Read Data From ADTF DAT Files

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This example shows how to read data from ADTF DAT files usingadtfFileReaderandadtfStreamReader对象。

To read the data, you first create anadtfFileReaderobject that will act as a file handler object for the DAT file. This object gives useful information about the streams present in the DAT file and its contents. Following are the three main ways you can create anadtfFileReaderobject:

Using DAT file only: Applies to image and video stream data
Using DAT file and DDL description file: Applies to structured data
使用ADTF插件，给定DAT文件和DDL说明文件: Applies to data which requires some ADTF plugins

Next, you select the data to be read from the DAT file, which creates anadtfStreamReader目的。然后，您可以使用此对象读取数据。以下是您可以读取数据的一些常见方法：

The data you read from the DAT file will be present in the MATLAB workspace, in raw form.

Create`adtfFileReader`目的

Using DAT file only

Create anadtfFileReaderobject by specifying ADTF DAT file name as the only argument to create the file reader object, to read data from streams like images and videos.

datfileName = fullfile（“C：”,“数据”,"sample_can_video.dat"）；fileReader = adtfFileReader(datFileName)％＃好的

fileReader = DataFileName: "C:\data\sample_can_video.dat" DescriptionFileName: "" PluginDirectory: "" StreamCount: 2 StreamInfo: StreamIndex StreamName StreamType StartTime EndTime ItemCount ___________ __________ _______________ _________ __________ _________ 1 {'rawcan'} {'UNSUPPORTED'} 0 sec 14.805 sec 743 2 {'video' } {'adtf/image' } 0 sec 14.799 sec 149

From theStreamInfoproperty, note that

Stream 1 is named 'RAWCAN'。它包含743个数据项，范围从0到14.805秒。但是，此流不支持阅读为“万博1manbetx流类型' 是 '不支万博1manbetx持'。To read such streams, we might need to some additional ADTF plugins, as explainedhere.
Stream 2 is named ‘视频’。它是一个 'adtf/image' stream, which is a common ADTF stream type for video and image streams. It contains 149 image frames, recorded over an interval of 14.799 seconds.

Using DAT file and DDL description file

Some DAT files contain structured data (for example, CAN data). To read such data into MATLAB workspace, you need a DDL description file containing details about the structure of the data within the streams. Specify the name of the DDL description file as an additional argument while creating anadtfFileReader目的。Note that the DAT filesample_can.adtfdatcontains dummy data and is used for demonstration purposes only.

datfileName = fullfile（“C：”,“数据”,"sample_can.adtfdat"）；ddlfilename = fullfile（“C：”,“数据”,"sample_can.description"）；filereader = adtffilereader（datfileName，ddlfileName）％＃好的

fileReader = DataFileName: "C:\data\sample_can.adtfdat" DescriptionFileName: "C:\data\sample_can.description" PluginDirectory: "" StreamCount: 1 StreamInfo: StreamIndex StreamName StreamType StartTime EndTime ItemCount ___________ __________ _________________ _________ ________ _________ 1 rawcan adtf/devicetb/can 0 sec 0.98 sec 99

Note that the above output shows a different stream type, 'adtf/devicetb/can',对于罐头，与'不支万博1manbetx持'流类型在上一节中。这是因为样本_can.adtfdatis in ADTF 3.0 format file whereas sample_CAN_VIDEO.DAT是ADTF 2.0格式文件。对于2.0格式，可能需要其他插件来读取数据。

Use ADTF Plugins, Given a DAT File and DDL Description File

An ADTF Plugin is a compiled object that provides aditional functionality to ADTF Runtime. They are very specific to ADTF framework and you can read more about themhere.

In certain cases, ADTF Plugins are necessary to read data from streams. For such cases, specify the path to the folder storing the plugins as an additional argument while creating anadtfFileReader目的。Replace the value of插件文件夹带有包含插件的系统上的路径的变量。

datfileName = fullfile（“C：”,“数据”,"sample_can_video.dat"）；ddlfilename = fullfile（“C：”,“数据”,"sample_can_video.description"）；插件文件夹= fullfile(“C：”,“插件”）；fileReader = adtfFileReader(datFileName, ddlFileName, pluginFolder)％＃好的

fileReader = DataFileName: "C:\data\sample_can_video.dat" DescriptionFileName: "C:\data\sample_can_video.description" PluginDirectory: "C:\pluginFolder" StreamCount: 2 StreamInfo: StreamIndex StreamName StreamType StartTime EndTime ItemCount ___________ __________ _____________________ _________ ___________________ 1 {'rawcan'} {'adtf/devicetb/can'} 0 sec 14.805 sec 743 2 {'video'} {'adtf/image'} 0 sec 14.799 sec 149

请注意，每个操作系统都有不同版本的同一插件。如果需要插件在DAT文件中读取流，并且您不指定其路径，则流类型value for those will be‘不支万博1manbetx持’。

Select and Read Data

从单流读取数据

创建adtfFileReader目的。Note that the DAT filesample_struct.datcontains dummy data and is used for demonstration purposes only.

datfileName = fullfile（“C：”,“数据”,“ sample_struct.dat”）；ddlfilename = fullfile（“C：”,“数据”,"sample_struct.description"）；filereader = adtffilereader（datfileName，ddlfileName）

fileReader = DataFileName: "C:\data\sample_struct.dat" DescriptionFileName: "C:\data\sample_struct.description" PluginDirectory: "" StreamCount: 2 StreamInfo: StreamIndex StreamName StreamType StartTime EndTime ItemCount ___________ ________________ ________________ _________ ________ _________ 1 {'firststream'} {'adtf2/legacy'} 0.09 sec 1.07 sec 99 2 {'secondstream'} {'adtf2/legacy'} 0.09 sec 0.98 sec 90

Select the stream to be read by specifying their stream index.

streamReader = select(fileReader, 1);

Read the first item in the selected stream.

item = readNext(streamReader)

item =带有字段的结构：StreamIndex：1数据：[1×1结构]

In the structure,数据项,'StreamIndex”字段显示了选定的流指数和“Data'字段包含带有时间戳（以微秒为单位）的实际数据项，将这些数据记录到DAT文件中。

％显示时间戳fprintf(“时间戳=％d \ n”，item.data.timestamp）;

时间戳= 90000

% Display datadisp（item.data.item）

信号1：[1×1 struct] Signal2：[2×1 double] Signal1：[1×1 struct] Signal2：[2×1 double]

你也可以在遍历所有的数据项e selected stream.

% Read one item at a time尽管hasnext(streamReader) item = readNext(streamReader);% Process data结尾

Alternatively, you can read all data items at once and iterate over it later.

% Read everythin at onceitems = read(streamReader);％迭代数据为了i=1:streamReader.DataCount timestamp = items.Data(i).Timestamp; data = items.Data(i).Item;% Process data结尾

Read Data with`TimeRange`and`索引`过滤器

创建adtfFileReader目的。

datfileName = fullfile（“C：”,“数据”,"sample_can.adtfdat"）；ddlfilename = fullfile（“C：”,“数据”,"sample_can.description"）；filereader = adtffilereader（datfileName，ddlfileName）

fileReader = DataFileName: "C:\data\sample_can.adtfdat" DescriptionFileName: "C:\data\sample_can.description" PluginDirectory: "" StreamCount: 1 StreamInfo: StreamIndex StreamName StreamType StartTime EndTime ItemCount ___________ __________ _________________ _________ ________ _________ 1 rawcan adtf/devicetb/can 0 sec 0.98 sec 99

Use the name-value argument,索引, in the选择function to filter the search to the last 10 data items in the selected stream.

StreamIndex = 1;startIndex = filereader.streaminfo（StreamIndex）.Itemcount -9;％的％第10元素索引结尾Index = fileReader.StreamInfo(streamIndex).ItemCount;% last indexstreamReader = select(fileReader, streamIndex, IndexRange=[startIndex endIndex]);％＃好的

Use the name-value argument,TimeRange, to filter the search to all the data items recorded between 1 to 2 seconds, across the selected streams.

starttime =秒（0.1）;末日=秒（0.2）;streamReader = select（fileReader，timerange = [starttime endtime]）;％＃好的

INFO : All streams are selected.

接下来，您可以使用该项目使用读Nextandhasnextfunctions, or read all items at once using读Nextfunction. See从单流读取数据section了解更多信息。

Reading multiple streams

创建adtfFileReader目的。

datfileName = fullfile（“C：”,“数据”,“ sample_struct.dat”）；ddlfilename = fullfile（“C：”,“数据”,"sample_struct.description"）；filereader = adtffilereader（datfileName，ddlfileName）

fileReader = DataFileName: "C:\data\sample_struct.dat" DescriptionFileName: "C:\data\sample_struct.description" PluginDirectory: "" StreamCount: 2 StreamInfo: StreamIndex StreamName StreamType StartTime EndTime ItemCount ___________ ________________ ________________ _________ ________ _________ 1 {'firststream'} {'adtf2/legacy'} 0.09 sec 1.07 sec 99 2 {'secondstream'} {'adtf2/legacy'} 0.09 sec 0.98 sec 90

您可以通过指定其流索引来选择流。要默认选择所有流，请勿指定任何流索引。

While reading data from multiple streams simultaneously, it is possible that there are unequal number of data items across different streams. To illustrate, perform the following selection.

firstStreamIndex = 1; secondStreamIndex = 2; startTime = seconds(0.98); endTime = seconds(2.0); streamReader = select(fileReader, [firstStreamIndex, secondStreamIndex], TimeRange=[startTime endTime]); fprintf("Number of elements in stream 1 = %d\n"，streamReader.dataCount（firstStreamIndex））;

流1 = 10中的元素数量

fprintf(“流2 =％d \ n中的元素数”，streamReader.dataCount（secondstreamIndex））;

流2 = 1中的元素数量

请注意，第一流有10个项目，第二个流只有1个项目。如果您立即读取所有数据项读function, then stream 1 will return an array of 10 structures, and stream 2 will return a single structure.

allData = read(streamReader)

alldata =带有字段的2×1结构数组：StreamIndex Data

当您逐一阅读数据时，在第一次呼叫中读Next,您会根据预期获得每个流的一个结构。

data1 = readNext(streamReader)

data1 =带有字段的2×1结构数组：StreamIndex Data

In the next call to读Next，我们只获得流1的项目。

data2 = readnext（streamReader）

data2 =带有字段的结构：StreamIndex：1数据：[1×1结构]

请注意，尽管其中一条流已经达到了选择的结尾，但是读Nextstill returns the data items from the remaining streams. Similarly, thehasnext功能将返回true即使选择中的一个流也可以读取数据。

hasnext(streamReader)

ans =logical1