Hacker News: _Gyan_

New comment by _Gyan_ in "All the giant companies used ffmpeg (2020)"

_Gyan_ — Sat, 25 Dec 2021 14:28:56 +0000

libav is a part of FFmpeg, and the heart of it. But FFmpeg isn't just a skeleton. Most decoders + protocols + demuxers / muxsers + filters + scaler + resampler are native components.

The most well-known 3rd party libs provide a few (albeit commonly used) video encoders. Of course, having interfaces for these external libs is what allows media operations to be consolidated into a single process workflow. As standalone tools, x264/x265 would be more cumbersome to integrate into a pipeline.

New comment by _Gyan_ in "All the giant companies used ffmpeg (2020)"

_Gyan_ — Sat, 25 Dec 2021 06:40:28 +0000

API/ABI is meant to be preserved within a major version, but not across. The deprecation period is typically two years, but deletion is usually much later.

Do you have examples to the contrary from the past few years?

New comment by _Gyan_ in "All the giant companies used ffmpeg (2020)"

_Gyan_ — Sat, 25 Dec 2021 04:15:13 +0000

For a few years, the default aac coder has been fast. But the twoloop coder is better but slower, and was made default in May 2021. Add `-aac_coder twoloop` (in older builds) and recheck.

New comment by _Gyan_ in "Hacking YouTube with a MP4"

_Gyan_ — Tue, 12 Oct 2021 04:57:50 +0000

With ffmpeg, use the below command to calculate maximum timestamps

    ffmpeg -i INPUT -map 0:v -map 0:a -enc_time_base -1 -c copy -f null -

Note the time= value at the end of the process.

New comment by _Gyan_ in "FFmpeg to WebRTC"

_Gyan_ — Wed, 22 Sep 2021 11:44:05 +0000

For `-f h264`, `-bsf:v h264_mp4toannexb` is not needed. It will be automatically inserted as needed, with ffmpeg 4.0 or later.

For latency, specify a short GOP size, e.g. `-g 50`

New comment by _Gyan_ in "Simple mathematical law predicts movement in cities around the world"

_Gyan_ — Wed, 15 Sep 2021 09:21:26 +0000

Except for many primate cities: https://en.wikipedia.org/wiki/Primate_city#List

New comment by _Gyan_ in "Beneath the surface of Bach’s music is a world of numerology and cunning craft"

_Gyan_ — Mon, 13 Sep 2021 17:14:29 +0000

Don't think that's the main reason. Hollywood has no compunction or lack of skill to embellish or dramatize a mundane life if they need to.

I suspect Bach's place at the top is received rather than recognized, which is not to say he doesn't deserve it. His skill lays in counterpoint and other facets of harmony. His music has structural elegance and ornamental beauty, not the full orchestral rabble rousing of Beethoven or delicate pianism of Chopin. Not exactly directly translatable to a poster or trailer.

New comment by _Gyan_ in "Space station astronaut captures breathtaking view of the edge of the Earth"

_Gyan_ — Wed, 08 Sep 2021 13:33:18 +0000

See a video with similar setup of a rocket launch constructed out of a timelapse photo sequence: https://www.youtube.com/watch?v=aJy1u-N3NY0

New comment by _Gyan_ in "Satellites Spot Oceans Aglow with Trillions of Organisms"

_Gyan_ — Mon, 30 Aug 2021 09:55:58 +0000

A profitable strategy only if it attracts a lot more prey than predators.

New comment by _Gyan_ in "Smart tech is not making us stupid, instead is cognitively beneficial"

_Gyan_ — Sun, 04 Jul 2021 05:29:55 +0000

The intro of the actual paper* is ambivalent, rather than what the post title asserts.

"We critically examine relevant findings and argue that there is no clear evidence for detrimental lasting effects of digital technology on cognitive abilities."

*https://www.nature.com/articles/s41562-021-01162-0

New comment by _Gyan_ in "I'm Sorry I Haven't a Clue is back"

_Gyan_ — Sat, 03 Jul 2021 12:00:10 +0000

It's a shame that Graeme Garden and Barry Cryer appear to have retired.

Top 100 3D Renders from the Internet's Largest CG Challenge

_Gyan_ — Sat, 19 Jun 2021 09:06:49 +0000

Article URL: https://www.youtube.com/watch?v=iKBs9l8jS6Q

Comments URL: https://news.ycombinator.com/item?id=27559014

Points: 1

# Comments: 0

Human Cell Atlas

_Gyan_ — Mon, 31 May 2021 15:00:54 +0000

Article URL: https://www.humancellatlas.org/

Comments URL: https://news.ycombinator.com/item?id=27344727

Points: 2

# Comments: 0

New comment by _Gyan_ in "One week of Libera Chat"

_Gyan_ — Wed, 26 May 2021 11:24:57 +0000

FFmpeg already has registered channels there. Will update website within a day.

New comment by _Gyan_ in "FFmpeg Cheat Sheet"

_Gyan_ — Sun, 25 Apr 2021 05:17:04 +0000

It hasn't, since ffmpeg's inception. It's very unlikely - it would require that ffmpeg verify codec compatibility with the output muxer. Not all muxers have registered a codec tags list , so that can't happen.

New comment by _Gyan_ in "FFmpeg Cheat Sheet"

_Gyan_ — Sun, 25 Apr 2021 03:41:58 +0000

It's not the first tracks. Read http://ffmpeg.org/ffmpeg.html#Stream-selection

New comment by _Gyan_ in "FFmpeg Cheat Sheet"

_Gyan_ — Sun, 25 Apr 2021 03:41:24 +0000

The first one will re-encode.

New comment by _Gyan_ in "FFmpeg and a Thousand Fixes (2014)"

_Gyan_ — Fri, 23 Apr 2021 06:24:39 +0000

There have been 2000 fixes related to fuzzer issues so far, averaging 400 fixes in recent years. Almost all of them are taken care of by Michael.

New comment by _Gyan_ in "Open Source Goes to Mars"

_Gyan_ — Tue, 20 Apr 2021 07:05:51 +0000

I don't see FFmpeg on there.

See https://link.springer.com/article/10.1007/s11214-020-00765-9

"The core EDL data processing and compression engine is powered by FFMPEG (ffmpeg.org)."

New comment by _Gyan_ in "Pfizer 91% effective in updated data, protective against South African variant"

_Gyan_ — Thu, 01 Apr 2021 16:18:48 +0000

The primary endpoint is symptomatic infection, not any infection per se. And it's a bit of a kludge, as all the Phase III protocols I've read define symptomatic infection as X no. of symptoms for Y+ no. of days i.e. there are people with fewer symptoms who aren't counted (or even tested to check for infection).

The efficacy is the 1-relative risk of the primary endpoint.