 0) {
235 // Skip duplicate frames
239 if ((ret = ff_reget_buffer(avctx, c->pic, 0)) < 0) {
243 if (bytestream2_get_bytes_left(&gb) < 4) {
244 av_log(avctx, AV_LOG_ERROR, "Frame is too short\n");
245 return AVERROR_INVALIDDATA;
248 c->quant[0] = bytestream2_get_byte(&gb);
249 c->quant[1] = bytestream2_get_byte(&gb);
250 if (c->quant[0] < 2 || c->quant[0] > NUM_VLC_SETS + 1 ||
251 c->quant[1] < 2 || c->quant[1] > NUM_VLC_SETS + 1) {
252 av_log(avctx, AV_LOG_ERROR, "Invalid quantisers %d / %d\n",
253 c->quant[0], c->quant[1]);
254 return AVERROR_INVALIDDATA;
257 for (i = 0; i < 3; i++) {
258 c->q[0][i] = tscc2_quants[c->quant[0] - 2][i];
259 c->q[1][i] = tscc2_quants[c->quant[1] - 2][i];
262 bytestream2_skip(&gb, 1);
264 size = bytestream2_get_le32(&gb);
265 if (size > bytestream2_get_bytes_left(&gb)) {
266 av_log(avctx, AV_LOG_ERROR, "Slice properties chunk is too large\n");
267 return AVERROR_INVALIDDATA;
270 for (i = 0; i < size; i++) {
271 val = bytestream2_get_byte(&gb);
274 if (pos + len > num_mb) {
275 av_log(avctx, AV_LOG_ERROR, "Too many slice properties\n");
276 return AVERROR_INVALIDDATA;
278 memset(c->slice_quants + pos, val, len);
282 av_log(avctx, AV_LOG_ERROR, "Too few slice properties (%d / %d)\n",
284 return AVERROR_INVALIDDATA;
287 for (i = 0; i < c->mb_height; i++) {
288 size = bytestream2_peek_byte(&gb);
290 size = bytestream2_get_byte(&gb) - 1;
292 size = bytestream2_get_le32(&gb) >> 1;
295 int skip_row = 1, j, off = i * c->mb_width;
296 for (j = 0; j < c->mb_width; j++) {
297 if (c->slice_quants[off + j] == 1 ||
298 c->slice_quants[off + j] == 2) {
304 av_log(avctx, AV_LOG_ERROR, "Non-skip row with zero size\n");
305 return AVERROR_INVALIDDATA;
308 if (bytestream2_get_bytes_left(&gb) < size) {
309 av_log(avctx, AV_LOG_ERROR, "Invalid slice size (%"PRIu32"/%u)\n",
310 size, bytestream2_get_bytes_left(&gb));
311 return AVERROR_INVALIDDATA;
313 ret = tscc2_decode_slice(c, i, buf + bytestream2_tell(&gb), size);
315 av_log(avctx, AV_LOG_ERROR, "Error decoding slice %d\n", i);
318 bytestream2_skip(&gb, size);
322 if ((ret = av_frame_ref(data, c->pic)) < 0)
325 /* always report that the buffer was completely consumed */
329 static av_cold int tscc2_decode_end(AVCodecContext *avctx)
331 TSCC2Context * const c = avctx->priv_data;
333 av_frame_free(&c->pic);
334 av_freep(&c->slice_quants);
340 static av_cold int tscc2_decode_init(AVCodecContext *avctx)
342 TSCC2Context * const c = avctx->priv_data;
347 avctx->pix_fmt = AV_PIX_FMT_YUV444P;
349 if ((ret = init_vlcs(c)) < 0) {
350 av_log(avctx, AV_LOG_ERROR, "Cannot initialise VLCs\n");
354 c->mb_width = FFALIGN(avctx->width, 16) >> 4;
355 c->mb_height = FFALIGN(avctx->height, 8) >> 3;
356 c->slice_quants = av_malloc(c->mb_width * c->mb_height);
357 if (!c->slice_quants) {
358 av_log(avctx, AV_LOG_ERROR, "Cannot allocate slice information\n");
359 return AVERROR(ENOMEM);
362 c->pic = av_frame_alloc();
364 return AVERROR(ENOMEM);
369 AVCodec ff_tscc2_decoder = {
371 .long_name = NULL_IF_CONFIG_SMALL("TechSmith Screen Codec 2"),
372 .type = AVMEDIA_TYPE_VIDEO,
373 .id = AV_CODEC_ID_TSCC2,
374 .priv_data_size = sizeof(TSCC2Context),
375 .init = tscc2_decode_init,
376 .close = tscc2_decode_end,
377 .decode = tscc2_decode_frame,
378 .capabilities = AV_CODEC_CAP_DR1,
379 .caps_internal = FF_CODEC_CAP_INIT_CLEANUP,