Transcoder: Preserve source track's bitrate by default.
When no bitrate is passed in the transcoder now preserves the
source track's bitrate. If the bitrate is not available as metadata
the transcoder will sample the source track and estimate the bitrate.
Fixes: 160648740
Test: Unit tests.
Change-Id: I4e0284128aaa1116f5b61d908b52582b2ed3d7e4
diff --git a/media/libmediatranscoding/transcoder/MediaSampleReaderNDK.cpp b/media/libmediatranscoding/transcoder/MediaSampleReaderNDK.cpp
index a0096c7..6a00a10 100644
--- a/media/libmediatranscoding/transcoder/MediaSampleReaderNDK.cpp
+++ b/media/libmediatranscoding/transcoder/MediaSampleReaderNDK.cpp
@@ -21,6 +21,7 @@
#include <media/MediaSampleReaderNDK.h>
#include <algorithm>
+#include <cmath>
#include <vector>
namespace android {
@@ -189,6 +190,78 @@
return AMEDIA_OK;
}
+media_status_t MediaSampleReaderNDK::getEstimatedBitrateForTrack(int trackIndex, int32_t* bitrate) {
+ std::scoped_lock lock(mExtractorMutex);
+ media_status_t status = AMEDIA_OK;
+
+ if (trackIndex < 0 || trackIndex >= mTrackCount) {
+ LOG(ERROR) << "Invalid trackIndex " << trackIndex << " for trackCount " << mTrackCount;
+ return AMEDIA_ERROR_INVALID_PARAMETER;
+ } else if (bitrate == nullptr) {
+ LOG(ERROR) << "bitrate pointer is NULL.";
+ return AMEDIA_ERROR_INVALID_PARAMETER;
+ }
+
+ // Rewind the extractor and sample from the beginning of the file.
+ if (mExtractorSampleIndex > 0) {
+ status = AMediaExtractor_seekTo(mExtractor, 0, AMEDIAEXTRACTOR_SEEK_PREVIOUS_SYNC);
+ if (status != AMEDIA_OK) {
+ LOG(ERROR) << "Unable to reset extractor: " << status;
+ return status;
+ }
+
+ mExtractorTrackIndex = AMediaExtractor_getSampleTrackIndex(mExtractor);
+ mExtractorSampleIndex = 0;
+ }
+
+ // Sample the track.
+ static constexpr int64_t kSamplingDurationUs = 10 * 1000 * 1000; // 10 seconds
+ size_t lastSampleSize = 0;
+ size_t totalSampleSize = 0;
+ int64_t firstSampleTimeUs = 0;
+ int64_t lastSampleTimeUs = 0;
+
+ do {
+ if (mExtractorTrackIndex == trackIndex) {
+ lastSampleTimeUs = AMediaExtractor_getSampleTime(mExtractor);
+ if (totalSampleSize == 0) {
+ firstSampleTimeUs = lastSampleTimeUs;
+ }
+
+ lastSampleSize = AMediaExtractor_getSampleSize(mExtractor);
+ totalSampleSize += lastSampleSize;
+ }
+ } while ((lastSampleTimeUs - firstSampleTimeUs) < kSamplingDurationUs && advanceExtractor_l());
+
+ int64_t durationUs = 0;
+ const int64_t sampledDurationUs = lastSampleTimeUs - firstSampleTimeUs;
+
+ if (sampledDurationUs < kSamplingDurationUs) {
+ // Track is shorter than the sampling duration so use the full track duration to get better
+ // accuracy (i.e. don't skip the last sample).
+ AMediaFormat* trackFormat = getTrackFormat(trackIndex);
+ if (!AMediaFormat_getInt64(trackFormat, AMEDIAFORMAT_KEY_DURATION, &durationUs)) {
+ durationUs = 0;
+ }
+ AMediaFormat_delete(trackFormat);
+ }
+
+ if (durationUs == 0) {
+ // The sampled duration does not account for the last sample's duration so its size should
+ // not be included either.
+ totalSampleSize -= lastSampleSize;
+ durationUs = sampledDurationUs;
+ }
+
+ if (totalSampleSize == 0 || durationUs <= 0) {
+ LOG(ERROR) << "Unable to estimate track bitrate";
+ return AMEDIA_ERROR_MALFORMED;
+ }
+
+ *bitrate = roundf((float)totalSampleSize * 8 * 1000000 / durationUs);
+ return AMEDIA_OK;
+}
+
media_status_t MediaSampleReaderNDK::getSampleInfoForTrack(int trackIndex, MediaSampleInfo* info) {
std::scoped_lock lock(mExtractorMutex);