Changing the default bitrate of Ambarella based cameras using AFT

reverend

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#1
This question comes up a lot so figured I'd do a video example of how easy it is to change the bitrate - sorry @Tobi@s but I wasn't sure how to pronounce your name properly so I keep saying it twice :)

 

CheckYourLights

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#2
File type:Vanilla
Sounds yummy

Thanks for taking the time to go through the steps. Great video
 
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reverend

reverend

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#3
It took about 40 attempts to manage it without swearing. Although I did get a little excited about the picture thread :p
 

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#4
VLC can do screen grabs, if you haven't tried it yet, that are not time limited.
 
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reverend

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#5
I'll have to give that a go thanks mate - these were done in CamStudio which is free but throws a strop at 2GB - supposedly it's quite simple to remux the files together anyway so I may have to give that a go at some point as I've got VLC installed :)
 

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#6
Thanks for the video, reverend.

However, I'm seeing something very different when I open PRI.a7s as you can see below. Is this normal for a Mini 0806 and if so, what does it all mean?

Bitrate.gif
 

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#7
I've done a bit of digging.

It appears that the bitrate table of the 28 Nov 14 firmware and all preceding versions contain logical numbers but the 29 Dec 14 firmware and subsequent versions are a bit squiffy.

Something must have changed.
 

marsu66

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#11
When I try to edit bitratetable, I get error message "BitrateTable not found. Invalid PRI partition or pattern mismatch!"
Hi, I can easely understand that is an old topic and i'm talking about an old cam but i've got the same issue with A5S chipset builded Gopro HD2's firmware (v HD2.08.12.312) dowloadable here
I've tried with AFT 1.3.2 and 1.3.3 and with all 3 options from search pattern unsuccessfully

By the way, this tools from Tobi@s is working fine on my A7 builded cam, the SJCAM 5000+

Any idea or trick ?
 
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marsu66

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#13
Thanks, it works perfectly !!!!
By the way, i have some new questions :

1) how did you get that value ? I've searched for it or for 505FB0 (the same in hexa) in the previous menu, particularly here and here :

2) according to this A5S datasheet it'supporting VBR. I would like to increase the 15 Mbps to 18 (or more) and swap from CBR (1) to VBR (3) but i want to know if someone here has tested and found the "best values" (compatible with hardware, giving goood result).

3) Just for "validating" the process I've done the export of partitions and rom/rf no mod reimport then compilation => Firmware is shrinking from 51 to 15 Mo.... hum, i'm not confident in flashing my gopro with it... Any idea of what i've "lost" ?

Thanks
 
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Falsificator

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Ambarella A2-5-7-12...
#14
1) how did you get that value ?
This is the start address of the bitrate of the table.
These tables all firmware Ambarella identical in structure.
i want to know if someone here has tested and found the "best values"
Constant bitrate is more stable and allows more optimal and predictable result...
 

marsu66

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#15
This is the start address of the bitrate of the table.
These tables all firmware Ambarella identical in structure..
Hum, when I've edited my SJ5000+ Firmware (A7 SoC) I didn't have anything to modify.
By curiosity I've opened it again and use this value.... it doesn't work so....

So, I've translated your post as "identical for Gopro" . For checking that statement, I've edited a HD1 firmware but I was unable to open correctly the PRI file...
Can you please help me to understand what you meant by "indentical in structure" and/or how to/how did you find this value for HD2

Constant bitrate is more stable and allows more optimal and predictable result..
According to me the VBR was allowing a more adaptative response (but you're right you can have some loss).... but whatever, in fact even in VBR it looks more or less like CBR ! :


Last but not least.... any ideo for my 36 Mo missing ?

No one has done modification with Tobi@s' tool on Gopro HD2 ?
 
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Tobi@s

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#17
the custom offset youve entered does not seem to match the offset of the table inside the firmware
 
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#18
the custom offset youve entered does not seem to match the offset of the table inside the firmware
Thank you for the response. Could you provide some further information, what offset should I choose and why? I can't understand how this thing works yet :)
 

Tobi@s

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#19
Does it fail to find the table using search patterns from the drop down on the top left of the window?
 
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#20
Does it fail to find the table using search patterns from the drop down on the top left of the window?
Yes it fails everytime. Tried every possible setting in that drop down menu, get the same error until leaving custom ofset (dec) blank. I could provide a link with software I am trying to play with, its 20160601a_gs90c_a7la70_gps_ZhongXing_ard17_v2508 I found on DaschCamTalk forum and using in my camera :) (Also tried older versions, still same issue.. ) Here is a link of firmware. https://dl.dropboxusercontent.com/u/64768144/firmware.bin
 

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