Is there any way to compress the video data while taking from camera ? There is huge difference in video data bytes from taking camera and from photo library.I want to reduce some memory while taking video from camera. Is any way ?
Thanks
I filed a bug report with Apple on this matter, you could do the same, seems the more reports from developers the faster they fix things up.
No matter what videoQuality level you set on the UIImagePickerController, it always defaults to High when recording from the camera. Videos chosen from the user library respect your choice and compress really well with the hardware H.264 encoder present on the 3GS and up.
You can use FFMpeg to get video directly from camera, compress it and store it to a file.
Also FFMpeg is a standalone console application, and it doesn't need any other dlls.
Of course, this isn't objective-c, but it can be very useful in your case.
Related
In my app users record themselves singing over a backing track, and then later playback the recorded audio and this backing track at the same time. I use expo-av for my audio system. The problem is that at the playback stage the audio is often out of sync because expo only really supports asynchronous audio. Does anyone have any advice on how to approach this problem at a high level?
A few of my ideas:
Mix the two audio files into a single file for playback. This almost works except for the fact that the recording and backing track are also out of sync. If I knew exactly how much they were offset, I could just add that amount of silence to one of the files when mixing. However, I haven't found a way to accurately calculate this offset.
Reduce time it takes for recording and playback to start, so that the latency is not noticeable. Some things I've found that help here are recording at lower quality and using smaller audio files. Any other tips here would be appreciated.
Use a different audio library than expo-av. Is there one that comes to mind that better supports synchronous audio? Ideally it would also be supported by Expo or at least React Native.
I have mp4 video file,which i need to load on my page,i am using MSE for that,but i don't know how can i get my video in segments with .m4s extensions,with header.m4s as parent segment with all information about my video file stored in it?Please help.
I believe that if a video is embedded on the website, it can be downloaded.
The only thing you could do is make it difficult for download.
This might be helpful. It says using a flash video is a good option to make downloading videos a bit difficult. Never used it but you could give it a try.
To protect the video, you should probably not try to artificially obfuscate the video loading. MPEG DASH supports encrypted MP4 video and common encryption (CENC), that could be a thing you can look into.
I got a question of image capture with a PC camera(integrated note book camera or web cam). While I am developing a computer vision system in which high quality image capture is the key issue, most of the current method is use VFW or directShow to capture video stream and snap one frame as an image.
However, this method could not get high quality image ( or using up the full capacity of the camera). For example, I got a 5 mega pixel web cam. but the video stream is maximum 720P(USB bandwidth problem?). Video streaming is wasting some of the camera sensors.
Could I video streaming and taking picture independently? like inputing video with a 640*480 video stream and render on the stream. then take a picture of 1280*720 from the same cam? I guess this would be a hardware problem? the new HTC one X camera?
In short, it's there a way for a PC system to take a picture ,full use of the sensor capacity, without video streaming and capture one frame. Is this a hardware related problem? Does common web cam support this? Or a Software problem, I should learn DirectShow things?
Thanks a lot.
I vaguely remember (some) video sources offer both a capture and still pin, the latter I assume would offer you higher quality. You can easily test this in GraphEdit. If it works then yes, you'll have to learn DirectShow. Or pay someone to code this for you.
I am developing a desktop application in Adobe AIR that will be used to stream the user's camera video to a wowza media server. I want to encode the video on the fly, means transmit the H.264 encoded video instead of the default flash player encoded video for quality purpose. Is there any way around for this?
Waiting for the help from people around,
Rick
H.264 encoding is usually done in Native Code C or C++ because it is a cpu
intensive set of algorithms. The source code for x264 can give you an
idea of the code required but it is a tough read if you start from scratch.
Here is a book to get you started or you can read the original AVC standard
if you suffer from insomnia.
I have a multimedia application that among other things converts video using FFMpeg. Video conversion being the pain that it is, I have in my test suits some tests that check our ability to convert various video formats, with emphasis on sample videos known not to work.
A common problem we've noticed from users is that some videos end up with their audio desynched after being processed, and I am looking for a way to check this in my tests.
Extracting the audio portion of the resulting videos is not a problem.
My best idea so far would be to check the offset of the first non-silence at both the beginning and end and compare each between the two videos, but I'm hoping someone smart has a better idea.
The application language/environment is Java, but since this is for testing, I'm free to use any toolset.
The basic problem is likely that the video and audio are different lengths. Extract the audio and test its length vs. the video length. If they are significantly different (more than maybe .05 sec, I'm not really sure what is detectable as "off"), then there's a problem.
To fix it, re-encode the audio to match the video length, and then put the audio and video back into a container format.