Question

有没有人知道有关Audible Audio（.aa）文件规范的好资源？

我正在尝试编写一个可以使用它们的程序，如果没有人知道某个资源，那么有关逆向工程的技巧是什么？我在Hex编辑器中打开它并且四处张开，看起来像一个MP3，但有更多的标题信息。

Answer 1

此网站提供了有关.aa文件中某些数据块所在位置的更多信息。

http://wiki.multimedia.cx/index.php?title=Audible_Audio

Answer 2

我已经对Audible标题进行了一些研究，以便为我的汽车收音机/电脑创建一个播放器。基本上在文件的开头有一个3700个字符的块，包含许多感兴趣的字段，例如标题，作者，讲述者等。我在C＃中有一些有限的解析代码来显示来自的一些基本信息。 .aa文件。如下：

   private void ParseFields(string fileName)
    {
        string aaHeader;
        string tryDate;
        if (fileName == "") return;

        using (StreamReader sr = new StreamReader(fileName))
        {
            char[] buff = new char[3700];
            sr.Read(buff, 0, buff.Length);
            aaHeader = new string(buff);
        }
        try
        {
            _author = GetParsedItem(aaHeader, "author");
        }
        catch
        {
            _author = "?";
        }
        try
        {
            _title = GetParsedItem(aaHeader, "short_title");
        }
        catch
        {
            _title = "???";
        }
        try
        {
            _narrator = GetParsedItem(aaHeader, "narrator");
        }
        catch
        {
            _narrator = "?";
        }
        try
        {
            _description = GetParsedItem(aaHeader, "description");
        }
        catch
        {
            _description = "???";
        }
        try
        {
            _longDescription = GetParsedItem(aaHeader, "long_description");
        }
        catch
        {
            _longDescription = "";
        }
        try
        {
            tryDate = GetParsedItem(aaHeader, "pubdate");
            if (tryDate != "")
                _pubDate = Convert.ToDateTime(GetParsedItem(aaHeader, "pubdate"));
            else
                _pubDate = DateTime.Today;
        }
        catch
        {
            _pubDate = DateTime.Today; 
        }
    }
    private string GetParsedItem(string buffer, string fieldName)
    {
        if (buffer.Contains(fieldName))
        {
            int pos = buffer.IndexOf(fieldName);
            pos += fieldName.Length;
            int posEnd = buffer.IndexOf('\0',pos);
            //if the value for the field is empty, skip it and look for another
            if (pos == posEnd)
            {
                pos = buffer.IndexOf(fieldName, posEnd);
                pos += fieldName.Length;
                posEnd = buffer.IndexOf('\0', pos);
            }
            return buffer.Substring(pos, posEnd - pos);
        }
        else
            return "(not found - " + fieldName + ")";
    }

Answer 3

我认为，没有规范。看看Wikipedia/Audible.com：

报价：

[...]
Audible introduced one of the first digital audio players in 1997.
The following year it published a Web site from which audio files in its
proprietary .aa format could be downloaded. Audible holds a number of patents
in this area.
[...]

摘要：专有/专利

Audible Audio（.aa）文件规范？

3 个答案: