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FFmpeg 4.0 released

ffmpeg.org

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Re: FFmpeg 4.0 released

#61

Post by moltensyntax »

Cogito wrote: post #20

Love ffmpeg! I was trying to do something the other day and couldn’t figure it out, if anyone has any ideas. The end goal is to provide a set of video files, with time stamps for each, splicing them into one file while removing parts I don’t want. That is straightforward enough, as long as you’re willing to re-encode the whole file. Otherwise, it seems like ffmpeg is restricted to make cuts at key frames. It’s rare f…

Yes, this is possible, depending on the codec and container. I have done similar operations with h264+mp4.

It's good to be able to edit video without losing quality.

Are you sure you need sub-keyframe precision? In h264+aac+mp4, for example, if it's not keyframe aligned, the result is usually a stalled video frame for a split second, but since the audio continues smoothly, it's not that noticeable.

If you know the exact codec settings that were used to encode the video, you can create new pieces to be fit losslessly together. Otherwise, it is more difficult.

Contact me on twitter at @downpoured and I can describe more.

Re: FFmpeg 4.0 released

#62

Post by tinus_hn »

fulafel wrote: post #37

I hope Ubuntu gets better at updating FFmpeg by bringing it in from the "universe" category of unsupported packages. Or second best option, stops shipping it. Just this week there was an update showing that they had nearly a year-long window of vulnerability due to out of date version[1]. A media format christmas tree like this has really a lot of vulnerabilities & exposes the user to them fairly directly through med…

Seems like a good reason to keep it out of the base installation. Besides the patent minefield that comes with media players, of course.

Re: FFmpeg 4.0 released

#63

Post by stirner »

Bromskloss wrote: post #60
stirner wrote: post #34

Earlier quoted context omitted.

Not just command line. libav* is used in pretty much everything that deals with arbitrary AV formats/codecs.

What is the current relationship between Libav and FFmpeg? I could never figure out which one I should support when there was a falling out, and things might even have changed since then.

When I say libav*, I and most people mean libavformat, libavcodec, libswscale, etc.; the C libraries that form the basis of the command line tool and are widely used elsewhere.

libav (no wildcard) is a fork of FFmpeg that is broadly focused on reducing bloat and cleaning up the API. As such, libav tends to add features more slowly, while FFmpeg generally follows all of libav’s new features and bug fixes as well as its own [1]. Debian was on libav for a while but went back to FFmpeg in 2015 [2].

[1] http://blog.pkh.me/p/13-the-ffmpeg-libav-situation.html

[2] http://news.softpedia.com/news/Debian-Moves-to-FFmpeg-and-Dr...

Re: FFmpeg 4.0 released

#64

Post by Bromskloss »

stirner wrote: post #63
Bromskloss wrote: post #60

Earlier quoted context omitted.

What is the current relationship between Libav and FFmpeg? I could never figure out which one I should support when there was a falling out, and things might even have changed since then.

When I say libav*, I and most people mean libavformat, libavcodec, libswscale, etc.; the C libraries that form the basis of the command line tool and are widely used elsewhere. libav (no wildcard) is a fork of FFmpeg that is broadly focused on reducing bloat and cleaning up the API. As such, libav tends to add features more slowly, while FFmpeg generally follows all of libav’s new features and bug fixes as well as it…

> When I say libav*, I and most people mean libavformat, libavcodec, libswscale, etc.; the C libraries that form the basis of the command line tool and are widely used elsewhere.

Oh, so were those things called "libav" even before the fork, and were perhaps the origin for the name of the fork libav?

Re: FFmpeg 4.0 released

#65

Post by Hello71 »

Bromskloss wrote: post #64
stirner wrote: post #63

Earlier quoted context omitted.

When I say libav*, I and most people mean libavformat, libavcodec, libswscale, etc.; the C libraries that form the basis of the command line tool and are widely used elsewhere. libav (no wildcard) is a fork of FFmpeg that is broadly focused on reducing bloat and cleaning up the API. As such, libav tends to add features more slowly, while FFmpeg generally follows all of libav’s new features and bug fixes as well as it…

> When I say libav*, I and most people mean libavformat, libavcodec, libswscale, etc.; the C libraries that form the basis of the command line tool and are widely used elsewhere. Oh, so were those things called "libav" even before the fork, and were perhaps the origin for the name of the fork libav?

yes. some people (including me) would argue that they chose that name in part to cause deliberate confusion.

Re: FFmpeg 4.0 released

#66

Post by jesuslop »

mulvya wrote: post #39
jesuslop wrote: post #32

What does the "entropy video filter" do?

Generates a histogram of pixel values in a frame and then, in normal mode, calculates a (weighted) measure of the variance in pixel values. in diff mode, calculates a (weighted) measure of the variance in differences of pixel count between two neighbouring values (if 800 pixels have value 112 and 1400 pixels have value 113, then the (abs) difference is 600)

Thank you! Quality info.
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