Some refactoring and added support for another form of vbr headers.
related-to-bug: 3172324
Change-Id: Ic364da09eac7f0a815f9ceb719b6baa8a76e3730
diff --git a/media/libstagefright/VBRISeeker.cpp b/media/libstagefright/VBRISeeker.cpp
new file mode 100644
index 0000000..6608644
--- /dev/null
+++ b/media/libstagefright/VBRISeeker.cpp
@@ -0,0 +1,164 @@
+/*
+ * Copyright (C) 2010 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 "VBRISeeker"
+#include <utils/Log.h>
+
+#include "include/VBRISeeker.h"
+
+#include "include/MP3Extractor.h"
+
+#include <media/stagefright/foundation/ADebug.h>
+#include <media/stagefright/DataSource.h>
+#include <media/stagefright/Utils.h>
+
+namespace android {
+
+static uint32_t U24_AT(const uint8_t *ptr) {
+ return ptr[0] << 16 | ptr[1] << 8 | ptr[2];
+}
+
+// static
+sp<VBRISeeker> VBRISeeker::CreateFromSource(
+ const sp<DataSource> &source, off_t post_id3_pos) {
+ off_t pos = post_id3_pos;
+
+ uint8_t header[4];
+ ssize_t n = source->readAt(pos, header, sizeof(header));
+ if (n < (ssize_t)sizeof(header)) {
+ return NULL;
+ }
+
+ uint32_t tmp = U32_AT(&header[0]);
+ size_t frameSize;
+ int sampleRate;
+ if (!MP3Extractor::get_mp3_frame_size(tmp, &frameSize, &sampleRate)) {
+ return NULL;
+ }
+
+ // VBRI header follows 32 bytes after the header _ends_.
+ pos += sizeof(header) + 32;
+
+ uint8_t vbriHeader[26];
+ n = source->readAt(pos, vbriHeader, sizeof(vbriHeader));
+ if (n < (ssize_t)sizeof(vbriHeader)) {
+ return NULL;
+ }
+
+ if (memcmp(vbriHeader, "VBRI", 4)) {
+ return NULL;
+ }
+
+ size_t numFrames = U32_AT(&vbriHeader[14]);
+
+ int64_t durationUs =
+ numFrames * 1000000ll * (sampleRate >= 32000 ? 1152 : 576) / sampleRate;
+
+ LOGV("duration = %.2f secs", durationUs / 1E6);
+
+ size_t numEntries = U16_AT(&vbriHeader[18]);
+ size_t entrySize = U16_AT(&vbriHeader[22]);
+ size_t scale = U16_AT(&vbriHeader[20]);
+
+ LOGV("%d entries, scale=%d, size_per_entry=%d",
+ numEntries,
+ scale,
+ entrySize);
+
+ size_t totalEntrySize = numEntries * entrySize;
+ uint8_t *buffer = new uint8_t[totalEntrySize];
+
+ n = source->readAt(pos + sizeof(vbriHeader), buffer, totalEntrySize);
+ if (n < (ssize_t)totalEntrySize) {
+ delete[] buffer;
+ buffer = NULL;
+
+ return NULL;
+ }
+
+ sp<VBRISeeker> seeker = new VBRISeeker;
+ seeker->mBasePos = post_id3_pos;
+ seeker->mDurationUs = durationUs;
+
+ off_t offset = post_id3_pos;
+ for (size_t i = 0; i < numEntries; ++i) {
+ uint32_t numBytes;
+ switch (entrySize) {
+ case 1: numBytes = buffer[i]; break;
+ case 2: numBytes = U16_AT(buffer + 2 * i); break;
+ case 3: numBytes = U24_AT(buffer + 3 * i); break;
+ default:
+ {
+ CHECK_EQ(entrySize, 4u);
+ numBytes = U32_AT(buffer + 4 * i); break;
+ }
+ }
+
+ numBytes *= scale;
+
+ seeker->mSegments.push(numBytes);
+
+ LOGV("entry #%d: %d offset 0x%08lx", i, numBytes, offset);
+ offset += numBytes;
+ }
+
+ delete[] buffer;
+ buffer = NULL;
+
+ LOGI("Found VBRI header.");
+
+ return seeker;
+}
+
+VBRISeeker::VBRISeeker()
+ : mDurationUs(-1) {
+}
+
+bool VBRISeeker::getDuration(int64_t *durationUs) {
+ if (mDurationUs < 0) {
+ return false;
+ }
+
+ *durationUs = mDurationUs;
+
+ return true;
+}
+
+bool VBRISeeker::getOffsetForTime(int64_t *timeUs, off_t *pos) {
+ if (mDurationUs < 0) {
+ return false;
+ }
+
+ int64_t segmentDurationUs = mDurationUs / mSegments.size();
+
+ int64_t nowUs = 0;
+ *pos = mBasePos;
+ size_t segmentIndex = 0;
+ while (segmentIndex < mSegments.size() && nowUs < *timeUs) {
+ nowUs += segmentDurationUs;
+ *pos += mSegments.itemAt(segmentIndex++);
+ }
+
+ LOGV("getOffsetForTime %lld us => 0x%08lx", *timeUs, *pos);
+
+ *timeUs = nowUs;
+
+ return true;
+}
+
+} // namespace android
+