4 ms·
It's just bizarre that you would be doing the complete JPEG process at the instant you get the image from the sensor. As you note, there are a plethora of steps
by revelation 13y ago
It's just bizarre that you would be doing the complete JPEG process at the instant you get the image from the sensor. As you note, there are a plethora of steps that JPEG performs, from color space conversion, to DCT transformation (essentially a gigantic matrix multiplication), Huffman coding, quantization, arithmetic coding and encoding as JPEG bitstream.
The only reason would be that you are pressed for memory or bandwidth, but certainly you have the resources to store one full frame and produce deltas, or just apply part of the JPEG chain, enough to remedy memory pressure. You can always encode it to an actual JPEG after the process.
And yes, pulling single frames from a completely encoded video isn't helpful, because they can get away with more compression. But there are very sophisticated algorithms for eliminating the redundancy between frames, which would have been my first avenue in attempting to do something like this.
- jpap 13y agoOh, I actually do both---see the other thread on the topic. I buffer as much as possible, while also encoding on any other cores that are available. There's a reason why a "simple camera app" can total some 80 kLOC. :)
- gruseom 13y agowhich would have been my first avenue in attempting to do something like this. Have you attempted to do something like this? Because he not only has attempted, he's done it. Therefore I think you should stop talking down to him ("completely pointless", "it's just bizarre", "my first avenue"). It comes across as wanting to prove how smart you are instead of seeking to learn from someone who has done incredible work and—lucky for us—is bursting at the seams with enthusiasm to share it. Oh and congratulations jpap on what's looking like the most successful and technically solidest HN launch in quite some time! I hope your hard work pays off.
- eclipxe 13y agoThank you for saying what I'm sure a lot of us were thinking.
- zimpenfish 13y agowild applause
- tptacek 13y agoThis whole thread should be framed and hung in the HN lobby.
- philhippus 13y agoWhy is this comment getting downvoted? I see that it adds insight to the subject and makes some good points, which OP even acknowledges. The written complaint is that revelation is not being deferential enough, which is bullshit on an in-depth technical discussion.
- kelnos 13y agoThere's a difference between "not being deferential" (which I don't think the complaint is) and talking down to someone who's clearly built something very cool. Put another way, there's a difference between dismissing someone's approach and asking questions to try to understand it better.
- gruseom 13y ago"Deferential" has nothing to do with it. In a technical discussion, the focus should be purely on the content. Inserting one's self into it (such as by being supercilious) detracts from that.