I'm making an application which plays music from a remote server, and I would like to be able to sort by author/album/year/etc. AFAIK the only way to do this is by reading the metadata but I don't want to have to download the whole audio file just to read the metadata, is there any way to separate them and download only the metadata?

BTW. I am using webdav_client for flutter, which uses dio as a back-end so instructions for that specifically would be greatly appreciated. TY

CodePudding user response：

I don't think that it is possible to read just the ID3-metadata (at the beginning or the end) of the audiofile without downloading the entire file first.

One idea would be to extract this information on the server side and provide it separately, in addition to the audio file itself. To do this, you would need one of the well-known extraction tools available for your platform. However, if you need to download hundreds or thousands of companion files, I am not sure about the reliability of such a system.

CodePudding user response：

Firstly, you can usually make a request for a certain byte range by using ranged requests. This is dependent on server behavior. Most servers support it, but many don't.

Next, you need to figure out the location of the ID3 tags you want. Some versions of ID3 are located at the front of the file. Some are at the back. Therefore, you should probably request the first 128 KB or so of the file and search for ID3 data, while also getting the Length response header. Then if you don't find your tag at the beginning, you can make a request for the last 128 KB or whatever of the file, and search there.

Most MP3 files aren't very big, and bandwidth is usually plentiful. Depending on the size and scope of this project, you might actually find it more efficient to just download the whole files.