I would like to use the ffmpeg apis (not the command line) for clipping videos to a specific size (e.g say 1hr video, create a new video starting at 10 minutes and ending at 30 minutes). Are there any examples of doing this out there?
I have used the apis to stream and record video so I have a bit of background knowledge.
Thanks.
ffmpeg (the command line tool) is just a frontend to the APIs with some extras. The whole source of the ffmpeg CLI tool is contained in one single source file ffmpeg.c. I suggest you just take a look into that to see, how ffmpeg does it internally.
Related
I would like to create three audio chunks / segments from a 30-minute-long audio file using AWS MediaConvert. Is it possible to do this with MediaConvert and if so how?
Here is an example using ffmpeg
ffmpeg -i 30min_audio.wav -c copy -f segment -segment_times 0,600,1200 output%d.wav
Unfortunately, there isn't a way to do this in the service currently. The service does not support input clipping for audio only inputs [1].
A creative way (if you don't care about the output format as much) would be to use a adapative bitrate (ABR) packaging type, such as Apple HLS, set the segment length. Note this will give you consistent segmenting (except for the last segment).
One thing to point out is that in your ffmpeg command you are using the -c copy filter. This will perform a transmux. MediaConvert is a transcoding service, so an encode will be performed if you process jobs in the service.
I like to think of it as some bits in, new bits out.
Resources:
[1] https://docs.aws.amazon.com/mediaconvert/latest/ug/feature-limitations-for-audio-only.html
I have a video in fragmented form which is an output of an Azure Media Services Live Event (Smooth Streaming).
I'm trying to concatenate the segments to get a single MP4 file, however I've run into a A/V sync problem - no matter what I do (time-shifting/speeding up/slowing down/using FFmpeg filters), the audio delay is always floating. To get the output MP4 file, I tried concatenating the segments for video and audio streams (both at OS file level and with FFmpeg) and then muxing with FFmpeg.
I've tried everything I found on the web and I'm always ending up with exactly the same result. What's important, when I play the source from the manifest file, it's all good. That made me skim through the manifest once again, and I realized there's CodecPrivateData value which I'm not using anywhere in the process. What is it? Could it somehow help solving my problem?
Mystery solved: the manifest file contains the list of stream discontinuities, which need to be taken into account when concatenating the streams.
I'm developing a system using ffmpeg to store some ip camera videos.
i'm using the segmentation command for store each 5 minutes a video for camera.
I have a wpf view where i can search historycal videos by dates. In this case i use the ffmpeg command concat to generate a video with the desire duration.
All this work excelent, my question is: it's possible concatenate the current file of the segmentation? i need for example, make a serch from the X date to the current time, but the last file is not generated yet by the ffmpeg. when i concatenate the files, the last one is not showing because is not finish the segment.
I hope someone can give me some guidance on what I can do.
Some video formats can always be playable during the build process. That is, you can make a copy of the unfinished segmentation directly and use it to merge.
I suggest you use flv or ts format to do this. mp4 is not supported. Also note that there is a delay from encoding to actually writing to the disk.
I'm not sure if direct copy will cause some data problems at the end of the segmentation file, but ffmpeg will ignore this part of the data during the merge process, so the merged video should be fine.
I've unsuccessfully mucked around with this on my own and need help.
Given the public Web camera feed at https://itsvideo.arlingtonva.us:8011/live/cam58.stream/playlist.m3u8 I'd like to be able to be able to capture the video feed into an MP4 or MPG file with a reasonably accurate timestamp using the Windows command line (so I can put it into a batch script, etc.).
This is probably easy for someone who is already a wiz with VLC or FFmpeg or some such tool.
Additional wish list items would be to call up a higher resolution stream for a shorter duration (so as to balance I/O impact) and/or to just get still images instead of the video offered.
For instance, the m3u file has the following parameters:
#EXTM3U
#EXT-X-VERSION:3
#EXT-X-STREAM-INF:BANDWIDTH=214105,CODECS="avc1.100.40",RESOLUTION=352x288
chunklist_w977413411.m3u8
Would there be a way to substitute any of these to increase the resolution and reduce the video duration in a corresponding way so that net I/O is the same? Or even to just get a still image, whether higher res or not?
I have a serie of video files encoded in mpeg2 (I can change this encoding), and I have to produce a movie in flash flv (this is a requirement, I can't change that encoding).
One destination movie is a compilation of different source video files.
I have a playlist defining the destination movie. For example:
Video file Position Offset Length
little_gnomes 0 0 8.5
fairies 5.23 0.12 12.234
pixies 14 0 9.2
Video file is the name of the file, position is when the file should be started (in the master timeline), offset is the offset within the video file, and length is the length of the video to play. The numbers are seconds (in double).
This would result in something like that (final movie timeline):
0--5.23|--8.5|--14|--17.464|--23.2|
little_nomes **************
fairies *********************
pixies *****************
Where video overlaps, the last video to be added override the last one, the audio should be mixed.
The resulting video track would be:
0--5.23|--8.5|--14|--17.464|--23.2|
little_nomes *******
fairies ***********
pixies *****************
While the resulting audio would be:
0--5.23|--8.5|--14|--17.464|--23.2|
little_nomes 11111112222222
fairies 222222211112222222222
pixies 22222222221111111
Where 1 or 2 is the number of mixed audio tracks.
There can be a maximum of 3 audio tracks.
I need to write a program which takes the playlist as input and produce the flv file. I'm open to any solution (must be free/open source).
An existing tool that can do that would be the simplest, but I found none. As for making my own solution, I found only ffmpeg, I was able to do basic things with it, but the documentation is terribly lacking.
It can be any language, it doesn't have to be super fast (if it takes 30 minutes to build a 1h movie it's fine).
The solution will run on opensolaris based x64 servers. If I have to use linux, this would work too. But windows is out of the question.
I finally ended writing my solution from scratch, using ffmpeg library. It's a lot of boiler plate code but in the end the logic in not complicated.
I found the MLT framework which helped me greatly.
Here are two related questions:
Command line video editing tools
https://superuser.com/questions/74028/linux-command-line-tool-for-video-editing
Avisynth sounds as if it might do what you want, but it's Windows-only.
You may very well end up writing your own application using the FFmpeg library. You're right, the documentation could be better... but the tutorial by Stephen Dranger is a good place to start (if you don't know it yet).
Well, if you prefer Java, I've written several similar programs using Xuggler's API.
If your videos / images are already online, you may use the Stupeflix API to create the final videos. You can change the soundtrack, add filters to the video and much more. Here the documentation and an online demo : https://developer.stupeflix.com/documentation/ .