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Show HN: Cimbar – File transfer via color barcodes and the Android camera

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Re: Show HN: Cimbar – File transfer via color barcodes and the Android camera

#11

Post by sz3 »

ggerganov wrote: post #9

I tried the browser encoder and here is what it looks like: https://youtu.be/RkpVhW7SuRY Wonder if someone can decode the .mp4 file from the video. It's not rickroll, I promise ;-)

I like the way you think. :)

Though I think 720p is towards the low end of resolutions this'll work on -- the cimbar code itself is 1024x1024, and while there's some wiggle room (hamming distance between the symbols), in my experience it gets pretty iffy below 900x900.

Also... I should probably update the overlay to auto-hide when a file is selected -- it helps a lot to have the full color range.

Re: Show HN: Cimbar – File transfer via color barcodes and the Android camera

#12

Post by ignoramous »

sz3 wrote: post #2

Hello all, You've seen QR codes, maybe Microsoft HCCB [0], maybe jabcode [1] – well, here's a prototype of something new for the pile. :) I saw txqr [2] a while back and was impressed, but also curious about how much throughput was possible with animated bar codes. I may have gotten carried away in my research into the question. cimbar is a single and multi-frame color barcode format using reed solomon (for now) and…

As a possible tangent, convert those images to inaudible audio to transfer files over the air: https://github.com/ganny26/awesome-audioqr

(air-gapped computers be damned)

Re: Show HN: Cimbar – File transfer via color barcodes and the Android camera

#13

Post by sz3 »

ignoramous wrote: post #12
sz3 wrote: post #2

Hello all, You've seen QR codes, maybe Microsoft HCCB [0], maybe jabcode [1] – well, here's a prototype of something new for the pile. :) I saw txqr [2] a while back and was impressed, but also curious about how much throughput was possible with animated bar codes. I may have gotten carried away in my research into the question. cimbar is a single and multi-frame color barcode format using reed solomon (for now) and…

As a possible tangent, convert those images to inaudible audio to transfer files over the air: https://github.com/ganny26/awesome-audioqr (air-gapped computers be damned)

Well, there's diminishing returns in format shifting. The encoded barcode contains various types of quasi-redundant visual information (e.g. error correction codes) to allow decoding to happen, so for audio-based transfer it'd be better to skip the image encode and blast out the file directly.

That said... given the somewhat remarkable way fountain codes work, there's nothing stopping us from having a protocol that uses the audio and the video channels simultaneously for better throughput...

Re: Show HN: Cimbar – File transfer via color barcodes and the Android camera

#14

Post by sz3 »

VikingCoder wrote: post #8

I'm a HUGE fan of air-gap data transfer, and this is very nearly what I want. Curious though, can't you make a web app to record the video, too?

Definitely. I had to draw a line somewhere for an initial "does anyone care about this?" release, so there's some rough edges here.

There are a number of loose ends that I'd like to look into down the road, and more flexibility for different use cases is on the list.

edit: I should mention: the main reason the decoder is a native Android app and not a WebAssembly app is that decoding performance is a throughput bottleneck. I wasn't too eager to pay the wasm tax, when I wasn't sure if even native performance would be good enough. As it happens, I now think decode performance is going to be ok -- but it's still a bit of a weak spot in the scheme.

Re: Show HN: Cimbar – File transfer via color barcodes and the Android camera

#16

Post by ggerganov »

ignoramous wrote: post #12
sz3 wrote: post #2

Hello all, You've seen QR codes, maybe Microsoft HCCB [0], maybe jabcode [1] – well, here's a prototype of something new for the pile. :) I saw txqr [2] a while back and was impressed, but also curious about how much throughput was possible with animated bar codes. I may have gotten carried away in my research into the question. cimbar is a single and multi-frame color barcode format using reed solomon (for now) and…

As a possible tangent, convert those images to inaudible audio to transfer files over the air: https://github.com/ganny26/awesome-audioqr (air-gapped computers be damned)

I don't think air-gapped audio transmission could ever reach a fast and reliable transmission so that it allows transferring files in reasonable amount of time over reasonable transmitter-receiver distances. It's just too many hardware and physical limitations for this approach.

Having said that, I am actually working on a small library for data-over-sound which can be used for small data chunk transmissions across the room [0].

[0] https://github.com/ggerganov/ggwave

Re: Show HN: Cimbar – File transfer via color barcodes and the Android camera

#17

Post by ktpsns »

sz3 wrote: post #2

Hello all, You've seen QR codes, maybe Microsoft HCCB [0], maybe jabcode [1] – well, here's a prototype of something new for the pile. :) I saw txqr [2] a while back and was impressed, but also curious about how much throughput was possible with animated bar codes. I may have gotten carried away in my research into the question. cimbar is a single and multi-frame color barcode format using reed solomon (for now) and…

Amazing! Do you know any variants of these which squeeze out the maximum transfer rate over a high quality connection? Thinking about data transfer from a VPN/RDP remote desktop where I want to grab the screen output on the client with very little loss in quality (basically only limited by the chosen video encoder).

Re: Show HN: Cimbar – File transfer via color barcodes and the Android camera

#18

Post by rmetzler »

sz3 wrote: post #13
ignoramous wrote: post #12

Earlier quoted context omitted.

As a possible tangent, convert those images to inaudible audio to transfer files over the air: https://github.com/ganny26/awesome-audioqr (air-gapped computers be damned)

Well, there's diminishing returns in format shifting. The encoded barcode contains various types of quasi-redundant visual information (e.g. error correction codes) to allow decoding to happen, so for audio-based transfer it'd be better to skip the image encode and blast out the file directly. That said... given the somewhat remarkable way fountain codes work, there's nothing stopping us from having a protocol that u…

Would it be beneficial to use one channel (either audio or visual) to transmit the information and the other one for responses like acknowledge? So kind of like TCP over two different channels?

Re: Show HN: Cimbar – File transfer via color barcodes and the Android camera

#19

Post by sz3 »

rmetzler wrote: post #18
sz3 wrote: post #13

Earlier quoted context omitted.

Well, there's diminishing returns in format shifting. The encoded barcode contains various types of quasi-redundant visual information (e.g. error correction codes) to allow decoding to happen, so for audio-based transfer it'd be better to skip the image encode and blast out the file directly. That said... given the somewhat remarkable way fountain codes work, there's nothing stopping us from having a protocol that u…

Would it be beneficial to use one channel (either audio or visual) to transmit the information and the other one for responses like acknowledge? So kind of like TCP over two different channels?

Well, as for acks specifically -- cimbar itself doesn't really need them, thanks to fountain codes [0].

But I can imagine a reverse (request?) channel being useful, if it had enough bandwidth for the desired application. :)

As /u/ggerganov notes elsewhere in this thread (with some expertise on the audio side -- I can't claim any), the bandwidth of any audio channel is probably going to be pretty bad.

edit: Notwithstanding how viable of an idea it might be, HTTP over audio+video would be pretty neat. :)

[0] https://en.wikipedia.org/wiki/Fountain_code

Re: Show HN: Cimbar – File transfer via color barcodes and the Android camera

#20

Post by cors-fls »

Very interesting but couldn't get it to work with my smartphone. Even with a 250Ko image file, I got bored before it finished ! My camera may be too low quality and/or my monitor too small.

A barcode size parameter may be useful (even though it reduces throughput) so that it is easier to scan on all devices.

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