Merge "ExternalCameraHAL: Get old image if taking picture without preview" into main (70c35c39) · Commits · e / os / android_hardware_interfaces

camera/device/default/ExternalCameraDeviceSession.cpp

+61 −29

Original line number	Diff line number	Diff line
		@@ -1136,6 +1136,11 @@ int ExternalCameraDeviceSession::configureV4l2StreamLocked(const SupportedV4L2Fo

		uint32_t v4lBufferCount = (fps >= kDefaultFps) ? mCfg.numVideoBuffers : mCfg.numStillBuffers;

		// Double the max lag in theory.
		mMaxLagNs = v4lBufferCount * 1000000000LL * 2 / fps;
		ALOGI("%s: set mMaxLagNs to %" PRIu64 " ns, v4lBufferCount %u", __FUNCTION__, mMaxLagNs,
		v4lBufferCount);

		// VIDIOC_REQBUFS: create buffers
		v4l2_requestbuffers req_buffers{};
		req_buffers.type = V4L2_BUF_TYPE_VIDEO_CAPTURE;
		@@ -1232,8 +1237,10 @@ std::unique_ptr<V4L2Frame> ExternalCameraDeviceSession::dequeueV4l2FrameLocked(n
		}
		}

		ATRACE_BEGIN("VIDIOC_DQBUF");
		uint64_t lagNs = 0;
		v4l2_buffer buffer{};
		do {
		ATRACE_BEGIN("VIDIOC_DQBUF");
		buffer.type = V4L2_BUF_TYPE_VIDEO_CAPTURE;
		buffer.memory = V4L2_MEMORY_MMAP;
		if (TEMP_FAILURE_RETRY(ioctl(mV4l2Fd.get(), VIDIOC_DQBUF, &buffer)) < 0) {
		@@ -1258,14 +1265,39 @@ std::unique_ptr<V4L2Frame> ExternalCameraDeviceSession::dequeueV4l2FrameLocked(n
		return ret;
		}

		nsecs_t curTimeNs = systemTime(SYSTEM_TIME_MONOTONIC);

		if (buffer.flags & V4L2_BUF_FLAG_TIMESTAMP_MONOTONIC) {
		// Ideally we should also check for V4L2_BUF_FLAG_TSTAMP_SRC_SOE, but
		// even V4L2_BUF_FLAG_TSTAMP_SRC_EOF is better than capture a timestamp now
		shutterTs = static_cast<nsecs_t>(buffer.timestamp.tv_sec) 1000000000LL +
		buffer.timestamp.tv_usec * 1000LL;
		} else {
		*shutterTs = systemTime(SYSTEM_TIME_MONOTONIC);
		*shutterTs = curTimeNs;
		}

		// The tactic only takes effect on v4l2 buffers with flag V4L2_BUF_FLAG_TIMESTAMP_MONOTONIC.
		// Most USB cameras should have the feature.
		if (curTimeNs < *shutterTs) {
		lagNs = 0;
		ALOGW("%s: should not happen, the monotonic clock has issue, shutterTs is in the "
		"future, curTimeNs %" PRId64 " < "
		"shutterTs %" PRId64 "",
		__func__, curTimeNs, *shutterTs);
		} else {
		lagNs = curTimeNs - *shutterTs;
		}

		if (lagNs > mMaxLagNs) {
		ALOGI("%s: drop too old buffer, index %d, lag %" PRIu64 " ns > max %" PRIu64 " ns", __FUNCTION__,
		buffer.index, lagNs, mMaxLagNs);
		int retVal = ioctl(mV4l2Fd.get(), VIDIOC_QBUF, &buffer);
		if (retVal) {
		ALOGE("%s: unexpected VIDIOC_QBUF failed, retVal %d", __FUNCTION__, retVal);
		return ret;
		}
		}
		} while (lagNs > mMaxLagNs);

		{
		std::lock_guard<std::mutex> lk(mV4l2BufferLock);

camera/device/default/ExternalCameraDeviceSession.h

+3 −0

Original line number	Diff line number	Diff line
		@@ -382,6 +382,9 @@ class ExternalCameraDeviceSession : public BnCameraDeviceSession, public OutputT
		std::string mExifMake;
		std::string mExifModel;
		/* End of members not changed after initialize() */

		// The max tolerant lag between the dequeued v4l2 buffer and current capture request.
		uint64_t mMaxLagNs;
		};

		} // namespace implementation