metadata

问题 I can't seem to get image metadata to be written to the image correctly if the key/val is already present in the original image metadata with CGImageDestination. It works just fine if it they key/val is not present in the original metadata. It's almost as though image metadata properties in the original image take precedence over modifications. Is this some kind of byzantine formatting issue I am not aware of, where I need to populate the key/val in some unusual way, a bug, or? Anyone else

问题 I have successfully added metadata to a jpg created within the app and saved it to the Camera Roll using the writeImageToSavedPhotosAlbum: metadata: completionBlock: method. However I would also like the option of emailing this jpg with the metadata (such as location, exit, etc.). I use this to email: MFMailComposeViewController *picker = [[MFMailComposeViewController alloc] init]; picker.mailComposeDelegate = self; NSData *myData = UIImageJPEGRepresentation(emailImage, 0.8); [picker

问题 I have successfully added metadata to a jpg created within the app and saved it to the Camera Roll using the writeImageToSavedPhotosAlbum: metadata: completionBlock: method. However I would also like the option of emailing this jpg with the metadata (such as location, exit, etc.). I use this to email: MFMailComposeViewController *picker = [[MFMailComposeViewController alloc] init]; picker.mailComposeDelegate = self; NSData *myData = UIImageJPEGRepresentation(emailImage, 0.8); [picker

问题 properties> date created... i thought this meant the date the video was created, but finally realized that date changes every time i move, reorganize, even open a file. often, the date modified is earlier than date created. the date a jpeg was taken is readily available. is there any way to get the same information from an AVI or MP4 FILE? thank you for any information you can give. 回答1: There doesn't seem to be a well defined standard for video metadata (compared to photos and audio files,

问题 This question was migrated from Server Fault because it can be answered on Stack Overflow. Migrated 10 years ago . I know things like images, music, videos support metadata. My idea is that I want to write a download manager that adds info to the files I download: the URL I downloaded it from, the date and time I downloaded it, possibly some more. For this to work I need to add info for more than just photos and videos. I could just save a hidden .XML flie, but if Windows supports this

问题 I want to enhance my sites loading speed, so I use http://gtmetrix.com/, to check what I could improve. One of the lowest rating I get for "Leverage browser caching". I found, that my files (mainly images), have problem "expiration not specified". Okay, problem is clear, I thought. I start to googling and I found that amazon S3 prefer Cache-Control meta data over Expiry date (I lost this link, now I think maybe I misunderstood something). Anyway, I start looking for how to add cache-control

问题 I am looking for some library to read/write IPTC metadata from Jpg files. Open source or paid, doesn't matter. It should work with .NET 3.5 and c#. Does anybody know such a library? I googled but haven't found anything. 回答1: *http://msdn.microsoft.com/en-us/library/system.windows.media.imaging.aspx using System; using System.IO; using System.Linq; using System.Windows.Media.Imaging; namespace wictest { class Program { static void Main(string[] args) { var stream = new FileStream("1.jpg",

问题 I have to create app that provides online radio streaming (icecast), preferably .ogg format. So I have next questions: How can I play .ogg format audio stream? Are there any supported classes? Because I can't find any, so I think that it is impossible without many bitwise operations using CFNetwork , CoreAudio , AudioToolbox etc. (I don't look at cocos2d, because it's ridiculous) Am i wrong? I'm playing mp3 stream for now (no possibility for .ogg for me). I tried to use AVPlayer ,

问题 I'm developing an Android application that relies on FFmpeg to retrieve audio metadata. I know it's possible to retrieve album art programmatically using FFMpeg. However, once you have decoded the art (a video frame within an MP3) how do generate an image file (a PNG) for use within an application? I've search all over but can't seem to find a working example. Edit, here is the solution: #include <libavcodec/avcodec.h> #include <libavformat/avformat.h> void retrieve_album_art(const char *path

问题 I've seen the extraction of basic metadata (ie. author, title) using iTextSharp and it usually looks something like this: var pdfReader = new PdfReader(pdfData); var author = pdfReader.Info["author"] However, in my case I'm after something a bit more exotic, the additional "advanced" metadata that the document may contain. Pardon the paint highlights, but here is a screenshot from within Adobe Acrobat showing the data in question: In this case, it doesn't seem like this data is available