Hardware vs Software & Digital Video - Computerphile

RISC processors kept things simple, but when do you need to make your hardware more complicated and when can you leave it to the software? We asked ARM's Jem Davies.

Note: At 4min 12secs the graphic says 'nearly 1GB' when it should say 'nearly 10GB'

This video was filmed and edited by Sean Riley.

[DrRChandra]

Periodically, instead of sending frame deltas, the entire frame is sent...called a keyframe. This is so an interruption or corruption of the data stream can have the decoder recover. If keyframes weren't sent, once one glitch happens, it'd be virtually impossible to have anything intelligible on the screen. This also makes it possible to join a stream in the middle; just look for a keyframe and start with that.

[SharpblueCreative]

I've been trying to explain this to friends for some time. So elegantly put here. I couldn't get it across even when I said only the bits that move are transmitted. So I'll share this video. Thank you.

[kenmas]

Awesome vid! I would love to see one explaining the perceptual coding techniques behind the MP3 i.e taking out the frequencies that you wouldn't hear anyway to make the file smaller.

[feastures]

This man is amazing. Would love to see more interviews with him.

[IstasPumaNevada]

Very interesting video, as usual. Thanks for all the great topics.

[thefidgetspinnerofdoom]

So it basically becomes a question whether the processing power of the new hardware outweighs the expense of developing said specialized hardware? Great video, as always!

[rentAscout]

Speaking of brains picking up on random information. Jem is missing the tip of his finger. Those sort of things have good stories.

[lowlypawn]

I like the info on video compression but I wish it was more in depth. I would love to see the "most complicated frame possible" in fact 30 seconds of that would be very interesting. Years ago I made a render test video and one of the scenes was a focus chart spinning and zooming. That really messed up some of the codecs. I think Microsoft WMV would actually crash. I was testing to see what looked the best on YouTube. I never did find the "best YouTube render settings". Now days I just use Sony AVC and max out the bit rate and hope for the best.

[Verrisin]

so if aliens watch our videos, they would likely think they look horrible, choppy, have wrong colors and overall completely unrealistic? XD

[francistremblay]

I wonder if in some cases the programming language can determine the hardware engineering and if in other cases the hardware engineering determine the programming language. If both ways are possible are their limitations and advantages.

[Timooooooooooooooo]

Great video, but what's up with the audio? It doesn't sound right to me, but that might be me. Like, more quiet, muffled.

[LifeSizeTeddyBear]

I would really love to see an interview with Sophie Wilson about her work on the ARM.

[ImNotADrug]

Great video like always.. I'd just like more frequent uploads but if it's not possible its ok

[HMFons]

Shouldn't it be nearly 10GB per minute at 4:12?
150MB*60=9000MB

[Q_]

So what does the most computationally expensive image to compress look like?

[Emanuel-sla-hi]

Great explanation!

Now, how does the most complex frame you can reasonably expect to get look like?

:D

[chrisofnottingham]

The other thing about using hardware over software is that hardware functions are concurrent. So apart from pipeline delay, hardware processing has little effect on the overall time taken to do a whole new function. Whereas for one core, all its software processing just keeps adding up.

[RMoribayashi]

The first time I saw anything that looked like a corrupted digital video stream was during the 1976 Summer Olympics in Montreal. The program froze on a single frame then square bits of different size were slowly replaced with picture or noise for several minutes until the network broke in. What it could have been 40 years ago I have no idea. I don't know if the US network was getting the feed by cable or used the same satellite signal that was serving other countries.

[Reavenk]

Maybe this is a good segue for covering data moshing and optical flow?

[UXXV]

Great vid. Get a portable tripod though guys :D