| /* |
| * MPEG-1/2 decoder |
| * Copyright (c) 2000, 2001 Fabrice Bellard |
| * Copyright (c) 2002-2004 Michael Niedermayer <michaelni@gmx.at> |
| * |
| * This file is part of FFmpeg. |
| * |
| * FFmpeg is free software; you can redistribute it and/or |
| * modify it under the terms of the GNU Lesser General Public |
| * License as published by the Free Software Foundation; either |
| * version 2.1 of the License, or (at your option) any later version. |
| * |
| * FFmpeg is distributed in the hope that it will be useful, |
| * but WITHOUT ANY WARRANTY; without even the implied warranty of |
| * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU |
| * Lesser General Public License for more details. |
| * |
| * You should have received a copy of the GNU Lesser General Public |
| * License along with FFmpeg; if not, write to the Free Software |
| * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA |
| */ |
| |
| /** |
| * @file |
| * MPEG-1/2 decoder |
| */ |
| |
| #include "libavutil/attributes.h" |
| #include "libavutil/avassert.h" |
| #include "libavutil/timecode.h" |
| |
| #include "internal.h" |
| #include "avcodec.h" |
| #include "mpegvideo.h" |
| #include "error_resilience.h" |
| #include "mpeg12.h" |
| #include "mpeg12data.h" |
| #include "mpegvideodata.h" |
| #include "bytestream.h" |
| #include "thread.h" |
| |
| uint8_t ff_mpeg12_static_rl_table_store[2][2][2*MAX_RUN + MAX_LEVEL + 3]; |
| |
| static const uint8_t table_mb_ptype[7][2] = { |
| { 3, 5 }, // 0x01 MB_INTRA |
| { 1, 2 }, // 0x02 MB_PAT |
| { 1, 3 }, // 0x08 MB_FOR |
| { 1, 1 }, // 0x0A MB_FOR|MB_PAT |
| { 1, 6 }, // 0x11 MB_QUANT|MB_INTRA |
| { 1, 5 }, // 0x12 MB_QUANT|MB_PAT |
| { 2, 5 }, // 0x1A MB_QUANT|MB_FOR|MB_PAT |
| }; |
| |
| static const uint8_t table_mb_btype[11][2] = { |
| { 3, 5 }, // 0x01 MB_INTRA |
| { 2, 3 }, // 0x04 MB_BACK |
| { 3, 3 }, // 0x06 MB_BACK|MB_PAT |
| { 2, 4 }, // 0x08 MB_FOR |
| { 3, 4 }, // 0x0A MB_FOR|MB_PAT |
| { 2, 2 }, // 0x0C MB_FOR|MB_BACK |
| { 3, 2 }, // 0x0E MB_FOR|MB_BACK|MB_PAT |
| { 1, 6 }, // 0x11 MB_QUANT|MB_INTRA |
| { 2, 6 }, // 0x16 MB_QUANT|MB_BACK|MB_PAT |
| { 3, 6 }, // 0x1A MB_QUANT|MB_FOR|MB_PAT |
| { 2, 5 }, // 0x1E MB_QUANT|MB_FOR|MB_BACK|MB_PAT |
| }; |
| |
| av_cold void ff_init_2d_vlc_rl(RLTable *rl, unsigned static_size, int flags) |
| { |
| int i; |
| VLC_TYPE table[680][2] = {{0}}; |
| VLC vlc = { .table = table, .table_allocated = static_size }; |
| av_assert0(static_size <= FF_ARRAY_ELEMS(table)); |
| 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); |
| |
| for (i = 0; i < vlc.table_size; i++) { |
| int code = vlc.table[i][0]; |
| int len = vlc.table[i][1]; |
| int level, run; |
| |
| if (len == 0) { // illegal code |
| run = 65; |
| level = MAX_LEVEL; |
| } else if (len<0) { //more bits needed |
| run = 0; |
| level = code; |
| } else { |
| if (code == rl->n) { //esc |
| run = 65; |
| level = 0; |
| } else if (code == rl->n+1) { //eob |
| run = 0; |
| level = 127; |
| } else { |
| run = rl->table_run [code] + 1; |
| level = rl->table_level[code]; |
| } |
| } |
| rl->rl_vlc[0][i].len = len; |
| rl->rl_vlc[0][i].level = level; |
| rl->rl_vlc[0][i].run = run; |
| } |
| } |
| |
| av_cold void ff_mpeg12_common_init(MpegEncContext *s) |
| { |
| |
| s->y_dc_scale_table = |
| s->c_dc_scale_table = ff_mpeg2_dc_scale_table[s->intra_dc_precision]; |
| |
| } |
| |
| void ff_mpeg1_clean_buffers(MpegEncContext *s) |
| { |
| s->last_dc[0] = 1 << (7 + s->intra_dc_precision); |
| s->last_dc[1] = s->last_dc[0]; |
| s->last_dc[2] = s->last_dc[0]; |
| memset(s->last_mv, 0, sizeof(s->last_mv)); |
| } |
| |
| |
| /******************************************/ |
| /* decoding */ |
| |
| VLC ff_mv_vlc; |
| |
| VLC ff_dc_lum_vlc; |
| VLC ff_dc_chroma_vlc; |
| |
| VLC ff_mbincr_vlc; |
| VLC ff_mb_ptype_vlc; |
| VLC ff_mb_btype_vlc; |
| VLC ff_mb_pat_vlc; |
| |
| av_cold void ff_mpeg12_init_vlcs(void) |
| { |
| static int done = 0; |
| |
| if (!done) { |
| done = 1; |
| |
| INIT_VLC_STATIC(&ff_dc_lum_vlc, DC_VLC_BITS, 12, |
| ff_mpeg12_vlc_dc_lum_bits, 1, 1, |
| ff_mpeg12_vlc_dc_lum_code, 2, 2, 512); |
| INIT_VLC_STATIC(&ff_dc_chroma_vlc, DC_VLC_BITS, 12, |
| ff_mpeg12_vlc_dc_chroma_bits, 1, 1, |
| ff_mpeg12_vlc_dc_chroma_code, 2, 2, 514); |
| INIT_VLC_STATIC(&ff_mv_vlc, MV_VLC_BITS, 17, |
| &ff_mpeg12_mbMotionVectorTable[0][1], 2, 1, |
| &ff_mpeg12_mbMotionVectorTable[0][0], 2, 1, 266); |
| INIT_VLC_STATIC(&ff_mbincr_vlc, MBINCR_VLC_BITS, 36, |
| &ff_mpeg12_mbAddrIncrTable[0][1], 2, 1, |
| &ff_mpeg12_mbAddrIncrTable[0][0], 2, 1, 538); |
| INIT_VLC_STATIC(&ff_mb_pat_vlc, MB_PAT_VLC_BITS, 64, |
| &ff_mpeg12_mbPatTable[0][1], 2, 1, |
| &ff_mpeg12_mbPatTable[0][0], 2, 1, 512); |
| |
| INIT_VLC_STATIC(&ff_mb_ptype_vlc, MB_PTYPE_VLC_BITS, 7, |
| &table_mb_ptype[0][1], 2, 1, |
| &table_mb_ptype[0][0], 2, 1, 64); |
| INIT_VLC_STATIC(&ff_mb_btype_vlc, MB_BTYPE_VLC_BITS, 11, |
| &table_mb_btype[0][1], 2, 1, |
| &table_mb_btype[0][0], 2, 1, 64); |
| ff_rl_init(&ff_rl_mpeg1, ff_mpeg12_static_rl_table_store[0]); |
| ff_rl_init(&ff_rl_mpeg2, ff_mpeg12_static_rl_table_store[1]); |
| |
| INIT_2D_VLC_RL(ff_rl_mpeg1, 680, 0); |
| INIT_2D_VLC_RL(ff_rl_mpeg2, 674, 0); |
| } |
| } |
| |
| /** |
| * Find the end of the current frame in the bitstream. |
| * @return the position of the first byte of the next frame, or -1 |
| */ |
| int ff_mpeg1_find_frame_end(ParseContext *pc, const uint8_t *buf, int buf_size, AVCodecParserContext *s) |
| { |
| int i; |
| uint32_t state = pc->state; |
| |
| /* EOF considered as end of frame */ |
| if (buf_size == 0) |
| return 0; |
| |
| /* |
| 0 frame start -> 1/4 |
| 1 first_SEQEXT -> 0/2 |
| 2 first field start -> 3/0 |
| 3 second_SEQEXT -> 2/0 |
| 4 searching end |
| */ |
| |
| for (i = 0; i < buf_size; i++) { |
| av_assert1(pc->frame_start_found >= 0 && pc->frame_start_found <= 4); |
| if (pc->frame_start_found & 1) { |
| if (state == EXT_START_CODE && (buf[i] & 0xF0) != 0x80) |
| pc->frame_start_found--; |
| else if (state == EXT_START_CODE + 2) { |
| if ((buf[i] & 3) == 3) |
| pc->frame_start_found = 0; |
| else |
| pc->frame_start_found = (pc->frame_start_found + 1) & 3; |
| } |
| state++; |
| } else { |
| i = avpriv_find_start_code(buf + i, buf + buf_size, &state) - buf - 1; |
| if (pc->frame_start_found == 0 && state >= SLICE_MIN_START_CODE && state <= SLICE_MAX_START_CODE) { |
| i++; |
| pc->frame_start_found = 4; |
| } |
| if (state == SEQ_END_CODE) { |
| pc->frame_start_found = 0; |
| pc->state=-1; |
| return i+1; |
| } |
| if (pc->frame_start_found == 2 && state == SEQ_START_CODE) |
| pc->frame_start_found = 0; |
| if (pc->frame_start_found < 4 && state == EXT_START_CODE) |
| pc->frame_start_found++; |
| if (pc->frame_start_found == 4 && (state & 0xFFFFFF00) == 0x100) { |
| if (state < SLICE_MIN_START_CODE || state > SLICE_MAX_START_CODE) { |
| pc->frame_start_found = 0; |
| pc->state = -1; |
| return i - 3; |
| } |
| } |
| if (pc->frame_start_found == 0 && s && state == PICTURE_START_CODE) { |
| ff_fetch_timestamp(s, i - 3, 1, i > 3); |
| } |
| } |
| } |
| pc->state = state; |
| return END_NOT_FOUND; |
| } |
| |
| #define MAX_INDEX (64 - 1) |
| |
| int ff_mpeg1_decode_block_intra(GetBitContext *gb, |
| const uint16_t *quant_matrix, |
| uint8_t *const scantable, int last_dc[3], |
| int16_t *block, int index, int qscale) |
| { |
| int dc, diff, i = 0, component; |
| RLTable *rl = &ff_rl_mpeg1; |
| |
| /* DC coefficient */ |
| component = index <= 3 ? 0 : index - 4 + 1; |
| |
| diff = decode_dc(gb, component); |
| if (diff >= 0xffff) |
| return AVERROR_INVALIDDATA; |
| |
| dc = last_dc[component]; |
| dc += diff; |
| last_dc[component] = dc; |
| |
| block[0] = dc * quant_matrix[0]; |
| |
| { |
| OPEN_READER(re, gb); |
| UPDATE_CACHE(re, gb); |
| if (((int32_t)GET_CACHE(re, gb)) <= (int32_t)0xBFFFFFFF) |
| goto end; |
| |
| /* now quantify & encode AC coefficients */ |
| while (1) { |
| int level, run, j; |
| |
| GET_RL_VLC(level, run, re, gb, rl->rl_vlc[0], |
| TEX_VLC_BITS, 2, 0); |
| |
| if (level != 0) { |
| i += run; |
| if (i > MAX_INDEX) |
| break; |
| |
| j = scantable[i]; |
| level = (level * qscale * quant_matrix[j]) >> 4; |
| level = (level - 1) | 1; |
| level = (level ^ SHOW_SBITS(re, gb, 1)) - |
| SHOW_SBITS(re, gb, 1); |
| SKIP_BITS(re, gb, 1); |
| } else { |
| /* escape */ |
| run = SHOW_UBITS(re, gb, 6) + 1; |
| LAST_SKIP_BITS(re, gb, 6); |
| UPDATE_CACHE(re, gb); |
| level = SHOW_SBITS(re, gb, 8); |
| SKIP_BITS(re, gb, 8); |
| |
| if (level == -128) { |
| level = SHOW_UBITS(re, gb, 8) - 256; |
| SKIP_BITS(re, gb, 8); |
| } else if (level == 0) { |
| level = SHOW_UBITS(re, gb, 8); |
| SKIP_BITS(re, gb, 8); |
| } |
| |
| i += run; |
| if (i > MAX_INDEX) |
| break; |
| |
| j = scantable[i]; |
| if (level < 0) { |
| level = -level; |
| level = (level * qscale * quant_matrix[j]) >> 4; |
| level = (level - 1) | 1; |
| level = -level; |
| } else { |
| level = (level * qscale * quant_matrix[j]) >> 4; |
| level = (level - 1) | 1; |
| } |
| } |
| |
| block[j] = level; |
| if (((int32_t)GET_CACHE(re, gb)) <= (int32_t)0xBFFFFFFF) |
| break; |
| |
| UPDATE_CACHE(re, gb); |
| } |
| end: |
| LAST_SKIP_BITS(re, gb, 2); |
| CLOSE_READER(re, gb); |
| } |
| |
| if (i > MAX_INDEX) |
| i = AVERROR_INVALIDDATA; |
| |
| return i; |
| } |
