Test system and test procedure for determining processing parameters of audio and / or video data

Abstract

Test system for determining at least one processing parameter of audio and / or video data in a mobile device (30) with a test device (10) with - an audio / video unit (11) that outputs audio and / or video data, - a mobile communication unit (12) connected to the audio / video unit (11) of the test device (10), wherein the mobile communication unit (12) is configured to transmit the audio and / or video data via a mobile communication interface (17) to the mobile communication device (30) under test, - a detection unit (13) which is connected via a cable to a decoder (36) in an audio / video unit (31) of the mobile communication device (30) under test and is designed to detect audio and / or video data, and - an analysis unit (14) which is connected to an analysis interface (15) between the audio / video unit (11) of the test device (10) and the mobile communication unit (12) and to the detection unit (13) and which is configured to detect the audio and / or video data at the analysis interface (15) and in the detection unit (13).

Description

[0001] The invention relates to a test system and a method for determining processing parameters, in particular the processing speed, of audio and / or video data in a mobile communication device.

[0002] Modern mobile devices can perform multimedia services, such as video chats, in addition to simple voice calls. Before being deployed in a mobile network, these devices are tested for functionality by both the manufacturer and the mobile network operators.

[0003] Document US 2011 / 0263243A1 provides a system and method for determining the quality of audiovisual services from a mobile phone. In one embodiment, the method includes wirelessly receiving streaming audio-video content on the mobile phone, wherein the audio-video content comprises video content and audio content. The video content consists of a plurality of video frames, each encoded with one or more video symbols. The audio content consists of a plurality of audio segments, each encoded with a sequence of tones. The method further includes outputting the audio content to the mobile phone and displaying the video content to the mobile phone.A computer processes the video symbols of each frame of the displayed video content to determine the video quality, and processes the audio sequences of the output content to determine the audio quality. The computer then outputs the determined audio and video quality.

[0004] Document US 2004 / 0170392A1 concerns a "music video parser" that automatically detects and segments music videos in a combined audio-video media stream. Automatic detection and segmentation are achieved by integrating shot boundary detection, video-text recognition, and audio analysis to automatically identify the temporal boundaries of each music video within the media stream. In one embodiment, information for identifying songs, such as the song title, artist name, album name, etc., is automatically extracted from the media stream using optical character recognition (OCR). In alternative embodiments, this information is then used to catalog, index, and select specific music videos, as well as to compile statistics, such as the times specific music videos were played and the number of times each music video was played.Document EP 2 127 430 B1 describes, by way of example, a test procedure and a test device for testing such modern mobile communication devices with multiple antennas. In this procedure, a test bit sequence is generated in a test device and converted into a test signal according to a specific mobile communication standard and transmitted to the mobile communication device. The mobile communication device receives the test signal and, taking the evaluated test signal into account, generates a response signal and establishes a transmission scheme for sending the response signal back to the test device.

[0005] These tests examine the mobile device's functions necessary for the cellular-specific transmission of signals. In addition to these cellular-specific functions, it is also necessary to test the functionalities for applications such as the generation and reception of audio and / or video data, or audio / video data for short.

[0006] A mobile device can not only play music and videos, but also generate its own audio / video data. This is done, for example, using a camera and a microphone. It is important to measure the processing speed (delay) of the mobile device's internal hardware and software in order to generate digital signals from the analog data. It is also important to know whether the processing speed changes over time. This is also known as jitter. Furthermore, other processing parameters such as packet error rates are also important.

[0007] In previous tests, the time between reading audio / video data from a memory in a test device and playing this audio / video data back on a display of the mobile device is usually measured, whereby, for example, an external camera registers the appearance of the data on the screen and the end time of the transmission is determined from this.

[0008] This has the disadvantage that, on the one hand, additional devices such as a camera are required to determine the end time in the test system. Furthermore, in addition to the functionalities for wireless transmission via the mobile network, the test setup requires further functionalities such as an encoder, a packetizer, and functionalities for segmenting and formatting the data for transmission with a protocol stack. These account for up to 50% of the processing time by the test setup. Therefore, no conclusions can be drawn about the actual processing speed of the audio / video data in the mobile device itself.

[0009] The object of the present invention is therefore to provide a test system and a method with which processing parameters of audio / video data in a mobile device can be determined without measuring processing times outside the mobile device, which are generated in particular by audio / video functions in the test device.

[0010] The problem is solved by the test system according to claim 1 and the method according to claim 8. Advantageous embodiments of the system and the method according to the invention are described in the dependent claims.

[0011] The test system according to the invention for determining processing parameters of audio and / or video data in a mobile communication device, comprising a test device with an audio / video unit that stores audio / video data and outputs it as audio and / or video data. The test device further comprises a mobile communication unit connected to the audio / video unit, wherein the mobile communication unit is configured to transmit the audio and / or video data to the mobile communication device under test via a mobile communication interface, a detection unit connected to the mobile communication device under test and configured to detect audio and / or video data, and an analysis unit connected to an analysis interface between the audio / video unit and the mobile communication unit and to the detection unit.The analysis unit is designed to detect the audio and / or video data at the analysis interface and in the detection unit. Therefore, only the processing parameters in the mobile device are considered; the processing parameters of the audio / video unit in the test device are not included in the measurement.

[0012] It is particularly advantageous if the processing parameter is the processing speed and the analysis unit is designed to determine the processing parameters from the runtime of the audio and / or video data between the first interface and the detection unit.

[0013] This has the advantage that the processing time of the audio / video data in the audio / video unit of the test device, especially the highly variable processing speed of an encoder, is not taken into account in the runtime measurement. The runtime of the data through the mobile communication unit of the test device is known with sufficient accuracy and can be subtracted from the measured runtime with good precision. Thus, the runtime of the data solely through the mobile communication unit can be determined with sufficient accuracy.

[0014] It is particularly advantageous if the analysis unit at the analysis interface measures the audio and / or video data, derives a statistical value from it, and defines the start and / or end time of the measurement when a change in the statistical value occurs. Audio / video data is typically transmitted to the target device using an IP transmission protocol. Data packets of varying sizes and at different time intervals are created, depending on the amount of data to be transmitted. Various statistical values, and especially abrupt changes, can be easily measured by monitoring the data stream after the audio / video unit. Furthermore, audio / video data with a corresponding output of data packets is easy to generate.

[0015] It is particularly advantageous to determine the packet rate and / or packet size as statistical measures. This is especially easy to determine, as only the beginning and / or end of a data packet needs to be recorded.

[0016] It is particularly advantageous if the audio / video unit in the test device generates test data and / or the mobile device acquires and / or outputs test data, and if the test data causes a change in a statistically significant variable. This enables automatic detection of the start and end times of the measurement at the analysis interface, without segmenting the test data or explicitly setting markers within the test data.

[0017] Advantageously, the test data includes video data with at least one transition from a still image to a changing image sequence, especially an image sequence containing noise, or audio data with at least one transition from silence to noise. When transmitting video data, information is typically only generated for the image parts that have changed compared to the previous image. Therefore, when transmitting a still image, i.e., without any changes to the image information within an image sequence, very few data packets are generated, and these packets are also quite small. An image sequence containing noise, e.g., white noise, consists of successive images in which a large number of pixels differ from the previous image. This results in a very large amount of data to be transmitted, and the packet rate and / or packet size increases sharply and abruptly.The same applies to audio data with a transition from silence to noise. Such transitions result in a significant change in the statistical parameters of the packet transmission and are therefore ideally suited as trigger points for measurement.

[0018] Advantageously, the test data is stored in the mobile device in encoded form. Encoded and therefore compressed data has a significantly smaller data volume than uncompressed data and thus requires a much lower read rate from the audio / video unit in the mobile device. This allows even mobile devices with low read rates to be tested and longer audio and / or video sequences to be used.

[0019] It is advantageous if the detection device is connected to a decoder in the mobile device under test, and if the mobile device is configured to forward the audio / video data to its decoder during transmission from the mobile device to the test device, and then simultaneously forward the test data to the detection unit and an encoder in the mobile device after the decoder. This ensures that during an uplink measurement—that is, when data is transmitted from the mobile device to the mobile network or, in this case, to the test device—the transmission of the data via the mobile device's decoder to the detection unit can be recorded, thus registering the start time. Specifically, the start time is measured after the decoder, so its fluctuating processing time is not included in the measurement.The data output to the encoder of the mobile device is forwarded to the test device via the audio / video function of the mobile device, so that the processing time through the entire audio / video processing chain is measured.

[0020] The inventive method for determining at least one processing parameter of audio and / or video data in a mobile communication device, comprising a test device with an audio / video unit, a mobile communication unit, a detection unit, and an analysis unit, comprises, as a first step, the provision and output of audio and / or video data as data packets by the audio / video unit. The data packets are then sent to the mobile communication unit. The audio and / or video data are received and processed in the mobile communication device under test and then detected in the detection unit. Thus, the processing parameters for audio / video data processing in a mobile communication device can be measured independently of an audio / video unit in the test device, which can vary considerably over time. No standardized encoder is required in the test device.

[0021] Exemplary embodiments of the test system according to the invention are shown in the drawings and are explained in more detail below. The drawings show: Fig. 1. A first embodiment of a test system according to the invention in schematic representation; Fig. 2 a diagram of a determined statistical quantity according to the invention, for determining the start or end time; Fig. 3 an embodiment of the method according to the invention for determining a processing parameter during a transmission from the tester to the mobile device; and Fig. 4 An embodiment of the method according to the invention in a schematic representation for the transmission of audio / video data from the mobile phone device to the test device.

[0022] Corresponding parts in all figures are marked with the same reference symbols. Throughout this description, audio and / or video data are also referred to simply as audio / video data.

[0023] Fig. Figure 1 shows a test system according to the invention, comprising a test device 10 and a mobile communication device 30, e.g., a mobile device for user participation in cellular mobile communications, e.g., according to the GSM, EDGE, 3G, or LTE standard. The test device 10 includes an audio / video unit 11 which is connected to a mobile communication unit 12 via an analysis interface 15. The audio / video unit 11 includes all functional units necessary for generating and receiving audio / video data. The mobile communication unit 12 includes all means necessary for transmitting the audio / video data over the air interface 17 of the mobile communication network. An antenna 16 is connected to the mobile communication unit 12, via which the processed data packets are transmitted to the mobile communication device 30 under test. The mobile communication device 30 also has an antenna 37, which is connected to a mobile communication unit 35 of the mobile communication device 30.In the mobile communication device 30, the mobile communication unit 35 is in turn connected to an audio / video unit 31. Alternatively, instead of wireless transmission, the test device and the mobile communication device 20 can be connected via a cable.

[0024] The audio / video data received by the mobile device 30 is received in the mobile unit 35 and forwarded to the audio / video unit 31 of the mobile device 30. There, the audio / video data is processed and, for example, displayed on a screen of the mobile device 30. In parallel or alternatively, the audio / video data is forwarded by a decoder 36 in the audio / video unit 31 to a detection unit 13.

[0025] A detection unit 13 in the test device 10 is connected to a decoder 36 in the audio / video unit 31 of the mobile device 30. The connection is established, for example, via a fixed connection, such as a cable, and is therefore short and time-stable compared to, for example, wireless connections. The detection unit 13 can be an MHL-HDMI (Mobile High-Definition Link / High Definition Multimedia Interface), a VGA (Video Graphics Array) analyzer, or an image sensor. Other detectors are also possible.

[0026] An analysis unit 14 is connected to the detection unit 13 and registers, for example, the time at which an image change is registered in the detection unit 13. This time is referred to as the second time point and defines either the start or end time of a measurement. The analysis unit 14 is also connected to the analysis interface 15. The analysis unit 14 monitors the data stream at the analysis interface 15 and determines a statistical quantity from it. This statistical quantity can be, for example, the packet rate (i.e., the number of packets per unit of time), the data rate (i.e., the amount of data per unit of time), the packet length, or others. A first time point is recorded in the analysis unit 14 when an abrupt change in a statistical quantity is registered. The first time point indicates the start time of a measurement in the downlink, i.e., from the test device 10 to the mobile device 30.The end time of a measurement in the uplink, i.e., from mobile device 30 to test device 10, is recorded. The measurement points for the first and second time points are thus synchronized.

[0027] In Fig. 2 is a diagram showing the determined packet rate plotted over time. At a time <t0 weist die Paketrate einen niedrigen Wert 42 auf, der nach dem Zeitpunkt t0 zu einer hohen Paketrate 41 wechselt. Der Übergang von der niedrigen 42 zu hohen 41 Paketrate beträgt ca. 20 ms und ist durch den minimalen Abstand zwischen zwei Paketen gegeben. Eine solche Flanke 43 bzw. ein solcher Anstieg oder auch Abfall wird durch Video-Daten erzeugt, die beispielsweise einen Wechsel von einem Standbild zu einer Bildfolge mit Rauschen, von einer Bildfolge mit vollkommen schwarzen Bildern auf Rauschen oder auch umgekehrt von einer Bildfolge mit Rauschen zu einem Standbild aufweisen.

[0028] Audio data containing at least one transition from silence to noise or from loud to quiet is also suitable as test data. When there is silence, only a few, mostly short, data packets are generated, whereas when noise begins, the number and / or length of the data packets increases significantly.

[0029] Based on Fig. Section 3 now describes in detail the test system and the procedure for determining the processing speed of audio and / or video data in a mobile device during downlink transmission, i.e., from the test device 10 to the mobile device 30. The audio / video unit 11 of the test device 10 includes a memory 21, which is connected to an encoder 22 and in which test data is stored. The encoder 22 is connected to a packet converter 23, and this in turn is connected to a protocol unit 24.

[0030] At the start of a measurement, the test data in the test device 10 is transferred from memory 21 to encoder 22, which encodes the test data according to a coding procedure. Encoder 22 then forwards the data to packetizer 23, which combines the encoded data into frames. Packer 23 passes the frames to a protocol unit 24, where the frames are segmented and provided with control information according to the selected application and transmission protocol, for example, an RTP / UDP / IP protocol stack. These data packets are then forwarded via the first interface 15 to the cellular unit 12, which prepares the data for transmission on a cellular air interface 28.

[0031] The data is now transmitted from the test device 10 to the mobile communication unit 30 and evaluated in the mobile communication unit 35 of the mobile communication unit 30. The mobile communication unit 35 is connected to the audio / video unit 31, which in turn has an application and transmission protocol unit 34 connected to a packetizing unit 33, which is in turn connected to a decoder 36, which is in turn connected to a display 39. From the mobile communication unit 35, the data is transferred to the audio / video unit 31 and from the protocol unit 34 via the packetizing unit 33 to the decoder 36. The decoded data packets are then either displayed on a display 39 and / or directly from the decoder 36 to the connected detection unit 13 of the test device 10.

[0032] The analysis unit 14 in the test device 10 detects an abrupt change at the first interface 15, for example, in the packet rate, and uses this to identify the start time of the measurement. The analysis unit 14 also registers the arrival of the image change at the detection unit 13 and records this as the end time of the measurement. From this, together with the amount of data transmitted, the transmission speed or processing speed of the audio / video unit 31 of the mobile device 30 can be determined. The processing time in the mobile units 25 of the test device is very short compared to the processing time in, for example, an encoder, and is also very stable over time. It can be determined separately if required and can therefore be calculated from the measured time with good accuracy. The same applies to the processing time of the mobile unit 35 in the mobile device.

[0033] The mobile device 30 typically includes an external interface for outputting received audio / video data, which is used to connect the detection unit 13. Therefore, no internal interface is required in the mobile device 30 for measurement. This makes the method universally applicable, particularly for different mobile communication systems or from different manufacturers.

[0034] The procedure for determining the transmission parameters of audio / video data in a mobile device during an uplink transmission, i.e., from a mobile device 30 to the test facility 10, is described in Fig.Figure 4 illustrates this process. Before the measurement, test data of the content described above is stored on memory 38. The mobile radio 30 is placed in a special test state in which, firstly, the audio / video data from memory 38 is output to a decoder 36, which in turn outputs it to an output of the mobile radio connected to the detection unit 13. Secondly, the decoded audio / video signals are duplicated after the decoder 36 and passed on to an encoder 33 for transmission via the air interface. Most mobile radios already provide this functionality. This allows the audio / video recordings to be viewed during transmission.

[0035] After the encoder 32, the audio / video data is passed from the packetizer 33 to the protocol unit 34 and processed in the mobile communication unit 35 for transmission 29 via the mobile communication air interface. As already mentioned, transmission via a cable can also be used instead of the air interface. In the test device 10, the signals are received and passed from the mobile communication unit 12 to the audio / video unit 24 via the first interface 15.

[0036] The detection unit 13 receives the audio / video signals output by the decoder 36. The connected analysis unit 14 detects the abrupt change in the image sequence and registers the time of the change as the start time for the measurement. The analysis unit 14 monitors the analysis interface 15 and registers the end time of the measurement when the statistical variable changes. The difference between the two measured times is the processing time, in this case in the uplink direction. The unit 22 acts as a decoder in this case.

[0037] Measuring the processing time after decoder 36 has the advantage that the specific design of decoder 36 in the mobile device is not taken into account during the uplink measurement. Thus, only the functionality of the mobile device 30 for transmitting the audio / video data is measured. By measuring the end time at the first interface 5 in the test device 10, decoder-specific processing times, etc., are irrelevant for the measurement. The determined processing time in the mobile device 30 can therefore be tested independently of other influences.

[0038] The mobile device 30 requires only an internal interface, which is connected to the detection unit 13. This interface is already present as an external interface in many mobile devices. If this is not the case, it can be implemented easily.

[0039] Analysis Unit 14 determines various processing parameters of audio / video data in a mobile device, such as the processing speed, also known as delay, and / or the fluctuation of the processing speed. Other parameters are not excluded. The accuracy of the determined parameters is within the range of the measurement accuracy for abrupt changes in the statistical quantity used to determine the start and end times. This is approximately 20 ms, for example, and represents sufficient accuracy for an average transmission duration of 200 ms.

[0040] Advantageously, such a measurement is repeated multiple times to increase the accuracy of the determined processing parameters using statistical methods. For this purpose, test data with repetitive image transitions is used for both the uplink and downlink measurements. This allows a large number of measurements to be performed sequentially and without intervention from test personnel.

[0041] The invention is not limited to the described embodiments. In particular, processing parameters such as packet error rates, packet loss rates, etc., can also be determined. All described and / or illustrated features can be advantageously combined within the scope of the invention.

Claims

[1] Test system for determining at least one processing parameter of audio and / or video data in a mobile device (30) with a test device (10) with - an audio / video unit (11) that outputs audio and / or video data, - a mobile communication unit (12) connected to the audio / video unit (11) of the test device (10), wherein the mobile communication unit (12) is configured to transmit the audio and / or video data via a mobile communication interface (17) to the mobile communication device (30) under test, - a detection unit (13) which is connected via a cable to a decoder (36) in an audio / video unit (31) of the mobile communication device (30) under test and is designed to detect audio and / or video data, and - an analysis unit (14) which is connected to an analysis interface (15) between the audio / video unit (11) of the test device (10) and the mobile communication unit (12) and to the detection unit (13) and which is configured to detect the audio and / or video data at the analysis interface (15) and in the detection unit (13). [2] Test system according to claim 1, characterized by , that the processing parameter is a processing speed and that the analysis unit (14) is designed to determine the processing speed from the runtime of the audio and / or video data between the analysis interface (15) and the detection unit (13). [3] Test system according to claim 1 or 2, characterized by, that the analysis unit (14) at the analysis interface (15) measures the audio and / or video data, determines a statistical value from it and sets a start time and / or an end time of a measurement when a change in the statistical value occurs. [4] Test system according to claim 3, characterized by that the statistical quantity is a packet rate and / or a packet size. [5] Test system according to any one of claims 1 to 4, characterized by , that the audio / video unit (11, 31) in the test device (10) generates test data and / or in the mobile device (30) acquires and / or outputs test data, and the test data causes an abrupt change in the statistical magnitude. [6] Test system according to claim 5, characterized by that the test data includes video data with at least one transition from a still image to a changing sequence of images. [7] Test system according to claim 5 or 6, characterized bythat the test data includes audio data with at least one transition from silence to noise. [8] Method for determining at least one processing parameter of audio and / or video data in a mobile communication device (30) with a test device (10) comprising an audio / video unit (11), a mobile communication unit (12), a detection unit (13) and an analysis unit (14), comprising the following method steps: - Providing and outputting audio and / or video data as data packets through the audio / video unit (11) of the test device (10), - Sending audio and / or video data through the mobile communication unit (12), - Receiving and processing the audio and / or video data in the mobile device under test (30), and - Detecting the processed audio and / or video data in the detection unit (13), which is connected via a cable to a decoder (36) in an audio / video unit (31) of the mobile device (30) under test. [9] Method according to claim 8, characterized by , that the analysis unit (14) determines a first time at which the audio and / or video data pass through an analysis interface (15) between the audio / video unit (11) of the test device (10) and the mobile communication unit (12) and the analysis unit (14) determines a second time at which the audio and / or video data are detected in the detection unit (13). [10] Method according to claim 8 or 9, characterized by , that the audio and / or video data are measured at the analysis interface (15), a statistical quantity is determined from it, and the first time point is determined by a change in the statistical quantity. [11] Method according to claim 10, characterized by that a packet rate and / or a packet size are determined as a statistical measure. [12] Method according to any one of claims 8 to 11, characterized by , that test data are generated by the audio / video unit (11) in the test device (10) and / or are acquired and / or output by the audio / video unit (31) in the mobile device (30) and the test data cause an abrupt change in a statistical quantity. [13] Method according to claim 12, characterized by , that video data with at least one transition from a still image to a changing image sequence is used as test data. [14] Method according to claim 12 or 13, characterized by , that audio data with at least one transition from silence to noise is used as test data.

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