使用Qt通过TagLib获取mp3封面

Question

I'm making an audioplayer for my course project in university. I'm a first-year student, so I'm not a professional programmer.

I'm using Qt 5.4 and QtCreator 3.3.1. I've included bass.dll and TagLib libraries to work with audiofiles. What am I trying to do is to get the song's cover art and pass it to QLabel (or any other widget if more convenient) on my player's GUI. I haven't really figured out how to do it. I've been searching for examples for a while but I always end up in having errors or wrong examples. Below is the last code I've tried to use.

TagLib::MPEG::File file(reinterpret_cast<const wchar_t*>(curSong->path.constData()));
TagLib::ID3v2::Tag *m_tag = file.ID3v2Tag(true);
TagLib::ID3v2::FrameList frameList = m_tag->frameList("APIC");
   if(frameList.isEmpty()) {
       return QImage();
   }

   TagLib::ID3v2::AttachedPictureFrame *coverImg = static_cast<TagLib::ID3v2::AttachedPictureFrame *>(frameList.front());

   QImage coverQImg;
   coverQImg.loadFromData((const uchar *) coverImg->picture().data(), coverImg->picture().size());

   return coverQImg;

This one doesn't work for me because it causes errors such as

C:\Qt\Projects\audioPlayer\mainwindow.cpp:553: error: undefined reference to `TagLib::List<TagLib::ID3v2::Frame*>::List(TagLib::List<TagLib::ID3v2::Frame*> const&)'

I suppose I've messed up with libraries, but I'm sure I've included id3v2frame.h and id3v2tag.h

Answer 1

不知道在哪里找到了id3v3frame.h （最新版本是id3v2frame.h ），但是TagLib::ID3v2::FrameList是在id3v2tag.h声明的。

Answer 2

You may explore a solution with ffmpeg .

ffmpeg -i input.mp3 -an -vcodec copy cover.jpg

• https://code.google.com/p/qtffmpegwrapper/