My favorite memory of FFmpeg involved wowing a friend with the "magic of computer hacking" by slicing a subsection of a youtube video, cutting the source audio, and replacing it with audio from a song he had discovered "fit perfectly". Never mind that the entire process took about 20 minutes of googling and trial/error with the Linux Subsystem for Windows. It was better than the native windows alternative :P
FFmpeg 4.3
81–90 of 226 posts
Re: FFmpeg 4.3
#82ffmpeg is amazing, but it’s like tar on steroids: I can never remember the right incantation. Google is required for even the simplest of things. I don’t know if it’s their goal, but I’d love a more user friendly set of command line arguments.
On my side, I frequently forget my own age, people's name, things my girlfriend remembers from 5 summers ago.
However, I'll never forget things like "tar -zxvf", "ffmpeg -i vid.mp4 image-%04d.png" and "convert image-*.png +dither anim.gif".
Re: FFmpeg 4.3
#83My favorite memory of FFmpeg involved wowing a friend with the "magic of computer hacking" by slicing a subsection of a youtube video, cutting the source audio, and replacing it with audio from a song he had discovered "fit perfectly". Never mind that the entire process took about 20 minutes of googling and trial/error with the Linux Subsystem for Windows. It was better than the native windows alternative :P https://…
I thought that was Mad Rush for a second.
Re: FFmpeg 4.3
#84I wanted to create a slideshow a couple weeks ago and came across this article [0] on creating a Ken Burns Effect Slideshow. Very cool and is a great demo of some of ffmpeg's functionality. However, the final command is a little crazy: ffmpeg -i 1.jpg -i 2.jpg -i 3.jpg -filter_complex "color=c=black:r=60:size=1280x800:d=10[black];[0:v]format=pix_fmts=yuva420p,crop=w=2*floor(iw/2):h=2*floor(ih/2),zoompan=z='if(eq(on,1…
FFmpeg is infamous for absurdly complex command options. It's really too much for a "one-liner" CLI. When I use it, I just look for "pre-baked recipes" otherwise it's a really unpleasant rabbit hole to get into.
I'd recommend looking at something like kdenlive, it generates the ffmpeg command and script for you. It's still complex and difficult to do somethings but it can be much nicer than trying to work out the command line interface for something you want to do. It's also nice because you can save the project at a higher level and reopen it later without having to do all the work of figuring things out again.
Re: FFmpeg 4.3
#85As a little side project, I've been trying to automate creation of those "1 second everyday" style videos [1], and used FFmpeg to achieve this. For things like trimming and concatenating videos, one thing that surprised me was that it was slower than using a tool like ScreenFlow. Note, we're talking about hundreds of gigabytes worth of 4K videos. slower = When I say slower, I mean, if I manually performed the same op…
> The slow way is free of quirks, whereas the fast way introduces something unexpected to the video, like a half a second of a black screen with audio continue playing like normal.
The reason here is the the "fast way" and the "slow way" work very differently behind the scenes.
The "fast way" looks only needs to look at the container, the bits of metadata that tell a player which bits of data need to be given to the decoder at which time. It can just take a blob of data and stick it in another blob of data without looking at the contents.
The "slow way" actually decodes the frames, that is, it takes the blobs of compressed data and turns them into actual pixels, which especially in the case of 4K video, is very slow.
The reason the "fast way" might be less accurate is that the frame you're asking for might not be possible to obtain without decoding the video. Modern video codecs have different kinds of frames and some frames depend on the frames before or after them. If you took such a frame and just jammed it into another video, things would break, because the other frames it refers to are missing.
> I'm still curious as to how a tool like ScreenFlow can achieve faster trimming/concatenation/subtitle overlaying, than FFmpeg.
It's likely that they have optimisations that FFmpeg doesn't or cannot have. FFmpeg has a bit of an emphasis of being able to play and handle pretty much anything you throw at it, no matter how broken. It could be that accurate input seeking is difficult while preserving that reliability.
One option that's probably not an option for you but you might consider is encoding your video in an all-intra format. This is fairly standard in the video editing world. All-intra means that all your frames are independent of each other and can be moved around by editing software without decoding anything. Doing this will result in larger files, however.
Re: FFmpeg 4.3
#86Earlier quoted context omitted.
If you're converting .aax files you should consider using .m4b as the output, since it preserves chapters and remembers your last listened timestamp [0]: > Audiobook and podcast files, which also contain metadata including chapter markers, images, and hyperlinks, can use the extension .m4a, but more commonly use the .m4b extension. An .m4a audio file cannot "bookmark" (remember the last listening spot), whereas .m4b…
I don't think that's quite accurate. There's no functional difference between a .m4b file and a .m4a file. Both use the MP4 container so adhere to the same specification, so support all the same features (including bookmarks). FFmpeg even uses the same muxer and demuxer for both "formats". The only difference is a non-standard convention used by certain software (like iTunes) to write autiobook-related metadata only…
Well, it's also worth noting that different file extensions can have different associations, so .m4b is more likely to open in an app that the user wants to use for audiobooks, rather than opening in a generic mp4 audio playing app.
Even iTunes, I think, would treat files differently between m4r (Ringtone) and m4a (audio) files, so despite there being no difference at all, using the 'correct' extension might be quite a bit more convenient in the long run.
Re: FFmpeg 4.3
#87Does anyone have a better documentation source for modern ffmpeg? Usually when I use it I get all sorts of different answers with different 'methods', and the official docs only confuse it more. Also I hope to see pure GPU transcoding sometime. H264 to h265 transcodes in pure GPU space are Uber fast, but so far only done by other software.
> Also I hope to see pure GPU transcoding sometime. H264 to h265 transcodes in pure GPU space are Uber fast, but so far only done by other software.
FFmpeg has had pure GPU transcoding for quite some time. See https://trac.ffmpeg.org/wiki/HWAccelIntro
It even has a GPU-based scaler for NVIDIA.
Re: FFmpeg 4.3
#88I have used ffmpeg. It's a damn good project, and under current development and support. It also appears to be the only game in town. Many commercial offerings are really just veneers over custom ffmpeg implementations. Tuning it is also pretty crazy. Some folks can make entire careers out of just tuning ffmpeg. I think the biggest issue with video software (besides it being difficult and performance-intensive), is t…
It's not the only game in town, the other major open source project for audio/video coding is gstreamer. https://gstreamer.freedesktop.org
Re: FFmpeg 4.3
#89I wanted to create a slideshow a couple weeks ago and came across this article [0] on creating a Ken Burns Effect Slideshow. Very cool and is a great demo of some of ffmpeg's functionality. However, the final command is a little crazy: ffmpeg -i 1.jpg -i 2.jpg -i 3.jpg -filter_complex "color=c=black:r=60:size=1280x800:d=10[black];[0:v]format=pix_fmts=yuva420p,crop=w=2*floor(iw/2):h=2*floor(ih/2),zoompan=z='if(eq(on,1…
FFmpeg is infamous for absurdly complex command options. It's really too much for a "one-liner" CLI. When I use it, I just look for "pre-baked recipes" otherwise it's a really unpleasant rabbit hole to get into.
If you look at it as more of a "composable" interface (as the sibling poster suggested), it makes a lot more sense.
No one is going to type out this one-liner from scratch, or have an easy time understanding what it means by reading it, but as it's made up of a series of smaller, more easily understood commands, in a shell or Python script it could be vastly more legible and, dare I say it, usable.
This is also the reason why there are so many frontends to ffmpeg, to simplify various specific tasks. I can't count how many one-off apps I've seen that do one thing and do it well, and just ship a full copy of ffmpeg to do that one thing. Making an actual GUI for all of this would be just... insane, really, but it's so versatile and flexible that you can basically do anything with it.
Re: FFmpeg 4.3
#90Can someone explain to me how FFmpeg seems to be the only open-source software to do even just basic functionality with audio. I was looking at getting the sound wave graph for a piece of audio a while ago, and not only was FFmpeg the only option I found to be able to do it, it was amazingly fast and also free.
Python with librosa is also quite practical. Can work interactively by doing it in a Jupyter notebook.
Some tutorials (from 2015).
https://www.youtube.com/watch?v=0ALKGR0I5MA
https://www.youtube.com/watch?v=MhOdbtPhbLU
Not affiliated with the project, just use it quite a lot.