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-rw-r--r--media/libstagefright/timedtext/TimedTextSRTSource.cpp286
1 files changed, 286 insertions, 0 deletions
diff --git a/media/libstagefright/timedtext/TimedTextSRTSource.cpp b/media/libstagefright/timedtext/TimedTextSRTSource.cpp
new file mode 100644
index 0000000..7b1f7f6
--- /dev/null
+++ b/media/libstagefright/timedtext/TimedTextSRTSource.cpp
@@ -0,0 +1,286 @@
+ /*
+ * Copyright (C) 2012 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.
+ */
+
+//#define LOG_NDEBUG 0
+#define LOG_TAG "TimedTextSRTSource"
+#include <utils/Log.h>
+
+#include <binder/Parcel.h>
+#include <media/stagefright/foundation/ADebug.h> // for CHECK_xx
+#include <media/stagefright/foundation/AString.h>
+#include <media/stagefright/DataSource.h>
+#include <media/stagefright/MediaDefs.h> // for MEDIA_MIMETYPE_xxx
+#include <media/stagefright/MediaErrors.h>
+#include <media/stagefright/MediaSource.h>
+#include <media/stagefright/MetaData.h>
+
+#include "TimedTextSRTSource.h"
+#include "TextDescriptions.h"
+
+namespace android {
+
+TimedTextSRTSource::TimedTextSRTSource(const sp<DataSource>& dataSource)
+ : mSource(dataSource),
+ mMetaData(new MetaData),
+ mIndex(0) {
+}
+
+TimedTextSRTSource::~TimedTextSRTSource() {
+}
+
+status_t TimedTextSRTSource::start() {
+ status_t err = scanFile();
+ if (err != OK) {
+ reset();
+ }
+ // TODO: Need to detect the language, because SRT doesn't give language
+ // information explicitly.
+ mMetaData->setCString(kKeyMediaLanguage, "");
+ return err;
+}
+
+void TimedTextSRTSource::reset() {
+ mMetaData->clear();
+ mTextVector.clear();
+ mIndex = 0;
+}
+
+status_t TimedTextSRTSource::stop() {
+ reset();
+ return OK;
+}
+
+status_t TimedTextSRTSource::read(
+ int64_t *startTimeUs,
+ int64_t *endTimeUs,
+ Parcel *parcel,
+ const MediaSource::ReadOptions *options) {
+ AString text;
+ status_t err = getText(options, &text, startTimeUs, endTimeUs);
+ if (err != OK) {
+ return err;
+ }
+
+ CHECK_GE(*startTimeUs, 0);
+ extractAndAppendLocalDescriptions(*startTimeUs, text, parcel);
+ return OK;
+}
+
+status_t TimedTextSRTSource::scanFile() {
+ off64_t offset = 0;
+ int64_t startTimeUs;
+ bool endOfFile = false;
+
+ while (!endOfFile) {
+ TextInfo info;
+ status_t err = getNextSubtitleInfo(&offset, &startTimeUs, &info);
+ switch (err) {
+ case OK:
+ mTextVector.add(startTimeUs, info);
+ break;
+ case ERROR_END_OF_STREAM:
+ endOfFile = true;
+ break;
+ default:
+ return err;
+ }
+ }
+ if (mTextVector.isEmpty()) {
+ return ERROR_MALFORMED;
+ }
+ return OK;
+}
+
+/* SRT format:
+ * Subtitle number
+ * Start time --> End time
+ * Text of subtitle (one or more lines)
+ * Blank lines
+ *
+ * .srt file example:
+ * 1
+ * 00:00:20,000 --> 00:00:24,400
+ * Altocumulus clouds occr between six thousand
+ *
+ * 2
+ * 00:00:24,600 --> 00:00:27,800
+ * and twenty thousand feet above ground level.
+ */
+status_t TimedTextSRTSource::getNextSubtitleInfo(
+ off64_t *offset, int64_t *startTimeUs, TextInfo *info) {
+ AString data;
+ status_t err;
+
+ // To skip blank lines.
+ do {
+ if ((err = readNextLine(offset, &data)) != OK) {
+ return err;
+ }
+ data.trim();
+ } while (data.empty());
+
+ // Just ignore the first non-blank line which is subtitle sequence number.
+ 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 TimedTextSRTSource::readNextLine(off64_t *offset, AString *data) {
+ data->clear();
+ while (true) {
+ ssize_t readSize;
+ char character;
+ if ((readSize = mSource->readAt(*offset, &character, 1)) < 1) {
+ if (readSize == 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 ((readSize = mSource->readAt(*offset, &character, 1)) < 1) {
+ if (readSize == 0) { // end of the stream
+ return OK;
+ }
+ return ERROR_IO;
+ }
+
+ (*offset)++;
+ if (character != 10) {
+ (*offset)--;
+ }
+ break;
+ }
+ data->append(character);
+ }
+ return OK;
+}
+
+status_t TimedTextSRTSource::getText(
+ const MediaSource::ReadOptions *options,
+ AString *text, int64_t *startTimeUs, int64_t *endTimeUs) {
+ text->clear();
+ int64_t seekTimeUs;
+ MediaSource::ReadOptions::SeekMode mode;
+ if (options != NULL && 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;
+ }
+ }
+ const TextInfo &info = mTextVector.valueAt(mIndex);
+ *startTimeUs = mTextVector.keyAt(mIndex);
+ *endTimeUs = info.endTimeUs;
+ mIndex++;
+
+ char *str = new char[info.textLen];
+ if (mSource->readAt(info.offset, str, info.textLen) < info.textLen) {
+ delete[] str;
+ return ERROR_IO;
+ }
+ text->append(str, info.textLen);
+ delete[] str;
+ return OK;
+}
+
+status_t TimedTextSRTSource::extractAndAppendLocalDescriptions(
+ int64_t timeUs, const AString &text, Parcel *parcel) {
+ const void *data = text.c_str();
+ size_t size = text.size();
+ int32_t flag = TextDescriptions::LOCAL_DESCRIPTIONS |
+ TextDescriptions::OUT_OF_BAND_TEXT_SRT;
+
+ if (size > 0) {
+ return TextDescriptions::getParcelOfDescriptions(
+ (const uint8_t *)data, size, flag, timeUs / 1000, parcel);
+ }
+ return OK;
+}
+
+sp<MetaData> TimedTextSRTSource::getFormat() {
+ return mMetaData;
+}
+
+} // namespace android
generated by cgit v1.1 at 2024-06-08 04:40:36 +0000