Tag Info

New answers tagged

2

Download Assuming the downloaded video is the same as the one you'd watch in your browser: $ youtube-dl https://vimeo.com/123456789 strings & grep Assuming x264 is used to encode, and the encoding settings weren't stripped out, you can see what version was used and view some of the particular settings. However, it does not mean that you should ...


0

The issue is apparently that ffmpeg cuts out dead space from captured video, and Audacity does not do likewise for audio. I've now noticed that ffmpeg's frame count stops incrementing over blank video. I believe this problem also happens when using two separate ffmpeg processes to capture video and ALSA audio.


1

In order to maintain the aspect ratio of the source movie through FFMpeg's scaler, you have to specify a scale with an unknown: ffmpeg -i input.mp4 -an -vcodec libx264 -profile:v main \ -pass 2 -vf scale=-1:180 -pix_fmt (etc...) The "-1" will tell the scaler to make the output 180px high, and however many pixels wide the output must be to preserve it's ...


4

I work as an assistant editor on feature films, and use ffmpeg all the time, primarily for two purposes: Transcoding files to be uploaded for producers to view on digital dailies systems (Dax, PIX, etc). I've written up shell scripts that accept property-of and recipient strings as command line input, along with target bitrate, and then generate the ...


1

What is Ogg Skeleton? From Ogg Skeleton 4: Ogg Skeleton provides structuring information for multitrack Ogg files. It is compatible with Ogg Theora and provides extra clues for synchronization and content negotiation such as language selection. The latest version of Skeleton, version 4.0, also provides keyframe indexes to enable optimal seeking ...


3

You can use AtomicParsley to parse the metadata of a MP4-file. For example AtomicParsley /path/to.mp4 -T 1 will print the whole atom tree.


3

All anyone might be able to say is that there are no known holes in the various players. (I don't know if that's true, just that it's impossible to know that there are no undiscovered bugs in a complex piece of code.) H.264 streams are complex enough to have lots of corner cases. They're parsed with speed-optimized code written in C and assembly. You're ...


0

Not sure off the top of my head how to do it on the fly (with multiple different video codec settings for different video streams going into the same output container). However, with 2 input files, this should work to mux all streams from multiple input file into a single output file. (parallel streams / multiple "programs", NOT concatenated.) ffmpeg -i ...


2

Any decent encoder can hit a target bitrate (with 2pass), but still spend the bits intelligently to achieve similar quality throughout the file. x264 2pass figures out what CRF will give the desired bitrate (pass1), and then uses it (pass2). (source: Dark Shikari. cf. the links I dug up for my answer on this question about VBR streaming). You only get ...


1

Use the subtitles filter to create hardsubs ("burnt-in" subtitles): ffmpeg -i input.mp4 -vf subtitles=subs.srt -target pal-dvd output.mpg -target pal-dvd will make the output have a frame rate of 25 and a frame size of 720x576. If you want NTSC output instead for a frame rate of 30000/1001 and frame size of 720x480, then use -target ntsc-dvd. For a frame ...



Top 50 recent answers are included