4 ms·

It's interesting to me that most of Bellard's work is basically turning specs into C. His most important projects are ffmpeg (codec specs), qEmu (ISA specs), Q

It's interesting to me that most of Bellard's work is basically turning specs into C. His most important projects are ffmpeg (codec specs), qEmu (ISA specs), QuickJS (the EcmaScript spec), tinyC (the C spec), and his telecom company (LTE specs). I guess the pi calculations and neural network stuff are exceptions. Just to be clear, this doesn't make his work any less impressive. Highly performant codec and emulator implementations are no easy feat; it's just interesting that most of this work falls into that relatively narrow area.

apitman 4mo ago
Maybe pi is a spec. Just not written by man.
reactordev 4mo ago
There was a time when we would spend an enormous amount of time defining a spec, so that we can farm out the code. Now, we farm out the spec so that we can spend an enormous amount of time with the code.
- jimbokun 4mo ago
  Now we replace both with prompts.
izacus 4mo ago
If you actually work with ffmpeg, it's rather quite impressive how pluggable the architecture is. The codecs have huge amount of quirks and disagreements about basics (what is a "frame" in audio, subtitle, and video worlds?) and even their environment (passing frames around software and hardware coders is way different). That fact that you can (almost) freely mix and match processing between such different worlds is quite an achievement and libav (IMO) is decently well designed to allow that.
- jimbokun 4mo ago
  This description feels like how jQuery unified all the disparate JavaScript implementations behind a single framework.
femto 4mo ago
It's worth noting that most communications specifications that involve an encoder/decoder pair communicating over a channel only specify the encoder. Standards purposely leave the decoder open to allow systems to progress as technology develops and to allow competition between implementations. This also makes a standard simpler, as a decoder is usually more complex than an encoder since it has to deal with noise and other effects introduced by the channel. Consequently, implementing a competitive standards compliant decoder involves R&D and is not a case of following a predefined path. I've always seen Bellard as an engineer who programs rather than a pure programmer.
- harrouet 4mo ago
  It is exactly the opposite for MPEG, which only specifies the decoder (i.e. how frames should be decoded).
  - kroeckx 4mo ago
    Maybe they meant encoding, the file format.
    - Tuna-Fish 4mo ago
      But that only specifies the decoder. The format for all modern video codecs is not the kind of format where any specific piece of uncompressed input should always be encoded the same way, but more like a very restricted programming language that gives the encoder a lot of tools to compress the video, and which tools they use and how they use them are up to them.
      - fc417fc802 4mo ago
        I think it's neither the encoder nor the decoder that's specified but rather the encoding ie the bitstream format. At least for video streams building a competitive encoder is far more difficult than the corresponding decoder.
  - femto 4mo ago
ChrisMarshallNY 4mo ago
That's actually how I was trained. The spec and the implementation (and the testing) were separate areas; sometimes, done by different people. These days, I tend to mix them all together, and I think I get good results. I strongly suspect that a lot of folks, these days, only do the middle one.
- mschuster91 4mo ago
  > I strongly suspect that a lot of folks, these days, only do the middle one. Ain't no one willing to pay for all of that. The clear separation is something you only see remaining in academia and industries where code quality issues have legal consequences (i.e. aerospace, marine, automotive and medical), and even there, pressure is high to relax rules viewed as "arcane". Writing good specifications, documentations, implementation code and tests each is an art form in itself
  - ChrisMarshallNY 4mo ago
    I’m not so sure. I see a lot of “Ready, Fire, Aim” behavior, hereabouts, and can’t help but imagine that it extends into our basic workflows. It’s entirely possible to create a huge ball o’ mud, that works, but is unmaintainable, and damn near impossible to adapt to changing circumstances. I just went through that, with my LLM. Really easy to simply say “Screw it. Let’s ship.”
    - fc417fc802 4mo ago
      It doesn't seem like you're disagreeing with him?
      - ChrisMarshallNY 4mo ago
        > Ain't no one willing to pay for all of that. That made me think that he didn't think it was possible. I guess I'm a cynic, but I think that many companies, these days, are willing to pay -and pay a great deal-, for exactly that.
tennfown 4mo ago
But I was told “spec implementators” were prime for LLM replacement
baobabKoodaa 4mo ago
> ffmpeg (codec specs) if your mental model is that somebody writes codec specs and then fabrice bellard comes in and turns the specs into C, you are dead wrong. first of all, codecs are usually reverse-engineered, there is no spec. second of all, even when a well specified document describes the codec, that spec does not describe how to efficiently encode or decode with that codec. people like fabrice bellard develop the algorithms that do that.
- HelloNurse 4mo ago
  Vocabulary please. A "codec" is software that CODes and DECodes multimedia content, while specs describe an encoded file or stream format (occasionally involving network protocols and other concerns). In a normal standard development process experimental codecs come first, then those that have proved to work well, including having good enough performance, are described in the spec; after standardization there's very little room to "develop the algorithms" because nonconformant implementations would be useless. Reverse engineering is limited to the abnormal case of having access to some codec but not to the standard that describes it.
  - baobabKoodaa 4mo ago
    > after standardization there's very little room to "develop the algorithms" because nonconformant implementations would be useless. there is A LOT OF ROOM to develop the algorithms. it seems that you are confused about what an algorithm is, since you seemingly think that there can be only 1 algorithm that can decode a given media file.
    - HelloNurse 4mo ago
      There is a lot of room to do exactly the same thing more efficiently, which doesn't count as different algorithms.
      - questionableans 4mo ago
        Are bubble sort and quick sort the same algorithm?
wswin 4mo ago
Interesting observation, similar manner of work as Linus Torvalds. These guys implement existing ideas well, consistent and open, but are not inventors.
- jimbokun 4mo ago
  Git?
  - avadodin 4mo ago
    That's his point. I do not agree with it at all, though. Linus himself phrased it as git being about applying his filesystems knowledge to source management. You can't take that statement at its face value. Many of Bellard's projects boil down to applied tcc but just being able to understand tcc in the first place is out of the reach of most people who call themselves "programmers". And then applying it to a novel field solving problems people didn't even know they had. That's exactly what "inventing" is. Carmack didn't invent logarithms. But without people like him who innovated building on someone else's innovation, and on many people's common knowledge, we'd be still running away from lions in the Savannah.
ex-aws-dude 4mo ago
I don’t think the distinction is actually that interesting as you could call any piece of software a spec

apitman 4mo ago

Maybe pi is a spec. Just not written by man.

reactordev 4mo ago

There was a time when we would spend an enormous amount of time defining a spec, so that we can farm out the code. Now, we farm out the spec so that we can spend an enormous amount of time with the code.

jimbokun 4mo ago
Now we replace both with prompts.

izacus 4mo ago

If you actually work with ffmpeg, it's rather quite impressive how pluggable the architecture is. The codecs have huge amount of quirks and disagreements about basics (what is a "frame" in audio, subtitle, and video worlds?) and even their environment (passing frames around software and hardware coders is way different). That fact that you can (almost) freely mix and match processing between such different worlds is quite an achievement and libav (IMO) is decently well designed to allow that.

jimbokun 4mo ago
This description feels like how jQuery unified all the disparate JavaScript implementations behind a single framework.

femto 4mo ago

It's worth noting that most communications specifications that involve an encoder/decoder pair communicating over a channel only specify the encoder. Standards purposely leave the decoder open to allow systems to progress as technology develops and to allow competition between implementations. This also makes a standard simpler, as a decoder is usually more complex than an encoder since it has to deal with noise and other effects introduced by the channel. Consequently, implementing a competitive standards compliant decoder involves R&D and is not a case of following a predefined path. I've always seen Bellard as an engineer who programs rather than a pure programmer.

harrouet 4mo ago
It is exactly the opposite for MPEG, which only specifies the decoder (i.e. how frames should be decoded).
- kroeckx 4mo ago
  Maybe they meant encoding, the file format.
  - Tuna-Fish 4mo ago
    But that only specifies the decoder. The format for all modern video codecs is not the kind of format where any specific piece of uncompressed input should always be encoded the same way, but more like a very restricted programming language that gives the encoder a lot of tools to compress the video, and which tools they use and how they use them are up to them.
    - fc417fc802 4mo ago
      I think it's neither the encoder nor the decoder that's specified but rather the encoding ie the bitstream format. At least for video streams building a competitive encoder is far more difficult than the corresponding decoder.
- femto 4mo ago

ChrisMarshallNY 4mo ago

That's actually how I was trained. The spec and the implementation (and the testing) were separate areas; sometimes, done by different people. These days, I tend to mix them all together, and I think I get good results. I strongly suspect that a lot of folks, these days, only do the middle one.

mschuster91 4mo ago
> I strongly suspect that a lot of folks, these days, only do the middle one. Ain't no one willing to pay for all of that. The clear separation is something you only see remaining in academia and industries where code quality issues have legal consequences (i.e. aerospace, marine, automotive and medical), and even there, pressure is high to relax rules viewed as "arcane". Writing good specifications, documentations, implementation code and tests each is an art form in itself
- ChrisMarshallNY 4mo ago
  I’m not so sure. I see a lot of “Ready, Fire, Aim” behavior, hereabouts, and can’t help but imagine that it extends into our basic workflows. It’s entirely possible to create a huge ball o’ mud, that works, but is unmaintainable, and damn near impossible to adapt to changing circumstances. I just went through that, with my LLM. Really easy to simply say “Screw it. Let’s ship.”
  - fc417fc802 4mo ago
    It doesn't seem like you're disagreeing with him?
    - ChrisMarshallNY 4mo ago
      > Ain't no one willing to pay for all of that. That made me think that he didn't think it was possible. I guess I'm a cynic, but I think that many companies, these days, are willing to pay -and pay a great deal-, for exactly that.

tennfown 4mo ago

But I was told “spec implementators” were prime for LLM replacement

baobabKoodaa 4mo ago

> ffmpeg (codec specs) if your mental model is that somebody writes codec specs and then fabrice bellard comes in and turns the specs into C, you are dead wrong. first of all, codecs are usually reverse-engineered, there is no spec. second of all, even when a well specified document describes the codec, that spec does not describe how to efficiently encode or decode with that codec. people like fabrice bellard develop the algorithms that do that.

HelloNurse 4mo ago
Vocabulary please. A "codec" is software that CODes and DECodes multimedia content, while specs describe an encoded file or stream format (occasionally involving network protocols and other concerns). In a normal standard development process experimental codecs come first, then those that have proved to work well, including having good enough performance, are described in the spec; after standardization there's very little room to "develop the algorithms" because nonconformant implementations would be useless. Reverse engineering is limited to the abnormal case of having access to some codec but not to the standard that describes it.
- baobabKoodaa 4mo ago
  > after standardization there's very little room to "develop the algorithms" because nonconformant implementations would be useless. there is A LOT OF ROOM to develop the algorithms. it seems that you are confused about what an algorithm is, since you seemingly think that there can be only 1 algorithm that can decode a given media file.
  - HelloNurse 4mo ago
    There is a lot of room to do exactly the same thing more efficiently, which doesn't count as different algorithms.
    - questionableans 4mo ago
      Are bubble sort and quick sort the same algorithm?

wswin 4mo ago

Interesting observation, similar manner of work as Linus Torvalds. These guys implement existing ideas well, consistent and open, but are not inventors.

jimbokun 4mo ago
Git?
- avadodin 4mo ago
  That's his point. I do not agree with it at all, though. Linus himself phrased it as git being about applying his filesystems knowledge to source management. You can't take that statement at its face value. Many of Bellard's projects boil down to applied tcc but just being able to understand tcc in the first place is out of the reach of most people who call themselves "programmers". And then applying it to a novel field solving problems people didn't even know they had. That's exactly what "inventing" is. Carmack didn't invent logarithms. But without people like him who innovated building on someone else's innovation, and on many people's common knowledge, we'd be still running away from lions in the Savannah.

ex-aws-dude 4mo ago

I don’t think the distinction is actually that interesting as you could call any piece of software a spec