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MCU1 with HW3 dashcam video. Very bad

Looks like MCU can't keep up with the encoding power needed causing the dropped frames. Can't be the USB write speed if it works fine on 3 unless MCU2 has hardware encoder. Does MCU2 have hardware encoder?

I'm afraid to upgrade to AP3 without doing MCU2 upgrade too because of potentially making my MCU1 slower than it is now.
 

chillaban

Active Member
May 5, 2016
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Bay Area
Looks like MCU can't keep up with the encoding power needed causing the dropped frames. Can't be the USB write speed if it works fine on 3 unless MCU2 has hardware encoder. Does MCU2 have hardware encoder?

I'm afraid to upgrade to AP3 without doing MCU2 upgrade too because of potentially making my MCU1 slower than it is now.
Intel MCUs have much much faster IO especially when it comes to USB compared to the ancient 32-bit ARM platform on the Tegra 3. The Gordon Peak chipset also has Intel QuickSync Video accelerated encoding but I’m not sure if MCU2 re-encodes the video stream.


MCU1 is so strained that I wouldn’t be surprised if dashcam takes last priority.
 

croman

Well-Known Member
Nov 21, 2016
5,296
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Chicago, IL
Actually, my MCU2 clip seems fine? All my clips are like the example. Rear is flawless and in color. Maybe it is the SSD used? I can upload the other ones if you'd like more examples.


EDIT: Watched YouTube clip I uploaded and it is way more compressed than what I viewed on my computer. I'll try to get YouTube to stop making it so lossy compressed but there is no artifacting like I see in other MCU1 FSD computer dashcam clips. My car is AP2 (as you can see).
 
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MorrisonHiker

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Mar 8, 2015
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My dashcam video is the same as above; choppy and pixelated. Must not be an MCU1 but rather original ap2.0 hardware.

Not mine, found it on twitter. Owner reports it was recording onto a high speed usb that was also used with his wife's model 3 and has no issues. MCU1 problem?
It could be related to the eMMC memory going bad in MCU1. My MCU2/AP3 car (upgraded from MCU1/AP2) doesn't have any stuttering.
 
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Looks like MCU can't keep up with the encoding power needed causing the dropped frames. Can't be the USB write speed if it works fine on 3 unless MCU2 has hardware encoder. Does MCU2 have hardware encoder?

I'm afraid to upgrade to AP3 without doing MCU2 upgrade too because of potentially making my MCU1 slower than it is now.
I did with no issue. Not planning on MCU2 upgrade unless my MCU1 fails. The only thing I use MCU for is Navigation, Spotify and Tune in. Performance is perfectly fine. I plan on trying dashcam I'll see how that goes. Can't imagine using MCU for internet or Netflix or games.
 
I recall Tesla noting that the AP3 computer detects significantly more data points than the AP2 (and even the AP2.5) computer. Even though the actual AP computer is supposedly doing all that processing, it still needs to interface with the MCU and is probably taxing the limited resources.

Anecdotally, this is probably why people are saying that the MCU1 is much more sluggish with the AP3 hardware. It's the age-old analogy of a fast thinker who talks really slow.
 

MorrisonHiker

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Mar 8, 2015
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Colorado
Dashcam doesn't use emmc. It writes directly to usb storage
I can imagine that a laggy MCU with failing memory would affect USB write speeds. Something has to control the USB and route data to it.

We have an AP2.5/MCU1 that now has similar poor video quality. This car is showing signs of eMMC failure as well. This car used to be able to record video just fine. We've tried using the same SSD that we use on other vehicles and it still has issues. The same drive in other cars works perfectly.

Our AP3/MCU2 car upgraded from AP2/MCU1 has no problems with video quality.
 

KyleDay

Active Member
Oct 29, 2016
1,529
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AZ
I can imagine that a laggy MCU with failing memory would affect USB write speeds. Something has to control the USB and route data to it.

We have an AP2.5/MCU1 that now has similar poor video quality. This car is showing signs of eMMC failure as well. This car used to be able to record video just fine. We've tried using the same SSD that we use on other vehicles and it still has issues. The same drive in other cars works perfectly.

Our AP3/MCU2 car upgraded from AP2/MCU1 has no problems with video quality.
Certainly mcu1 is over taxed from a cpu load perspective. My point was that dashcam/Sentry doesn't wear out emmc.
 
I have the same problem: the dashcam streams are corrupted.

MCU1 + HW3 in a late 2017 Model S. 2020.48.37.6. Using a 512GB SSD with 375MB/s write speed (benchmarked with BlackMagic). In addition to corrupted streams, drive disconnects at least once a day and I have to unplug-replug USB cable or restart the MCU to get it back online.

Tesla technician just debugged this remotely and concluded that they need to send over a mobile technician to further debug it.

Has anyone been able to resolve this issue without paying for MCU2?
 
Did some more debugging today.

Tested with three different drives:
1) 512GB SSD that I benchmarked to have 375MB/s write speed
2) 64GB SanDisk Ultra USB Stick that I benchmarked to have 90MB/s write speed
3) 400GB SanDisk Ultra microSDXC that I benchmarked to have 22MB/s write speed

Each of them is formatted with two ExFAT partitions - one for Music and another for Dashcam.

Recoding DashCam video with each of them is a hit or miss. When the car is moving, the data rate obviously increases hitting some internal bottleneck and the data stream gets corrupted. Here are frames taken from video saved today to each of the drives.

1) 512GB SSD
SSD test 2021-09-05_16-05-32-left_repeater Still.png

Full video in YouTube (they recompress, so not the original stream)



2) 64GB SanDisk Ultra USB Stick
USB Stick test 2021-09-05_16-15-57-front Still.png

Full video in YouTube (they recompress, so not the original stream)



3) 400GB SanDisk Ultra microSDXC
XCSD test 2021-09-05_16-12-54-right_repeater Still.png

Full video on YouTube (they recompress, so not the original stream)
 
While the car is on, this does not seem to be a problem. But this could be the cause for the drive being unmounted while the car is parked. Leaving a microXCSD (see above) to car tonight to see if this is unmounted as well.

microXCSD did not unmount during the night. Car was charging during the night, so I need to repeat this without car being plugged to wall.
 

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