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A Fictional Compression Metric Moves Into the Real World
Tekla Perry (3034735) writes The 'Weissman Score' — created for HBO's "Silicon Valley" to add dramatic flair to the show's race to build the best compression algorithm — creates a single score by considering both the compression ratio and the compression speed. While it was created for a TV show, it does really work, and it's quickly migrating into academia. Computer science and engineering students will begin to encounter the Weissman Score in the classroom this fall."
A "combined score" for speed and ratio is useless, as that relation is not linear.
Most ACs are not even worth the keystrokes to insult them. Be generically insulted by this and ignored otherwise.
The so-called Weissman score is just proportional to (compression ratio)/log(time to compress).
I guess the idea is that twice as much compression is always twice as good, while increases in time become less significant if you're already taking a long time. For example, taking a day to compress is much worse than taking an hour, but taking 24 days to compress is only somewhat worse than taking one day since you're talking offline/parallel processing anyway.
The log() seems kind of an arbitrary choice, but whatever. It's no better or worse than any other made-up metric, as long as you're not taking it too seriously.
"They were pure niggers." – Noam Chomsky
hey, "print 0" runs in O(1)!
My God, it's Full of Source!
OUTSIDE_IP=$(dig +short my.ip @outsideip.net)
Not only does it fail to account for loss or distortion, but also fails to consider the time to decompress. If a compression algorithm with a high Weissman score is applied to a video, it is useless if it cannot be decompressed fast enough to show the video at an appropriate frame rate.
Two scores would be useful, one for compression_time:size and decompression_time:size, since for many applications the latter is more important in compress-once consume-many applications.
They're talking about the Score, not the compression algorithm. And your link doesn't mention anything about the Score.
IIRC, the Drake equation was also a 'spitball' solution whipped off the cuff to address an inconvenient interviewer question. Subsequent tweaks have made it as accurate and reliable as when it was first spat out upon the world - and about as useless.
The fictional compression algorithm doesn't work. The metric for rating compression algorithms does work (insofar as more compressed/faster algorithms achieve a better rating).
Show About Self-Absorbed Assholes Who Think Their Stupid Ideas Are The Bees Knees Gains Popularity By Making Their Stupid Idea Sound Like Its The Bees Knees
it's for lossless compression only.
anyway, you can just add a term representing the lost information and throw it into this "score". hey, why not? just figure out how important the lossiness is relative to compression rate. if it's very important, take the exp() of the loss metric; if it's unimportant (like time is), take the log(); finally, if it's just kind of important, leave it linear, or maybe square or square root. whatever.
seriously, just make some shit up and throw it in. you won't compromise anything. it's already just made-up shit.
"They were pure niggers." – Noam Chomsky
In the TV show only lossless compression was being considered, so MP3 would fail.
The reason the Score is utter bullshit is that the scale is completely arbitrary and useless. It says that 2:1 compression that takes 1 second should have the same score as 4:1 compression that takes log(2) seconds, or 1 million to 1 compression that takes log(1 million) seconds.
WHY? State why log time is a better measure than straight time, or time squared, or square root of time. And look at the units of the ratio: reciprocal log seconds. What the hell is the significance of that? It also conveniently sidesteps the variability with different architectures. Maybe SSE helps algorithm A much more than it does algorithm B. Or B outperforms A on AMD, but not on Intel. Or maybe it is strongly dependent on size of source (there is an implicit assumption that all algorithms scale linearly with size of source; maybe in actual fact some are not linear and others are).
In real life, for some compression jobs you don't CARE how long it takes, and for other jobs you care very much. Or imagine an algorithm that compresses half as fast but decompresses 1000 times faster. That doesn't even register in the score.
It's bullshit.
Claiming that a score "works" has no meaning,
I could easily devise a cpu scoring methodology that scores CPU based on chip area / cost * clock speed / register width.
Such a score "works" in the sense that the function can be evaluated, but it wouldn't tell you anything about whether to buy an i7 vs a xeon vs a pentium 2.
The suggestion in the article is that the particular scoring methodology that was created for the show is useful for comparing compression algorithms, to the point that it may well be adopted by industry.
Therefore, the only interpretation of the hideously poor writing is that the submitter is claiming the algorithm works.
The writing was perfectly fine, your reading comprehension is what failed here.
And Jerry Gibson, a professor at the University of California at Santa Barbara, says he's going to introduce the metric into two classes this year. For a winter quarter class on information theory, he will ask students to use the score to evaluate lossless compression algorithms. In a spring quarter class on multimedia compression, he will use the score in a similar way, but in this case, because the Weissman Score doesn't consider distortion introduced in lossy compression, he will expect the students to weight that factor as well.
The scoring method as stated is only useful for evaluating lossless compression. One could also take into account the resemblance of the output to the input to allow a modified version of the score to evaluate lossy compression.
It is pitch black. You are likely to be eaten by a grue.
From the article:
Misra came up with a formula
So, now Jar Jar Binks does C.S.? Shit...
Given that only a subset of Slashdot users are HBO subscribers, how is this relevant?
I want to delete my account but Slashdot doesn't allow it.
That's correct. So what?
So, comment I was replying to
Using the "Weissman Score", MP3 is always better than FLAC
MP3 wouldn't even have a "Weissman Score" because it's not a lossless compression algorithm.