I have mp3 files stored on the iPhone and I my application should to be able to read the ID3 information, i.e length in seconds, artist, etc.
Does anyone know how to do this or what library to use in Objective-C?
Your thoughts are much appreciated.
ID3 information can be read retrieving the kAudioFilePropertyInfoDictionary property of an audio file using the AudioFileGetProperty function of the AudioToolbox framework.
A detailed explanation is available at iphonedevbook.com
edit: Original link is now down. InformIT has some similar sample code, but it's not as complete.
Look into the Media Player framework:
Guide
Reference
All documentation
This requires that the MP3 in question is part of the iPod library on the phone.
For example, determining the name of every media file on the phone (including movies, podcasts, etc.):
MPMediaQuery *everything = [[MPMediaQuery alloc] init];
NSArray *itemsFromGenericQuery = [everything items];
for (MPMediaItem *item in itemsFromGenericQuery) {
NSString *itemTitle = [item valueForProperty:MPMediaItemPropertyTitle];
// ...
}
It appears that the following properties are available:
MPMediaItemPropertyMediaType
MPMediaItemPropertyTitle
MPMediaItemPropertyAlbumTitle
MPMediaItemPropertyArtist
MPMediaItemPropertyAlbumArtist
MPMediaItemPropertyGenre
MPMediaItemPropertyComposer
MPMediaItemPropertyPlaybackDuration
MPMediaItemPropertyAlbumTrackNumber
MPMediaItemPropertyAlbumTrackCount
MPMediaItemPropertyDiscNumber
MPMediaItemPropertyDiscCount
MPMediaItemPropertyArtwork
MPMediaItemPropertyLyrics
MPMediaItemPropertyIsCompilation
Doing this without going through the media player framework will be somewhat difficult, and will need an external framework.
There are not many ID3 parsing libraries out there that are not GPLed. There is on Objective-C framework that could probably be modified to work on the iPhone when statically linked, but it is LGPL. In order to satisfy the terms of the LGPL with a statically linked binary you have to provide enough of the intermediary components that someone could relink it with their own version of the library, which is difficult (but not impossible) for an iPhone app. Of course since I have not been in a position where I have had to do that I have not actually discussed it with a lawyer, and since I am not one you should not take that as authoritative.
Your best bet if you don't feel like consulting a lawyer is to use a more liberally licensed C library like libID3 and wrap that in some Objective C classes. I would also recommend just directly including the code rather than dealing with all the static library build and link issues, but that is just a personal style thing.
Related
I'm attempting to create an iOS 5 app with some very basic FTP functionality and need some guidance. It will be connecting to a device on a local network and performing read/write actions with .dat/txt files. I've done some searching for the past few days and have seen various recommendations but nothing simple enough that I can pick up and quickly modify for my personal use.
My questions are these:
Are there any tutorials/sample code that you could recommend to me?
What frameworks and classes should I be working with for basic read/write operations?
Lastly, I should mention that I have given a considerable amount of time to analyzing the SimpleFTPSample from Apple but the sample code is giving "Connection Failure" and "Stream Open Error" notices for each example, so I'm a bit wary of its usefulness.
Forgive me if this has been answered elsewhere. All of the related posts have pieces of the answer I need, but not the whole thing. Thank you in advance!
EDIT for clarity: A well-defined example or step-by-step tutorial is what I would really like. My own Google searches have turned up nothing and I am desperately in need of some guidance here.
UPDATE:
I posted this question long ago but have continued using the FTPHelper mentioned in the accepted answer. I recently brushed the dust off the old project and realized there was a minor memory leak in FTPHelper's fetch function that can be an app-killer if called repeatedly. If anybdy stumbles across this question and chooses to use FTPHelper, be sure to add the CFRelease line seen in the code below.
- (void) fetch: (NSString *) anItem
{
if (!self.uname || !self.pword) COMPLAIN_AND_BAIL(#"Please set user name and password first");
if (!self.urlString) COMPLAIN_AND_BAIL(#"Please set URL string first");
NSString *ftpRequest = [NSString stringWithFormat:#"%#/%#", self.urlString, [anItem stringByAddingPercentEscapesUsingEncoding:NSUTF8StringEncoding]];
/* CFShow(ftpRequest); */
NSString *writepath = [NSHomeDirectory() stringByAppendingPathComponent:#"Documents"];
self.filePath = [writepath stringByAppendingPathComponent:anItem];
CFURLRef writeURL = CFURLCreateFromFileSystemRepresentation (NULL, (const UInt8 *) [writepath UTF8String], [writepath length], NO);
MySimpleDownload((CFStringRef)ftpRequest, writeURL, (CFStringRef) self.uname, (CFStringRef)self.pword);
CFRelease(writeURL);//ADD THIS LINE TO FIX MEMORY LEAK
}
The SimpleFTPSample app is running perfect, probably there is an issue that you can't see. What I can recommend you (except Apple's example) is to check THIS example which contains a helper class for all basic FTP operations. One thing to be aware of is iOS 5 ARC. Both Apple's example and the one I linked are for older iOS versions.
There are basically 2 ways to use them in iOS 5 - by telling the compiler to not use ARC by adding -fno-objc-arc flag in [Your project] -> TARGETS -> [Your app] -> Build Phases -> Compile Sources -> [Your file], or by using the built-in tool in Xcode for converting to ARC.
I personally have tested only the first method and it works for me.
If this does not help you I can write an example, but unfortunately today I am very busy.
UPDATED:
The basic mechanism is to use [FTPHelper list:THE_FTP_URL] to list the content of a folder, then create one list with the content and depending on the type (file or folder) download using [FTPHelper download: THE_FTP_URL_WITH_THE_FILENAME_FROM_LISTING]. From here you have to implement
- (void) downloadFinished
{
//do the reading depending on the file type
NSData *data = [NSData dataWithContentsOfFile:[FTPHelper sharedInstance].filePath];
}
The uploading is achieved in a similar way - using [FTPHelper upload:FILE_TO_UPLOAD] with a file from the filesystem.
There are many libraries which you could use and they are working great. :)
For example:
http://www.chilkatsoft.com/ftp-objc.asp
http://code.google.com/p/ios-ftp-server/
I recommend using them, because coding one by yourself would take a lot of time :)
One thing to remember, as o15a3d4l11s2 said, is to be aware of ARC. If you use it don't forget to add build flags to libraries which aren't ARC.
I have to use the CAArchiver class for the serialization of the data coming from the .bin file in my iPhone project (I need to use it in a C++ code snippet). How do I do this?
I have also researched the following link: http://msdn.microsoft.com/en-us/library/caz3zy5s(v=vs.80).aspx. This appears to be used in .NET technology.
What am I supposed to do?
CArchive (as per your link) is part of the Microsoft Foundation Class Library. It's very unlikely that you will find an implementation for them on the iOS platform.
If you need only to provide a kind of serialization, Jigneshs answer is the way to go. If you need to be compatible to other output from CArchive then chances are that you will have to implement this by yourself.
I do not know what you want:
but there is a class in iphone
NSData *data = [NSKeyedArchiver archivedDataWithRootObject:dictionary];
Where dictionary can be NSObject
NSObject *dictionary = [NSKeyedUnarchiver unarchiveObjectWithData:data];
Where data is a binary i.e. NSData
Using this, I think it will be helpful what you were looking for....
I have mp3 files stored on the iPhone and I my application should to be able to read the ID3 information, i.e length in seconds, artist, etc.
Does anyone know how to do this or what library to use in Objective-C?
Your thoughts are much appreciated.
ID3 information can be read retrieving the kAudioFilePropertyInfoDictionary property of an audio file using the AudioFileGetProperty function of the AudioToolbox framework.
A detailed explanation is available at iphonedevbook.com
edit: Original link is now down. InformIT has some similar sample code, but it's not as complete.
Look into the Media Player framework:
Guide
Reference
All documentation
This requires that the MP3 in question is part of the iPod library on the phone.
For example, determining the name of every media file on the phone (including movies, podcasts, etc.):
MPMediaQuery *everything = [[MPMediaQuery alloc] init];
NSArray *itemsFromGenericQuery = [everything items];
for (MPMediaItem *item in itemsFromGenericQuery) {
NSString *itemTitle = [item valueForProperty:MPMediaItemPropertyTitle];
// ...
}
It appears that the following properties are available:
MPMediaItemPropertyMediaType
MPMediaItemPropertyTitle
MPMediaItemPropertyAlbumTitle
MPMediaItemPropertyArtist
MPMediaItemPropertyAlbumArtist
MPMediaItemPropertyGenre
MPMediaItemPropertyComposer
MPMediaItemPropertyPlaybackDuration
MPMediaItemPropertyAlbumTrackNumber
MPMediaItemPropertyAlbumTrackCount
MPMediaItemPropertyDiscNumber
MPMediaItemPropertyDiscCount
MPMediaItemPropertyArtwork
MPMediaItemPropertyLyrics
MPMediaItemPropertyIsCompilation
Doing this without going through the media player framework will be somewhat difficult, and will need an external framework.
There are not many ID3 parsing libraries out there that are not GPLed. There is on Objective-C framework that could probably be modified to work on the iPhone when statically linked, but it is LGPL. In order to satisfy the terms of the LGPL with a statically linked binary you have to provide enough of the intermediary components that someone could relink it with their own version of the library, which is difficult (but not impossible) for an iPhone app. Of course since I have not been in a position where I have had to do that I have not actually discussed it with a lawyer, and since I am not one you should not take that as authoritative.
Your best bet if you don't feel like consulting a lawyer is to use a more liberally licensed C library like libID3 and wrap that in some Objective C classes. I would also recommend just directly including the code rather than dealing with all the static library build and link issues, but that is just a personal style thing.
I'm considering using YAML as part of my next iPhone application, but I haven't been able to find an Objective-C library to use.
The Wikipedia page for YAML mentions one, but the link is dead.
Is there an Objective-C library that can parse YAML into native collection objects (NSArray, NSDictionary, etc...)?
The Cocoa extensions for Syck are probably what you're looking for -- it's where the library that Shaggy Frog mentioned seems to be living these days.
You can try YAML.framework it's LibYAML based, it's fast and easy to use. Follows the same pattern as standard NSPropertyListSerialization.
You can use it for iOS (iPhone/iPad) development.
The YAMLKit framework is a thin wrapper around LibYAML. It does exactly what you want. For example:
[[YKParser alloc] init];
[p readString:#"- foo\n- bar\n- baz"];
id result = [p parse];
/* result is now an NSArray containing an NSArray with elements:
#"foo", #"bar", #"baz" */
[p release];
I recently wrote modern ObjC-YAML bindings, based on the standard NSCoder/NSKeyedArchiver interface: http://github.com/th-in-gs/YACYAML. I'm using them in my own projects, and intend to maintain them for at least as long as I continue to do so.
More here: http://www.blog.montgomerie.net/yacyaml
IF you are doing alot of c++ in your iPhone projects, then please have a look at yaml-cpp:
http://code.google.com/p/yaml-cpp/
has native iPhone support (via it's cmake build system)
has no dependencies beyond a good compiler and cmake
is very c++ friendly (thus, the name) with solid documentation (see the wiki/HowToParseADocument page)
I found this right from YAML's front page. But it looks like it might be out of date (c. 2004?), and the CVS link doesn't work for me.
I would bet that it's just a thin wrapper around an underlying C library like this or this... C code being "native" code that the Objective-C compiler will grok.
I found this question looking for YAML + objective C options. I ended up using this solution: https://github.com/icanzilb/JSONModel. Very cool, up to date and easy to use. Parses yaml directly into objective C models that you create inheriting the JSONModel class.
I need to write some code that will let me query a m4a file and extract the chapter information out. Including:
chapter name
chapter start time
chapter artwork
I did some quick searching and it seems this is viewed as proprietary information by Apple? I found some discussions, but most were from 2005. Also there have been some similar questions on here, but more for CREATING m4a files with chapters, not querying.
Is this just something I have to DIY, cause there isn't a nice apple API for me to use? Or am I missing something obvious?
Also, ideally I need whatever technique I end up using to work on the iPhone.
The metadata tags system is Apple-proprietary. To work with the tags, you have to (sigh) reverse-engineer it or work with a library that has already done this.
I found the following links, but honestly it seems like you will have to pull out the hex editor.
Binary format info (basic spec for generic tags)
Perl library for working with M4A files.
Turns out this is much simpler than talked about here in the "answers". Not sure if this works on the iPhone, but I just tested it in a command line app:
QTMovie* movie = [QTMovie movieWithFile:#"filename.m4a" error:nil];
NSInteger numChapters = [movie chapterCount];
NSLog(#"Number of Chapters: %d", numChapters);
NSArray* chapterArray = [movie chapters];
for ( NSDictionary* chapDict in chapterArray )
{
NSLog(#"%#", [chapDict objectForKey:#"QTMovieChapterName"] );
}
Easy as pie. DOH!
this library should solve your needs, but is not runnable on iphone without jailbreaking I would think. http://wmptagext.sourceforge.net/
oops if you need it to work on iphone there is probably an apple api to get this info. /me looks
it sounds like you need to play around with the ipodlibrary library....
http://developer.apple.com/iphone/library/documentation/Audio/Conceptual/iPodLibraryAccess_Guide/UsingTheiPodLibrary/UsingTheiPodLibrary.html#//apple_ref/doc/uid/TP40008765-CH101-SW1
If the files in question live in the iPod library,
maybe you can get your information via the MPMediaLibrary
query interface (3.0 upward).