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 #include "libavutil/thread.h"
31 #define BITSTREAM_READER_LE
33 #include "bytestream.h"
37 #include "tscc2data.h"
39 #define TSCC2_VLC_BITS 9
41 typedef struct TSCC2Context {
42 AVCodecContext *avctx;
44 int mb_width, mb_height;
45 uint8_t *slice_quants;
53 static VLC dc_vlc, nc_vlc[NUM_VLC_SETS], ac_vlc[NUM_VLC_SETS];
55 static av_cold void tscc2_init_vlc(VLC *vlc, int *offset, int nb_codes,
56 const uint8_t *lens, const void *syms,
59 static VLC_TYPE vlc_buf[15442][2];
61 vlc->table = &vlc_buf[*offset];
62 vlc->table_allocated = FF_ARRAY_ELEMS(vlc_buf) - *offset;
63 ff_init_vlc_from_lengths(vlc, TSCC2_VLC_BITS, nb_codes,
64 lens, 1, syms, sym_length, sym_length, 0,
65 INIT_VLC_STATIC_OVERLONG | INIT_VLC_OUTPUT_LE, NULL);
66 *offset += vlc->table_size;
69 static av_cold void tscc2_init_vlcs(void)
71 const uint16_t *ac_vlc_syms = tscc2_ac_vlc_syms;
72 const uint8_t *ac_vlc_lens = tscc2_ac_vlc_lens;
75 tscc2_init_vlc(&dc_vlc, &offset, DC_VLC_COUNT,
76 tscc2_dc_vlc_lens, tscc2_dc_vlc_syms, 2);
78 for (i = 0; i < NUM_VLC_SETS; i++) {
79 tscc2_init_vlc(&nc_vlc[i], &offset, 16,
80 tscc2_nc_vlc_lens[i], tscc2_nc_vlc_syms[i], 1);
82 tscc2_init_vlc(&ac_vlc[i], &offset, tscc2_ac_vlc_sizes[i],
83 ac_vlc_lens, ac_vlc_syms, 2);
84 ac_vlc_lens += tscc2_ac_vlc_sizes[i];
85 ac_vlc_syms += tscc2_ac_vlc_sizes[i];
89 #define DEQUANT(val, q) (((q) * (val) + 0x80) >> 8)
90 #define DCT1D(d0, d1, d2, d3, s0, s1, s2, s3, OP) \
91 OP(d0, 5 * ((s0) + (s1) + (s2)) + 2 * (s3)); \
92 OP(d1, 5 * ((s0) - (s2) - (s3)) + 2 * (s1)); \
93 OP(d2, 5 * ((s0) - (s2) + (s3)) - 2 * (s1)); \
94 OP(d3, 5 * ((s0) - (s1) + (s2)) - 2 * (s3)); \
96 #define COL_OP(a, b) a = (b)
97 #define ROW_OP(a, b) a = ((b) + 0x20) >> 6
99 static void tscc2_idct4_put(int *in, int q[3], uint8_t *dst, int stride)
105 for (i = 0; i < 4; i++) {
106 t0 = DEQUANT(q[0 + (i & 1)], in[0 * 4 + i]);
107 t1 = DEQUANT(q[1 + (i & 1)], in[1 * 4 + i]);
108 t2 = DEQUANT(q[0 + (i & 1)], in[2 * 4 + i]);
109 t3 = DEQUANT(q[1 + (i & 1)], in[3 * 4 + i]);
110 DCT1D(tblk[0 * 4 + i], tblk[1 * 4 + i],
111 tblk[2 * 4 + i], tblk[3 * 4 + i],
112 t0, t1, t2, t3, COL_OP);
114 for (i = 0; i < 4; i++) {
115 DCT1D(dst[0], dst[1], dst[2], dst[3],
116 tblk[i * 4 + 0], tblk[i * 4 + 1],
117 tblk[i * 4 + 2], tblk[i * 4 + 3], ROW_OP);
122 static int tscc2_decode_mb(TSCC2Context *c, int *q, int vlc_set,
123 uint8_t *dst, int stride, int plane)
125 GetBitContext *gb = &c->gb;
126 int prev_dc, dc, nc, ac, bpos, val;
131 val = get_bits(gb, 8);
132 for (i = 0; i < 8; i++, dst += stride)
133 memset(dst, val, 16);
135 if (get_bits_left(gb) < 16 * 8 * 8)
136 return AVERROR_INVALIDDATA;
137 for (i = 0; i < 8; i++) {
138 for (j = 0; j < 16; j++)
139 dst[j] = get_bits(gb, 8);
147 for (j = 0; j < 2; j++) {
148 for (k = 0; k < 4; k++) {
150 dc = get_bits(gb, 8);
152 dc = get_vlc2(gb, dc_vlc.table, TSCC2_VLC_BITS, 2);
154 dc = get_bits(gb, 8);
156 dc = (dc + prev_dc) & 0xFF;
160 nc = get_vlc2(gb, nc_vlc[vlc_set].table, TSCC2_VLC_BITS, 1);
163 memset(c->block + 1, 0, 15 * sizeof(*c->block));
164 for (l = 0; l < nc; l++) {
165 ac = get_vlc2(gb, ac_vlc[vlc_set].table, TSCC2_VLC_BITS, 2);
167 ac = get_bits(gb, 12);
170 return AVERROR_INVALIDDATA;
171 val = sign_extend(ac >> 4, 8);
172 c->block[ff_zigzag_scan[bpos++]] = val;
174 tscc2_idct4_put(c->block, q, dst + k * 4, stride);
181 static int tscc2_decode_slice(TSCC2Context *c, int mb_y,
182 const uint8_t *buf, int buf_size)
187 if ((ret = init_get_bits8(&c->gb, buf, buf_size)) < 0)
190 for (mb_x = 0; mb_x < c->mb_width; mb_x++) {
191 q = c->slice_quants[mb_x + c->mb_width * mb_y];
193 if (q == 0 || q == 3) // skip block
195 for (i = 0; i < 3; i++) {
196 off = mb_x * 16 + mb_y * 8 * c->pic->linesize[i];
197 ret = tscc2_decode_mb(c, c->q[q - 1], c->quant[q - 1] - 2,
198 c->pic->data[i] + off, c->pic->linesize[i], i);
207 static int tscc2_decode_frame(AVCodecContext *avctx, void *data,
208 int *got_frame, AVPacket *avpkt)
210 const uint8_t *buf = avpkt->data;
211 int buf_size = avpkt->size;
212 TSCC2Context *c = avctx->priv_data;
214 uint32_t frame_type, size;
215 int i, val, len, pos = 0;
216 int num_mb = c->mb_width * c->mb_height;
219 bytestream2_init(&gb, buf, buf_size);
220 frame_type = bytestream2_get_byte(&gb);
221 if (frame_type > 1) {
222 av_log(avctx, AV_LOG_ERROR, "Incorrect frame type %"PRIu32"\n",
224 return AVERROR_INVALIDDATA;
227 if (frame_type == 0) {
228 // Skip duplicate frames
232 if ((ret = ff_reget_buffer(avctx, c->pic, 0)) < 0) {
236 if (bytestream2_get_bytes_left(&gb) < 4) {
237 av_log(avctx, AV_LOG_ERROR, "Frame is too short\n");
238 return AVERROR_INVALIDDATA;
241 c->quant[0] = bytestream2_get_byte(&gb);
242 c->quant[1] = bytestream2_get_byte(&gb);
243 if (c->quant[0] < 2 || c->quant[0] > NUM_VLC_SETS + 1 ||
244 c->quant[1] < 2 || c->quant[1] > NUM_VLC_SETS + 1) {
245 av_log(avctx, AV_LOG_ERROR, "Invalid quantisers %d / %d\n",
246 c->quant[0], c->quant[1]);
247 return AVERROR_INVALIDDATA;
250 for (i = 0; i < 3; i++) {
251 c->q[0][i] = tscc2_quants[c->quant[0] - 2][i];
252 c->q[1][i] = tscc2_quants[c->quant[1] - 2][i];
255 bytestream2_skip(&gb, 1);
257 size = bytestream2_get_le32(&gb);
258 if (size > bytestream2_get_bytes_left(&gb)) {
259 av_log(avctx, AV_LOG_ERROR, "Slice properties chunk is too large\n");
260 return AVERROR_INVALIDDATA;
263 for (i = 0; i < size; i++) {
264 val = bytestream2_get_byte(&gb);
267 if (pos + len > num_mb) {
268 av_log(avctx, AV_LOG_ERROR, "Too many slice properties\n");
269 return AVERROR_INVALIDDATA;
271 memset(c->slice_quants + pos, val, len);
275 av_log(avctx, AV_LOG_ERROR, "Too few slice properties (%d / %d)\n",
277 return AVERROR_INVALIDDATA;
280 for (i = 0; i < c->mb_height; i++) {
281 size = bytestream2_peek_byte(&gb);
283 size = bytestream2_get_byte(&gb) - 1;
285 size = bytestream2_get_le32(&gb) >> 1;
288 int skip_row = 1, j, off = i * c->mb_width;
289 for (j = 0; j < c->mb_width; j++) {
290 if (c->slice_quants[off + j] == 1 ||
291 c->slice_quants[off + j] == 2) {
297 av_log(avctx, AV_LOG_ERROR, "Non-skip row with zero size\n");
298 return AVERROR_INVALIDDATA;
301 if (bytestream2_get_bytes_left(&gb) < size) {
302 av_log(avctx, AV_LOG_ERROR, "Invalid slice size (%"PRIu32"/%u)\n",
303 size, bytestream2_get_bytes_left(&gb));
304 return AVERROR_INVALIDDATA;
306 ret = tscc2_decode_slice(c, i, buf + bytestream2_tell(&gb), size);
308 av_log(avctx, AV_LOG_ERROR, "Error decoding slice %d\n", i);
311 bytestream2_skip(&gb, size);
315 if ((ret = av_frame_ref(data, c->pic)) < 0)
318 /* always report that the buffer was completely consumed */
322 static av_cold int tscc2_decode_end(AVCodecContext *avctx)
324 TSCC2Context * const c = avctx->priv_data;
326 av_frame_free(&c->pic);
327 av_freep(&c->slice_quants);
332 static av_cold int tscc2_decode_init(AVCodecContext *avctx)
334 TSCC2Context * const c = avctx->priv_data;
335 static AVOnce init_static_once = AV_ONCE_INIT;
339 avctx->pix_fmt = AV_PIX_FMT_YUV444P;
341 c->mb_width = FFALIGN(avctx->width, 16) >> 4;
342 c->mb_height = FFALIGN(avctx->height, 8) >> 3;
343 c->slice_quants = av_malloc(c->mb_width * c->mb_height);
344 if (!c->slice_quants) {
345 av_log(avctx, AV_LOG_ERROR, "Cannot allocate slice information\n");
346 return AVERROR(ENOMEM);
349 c->pic = av_frame_alloc();
351 return AVERROR(ENOMEM);
353 ff_thread_once(&init_static_once, tscc2_init_vlcs);
358 AVCodec ff_tscc2_decoder = {
360 .long_name = NULL_IF_CONFIG_SMALL("TechSmith Screen Codec 2"),
361 .type = AVMEDIA_TYPE_VIDEO,
362 .id = AV_CODEC_ID_TSCC2,
363 .priv_data_size = sizeof(TSCC2Context),
364 .init = tscc2_decode_init,
365 .close = tscc2_decode_end,
366 .decode = tscc2_decode_frame,
367 .capabilities = AV_CODEC_CAP_DR1,
368 .caps_internal = FF_CODEC_CAP_INIT_CLEANUP | FF_CODEC_CAP_INIT_THREADSAFE,