What does decoder mean?

A decoder is a hardware/software device that can decode and restore digital video and audio data streams into analog video and audio signals. It is a device that restores information from its encoded form to its original form. Decoders are divided into software decoders, hardware decoders and wireless decoders; the decoders in computers are software decoders, which decode audio and video data through software methods. The corresponding ones are DVD and VCD machines. Belongs to a hardware decoder.

The operating environment of this tutorial: Windows 7 system, Dell G3 computer.

A decoder is a hardware/software device that can decode and restore digital video and audio data streams into analog video and audio signals. It is a device that restores information from its encoded form to its original form. device. Encoders such as mpeg4 for video, mp3, ac3, and dts for audio can compress and store the original data, but these are still commonly used encoding formats, and there are also some professional encoding formats that are basically not used by ordinary families.

In order to play back these videos and audios on home devices or computers, you need to use decoding software, generally called plug-ins. For example, the mpeg4 decoding plug-in ffdshow, the ac3 decoding plug-in ac3filter, etc. Only your computer with various decoding plug-ins installed can play these images and sounds. In terms of multimedia, the encoder mainly compresses the analog video and audio signals into data-encoded files, while the decoder converts the data-encoded files into analog video and audio signals.

The main function of the decoder

1. Reading and clearing fault codes

Some decoders have more detailed descriptions of fault codes, such as whether they are historical fault codes or current fault codes, and how many times the fault code appears. If it is a historical fault code, it means that the fault occurred earlier. It no longer appears, but there is a certain amount of storage memory in the control unit ECU.

2. Actuator action test

The decoder can be used to manually control some actuators, such as fuel injectors, idle motors, etc., to detect whether the actuator is in good condition. Working conditions. For example, when the idle motor is tested while the engine is idling, its opening can be controlled.

3. Oscilloscope function

Because in the data flow function of the decoder, the signals of many sensors and actuators use voltage. Frequency or other values ​​expressed in digital form. During the actual operation of the engine, due to the rapid signal changes, it is difficult to find the problem from these changing numbers. Therefore, you can use the oscilloscope function of the decoder to analyze the electrical Controls the crankshaft sensor signal in the engine system.

Decoder classification

Decoders are divided into software decoders, hardware decoders and wireless decoders

Software decoder

The decoder in the computer is a software decoder, which decodes audio and video data through software methods. Corresponding to this are DVD and VCD players, which are hardware decoders. Usually, if a computer wants to play a video in a certain format, it needs a decoder that supports the video encoding, and the video decoder comes into being. RM/RMVB Real Media decoder MOV Quick Time decoder 3GP/MP4 decoder DVD/VOB decoder Divx decoder xvid decoder WMV decoder

Hardware decoder

The decoder exists because audio and video data must be compressed first, otherwise the amount of data will be too large, and compression requires certain encoding to store the highest quality audio and video data with the smallest capacity. Therefore, when you need to play the data, you must first decode it through a decoder. The digital encoding formats that can be decoded include AC-3, HDCD, DTS, etc. These are multi-channel audio and video encoding formats. If you want to achieve a high-fidelity level, there is two-channel PCM digital encoding. Therefore, when choosing a hardware decoder, you should pay attention to whether the software supports these formats. And check and update the required software in a timely manner.

Wireless decoder

The wireless decoder has a certain operating frequency bandwidth under the specified distortion and rated output power conditions, that is, the lowest operating frequency of the wireless decoder There is a range between the highest operating frequency. The actual operating frequency range of the wireless decoder may be greater than the defined operating frequency range.

Notes on using the decoder

1. Connection of the decoder to the gimbal and lens Don't make the line too long. Because the voltage that controls the lens is about 12 volts DC, if the transmission is too far, the voltage drop will be too large, which will cause the lens to be unable to be controlled. In addition, since multi-core control cables are more expensive than shielded twisted pairs, the cost will also increase.

2. The outdoor decoder must be waterproofed. It is a good method to seal the cable inlet with waterproof glue, and it is easy to operate.

3. Shielded twisted pairs are usually used from the host to the decoder. Multiple decoders can be connected in parallel on one line, with the total length not exceeding 1500 meters (depending on the site conditions). If the number of decoders is too large, it is necessary to add some auxiliary equipment, such as adding a control code distributor or connecting a matching resistor in parallel to the last decoder.

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