If yes, what movie format has best performance? And how would a simple setup look like? I have some views, and I want to play a short movie inside a view (not fullscreen). The movie is about 5 seconds long.
Looks like the system frameworks only support playing video full screen with the MPMoviePlayerController. Supported formats are basically flavors of H.264 and MPEG-4; more in the documentation.
Theoretically, you might be able to roll your own decoding and playback code, but I doubt you'd get acceptable performance. (And most of the Open Source media player examples I can think of are GPL. Not that I imagine they'd fare much better.)
If it's only 5 seconds long, you can fake it by playing the audio file in the background, and an animated UIImageView at the same time. Lots of apps do this like the ~50 or so baby sign language ones.
Related
I'm making a photo gallery app. I use the photos as slides and shows them one by one with transactions made by core animation.
Now I need to turn this process in to a video so that I can share it on Youtube, but I don't know where to start or which reference should I read.
To make video in iphone you can AVAssetWriter.
Also have a look this post. You can capture your animation as images and make the video.
The AVAsset Apple APIs is used to do this sort of thing is. But be warned, it is not easy to use. If you would like to check out a working example Xcode project, see AVDecodeEncode. This example shows decoding from h.264 and then encoding the result back to h.264. You could write all you own code to do this, but just be aware that it is not for the faint of heart.
I'm using the SimpleAudioEngine for cocos2d and when one track finished I would like to play another.
It only allows one background music to be preloaded at a time though. Would it be ridiculous to 'join' 2 .mp3s using audacity and then just convert to .caf and preload the whole thing?
Certainly not ridiculous, but be wary about how much memory your sounds require.
Also, why the conversion to .caf? You can play .mp3s. Is this just for compression?
I am playing a song in Cocos2D iphone using this line.
[[SimpleAudioEngine sharedEngine] playEffect:#"song.mp3"];
Suppose the mp3 is 1 min long, I want to play the song from 10 sec to 20 sec. Is it possible in Cocos2D iphone. Please help.
I don't think it is possible to "play the song from 10 sec to 20 sec" using the audio engine of cocos2d-iphone (which is named CocosDeshion).
SimpleAudioEngine is the main interface to CocosDeshion. Basically in cocos2d development we use audio files in two way - sound effect (short) and background music (long and usually loop). playEffect: is for the short ones, while playBackgroundMusic: and playBackgroundMusic:loop: is for the long ones. preloadBackgroundMusic: provides you the ability to cache the music in memory to avoid lag while playing, since they are often in compressed format.
As you can see in the documentation of SimpleAudioEngine (link above), there isn't such method for you to play a part of an audio file. Even the underlying class CDAudioManager doesn't support this.
I suggest to extract the 0:10 - 0:20 part as a separate audio file. But if you have a special reason to do this, you may want to use audio playback interfaces (such as AVAudioPlayer) in iOS SDK directly. Please refer to: http://developer.apple.com/library/ios/#documentation/AudioVideo/Conceptual/MultimediaPG/UsingAudio/UsingAudio.html
I need to play sounds (~5 seconds each) throughout my iphone application. When they're triggered, they need to play immediately.
For the moment I'm using AudioServices and (as you probably know) the first time you play a sound it lags, then every time there after it's perfect. Is there some code available that's clever enough to preload an AudioServices sound (by playing it silently maybe?). I've read adjusting the system volume programmatically will get your app rejected, so that's not an option. Seems AudioServices isn't made for volume correction from what I can see.
I've looked into OpenAL and while feasible seems a little over kill. AVAudioPlayer seems like a little bit of a better option, I'm using that for background music at present. Extending my music player to handle a 'sound board' might be my last resort.
On the topic of OpenAL, does anyone know of a place with a decent (app store friendly) OpenAL wrapper for the iPhone?
Thanks in advance
Finch could be perfect for you. It’s a tiny wrapper around OpenAL with very low latency and simple API. See also all SO questions tagged ‘Finch’.
If you use an AVAudioPlayer, you can call prepareToPlay when you initialize the object to reduce the delay between calling play and having the audio start.
I built an iPhone app using AudioServices to play short sounds. The first time a sound is played, there's a delay of half a second or so while the sound loads before it plays. This definitely makes for an awkward user experience.
Is there a way to preload sounds for AudioServices to play, or do I need to switch to audioQueues or some other method of playing sounds?
Thanks,
Maha
This is a well known problem. Everything in AudioServices is initialized lazily.
I think that your best choice is between Core Audio or OpenAL. OpenAL might be overkill, but it has a simple API. The oalTouch example is a good place to start.
Core Audio is a bit more raw, but it's well documented. The iPhone's OpenAL SDK is built on top of it.