3 * Copyright (c) 2000, 2001 Fabrice Bellard
4 * Copyright (c) 2002-2004 Michael Niedermayer <michaelni@gmx.at>
6 * This file is part of FFmpeg.
8 * FFmpeg is free software; you can redistribute it and/or
9 * modify it under the terms of the GNU Lesser General Public
10 * License as published by the Free Software Foundation; either
11 * version 2.1 of the License, or (at your option) any later version.
13 * FFmpeg is distributed in the hope that it will be useful,
14 * but WITHOUT ANY WARRANTY; without even the implied warranty of
15 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
16 * Lesser General Public License for more details.
18 * You should have received a copy of the GNU Lesser General Public
19 * License along with FFmpeg; if not, write to the Free Software
20 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
28 #define UNCHECKED_BITSTREAM_READER 1
30 #include "libavutil/attributes.h"
31 #include "libavutil/avassert.h"
32 #include "libavutil/timecode.h"
36 #include "mpegvideo.h"
37 #include "error_resilience.h"
39 #include "mpeg12data.h"
40 #include "mpegvideodata.h"
41 #include "bytestream.h"
44 static const uint8_t table_mb_ptype[7][2] = {
45 { 3, 5 }, // 0x01 MB_INTRA
46 { 1, 2 }, // 0x02 MB_PAT
47 { 1, 3 }, // 0x08 MB_FOR
48 { 1, 1 }, // 0x0A MB_FOR|MB_PAT
49 { 1, 6 }, // 0x11 MB_QUANT|MB_INTRA
50 { 1, 5 }, // 0x12 MB_QUANT|MB_PAT
51 { 2, 5 }, // 0x1A MB_QUANT|MB_FOR|MB_PAT
54 static const uint8_t table_mb_btype[11][2] = {
55 { 3, 5 }, // 0x01 MB_INTRA
56 { 2, 3 }, // 0x04 MB_BACK
57 { 3, 3 }, // 0x06 MB_BACK|MB_PAT
58 { 2, 4 }, // 0x08 MB_FOR
59 { 3, 4 }, // 0x0A MB_FOR|MB_PAT
60 { 2, 2 }, // 0x0C MB_FOR|MB_BACK
61 { 3, 2 }, // 0x0E MB_FOR|MB_BACK|MB_PAT
62 { 1, 6 }, // 0x11 MB_QUANT|MB_INTRA
63 { 2, 6 }, // 0x16 MB_QUANT|MB_BACK|MB_PAT
64 { 3, 6 }, // 0x1A MB_QUANT|MB_FOR|MB_PAT
65 { 2, 5 }, // 0x1E MB_QUANT|MB_FOR|MB_BACK|MB_PAT
68 av_cold void ff_init_2d_vlc_rl(RLTable *rl, unsigned static_size, int flags)
71 VLC_TYPE table[680][2] = {{0}};
72 VLC vlc = { .table = table, .table_allocated = static_size };
73 av_assert0(static_size <= FF_ARRAY_ELEMS(table));
74 init_vlc(&vlc, TEX_VLC_BITS, rl->n + 2, &rl->table_vlc[0][1], 4, 2, &rl->table_vlc[0][0], 4, 2, INIT_VLC_USE_NEW_STATIC | flags);
76 for (i = 0; i < vlc.table_size; i++) {
77 int code = vlc.table[i][0];
78 int len = vlc.table[i][1];
81 if (len == 0) { // illegal code
84 } else if (len<0) { //more bits needed
88 if (code == rl->n) { //esc
91 } else if (code == rl->n+1) { //eob
95 run = rl->table_run [code] + 1;
96 level = rl->table_level[code];
99 rl->rl_vlc[0][i].len = len;
100 rl->rl_vlc[0][i].level = level;
101 rl->rl_vlc[0][i].run = run;
105 av_cold void ff_mpeg12_common_init(MpegEncContext *s)
108 s->y_dc_scale_table =
109 s->c_dc_scale_table = ff_mpeg2_dc_scale_table[s->intra_dc_precision];
113 void ff_mpeg1_clean_buffers(MpegEncContext *s)
115 s->last_dc[0] = 1 << (7 + s->intra_dc_precision);
116 s->last_dc[1] = s->last_dc[0];
117 s->last_dc[2] = s->last_dc[0];
118 memset(s->last_mv, 0, sizeof(s->last_mv));
122 /******************************************/
128 VLC ff_dc_chroma_vlc;
135 av_cold void ff_mpeg12_init_vlcs(void)
142 INIT_VLC_STATIC(&ff_dc_lum_vlc, DC_VLC_BITS, 12,
143 ff_mpeg12_vlc_dc_lum_bits, 1, 1,
144 ff_mpeg12_vlc_dc_lum_code, 2, 2, 512);
145 INIT_VLC_STATIC(&ff_dc_chroma_vlc, DC_VLC_BITS, 12,
146 ff_mpeg12_vlc_dc_chroma_bits, 1, 1,
147 ff_mpeg12_vlc_dc_chroma_code, 2, 2, 514);
148 INIT_VLC_STATIC(&ff_mv_vlc, MV_VLC_BITS, 17,
149 &ff_mpeg12_mbMotionVectorTable[0][1], 2, 1,
150 &ff_mpeg12_mbMotionVectorTable[0][0], 2, 1, 266);
151 INIT_VLC_STATIC(&ff_mbincr_vlc, MBINCR_VLC_BITS, 36,
152 &ff_mpeg12_mbAddrIncrTable[0][1], 2, 1,
153 &ff_mpeg12_mbAddrIncrTable[0][0], 2, 1, 538);
154 INIT_VLC_STATIC(&ff_mb_pat_vlc, MB_PAT_VLC_BITS, 64,
155 &ff_mpeg12_mbPatTable[0][1], 2, 1,
156 &ff_mpeg12_mbPatTable[0][0], 2, 1, 512);
158 INIT_VLC_STATIC(&ff_mb_ptype_vlc, MB_PTYPE_VLC_BITS, 7,
159 &table_mb_ptype[0][1], 2, 1,
160 &table_mb_ptype[0][0], 2, 1, 64);
161 INIT_VLC_STATIC(&ff_mb_btype_vlc, MB_BTYPE_VLC_BITS, 11,
162 &table_mb_btype[0][1], 2, 1,
163 &table_mb_btype[0][0], 2, 1, 64);
165 INIT_2D_VLC_RL(ff_rl_mpeg1, 680, 0);
166 INIT_2D_VLC_RL(ff_rl_mpeg2, 674, 0);
171 * Find the end of the current frame in the bitstream.
172 * @return the position of the first byte of the next frame, or -1
174 int ff_mpeg1_find_frame_end(ParseContext *pc, const uint8_t *buf, int buf_size, AVCodecParserContext *s)
177 uint32_t state = pc->state;
179 /* EOF considered as end of frame */
185 1 first_SEQEXT -> 0/2
186 2 first field start -> 3/0
187 3 second_SEQEXT -> 2/0
191 for (i = 0; i < buf_size; i++) {
192 av_assert1(pc->frame_start_found >= 0 && pc->frame_start_found <= 4);
193 if (pc->frame_start_found & 1) {
194 if (state == EXT_START_CODE && (buf[i] & 0xF0) != 0x80)
195 pc->frame_start_found--;
196 else if (state == EXT_START_CODE + 2) {
197 if ((buf[i] & 3) == 3)
198 pc->frame_start_found = 0;
200 pc->frame_start_found = (pc->frame_start_found + 1) & 3;
204 i = avpriv_find_start_code(buf + i, buf + buf_size, &state) - buf - 1;
205 if (pc->frame_start_found == 0 && state >= SLICE_MIN_START_CODE && state <= SLICE_MAX_START_CODE) {
207 pc->frame_start_found = 4;
209 if (state == SEQ_END_CODE) {
210 pc->frame_start_found = 0;
214 if (pc->frame_start_found == 2 && state == SEQ_START_CODE)
215 pc->frame_start_found = 0;
216 if (pc->frame_start_found < 4 && state == EXT_START_CODE)
217 pc->frame_start_found++;
218 if (pc->frame_start_found == 4 && (state & 0xFFFFFF00) == 0x100) {
219 if (state < SLICE_MIN_START_CODE || state > SLICE_MAX_START_CODE) {
220 pc->frame_start_found = 0;
225 if (pc->frame_start_found == 0 && s && state == PICTURE_START_CODE) {
226 ff_fetch_timestamp(s, i - 3, 1, i > 3);
231 return END_NOT_FOUND;
234 #define MAX_INDEX (64 - 1)
236 int ff_mpeg1_decode_block_intra(GetBitContext *gb,
237 const uint16_t *quant_matrix,
238 uint8_t *const scantable, int last_dc[3],
239 int16_t *block, int index, int qscale)
241 int dc, diff, i = 0, component;
242 RLTable *rl = &ff_rl_mpeg1;
245 component = index <= 3 ? 0 : index - 4 + 1;
247 diff = decode_dc(gb, component);
249 return AVERROR_INVALIDDATA;
251 dc = last_dc[component];
253 last_dc[component] = dc;
255 block[0] = dc * quant_matrix[0];
259 UPDATE_CACHE(re, gb);
260 if (((int32_t)GET_CACHE(re, gb)) <= (int32_t)0xBFFFFFFF)
263 /* now quantify & encode AC coefficients */
267 GET_RL_VLC(level, run, re, gb, rl->rl_vlc[0],
276 level = (level * qscale * quant_matrix[j]) >> 4;
277 level = (level - 1) | 1;
278 level = (level ^ SHOW_SBITS(re, gb, 1)) -
279 SHOW_SBITS(re, gb, 1);
280 SKIP_BITS(re, gb, 1);
283 run = SHOW_UBITS(re, gb, 6) + 1;
284 LAST_SKIP_BITS(re, gb, 6);
285 UPDATE_CACHE(re, gb);
286 level = SHOW_SBITS(re, gb, 8);
287 SKIP_BITS(re, gb, 8);
290 level = SHOW_UBITS(re, gb, 8) - 256;
291 SKIP_BITS(re, gb, 8);
292 } else if (level == 0) {
293 level = SHOW_UBITS(re, gb, 8);
294 SKIP_BITS(re, gb, 8);
304 level = (level * qscale * quant_matrix[j]) >> 4;
305 level = (level - 1) | 1;
308 level = (level * qscale * quant_matrix[j]) >> 4;
309 level = (level - 1) | 1;
314 if (((int32_t)GET_CACHE(re, gb)) <= (int32_t)0xBFFFFFFF)
317 UPDATE_CACHE(re, gb);
320 LAST_SKIP_BITS(re, gb, 2);
321 CLOSE_READER(re, gb);
325 i = AVERROR_INVALIDDATA;