Analysis of the quality of budget Chinese DVRs
At the end of last year, I had the task of choosing a model of a budget Chinese DVR worth up to $ 20 in a series of 10 to 100 pieces to equip a fleet of cars. The goal is to record road events and audio installation in cars around the clock. It was necessary to analyze the quality of commercially available products.
The task was extremely clear: you need to find a miniature budget solution for automatic recording of road events. You do not need any "bells and whistles", only audio and video with a quality better than 720p. Operating temperature range -30 ... + 70 Âș. Everything must be configured once and run with the machine. Search start with familiar to all Ali Express. I choose 6 similar in characteristics Chinese models, go out to the manufacturer, I ask for samples. After a while, I get all this stuff in my hands and proceed to advanced testing.
Tests include:
1) external inspection of the device, identifying the advantages and disadvantages;
2) test run "on the table";
3) disassembly of the case, assessment of the build quality
4) check on the operating temperature range in the climate chamber;
5) field tests.
Immediately, I note that most Chinese manufacturers enter the Russian market under several trade names through different suppliers. They specifically develop products so that you can easily and fun change names with the help of additional stickers on the case and packaging. For large batches, there may be some changes in the plastic and software, for example, the application of the name on the case, minor modifications of the functional, etc. Since the purpose of the article is to provide a general overview of the technical parameters of products in the specified price range, the names of manufacturers and models are not indicated. Samples are numbered, however, they can be easily found from many suppliers in the Russian market.
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As test carriers, both conventional micro SD cards and industrial memory cards with an extended operating temperature range of -40 ° C ... + 85 ° C were used to eliminate their effect on the experimental results.
For all samples, the temperature range declared by the manufacturer is -20 ... + 60 Âș. However, in the correspondence I was assured that in the range of -30 ... + 70 Âș everything will work like a clock. Testing was performed in a slightly wider range of -40 ... + 70 Âș. It was interesting to evaluate how Chinese products behave under these conditions. The upper limit was chosen based on technical limitations: all samples use lithium-polymer batteries, which can ignite spontaneously at temperatures above 70 ° C. The testing procedure in the climate chamber is as follows: for one hour, the switched off sample is exposed to the desired temperature with a 3% accuracy. After that start is made. The very fact of starting the recording and the quality of the resulting image is evaluated. As a test image, a printout of gradations of colors on the camera wall was used.
To save time, we launched several pieces at once.
So let's get started.
Visually a good product, the manufacturer promises on the package HD picture quality with a resolution of 1920x1080. However, the package also shows the matrix from OmniVision OV7725 - without thinking twice I find the description on the manufacturerâs website, which clearly says: âarray size: 640x480â. Clear deception. I will add that in the recording settings of the recorder the maximum resolution is honestly indicated 640x480. Does not fit.
I was pleased that the inscription on the box is true. The resolution is 1280x720, externally the recorder looks nice, starts on the table and writes with the desired quality. However, the main flaw was discovered immediately, when unpacking.
It turned out that the fastening on the glass is fixed by a plastic part with weak snaps. Inside there is a spring-loaded metal ball, which fixes the recorder at the right angle. The whole structure is disassembled by lightly turning the corresponding part.
Since the ball is spring-loaded, it flies in an unknown direction. I searched for it for about 2 hours. The design is interesting by design, but terrible in implementation. In the car, when the device vibrates in an hour. Specially left this sample for field tests to evaluate the performance of this engineering masterpiece. After the first act of self-disassembly in the car had to fix the holder with scotch tape. However, look inside.
It's all pretty well. The matrix is ââlocated on a separate module, and yes, it is not deceived that OmniVision OV9712, according to the manual supports 720p. The processor STK2520BLQG also according to the documentation has this mode. The second design flaw came to light also immediately: it turned out that the micro SD slot was located with a certain offset relative to the plastic and was deeply recessed, which made it possible to accidentally shove a memory card inside the case past the slot.
They missed so much that the very first attempt at launch ended with the analysis of the recorder. Next, insert tweezers. Despite such obvious blunders, the registrar writes well, but this is more likely a merit of the processor and matrix. Even tests for the extended temperature range are satisfactory: within -10 ... + 70 Âș the recorder works stably. In the range from -40 Âș to -10 Âș it starts, on average, two times out of three. Closer to 70 Âș artifacts appear in the form of constantly burning dots.
For OV9712 this is normal. The documentation indicates the operating temperature range of -30 ... + 70 Âș, but only in the range of 0 ... + 50 Âș does the matrix give a stable image. In any case, because of the constructive is not suitable.
Inside is not bad.
The matrix is ââthe same OV9712, the processor is slightly different STK3228BLQG, but also quite decent. There are no complaints about the quality of soldering and electronic components.
The main disadvantage is also found literally in the box - this is a ring that provides a mount on the glass.
There is no mechanism for fixing the recorder in one position except the good old friction force; the device in the ring, under the action of the mass of the supply wire, dangles like a hinge. Again, the sample went for further tests out of sheer curiosity. Of the design features worth noting the original use of USB: it is used for data transfer, and for the transfer of analog video signal. In terms of climates, this sample has the best results: in the temperature range -40 ... + 70 Âș, the recorder starts stably, artifacts in the image expectedly appear closer to 70 Âș. Field tests naturally identified the attachment flaws. The construct clearly does not allow the use of this DVR.
The first sample that did not cause serious complaints at the initial examination. The main disadvantage is the cable attachment to the device.
It is seen that the mount is initially dubious. The supplier, however, assured us that this is only a problem of our sample. Plus you can note the original connector with retainer.
For recorders of this class - a rarity. The matrix, as in the previous two samples - OV9712, the processor was processed with some kind of chemistry so carefully that it was not possible to recognize it. The assembly is good, there are no complaints about the electronic part. In general, the design can be called successful. In the climate chamber it was tested the longest as the most promising sample. In the range of -30 ... + 70 Âș work is stable, below -30 Âș start-up problems start: it starts once from three at -35 Âș and does not start at all at -40 Âș. Not bad for a budget Chinese product. In field tests, the quality of the recorded image is average, it is slightly smeared.
Daytime shooting
Evening shooting
Night shooting
Presumably the problem is in focusing. On all the samples presented, the focusing of the lens is fixed with an adhesive once. This is standard practice for such products. The problem is that the quality of the focus can be controlled differently. If the control is weak, then you can get a copy with a blurred image and this can not be corrected. Honestly tried to pick off or dissolve the glue and fix the focus - eventually ruined the sample. Auto-brightness is also average. On the records it is clear that in daylight the quality is more or less; in the evening and at night it is below average. Despite the good design, the DVR is not suitable.
Samples numbered 5 and 6 came without packaging and documentation in one white cardboard box. These were the most inexpensive products. The initial examination showed that they were well assembled, there were no complaints about plastic and components.
However, the very first launch showed that free cheese is expensive: sample number 5 on the table refused to start - a clear marriage. Tester, oscilloscope and tambourine did not help. Sample # 6 was launched, but despite the loud writing on the case, the quality of the recording at 1080p does not look like. The format of the output file corresponds, however, the image is very blurry, the detail is very bad. An analysis of the entrails made it impossible to identify the type of matrix, but visually the image resembles an inferior image with a resolution of no more than 640x480 linearly interpolated to 1920x1080. Another worth noting is the inscription on the buttons and menus in Chinese, but these points are usually correctable. In any case, this product is not suitable.
What are the conclusions? Surely the reader who has reached this place expects to see here a recommendation on the choice of one of the models. It will not happen. Not one of their samples approached me. There was a strong impression that in the Chinese production cycle the cost of developing the device is incommensurable below its elementary testing. It sounds paradoxical, but did someone make electronics, write software, draw constructs and make molds for these recorders? At the same time, out of 6 samples, only one corresponds to the declared characteristics and has no obvious defects, the rest are more similar to deficiencies on an industrial scale. Sad on one side. On the other hand, this once again allows us to dispel the myth that everything in China has long been invented, made, put on stream and sold for three kopecks. For domestic developers of automotive electronics there is another reason to think about. Chinese goods, of course, attract with their price, however, quality things with this approach to production are rarely obtained.
The task was extremely clear: you need to find a miniature budget solution for automatic recording of road events. You do not need any "bells and whistles", only audio and video with a quality better than 720p. Operating temperature range -30 ... + 70 Âș. Everything must be configured once and run with the machine. Search start with familiar to all Ali Express. I choose 6 similar in characteristics Chinese models, go out to the manufacturer, I ask for samples. After a while, I get all this stuff in my hands and proceed to advanced testing.
Tests include:
1) external inspection of the device, identifying the advantages and disadvantages;
2) test run "on the table";
3) disassembly of the case, assessment of the build quality
4) check on the operating temperature range in the climate chamber;
5) field tests.
Immediately, I note that most Chinese manufacturers enter the Russian market under several trade names through different suppliers. They specifically develop products so that you can easily and fun change names with the help of additional stickers on the case and packaging. For large batches, there may be some changes in the plastic and software, for example, the application of the name on the case, minor modifications of the functional, etc. Since the purpose of the article is to provide a general overview of the technical parameters of products in the specified price range, the names of manufacturers and models are not indicated. Samples are numbered, however, they can be easily found from many suppliers in the Russian market.
')
As test carriers, both conventional micro SD cards and industrial memory cards with an extended operating temperature range of -40 ° C ... + 85 ° C were used to eliminate their effect on the experimental results.
For all samples, the temperature range declared by the manufacturer is -20 ... + 60 Âș. However, in the correspondence I was assured that in the range of -30 ... + 70 Âș everything will work like a clock. Testing was performed in a slightly wider range of -40 ... + 70 Âș. It was interesting to evaluate how Chinese products behave under these conditions. The upper limit was chosen based on technical limitations: all samples use lithium-polymer batteries, which can ignite spontaneously at temperatures above 70 ° C. The testing procedure in the climate chamber is as follows: for one hour, the switched off sample is exposed to the desired temperature with a 3% accuracy. After that start is made. The very fact of starting the recording and the quality of the resulting image is evaluated. As a test image, a printout of gradations of colors on the camera wall was used.
To save time, we launched several pieces at once.
So let's get started.
Sample # 1
Visually a good product, the manufacturer promises on the package HD picture quality with a resolution of 1920x1080. However, the package also shows the matrix from OmniVision OV7725 - without thinking twice I find the description on the manufacturerâs website, which clearly says: âarray size: 640x480â. Clear deception. I will add that in the recording settings of the recorder the maximum resolution is honestly indicated 640x480. Does not fit.
Sample number 2
I was pleased that the inscription on the box is true. The resolution is 1280x720, externally the recorder looks nice, starts on the table and writes with the desired quality. However, the main flaw was discovered immediately, when unpacking.
It turned out that the fastening on the glass is fixed by a plastic part with weak snaps. Inside there is a spring-loaded metal ball, which fixes the recorder at the right angle. The whole structure is disassembled by lightly turning the corresponding part.
Since the ball is spring-loaded, it flies in an unknown direction. I searched for it for about 2 hours. The design is interesting by design, but terrible in implementation. In the car, when the device vibrates in an hour. Specially left this sample for field tests to evaluate the performance of this engineering masterpiece. After the first act of self-disassembly in the car had to fix the holder with scotch tape. However, look inside.
It's all pretty well. The matrix is ââlocated on a separate module, and yes, it is not deceived that OmniVision OV9712, according to the manual supports 720p. The processor STK2520BLQG also according to the documentation has this mode. The second design flaw came to light also immediately: it turned out that the micro SD slot was located with a certain offset relative to the plastic and was deeply recessed, which made it possible to accidentally shove a memory card inside the case past the slot.
They missed so much that the very first attempt at launch ended with the analysis of the recorder. Next, insert tweezers. Despite such obvious blunders, the registrar writes well, but this is more likely a merit of the processor and matrix. Even tests for the extended temperature range are satisfactory: within -10 ... + 70 Âș the recorder works stably. In the range from -40 Âș to -10 Âș it starts, on average, two times out of three. Closer to 70 Âș artifacts appear in the form of constantly burning dots.
For OV9712 this is normal. The documentation indicates the operating temperature range of -30 ... + 70 Âș, but only in the range of 0 ... + 50 Âș does the matrix give a stable image. In any case, because of the constructive is not suitable.
Sample number 3
Inside is not bad.
The matrix is ââthe same OV9712, the processor is slightly different STK3228BLQG, but also quite decent. There are no complaints about the quality of soldering and electronic components.
The main disadvantage is also found literally in the box - this is a ring that provides a mount on the glass.
There is no mechanism for fixing the recorder in one position except the good old friction force; the device in the ring, under the action of the mass of the supply wire, dangles like a hinge. Again, the sample went for further tests out of sheer curiosity. Of the design features worth noting the original use of USB: it is used for data transfer, and for the transfer of analog video signal. In terms of climates, this sample has the best results: in the temperature range -40 ... + 70 Âș, the recorder starts stably, artifacts in the image expectedly appear closer to 70 Âș. Field tests naturally identified the attachment flaws. The construct clearly does not allow the use of this DVR.
Sample number 4
The first sample that did not cause serious complaints at the initial examination. The main disadvantage is the cable attachment to the device.
It is seen that the mount is initially dubious. The supplier, however, assured us that this is only a problem of our sample. Plus you can note the original connector with retainer.
For recorders of this class - a rarity. The matrix, as in the previous two samples - OV9712, the processor was processed with some kind of chemistry so carefully that it was not possible to recognize it. The assembly is good, there are no complaints about the electronic part. In general, the design can be called successful. In the climate chamber it was tested the longest as the most promising sample. In the range of -30 ... + 70 Âș work is stable, below -30 Âș start-up problems start: it starts once from three at -35 Âș and does not start at all at -40 Âș. Not bad for a budget Chinese product. In field tests, the quality of the recorded image is average, it is slightly smeared.
Daytime shooting
Evening shooting
Night shooting
Presumably the problem is in focusing. On all the samples presented, the focusing of the lens is fixed with an adhesive once. This is standard practice for such products. The problem is that the quality of the focus can be controlled differently. If the control is weak, then you can get a copy with a blurred image and this can not be corrected. Honestly tried to pick off or dissolve the glue and fix the focus - eventually ruined the sample. Auto-brightness is also average. On the records it is clear that in daylight the quality is more or less; in the evening and at night it is below average. Despite the good design, the DVR is not suitable.
Samples numbered 5 and 6 came without packaging and documentation in one white cardboard box. These were the most inexpensive products. The initial examination showed that they were well assembled, there were no complaints about plastic and components.
Sample # 5
Sample # 6
However, the very first launch showed that free cheese is expensive: sample number 5 on the table refused to start - a clear marriage. Tester, oscilloscope and tambourine did not help. Sample # 6 was launched, but despite the loud writing on the case, the quality of the recording at 1080p does not look like. The format of the output file corresponds, however, the image is very blurry, the detail is very bad. An analysis of the entrails made it impossible to identify the type of matrix, but visually the image resembles an inferior image with a resolution of no more than 640x480 linearly interpolated to 1920x1080. Another worth noting is the inscription on the buttons and menus in Chinese, but these points are usually correctable. In any case, this product is not suitable.
What are the conclusions? Surely the reader who has reached this place expects to see here a recommendation on the choice of one of the models. It will not happen. Not one of their samples approached me. There was a strong impression that in the Chinese production cycle the cost of developing the device is incommensurable below its elementary testing. It sounds paradoxical, but did someone make electronics, write software, draw constructs and make molds for these recorders? At the same time, out of 6 samples, only one corresponds to the declared characteristics and has no obvious defects, the rest are more similar to deficiencies on an industrial scale. Sad on one side. On the other hand, this once again allows us to dispel the myth that everything in China has long been invented, made, put on stream and sold for three kopecks. For domestic developers of automotive electronics there is another reason to think about. Chinese goods, of course, attract with their price, however, quality things with this approach to production are rarely obtained.
Source: https://habr.com/ru/post/375849/
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