GPUImageMovieWriter and avfiletypempeg4 filetype

Question

First of all I would like congratulate Brad for the amazing work on GPUImage.

I'm trying to apply a rotation to a given video file and obtain an mpeg4 (AVFileTypeMPEG4) file as output.

When doing this I obtain the following message :

* -[AVAssetWriterInput appendSampleBuffer:] Input buffer must be in an uncompressed format when outputSettings is not nil

This problem occurs when using the following init method of GPUImageMovieWriter with filetype set to AVFileTypeMPEG4 :

- (id)initWithMovieURL:(NSURL *)newMovieURL size:(CGSize)newSize fileType:(NSString *)newFileType outputSettings:(NSMutableDictionary *)outputSettings;

However it works for the another init method which in fact generate quicktime movie (AVFileTypeQuickTimeMovie is set by default).

- (id)initWithMovieURL:(NSURL *)newMovieURL size:(CGSize)newSize;

Please can anybody say me if GPUImageWriter is capable from now to output mpeg4 movie file.

After many investigation and tries you can see below one of the several code I made.

movieFile = [[GPUImageMovie alloc] initWithURL:inputUrl];
movieFilter = [[GPUImageBrightnessFilter alloc] init];
[movieFilter setInputRotation:videoRotationMode atIndex:0];
[movieFile addTarget:movieFilter];
unlink([[outputUrl path] UTF8String]); // If a file already exists, AVAssetWriter won't let you record new frames, so delete the old movie

NSMutableDictionary *videoSettings = [[NSMutableDictionary alloc] init];;
[videoSettings setObject:AVVideoCodecH264 forKey:AVVideoCodecKey];
[videoSettings setObject:[NSNumber numberWithInteger:width] forKey:AVVideoWidthKey];
[videoSettings setObject:[NSNumber numberWithInteger:height] forKey:AVVideoHeightKey];



AudioChannelLayout channelLayout;
memset(&channelLayout, 0, sizeof(AudioChannelLayout));
channelLayout.mChannelLayoutTag = kAudioChannelLayoutTag_Stereo;

NSDictionary *audioSettings = [NSDictionary dictionaryWithObjectsAndKeys:
                                [ NSNumber numberWithInt: kAudioFormatMPEG4AAC], AVFormatIDKey,
                                [ NSNumber numberWithInt: 2 ], AVNumberOfChannelsKey,
                                [ NSNumber numberWithFloat: 16000.0 ], AVSampleRateKey,
                                [ NSData dataWithBytes:&channelLayout length: sizeof( AudioChannelLayout ) ], AVChannelLayoutKey,
                                [ NSNumber numberWithInt: 32000 ], AVEncoderBitRateKey,
                                nil];



// Will create quicktime file
movieWriter = [[GPUImageMovieWriter alloc] initWithMovieURL:outputUrl size:CGSizeMake(640.0, 480.0) fileType:AVFileTypeMPEG4 outputSettings:videoSettings];


[movieFilter addTarget:movieWriter];
// Configure this for video from the movie file, where we want to preserve all video frames and audio samples
movieWriter.shouldPassthroughAudio = NO; // default YES
[movieWriter setHasAudioTrack:TRUE audioSettings:audioSettings];
movieFile.audioEncodingTarget = movieWriter;
[movieFile enableSynchronizedEncodingUsingMovieWriter:movieWriter];

[movieWriter setDelegate:self];
[movieWriter startRecording];
[movieFile startProcessing];

Thanks in advance

PS : I'm using iOS6