Add new screenrecording winscope meta data
New mp4 track with following meta data:
- Metadata version
- Realtime-to-monotonic time offset
- Monotonic timestamp for each frame
Bug: 235196806
Test: record and view traces + screen recording with winscope
Change-Id: If43e43bc79be960afe9197480c8c311b09111904
diff --git a/cmds/screenrecord/screenrecord.cpp b/cmds/screenrecord/screenrecord.cpp
index b277bed..b1dbb00 100644
--- a/cmds/screenrecord/screenrecord.cpp
+++ b/cmds/screenrecord/screenrecord.cpp
@@ -13,6 +13,9 @@
* See the License for the specific language governing permissions and
* limitations under the License.
*/
+#include <algorithm>
+#include <string_view>
+#include <type_traits>
#include <assert.h>
#include <ctype.h>
@@ -100,7 +103,6 @@
static const uint32_t kFallbackHeight = 720;
static const char* kMimeTypeAvc = "video/avc";
static const char* kMimeTypeApplicationOctetstream = "application/octet-stream";
-static const char* kWinscopeMagicString = "#VV1NSC0PET1ME!#";
// Command-line parameters.
static bool gVerbose = false; // chatty on stdout
@@ -354,14 +356,15 @@
}
/*
- * Writes an unsigned integer byte-by-byte in little endian order regardless
+ * Writes an unsigned/signed integer byte-by-byte in little endian order regardless
* of the platform endianness.
*/
-template <typename UINT>
-static void writeValueLE(UINT value, uint8_t* buffer) {
- for (int i = 0; i < sizeof(UINT); ++i) {
- buffer[i] = static_cast<uint8_t>(value);
- value >>= 8;
+template <typename T>
+static void writeValueLE(T value, uint8_t* buffer) {
+ std::remove_const_t<T> temp = value;
+ for (int i = 0; i < sizeof(T); ++i) {
+ buffer[i] = static_cast<std::uint8_t>(temp & 0xff);
+ temp >>= 8;
}
}
@@ -377,16 +380,18 @@
* - for every frame its presentation time relative to the elapsed realtime clock in microseconds
* (as little endian uint64).
*/
-static status_t writeWinscopeMetadata(const Vector<int64_t>& timestamps,
+static status_t writeWinscopeMetadataLegacy(const Vector<int64_t>& timestamps,
const ssize_t metaTrackIdx, AMediaMuxer *muxer) {
- ALOGV("Writing metadata");
+ static constexpr auto kWinscopeMagicStringLegacy = "#VV1NSC0PET1ME!#";
+
+ ALOGV("Writing winscope metadata legacy");
int64_t systemTimeToElapsedTimeOffsetMicros = (android::elapsedRealtimeNano()
- systemTime(SYSTEM_TIME_MONOTONIC)) / 1000;
sp<ABuffer> buffer = new ABuffer(timestamps.size() * sizeof(int64_t)
- + sizeof(uint32_t) + strlen(kWinscopeMagicString));
+ + sizeof(uint32_t) + strlen(kWinscopeMagicStringLegacy));
uint8_t* pos = buffer->data();
- strcpy(reinterpret_cast<char*>(pos), kWinscopeMagicString);
- pos += strlen(kWinscopeMagicString);
+ strcpy(reinterpret_cast<char*>(pos), kWinscopeMagicStringLegacy);
+ pos += strlen(kWinscopeMagicStringLegacy);
writeValueLE<uint32_t>(timestamps.size(), pos);
pos += sizeof(uint32_t);
for (size_t idx = 0; idx < timestamps.size(); ++idx) {
@@ -395,10 +400,68 @@
pos += sizeof(uint64_t);
}
AMediaCodecBufferInfo bufferInfo = {
- 0,
+ 0 /* offset */,
static_cast<int32_t>(buffer->size()),
- timestamps[0],
- 0
+ timestamps[0] /* presentationTimeUs */,
+ 0 /* flags */
+ };
+ return AMediaMuxer_writeSampleData(muxer, metaTrackIdx, buffer->data(), &bufferInfo);
+}
+
+/*
+ * Saves metadata needed by Winscope to synchronize the screen recording playback with other traces.
+ *
+ * The metadata (version 1) is written as a binary array with the following format:
+ * - winscope magic string (#VV1NSC0PET1ME2#, 16B).
+ * - the metadata version number (4B).
+ * - Realtime-to-monotonic time offset in nanoseconds (8B).
+ * - the recorded frames count (8B)
+ * - for each recorded frame:
+ * - System time in monotonic clock timebase in nanoseconds (8B).
+ *
+ * All numbers are Little Endian encoded.
+ */
+static status_t writeWinscopeMetadata(const Vector<std::int64_t>& timestampsMonotonicUs,
+ const ssize_t metaTrackIdx, AMediaMuxer *muxer) {
+ ALOGV("Writing winscope metadata");
+
+ static constexpr auto kWinscopeMagicString = std::string_view {"#VV1NSC0PET1ME2#"};
+ static constexpr std::uint32_t metadataVersion = 1;
+ const std::int64_t realToMonotonicTimeOffsetNs =
+ systemTime(SYSTEM_TIME_REALTIME) - systemTime(SYSTEM_TIME_MONOTONIC);
+ const std::uint32_t framesCount = static_cast<std::uint32_t>(timestampsMonotonicUs.size());
+
+ sp<ABuffer> buffer = new ABuffer(
+ kWinscopeMagicString.size() +
+ sizeof(decltype(metadataVersion)) +
+ sizeof(decltype(realToMonotonicTimeOffsetNs)) +
+ sizeof(decltype(framesCount)) +
+ framesCount * sizeof(std::uint64_t)
+ );
+ std::uint8_t* pos = buffer->data();
+
+ std::copy(kWinscopeMagicString.cbegin(), kWinscopeMagicString.cend(), pos);
+ pos += kWinscopeMagicString.size();
+
+ writeValueLE(metadataVersion, pos);
+ pos += sizeof(decltype(metadataVersion));
+
+ writeValueLE(realToMonotonicTimeOffsetNs, pos);
+ pos += sizeof(decltype(realToMonotonicTimeOffsetNs));
+
+ writeValueLE(framesCount, pos);
+ pos += sizeof(decltype(framesCount));
+
+ for (const auto timestampMonotonicUs : timestampsMonotonicUs) {
+ writeValueLE<std::uint64_t>(timestampMonotonicUs * 1000, pos);
+ pos += sizeof(std::uint64_t);
+ }
+
+ AMediaCodecBufferInfo bufferInfo = {
+ 0 /* offset */,
+ static_cast<std::int32_t>(buffer->size()),
+ timestampsMonotonicUs[0] /* presentationTimeUs */,
+ 0 /* flags */
};
return AMediaMuxer_writeSampleData(muxer, metaTrackIdx, buffer->data(), &bufferInfo);
}
@@ -418,11 +481,12 @@
static int kTimeout = 250000; // be responsive on signal
status_t err;
ssize_t trackIdx = -1;
+ ssize_t metaLegacyTrackIdx = -1;
ssize_t metaTrackIdx = -1;
uint32_t debugNumFrames = 0;
int64_t startWhenNsec = systemTime(CLOCK_MONOTONIC);
int64_t endWhenNsec = startWhenNsec + seconds_to_nanoseconds(gTimeLimitSec);
- Vector<int64_t> timestamps;
+ Vector<int64_t> timestampsMonotonicUs;
bool firstFrame = true;
assert((rawFp == NULL && muxer != NULL) || (rawFp != NULL && muxer == NULL));
@@ -520,9 +584,9 @@
sp<ABuffer> buffer = new ABuffer(
buffers[bufIndex]->data(), buffers[bufIndex]->size());
AMediaCodecBufferInfo bufferInfo = {
- 0,
+ 0 /* offset */,
static_cast<int32_t>(buffer->size()),
- ptsUsec,
+ ptsUsec /* presentationTimeUs */,
flags
};
err = AMediaMuxer_writeSampleData(muxer, trackIdx, buffer->data(), &bufferInfo);
@@ -532,7 +596,7 @@
return err;
}
if (gOutputFormat == FORMAT_MP4) {
- timestamps.add(ptsUsec);
+ timestampsMonotonicUs.add(ptsUsec);
}
}
debugNumFrames++;
@@ -565,6 +629,7 @@
if (gOutputFormat == FORMAT_MP4) {
AMediaFormat *metaFormat = AMediaFormat_new();
AMediaFormat_setString(metaFormat, AMEDIAFORMAT_KEY_MIME, kMimeTypeApplicationOctetstream);
+ metaLegacyTrackIdx = AMediaMuxer_addTrack(muxer, metaFormat);
metaTrackIdx = AMediaMuxer_addTrack(muxer, metaFormat);
AMediaFormat_delete(metaFormat);
}
@@ -604,10 +669,16 @@
systemTime(CLOCK_MONOTONIC) - startWhenNsec));
fflush(stdout);
}
- if (metaTrackIdx >= 0 && !timestamps.isEmpty()) {
- err = writeWinscopeMetadata(timestamps, metaTrackIdx, muxer);
+ if (metaLegacyTrackIdx >= 0 && metaTrackIdx >= 0 && !timestampsMonotonicUs.isEmpty()) {
+ err = writeWinscopeMetadataLegacy(timestampsMonotonicUs, metaLegacyTrackIdx, muxer);
if (err != NO_ERROR) {
- fprintf(stderr, "Failed writing metadata to muxer (err=%d)\n", err);
+ fprintf(stderr, "Failed writing legacy winscope metadata to muxer (err=%d)\n", err);
+ return err;
+ }
+
+ err = writeWinscopeMetadata(timestampsMonotonicUs, metaTrackIdx, muxer);
+ if (err != NO_ERROR) {
+ fprintf(stderr, "Failed writing winscope metadata to muxer (err=%d)\n", err);
return err;
}
}