diff options
Diffstat (limited to 'media/libstagefright/timedtext/TimedTextParser.cpp')
| -rw-r--r-- | media/libstagefright/timedtext/TimedTextParser.cpp | 257 |
1 files changed, 257 insertions, 0 deletions
diff --git a/media/libstagefright/timedtext/TimedTextParser.cpp b/media/libstagefright/timedtext/TimedTextParser.cpp new file mode 100644 index 0000000..0bada16 --- /dev/null +++ b/media/libstagefright/timedtext/TimedTextParser.cpp @@ -0,0 +1,257 @@ +/* + * Copyright (C) 2011 The Android Open Source Project + * + * Licensed under the Apache License, Version 2.0 (the "License"); + * you may not use this file except in compliance with the License. + * You may obtain a copy of the License at + * + * http://www.apache.org/licenses/LICENSE-2.0 + * + * Unless required by applicable law or agreed to in writing, software + * distributed under the License is distributed on an "AS IS" BASIS, + * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. + * See the License for the specific language governing permissions and + * limitations under the License. + */ + +#include "TimedTextParser.h" +#include <media/stagefright/DataSource.h> + +namespace android { + +TimedTextParser::TimedTextParser() + : mDataSource(NULL), + mOffset(0), + mIndex(0) { +} + +TimedTextParser::~TimedTextParser() { + reset(); +} + +status_t TimedTextParser::init( + const sp<DataSource> &dataSource, FileType fileType) { + mDataSource = dataSource; + mFileType = fileType; + + status_t err; + if ((err = scanFile()) != OK) { + reset(); + return err; + } + + return OK; +} + +void TimedTextParser::reset() { + mDataSource.clear(); + mTextVector.clear(); + mOffset = 0; + mIndex = 0; +} + +// scan the text file to get start/stop time and the +// offset of each piece of text content +status_t TimedTextParser::scanFile() { + if (mFileType != OUT_OF_BAND_FILE_SRT) { + return ERROR_UNSUPPORTED; + } + + off64_t offset = 0; + int64_t startTimeUs; + bool endOfFile = false; + + while (!endOfFile) { + TextInfo info; + status_t err = getNextInSrtFileFormat(&offset, &startTimeUs, &info); + + if (err != OK) { + if (err == ERROR_END_OF_STREAM) { + endOfFile = true; + } else { + return err; + } + } else { + mTextVector.add(startTimeUs, info); + } + } + + if (mTextVector.isEmpty()) { + return ERROR_MALFORMED; + } + return OK; +} + +// read one line started from *offset and store it into data. +status_t TimedTextParser::readNextLine(off64_t *offset, AString *data) { + char character; + + data->clear(); + + while (true) { + ssize_t err; + if ((err = mDataSource->readAt(*offset, &character, 1)) < 1) { + if (err == 0) { + return ERROR_END_OF_STREAM; + } + return ERROR_IO; + } + + (*offset) ++; + + // a line could end with CR, LF or CR + LF + if (character == 10) { + break; + } else if (character == 13) { + if ((err = mDataSource->readAt(*offset, &character, 1)) < 1) { + if (err == 0) { // end of the stream + return OK; + } + return ERROR_IO; + } + + (*offset) ++; + + if (character != 10) { + (*offset) --; + } + break; + } + + data->append(character); + } + + return OK; +} + +/* SRT format: + * Subtitle number + * Start time --> End time + * Text of subtitle (one or more lines) + * Blank line + * + * .srt file example: + * 1 + * 00:00:20,000 --> 00:00:24,400 + * Altocumulus clouds occur between six thousand + * + * 2 + * 00:00:24,600 --> 00:00:27,800 + * and twenty thousand feet above ground level. + */ +status_t TimedTextParser::getNextInSrtFileFormat( + off64_t *offset, int64_t *startTimeUs, TextInfo *info) { + AString data; + status_t err; + if ((err = readNextLine(offset, &data)) != OK) { + return err; + } + + // to skip the first line + if ((err = readNextLine(offset, &data)) != OK) { + return err; + } + + int hour1, hour2, min1, min2, sec1, sec2, msec1, msec2; + // the start time format is: hours:minutes:seconds,milliseconds + // 00:00:24,600 --> 00:00:27,800 + if (sscanf(data.c_str(), "%02d:%02d:%02d,%03d --> %02d:%02d:%02d,%03d", + &hour1, &min1, &sec1, &msec1, &hour2, &min2, &sec2, &msec2) != 8) { + return ERROR_MALFORMED; + } + + *startTimeUs = ((hour1 * 3600 + min1 * 60 + sec1) * 1000 + msec1) * 1000ll; + info->endTimeUs = ((hour2 * 3600 + min2 * 60 + sec2) * 1000 + msec2) * 1000ll; + if (info->endTimeUs <= *startTimeUs) { + return ERROR_MALFORMED; + } + + info->offset = *offset; + + bool needMoreData = true; + while (needMoreData) { + if ((err = readNextLine(offset, &data)) != OK) { + if (err == ERROR_END_OF_STREAM) { + needMoreData = false; + } else { + return err; + } + } + + if (needMoreData) { + data.trim(); + if (data.empty()) { + // it's an empty line used to separate two subtitles + needMoreData = false; + } + } + } + + info->textLen = *offset - info->offset; + + return OK; +} + +status_t TimedTextParser::getText( + AString *text, int64_t *startTimeUs, int64_t *endTimeUs, + const MediaSource::ReadOptions *options) { + Mutex::Autolock autoLock(mLock); + + text->clear(); + + int64_t seekTimeUs; + MediaSource::ReadOptions::SeekMode mode; + if (options && options->getSeekTo(&seekTimeUs, &mode)) { + int64_t lastEndTimeUs = mTextVector.valueAt(mTextVector.size() - 1).endTimeUs; + int64_t firstStartTimeUs = mTextVector.keyAt(0); + + if (seekTimeUs < 0 || seekTimeUs > lastEndTimeUs) { + return ERROR_OUT_OF_RANGE; + } else if (seekTimeUs < firstStartTimeUs) { + mIndex = 0; + } else { + // binary search + ssize_t low = 0; + ssize_t high = mTextVector.size() - 1; + ssize_t mid = 0; + int64_t currTimeUs; + + while (low <= high) { + mid = low + (high - low)/2; + currTimeUs = mTextVector.keyAt(mid); + const int diff = currTimeUs - seekTimeUs; + + if (diff == 0) { + break; + } else if (diff < 0) { + low = mid + 1; + } else { + if ((high == mid + 1) + && (seekTimeUs < mTextVector.keyAt(high))) { + break; + } + high = mid - 1; + } + } + + mIndex = mid; + } + } + + TextInfo info = mTextVector.valueAt(mIndex); + *startTimeUs = mTextVector.keyAt(mIndex); + *endTimeUs = info.endTimeUs; + mIndex ++; + + char *str = new char[info.textLen]; + if (mDataSource->readAt(info.offset, str, info.textLen) < info.textLen) { + delete[] str; + return ERROR_IO; + } + + text->append(str, info.textLen); + delete[] str; + return OK; +} + +} // namespace android |