i'm writing an app to play some media encrypted files
Normally,we can decrypt these files and play it.But i don't want anybody can get this decrypt file when app is playing this file.
Or i want protect these file.
I'm researching but i don't find a solution.
Can anyone suggest to me a solution?Can anyway to protect media files without encryption?
Thanks so much.
Regards
The short answer: You can't stop copying, no matter how hard you try.
The long answer: This problem has been around since the dawn of Internet distribution. Nobody has solved it effectively yet. The problem is that if a user jailbreaks a device they can do anything that the hardware is capable of. This includes recording directly from the audio buffer into a file, making it a simple process to capture your file while it is playing and dump the contents into another file. Therefore, if you can play it, you can copy it. The only solution that I can see working is to build your own hardware that doesn't allow external access to the audio buffer, but that is impossible for 99% of people and impractical for 100%.
The compromise: The best you can do is make it more trouble than it is worth for the user. If you can decrypt into a memory buffer then it will be an annoying task to get the data, and most people will probably not put the effort into it.
Related
Summary:
While a video is streaming in the internet browser, packets of mp4 files are being downloaded.
I would like to write some code that saves the packets into one file so the video is preserved after it is done streaming.
I think this could be done by taking the packets in as byte files, removing how ever many bytes the addressing header at the front is made out of, and then concatenating the rest, but I will be the first to admit that I have never done anything like this before and don't really know what I am doing.
If anyone out there has experience with with this kind of thing, I am not looking for much, just a few words to point me in the right direction, or at least keep me from going too far in the wrong direction. I am really just coming at this project with half a CS degree and some notions about what to google right now.
Specific Questions:
Do you know how I can access the data packs being downloaded from the internet? For example, if I wanted to make a script that grabbed each of the mp4 data packs as they came in, what kind of command would I use to access them?
Do you know what would be the best way to save the video file? Should I access the data packs as they come in? or should I access them later, as they have been strung together by the media player? Is the second part even possible or would the data be protected by that time?
If you don't have answers to these questions, are you able to give me a reference to a place the does? I haven't been able to find this subject on stack. Even some good keywords to search for would be useful.
Thanks for taking the time to read,
-Coder 357
TLDR: Trying to make code or script to save the mp4 packets into video files as they are streamed.
Progress So Far:
I suppose all I have done is press f12 and open up the network activity section of the internet page, streaming the video I want to capture. I know that I am rapidly fetching mp4 files in the kb and mb size range. That is what lead me to my conclusion that I will likely need to string these mp4 files together into one file, after removing any extra bits and bytes at the front and end.
That being said, I don't have an understanding of how my media player holds the data, so there may be a much more convenient way to do this that I am not seeing.
Goal:
My best case expectation for the project is to have a program or script which can be run from the command line and will then combined mp4 data packets, from a given website, into a single video file.
I'm working on a mobile application that can perform basic analysis on audio input from the microphone in real time. However, the usual way to do it using the 'AVAudioRecorder` as shown in this guide and the API requires you to save it to a file first.
Since the app is meant to stay on for a long time and be used multiple times a day, I want to avoid clutter the phone with many audio files or audio files that are too big. However, I can't seem to find the way around it. Searching for solutions on the internet always lead to solutions of how to save an audio to a file, instead of avoiding saving to a file and work with some kind of buffer.
Any pointers would be super helpful!
Both the iOS Audio Unit and the Audio Queue APIs allow one to process short buffers of audio input in real-time without saving to a file.
You can also use a tap on the AVAudioEngine. See Apple's documentation: https://developer.apple.com/library/ios/samplecode/AVAEMixerSample/Introduction/Intro.html
You can use /dev/null as path in the AVAudioRecorder instance. This way it will not save to a file, but just discard the data.
var url = NSUrl.FromString("/dev/null");
var recorder = new AVAudioRecorder(url, settings, out error);
I've got an app that currently ships with all the videos it can play embedded in it. This doesn't scale well, and unless you want to play all the movies, wastes disk space. It also makes it less desirable to upgrade the app because you have to re-download all movies.
What I would like to do is download the movie on the fly, play it back while downloading, and then if it's successfully downloaded, save it to the file system so that next time they want to watch it, it streams from the local file.
I can do whatever is needed to the video, but currently I'm serving it up as an .mp4 file from Amazon S3, with a mimetype of video/mp4, and so the first half of my issue works fine: the movie downloads, and MPMovieViewController will start playing it as soon as it thinks it has downloaded "enough."
Is there any way to tap into the cache of that video file so that I can save it and control how long it resides on the filesystem? This seems like it would be the easiest approach.
I am targeting iOS 5+6, but if the only solution available required iOS 6, I would consider it also. Thanks!
UPDATE: Using AFNetworking, I am now half-way there, I think. I am downloading the video file from the server, and listening for the download progress. Once I see 25% of the video has been downloaded, I start playback on the local file using an MPMoviePlayerController.
The main issue I'm running into now is playback seems to get screwed up. It's going along fine, 25% downloaded, playback starts... download continues normally... then the file finishes downloading completely, and shortly thereafter video freezes. The onscreen playback timer still indicates playback is ongoing and I don't see any "playback finished" type notifications, but the video is frozen. My guess based on the behavior is that perhaps the initial buffer for the video playback was used up, and it isn't detecting that more video is available on disk now?
Is there any way to interact with MPMoviePlayerController to let it know periodically to refresh the buffer it's playing out of? Or some other way to handle this situation?
UPDATE: Make sure to see the newer answer from #TomHamming.
I have yet to find a conclusive answer, but at this time I believe the answer is: you can't reliably do this. At least not without a lot of work which seems too much like a hack. I filed a feature request with Apple as it really seems like this should be possible with some adjustments to MPMoviePlayerController.
I will go over the variety of things I tried or considered, and the results I encountered.
Pass MPMoviePlayerController a URL to your movie file, which allows it to stream, and then pull the file out of the cache it was saved into, into your local Documents folder. Won't work, as of iOS 6. I filed a feature request with Apple, but as it stands now there's no way to get your hands on the file they are downloading, AFAIK.
Start downloading the movie file with NSURLConnection (or something like AFNetwork), and then when a "decent amount" has been downloaded to the device, pass the file URL to the MPMoviePlayerController and let it stream from disk. Sort of works, but not well. Three problems:
It's really hard to know when to start playing the file. I haven't figured out the algorithm Apple uses, and so I always erred on the side of caution, waiting for 25% to be downloaded before playing.
The MPMoviePlayerController interface provides no sense of the movie being streamed, as it does when Apple is doing the calculations via the network. It appears to the user that the file is totally downloaded when it really is not.
And most importantly, MPMoviePlayerController seems to not work well with playing a file that is not completely downloaded. I experienced playback problems once the file finished downloading, or if the player caught up with the amount downloaded, and never found a graceful way to handle these situations.
Same procedure as above, but use AVFoundation classes to more finely control the playback process, and avoid the issues described above regarding playback stopping, etc. Might work, but I want all the features of MPMoviePlayerController. Re-implementing MPMoviePlayerController myself just to get this one feature seems like a waste of time.
Same procedure as #1 above, but run a small web server in your app to handle streaming the video from the disk to MPMoviePlayerController, with the hope being that the streaming would work more like it normally does when streaming the file directly from an external web server. Works, but results were still sporadic and performance seemed to suffer. I did my test with CocoaHTTP. I decided against this approach because it just felt like a terrible hack.
Run a lightweight HTTP proxy, thus intercepting the downloaded movie file data as it gets streamed from the internet into your MPMoviePlayerController. Not sure if this works or not. I was not able to test this yet, as I have not found a lightweight HTTP proxy written in Objective-C, and at this point don't feel like implementing one just to try this experiment. It seems like the next easiest of all these hacks to implement -- if you don't have to write the proxy!
At this point I've decided to go the less-hacky, but also less user-friendly route of simply downloading the file completely, and then passing it to MPMoviePlayerController, until a better solution comes along.
You can do this as of iOS 10 with AVAssetDownloadTask. See this WWDC 2016 session and this documentation.
Alternatively, if your movie isn't DRM'd, you can do it with AVAssetResourceLoaderDelegate, which effectively lets you give an AVPlayer an arbitrary stream of bytes. See this walkthrough.
I have a little app that works with iCloud. It stores audio files into the cloud. I noticed that loading the audio files from a second device doesn't work immediately. So I implemented
- (BOOL)downloadFileIfNotAvailable:(NSURL*)file
That helped but still it works sluggish.
I wanted to speed up the downloading process on other iCloud devices by wrapping the audio file in a UIDocument. Is this even possible? I could store the file contents in a NSData, but is there a point (seeing as how AVAudioPlayer wants a URL)? Is there another way for me to speed up the synchronization?
Thanks
You can use NSFileCoordinator's coordinateReadingItemAtURL method for this. Take a look at the answer from this SO?
It is possible to implement a feature that allows users to watch videos as they are uploaded to server by others. Is html 5 suitable for this task? But flash? Are there any read to go solutions, don't want to reinvent the wheel. The application will be hosted on a dedicated server.
Thanks.
Of course it is possible, the data is there isnt it?
However it will be very hard to implement.
Also I am not so into python and I am not aware of a library or service suiting your requirements, but I can cover the basics of video streaming.
I assume you are talking about video files that are uploaded and not streams. Because, for that, there are obviously thousands of solutions out there...
In the most simple case the video being uploaded is already ready to be served to your clients and has a so called "faststart atom". They are container format specific and there are sometimes a bunch of them. The most common is the moov-atom. It contains a lot of data and is very complex, however in our use case, in a nutshell, it holds the data that enables the client to begin playing the video right away using the data available from the beginning.
You need that if you have progressive download videos (youtube...), meaning where a file is served from a Webserver. You obviously have not downloaded the full file and the player already can start playing.
If the fastastart atom was not present, that would not be possible.
Sometimes it is, but the player for example cannot display a progress bar, because it doesnt know how long the file is.
Having that covered the file could be uploaded. You will need an upload solution that writes the data directly to a buffer or a file. (file will be easier...).
This is almost always the case, for example PHP creates a file in the tmp_dir. You can also specify it if you want to find the video while its being uploaded.
Well, now you can start reading that file byte by byte and print that data to a connection to another client. Just be sure not to go ahead of what has already been recieved and written. You would probaby initiate your upload with a metadata set in memory that holds the current recieved byte position and location of the file.
Anyone who requests the file after the uploaded has started can just recieve the entire file, or if the upload is not yet finished, get it from your application.
You will have to throttle the data delivery or pause it when the data becomes short. This will appear to the client almost as a "slow connection". However you will have to echo some data from time to time to prevent the connection from closing. But if your upload doesnt stall, and why shoud it?, that shouldnt be a problem.
Now if you want to have someting like on the fly transcoding of various input formats into your desired output format, things get interesting.
AFAIK ffmpeg has neat apis which lets you directly deal with datasterams.
Also handbrake is a very good tool, however you would need to take the long road using external executeables.
I am not really aware of your requirements, however if your clients are already tuned in, for example on a red 5 streaming server, feeding data into a stream should also work fine.
Yes, take a look at Qik, http://qik.com/
"Instant Video Sharing ... Videos can be viewed live (right as they are being recorded) or anytime later."
Qik provides developer APIs, including ones like these:
qik.stream.subscribe_public_recent -- Subscribe to the videos (live and recorded)
qik.user.following -- Provides the list of people the user is following
qik.stream.public_info -- Get public information for a specific video
It is most certainly to do this, but it won't be trivial. And no, I don't think that you will find an "out of the box" solution that will require little effort on your behalf.
You say you want to let:
users watch videos as they are uploaded to server by others
Well, this could be interpreted two different ways:
Do you mean that you don't want a user to have to refresh the page before seeing new videos that other users have just finished uploading?
Or do you mean that you want one user to be able to watch a partially uploaded video (aka another user is still in the process of uploading it and right now the server only contains a partial upload of the video)?
Implementing #1 wouldn't be hard at all whatsoever. You would just need an AJAX script to check for newly uploaded videos, and those videos could then be served to the user in whatever way you choose. HTML5 vs. Flash isn't really a consideration here.
The second scenario, on the other hand, would require quite a bit of effort. I am guessing that HTML5 might not be mature enough to handle this type of situation. If you are not looking
to reinvent the wheel and don't have a lot of time to dedicate to this feature than I would say that you would be out of luck. You may be able to use ffmpeg to parse partial video files and feed them to a Flash player, but I would think of this as a large task.