141–150 of 210 posts
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This is very nice. I've been surprised how many people don't know HN, it can definitely use some promotion.
Be careful what you wish for!
I absolutely love ffmpeg, but for the life of me I cannot understand how its pipeline system works. Each time I need to use it, I attempt to construct the command myself, but end up giving up and consulting StackOverflow. Amazingly, someone has usually done the exact thing I need to do and posted their command line to StackOverflow, so I'm never out of luck! How do I actually start understanding how ffmpeg works? I w…
https://github.com/elamperti/dotfiles/blob/master/docs/ffmpe...
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I know some services do this somehow, so I was thinking maybe there is a way in ffmpeg.
Hmm. Example of such a service? Wonder if we can reverse engineer it.
The video needs to be Prores and I'm not able to guarantee it's not touching any other part of the frame but it feels like it's just the effected section of the video frame that is getting changed.
If you are trying it out make a copy of your original video before you start, it does the edits in place.
[1] https://mogurenko.com/2021/01/29/amcdx-video-patcher-v0-6-7/ [2] https://youtu.be/T-EJRB-xAdU?t=44
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It’s bad at counting because counting relies on a stateful O(N) algorithm you run in your brain. GPT is trained to reproduce human text, which tends to simply have the output of this O(N) counting process, but not the process itself. So GPT “thinks” it should be able to just spit out the number just like human text implies we do. It doesn’t know we are relying on an offline O(N) algorithm. If you have it emit a numbe…
Shouldn't RHLF help with this? So it learns that when people specify a number, they mean something very specific.
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I know a lot of people look down on ChatGpt. But I have been using it for creating scripts to use with ffmpeg and I was able to get most of the things that I needed with very little massaging required. You can then ask ChatGpt about what it did and why so it will explain it as well so you can get some basic understanding on how things work. People don't realise what kind of tool Chat Gpt is and how to properly utilis…
It really works! With few interactions, ChatGPT was able to create a not so obvious -filter_complex pipeline, like: ffmpeg -ss 00:01:00 -t 00:02:00 -i input1.mp4 -ss 00:03:00 -t 00:02:30 -i input2.mp4 -filter_complex "[0:v][0:a][1:v][1:a]concat=n=2:v=1:a=1[v][a];[v]eq=brightness=0.3[outv]" -map "[outv]" output.mp4
This command uses FFmpeg to create a single output video file from two input video files. It starts by specifying a start and duration for each of the two files (input1.mp4 and input2.mp4). It then applies a filter complex to the two files, which combines the two videos and audio into one stream, and adds a brightness filter with a value of 0.3. Finally, it maps the output video stream to the output file (output.mp4).
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YUV420p is the only pixel format that all H.264 compatible decoders MUST support. Other formats are optional. In practice that means that most hardware decoders (not just iPhones, also other phones, TVs, older PC GPUs) won't be able to decode YUV 4:2:2 or YUV 4:4:4 videos. It's kinda annoying, since YUV420 really messes up red text in screen captures for example. You need this parameter to force ffmpeg to convert the…
>since YUV420 really messes up red text in screen captures for example Is there an detailed explanation why red is especially bad after chroma subsampling? Have been wondering about this for awhile. I assume it's because red has low brightness/luminance (no idea if correct or not)?
I love software that just does what it’s supposed to do and is so good at it that it’s an underpinning for other projects. FFmpeg, curl, nmap, et., al.
It is such a swiss knife kind of tool, there's just almost nothing it can't do when it comes to video, audio and image modifications. I wonder how many big companies uses it "in secret" that we don't know off, or distributes it with mentions buried deep underneath usage agreement.
Until they keep away from c++ or the ISO planned obsolescence of the C language, keep the SDK minimal, I guess I tolerate their excessive heavy use of nasm macro preprocessor.
If the video is mostly about versioning, well since I use a weekly ffmpeg git...
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It is such a swiss knife kind of tool, there's just almost nothing it can't do when it comes to video, audio and image modifications. I wonder how many big companies uses it "in secret" that we don't know off, or distributes it with mentions buried deep underneath usage agreement.
It’s used heavily by professional broadcasters and TV/movie studios. AWS run it, satellite TV services use it, some VFX studios use it, etc. it’s become pretty foundational industry tech.