| /* |
| * JPEG2000 parser |
| * Copyright (c) 2020 Gautam Ramakrishnan |
| * |
| * 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 |
| * JPEG2000 parser. |
| */ |
| |
| #include "parser.h" |
| |
| /* Whether frame is jp2 file or codestream |
| */ |
| enum frame_type { |
| jp2_file = 1, |
| j2k_cstream |
| }; |
| |
| typedef struct JPEG2000ParserContext { |
| ParseContext pc; |
| uint64_t bytes_read; |
| uint64_t fheader_state; |
| uint32_t skip_bytes; // skip bytes inside codestream data |
| enum frame_type ft; // 1 if file, 2 if codestream |
| uint8_t fheader_read; // are we reading |
| uint8_t reading_file_header; |
| uint8_t skipped_codestream; |
| uint8_t read_tp; |
| uint8_t in_codestream; |
| } JPEG2000ParserContext; |
| |
| static inline void reset_context(JPEG2000ParserContext *m) |
| { |
| ParseContext *pc = &m->pc; |
| |
| pc->frame_start_found= 0; |
| pc->state64 = 0; |
| m->bytes_read = 0; |
| m->ft = 0; |
| m->skipped_codestream = 0; |
| m->fheader_read = 0; |
| m->skip_bytes = 0; |
| m->read_tp = 0; |
| m->in_codestream = 0; |
| } |
| |
| /* Returns 1 if marker has any data which can be skipped |
| */ |
| static uint8_t info_marker(uint16_t marker) |
| { |
| static const uint8_t lut[256] = { |
| 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, |
| 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, |
| 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, |
| 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, |
| 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 0, // 0xFF4F |
| 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, |
| 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, |
| 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, |
| 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, |
| 0, 1, 0, 0, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, // 0xFF90 0xFF92 0xFF93 |
| 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, |
| 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, |
| 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, |
| 1, 1, 1, 1, 1, 1, 1, 1, 1, 0, 1, 1, 1, 1, 1, 1, // 0xFFD9 |
| 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, |
| 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, |
| }; |
| return marker < 0xFF00 ? 0 : lut[marker & 0xFF]; |
| } |
| |
| /** |
| * Find the end of the current frame in the bitstream. |
| * @return the position of the first byte of the next frame, or -1 |
| */ |
| static int find_frame_end(JPEG2000ParserContext *m, const uint8_t *buf, int buf_size) |
| { |
| ParseContext *pc= &m->pc; |
| int i; |
| uint64_t state64 = pc->state64; |
| uint64_t bytes_read = m->bytes_read; |
| |
| if (buf_size == 0) { |
| return 0; |
| } |
| |
| for (i = 0; i < buf_size; i++) { |
| state64 = state64 << 8 | buf[i]; |
| bytes_read++; |
| if (m->skip_bytes) { |
| // handle long skips |
| if (m->skip_bytes > 8) { |
| // need -9 else buf_size - i == 8 ==> i == buf_size after this, |
| // and thus i == buf_size + 1 after the loop |
| int skip = FFMIN(FFMIN((int64_t)m->skip_bytes - 8, buf_size - i - 9), INT_MAX); |
| if (skip > 0) { |
| m->skip_bytes -= skip; |
| i += skip; |
| bytes_read += skip; |
| } |
| } |
| m->skip_bytes--; |
| continue; |
| } |
| if (m->read_tp) { // Find out how many bytes inside Tile part codestream to skip. |
| if (m->read_tp == 1) { |
| m->skip_bytes = (state64 & 0xFFFFFFFF) - 9 > 0? |
| (state64 & 0xFFFFFFFF) - 9 : 0; |
| } |
| m->read_tp--; |
| continue; |
| } |
| if (m->fheader_read) { |
| if (m->fheader_read == 1) { |
| if (state64 == 0x6A5020200D0A870A) { // JP2 signature box value. |
| if (pc->frame_start_found) { |
| pc->frame_start_found = 0; |
| reset_context(m); |
| return i - 11; |
| } else { |
| pc->frame_start_found = 1; |
| m->ft = jp2_file; |
| } |
| } |
| } |
| m->fheader_read--; |
| } |
| if ((state64 & 0xFFFFFFFF) == 0x0000000C && bytes_read >= 3) { // Indicates start of JP2 file. Check signature next. |
| m->fheader_read = 8; |
| } else if ((state64 & 0xFFFF) == 0xFF4F) { |
| m->in_codestream = 1; |
| if (!pc->frame_start_found) { |
| pc->frame_start_found = 1; |
| m->ft = j2k_cstream; |
| } else if (pc->frame_start_found && m->ft == jp2_file && m->skipped_codestream) { |
| reset_context(m); |
| return i - 1; |
| } |
| } else if ((state64 & 0xFFFF) == 0xFFD9) { |
| if (pc->frame_start_found && m->ft == jp2_file) { |
| m->skipped_codestream = 1; |
| } else if (pc->frame_start_found && m->ft == j2k_cstream) { |
| reset_context(m); |
| return i + 1; // End of frame detected, return frame size. |
| } |
| m->in_codestream = 0; |
| } else if (m->in_codestream) { |
| if ((state64 & 0xFFFF) == 0xFF90) { // Are we in tile part header? |
| m->read_tp = 8; |
| } else if (info_marker((state64 & 0xFFFF0000)>>16) && pc->frame_start_found && (state64 & 0xFFFF)) { |
| // Calculate number of bytes to skip to get to end of the next marker. |
| m->skip_bytes = (state64 & 0xFFFF)-1; |
| |
| // If the next marker is an info marker, skip to the end of of the marker length. |
| if (i + m->skip_bytes + 1 < buf_size) { |
| uint32_t next_state = (buf[i + m->skip_bytes] << 8) | buf[i + m->skip_bytes + 1]; |
| if (info_marker(next_state)) { |
| // Skip an additional 2 bytes to get to the end of the marker length. |
| m->skip_bytes += 2; |
| } |
| } |
| } |
| } |
| } |
| |
| pc->state64 = state64; |
| m->bytes_read = bytes_read; |
| return END_NOT_FOUND; |
| } |
| |
| static int jpeg2000_parse(AVCodecParserContext *s, |
| AVCodecContext *avctx, |
| const uint8_t **poutbuf, int *poutbuf_size, |
| const uint8_t *buf, int buf_size) |
| { |
| JPEG2000ParserContext *m = s->priv_data; |
| ParseContext *pc = &m->pc; |
| int next; |
| |
| if(s->flags & PARSER_FLAG_COMPLETE_FRAMES) { |
| next= buf_size; |
| } else { |
| next= find_frame_end(m, buf, buf_size); |
| |
| if (ff_combine_frame(pc, next, &buf, &buf_size) < 0) { |
| *poutbuf = NULL; |
| *poutbuf_size = 0; |
| return buf_size; |
| } |
| } |
| |
| *poutbuf = buf; |
| *poutbuf_size = buf_size; |
| return next; |
| } |
| |
| const AVCodecParser ff_jpeg2000_parser = { |
| .codec_ids = { AV_CODEC_ID_JPEG2000 }, |
| .priv_data_size = sizeof(JPEG2000ParserContext), |
| .parser_parse = jpeg2000_parse, |
| .parser_close = ff_parse_close, |
| }; |