I would like to check used bandwidth when playing a video with MPMoviePlayerController to be able to play a video which matched client bandwidth.
For now, I download a part of my file by using NSURLConnection and I can find bandwidth. But I think it's not a good idea to download more data than expected (and the goal is to use as less bandwidth as possible).
Does a 'current downloaded bytes' property, or something like that, exist ? I hope you can help me.
Thanks a lot !
Take a look at the Reachability sample code, it will help you determine if the client is on WiFi,WWAN (3G/Edge), etc. You can make certain assumptions based on these findings. If you want exact speed, you'll download a file and check the speed.
You may want to look into HTTP video streaming, you can provide different (varying level of quality) versions of the video for each connection speed. The server determines the version to send.
Some docs on HTTP Streaming:
http://developer.apple.com/iphone/library/documentation/NetworkingInternet/Conceptual/StreamingMediaGuide/Introduction/Introduction.html
http://www.scribd.com/doc/20173481/iPhone-Streaming
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Developing an app that uses data synchronization. Sending images (even resized) takes time if it's done over slow internet connection. Thinking, it would be best first to check internet speed, and sent data only if the speed is acceptable. There's Apple Reachability class but it only has method for checking wifi is on. I guess for me, it would be enough to ping a host and grab delay information out of the ping cmd result. That delay info I would use for deciding is it worth to send data now or to wait.
Reachability or ping won't tell you how fast or slow the file will be transmitted. That is a function of ping_time + (file_size / bandwidth). For any large file, the ping_time is much smaller than file_size/bandwidth.
The easiest way to measure this is for the app to download and upload a not-too-small-not-too-large file and decide if in fact the upload and download speeds are "fast enough".
Doing this is fairly involved, however Apple has a complete working example program here:
https://developer.apple.com/library/mac/#samplecode/SimplePing/Introduction/Intro.html#//apple_ref/doc/uid/DTS10000716-Intro-DontLinkElementID_2
Once a month the mp3 streams messes up and the only way to tell it has messed up is by listening to it as it streams. Is there a script or program or tool I can use to monitor the live streams at a given url and send some kind of flag when it corrupts?
What happens is normally it plays a song for example or some music but once a month, every month, randomly, the stream corrupts and starts random chimpmunk like trash audio. Any ideas on this? I am just getting started at this with no idea at all.
Typically, this will happen when you play a track of the wrong sample rate.
Most (all that I've seen) SHOUTcast/Icecast encoders (going straight from files) will compress for MP3 just fine, but assume a fixed sample rate of whatever they are configured for. Typically this will be 44.1kHz. If you drop in a 48kHz track, or a 22.05kHz track, they will play at different speeds while causing all sorts of random issues with the stream.
The problem is easy enough to verify. Simply create a file of a different sample rate and test it. I suspect you will reproduce the problem. If that is the case, to my knowledge there is no way to detect it, since your stream isn't actually corrupt... it just sounds incorrect. You will have to scan all of your files for sample rate. FFMPEG in a script should be able to help you with that.
Now, if the problem actually is a corrupt MP3 stream, then you have problems on your encoding side. I suspect simply swapping out whatever DLL or module you're using with a recent stable version of LAME will help.
To detect a corrupt MP3 stream, your encoder must be using CRC. If you enable it, you should be able to read through the headers of each frame to find the CRC, and then run it on the audio data. In the event you get an error (or several frames with errors), you can then trigger a warning.
You can find information on the MP3 stream header here:
http://www.mp3-tech.org/programmer/frame_header.html
I just caught with a task which is how should i go about capturing a video in my app and saving it directly on some server. I have the sample code discussed in WWDC2010 but i just need some other more helpful links or tutorials to complete this task.
Please give me your opinion or share any links if you have.
Thanks,
There is nothing in the APIs that will allow you to do this. The only way is to use AVAssetWriters to segment the video. You would then stream the completed segments. These would need to be reassembled on the server side if you require a single file.
I am attempting to stream video using Apple's http streaming technology. I am beginning to suspect that either the player on the iPhone or the Apple tools used to segment the videos is buggy.
http://developer.apple.com/iphone/library/documentation/NetworkingInternet/Conceptual/StreamingMediaGuide/Introduction/Introduction.html
I am getting really terrible behavior. The app never seems to do a good job of choosing what quality stream to use. It always starts at the lowest quality and often will job to the highest very suddenly and not be able to keep up. I have tried various ways of altering the bandwidth settings to test it.
#EXT-X-STREAM-INF:PROGRAM-ID=1, BANDWIDTH=5000
3/prog_index.m3u8
#EXT-X-STREAM-INF:PROGRAM-ID=1, BANDWIDTH=10000
4/prog_index.m3u8
#EXT-X-STREAM-INF:PROGRAM-ID=1, BANDWIDTH=459319
5/prog_index.m3u8
#EXT-X-STREAM-INF:PROGRAM-ID=1, BANDWIDTH=90268800
I have used very large and small setting to make certain streams the obvious choice, but it doesn't matter. Obviously I also have used default the values set by Apple's variantplaylistcreator tool. It always starts at the lowest quality and will jump to seaming random other qualities.
Anyone know whats going on with this?
Have you tried the sample reference streams provided at the bottom of the page here? Apple tests against these, so if it works there, you know it's on your end.
I'm trying to read a real-time http video stream (I've set one up using VLC and my webcam) using libavcodec from ffmpeg. so far I've been able to read an mpeg file fine but when I pass a url instead of the file name it hangs (I assume it's waiting for the end of the file).
anyone have experience/ideas on how to do this? I'm also open to alternatives if people have other suggestions.
the end goal is to do live video-streaming on the iphone. apple's http live streaming has too much lag for what I need but that's for another post :)
any help is greatly appreciated!
if you aren't using apple's way, you can't.
I have to admit I dont quite understand what you want to achieve, however, based on my interpretation of the question it seems like it is related to the segmenting of the video.
The segmenting can be achieved using ffmpeg and libavcodec (look for example here, key line is the one with packet.flags). Just remember that the segment length (in time) depends on the keyframe interval (for h264 at least). If you want an example of a full segmented streaming solution that works (most of the time), check here.
Otherwise, you have to dig into the codec and create the transport stream manually. The MPEG2-TS, which is what iOS supports, can be a little bit difficult sometimes, but it is not too bad. Good luck!
you can use libcurl to download http segment file