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?
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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 have a link to some video stream (web cam that is always recording some place). I would like to be able to take a screenshot of what ever is on that video stream at the moment a user goes to my app.
Can it be done and how?
I have looked but all I could find was for taking screenshots out of a movie/video, not out of a streaming video.
I suspect ffmpeg connected to the streaming service as an input could probably extract thumbnails for you. You could either leave it running and pick up latest thumbnails, or fire it up with a system command and make it connect and emit a single screenshot. The latter would be more efficient and easier to code if you have a low number of hits, but would have a high latency on each request.
I did a quick search for you, but the most common uses of ffmpeg with streaming input is to re-format and re-stream, or to use it in personal video recorder setup. Ffmpeg is quite complex, so I could not complete the search in the time I have had so far.
As you may know, when you record a video on a windows phone, it is saved as a .mp4. I want to be able to access the video file (even if it's only stored in isolated storage for the app), and manipulate the pixel values for each frame.
I can't find anything that allows me to load a .mp4 into an app, then access the frames. I want to be able to save the manipulated video as .mp4 file as well, or be able to share it.
Has anyone figured out a good set of steps to do this?
My guess was to first load the .mp4 file into a Stream object. From here I don't know what exactly I can do, but I want to get it into a form where I can iterate through the frames, manipulate the pixels, then create a .mp4 with the audio again once the manipulation is completed.
I tried doing the exact same thing once. Unfortunately, there are no publicly available libraries that will help you with this. You will have to write your own code to do this.
The way to go about this would be to first read up on the storage format of mp4 and figure out how the frames are stored there. You can then read the mp4, extract the frames, modify them and stitch them back in the original format.
My biggest concern is that the hardware might not be powerful enough to accomplish this in a sufficiently small amount of time.
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.