Task 050: .AX File Format
Task 050: .AX File Format
The .AX file format, based on available information, is primarily associated with Microsoft’s DirectShow Filter, which is a type of plugin used by media players like Windows Media Player to process video and audio data streams. These files are essentially DLLs (Dynamic Link Libraries) with an .AX extension, used for tasks such as decoding, encoding, parsing, and rendering multimedia content. However, there is no publicly available, detailed specification for the internal structure of .AX files, as they are proprietary and part of Microsoft’s DirectShow framework. Additionally, some sources mention other uses of the .AX extension (e.g., Opera AX Data or Modula-3 Linker Information), but these are less common and lack detailed specifications as well. For this response, I’ll focus on the DirectShow Filter context, as it’s the most prevalent and well-documented use of the .AX extension.
Since the exact internal structure (e.g., binary layout, headers, or metadata) of .AX files is not publicly documented, I’ll define a set of intrinsic properties based on their role as DirectShow filters and their general behavior as DLLs in the Windows file system. For the programming tasks, I’ll assume a simplified model where we treat the .AX file as a DLL and extract available metadata (e.g., file properties like size, path, and version info) and attempt to identify its role as a DirectShow filter. The code will focus on reading and writing basic file data and printing relevant properties, as decoding the proprietary filter logic requires reverse-engineering, which is beyond the scope of this task.
1. Properties of the .AX File Format Intrinsic to Its File System
Based on the role of .AX files as DirectShow Filter plugins (DLLs), the following properties are intrinsic to their file system representation:
- File Extension: .AX
- File Type: Dynamic Link Library (DLL), specifically a DirectShow filter.
- MIME Type: application/octet-stream (typical for DLLs).
- File Size: Size of the file in bytes, variable depending on the filter’s complexity.
- File Path: Absolute or relative path where the .AX file resides in the file system.
- Creation Date: Timestamp when the file was created.
- Modification Date: Timestamp when the file was last modified.
- Access Date: Timestamp when the file was last accessed.
- File Attributes: Standard Windows file attributes (e.g., read-only, hidden, system).
- DLL Version Information: Metadata embedded in the DLL, such as version number, company name (e.g., Microsoft), and description (e.g., “DirectShow Filter”).
- Filter Type: Functional role in DirectShow (e.g., source filter, parsing filter, rendering filter), though this may require parsing internal DLL metadata.
- Digital Signature: Whether the file is digitally signed (common for Microsoft-provided .AX files like Msnp.ax or Mpeg2data.ax).
These properties are derived from the file’s role as a DLL and its integration into the Windows file system, as no public specification details the internal binary structure of .AX files.
2. Python Class for .AX File Handling
import os
import win32api
import win32con
import datetime
from pathlib import Path
import pefile
class AXFileHandler:
def __init__(self, filepath):
self.filepath = filepath
self.properties = {}
def read_properties(self):
"""Read and decode properties of the .AX file."""
try:
# Basic file system properties
file_stats = os.stat(self.filepath)
self.properties['File Extension'] = Path(self.filepath).suffix
self.properties['File Type'] = 'DirectShow Filter (DLL)'
self.properties['MIME Type'] = 'application/octet-stream'
self.properties['File Size'] = file_stats.st_size
self.properties['File Path'] = self.filepath
self.properties['Creation Date'] = datetime.datetime.fromtimestamp(file_stats.st_ctime).isoformat()
self.properties['Modification Date'] = datetime.datetime.fromtimestamp(file_stats.st_mtime).isoformat()
self.properties['Access Date'] = datetime.datetime.fromtimestamp(file_stats.st_atime).isoformat()
self.properties['File Attributes'] = self._get_file_attributes()
# DLL-specific properties using pefile
pe = pefile.PE(self.filepath)
version_info = self._get_version_info()
self.properties['DLL Version'] = version_info.get('FileVersion', 'Unknown')
self.properties['Company Name'] = version_info.get('CompanyName', 'Unknown')
self.properties['Description'] = version_info.get('FileDescription', 'DirectShow Filter')
self.properties['Digital Signature'] = self._has_digital_signature(pe)
# Filter type (heuristic, as exact type requires internal parsing)
self.properties['Filter Type'] = self._guess_filter_type()
except Exception as e:
print(f"Error reading properties: {e}")
def _get_file_attributes(self):
"""Get Windows file attributes."""
attrs = win32api.GetFileAttributes(self.filepath)
attr_list = []
if attrs & win32con.FILE_ATTRIBUTE_READONLY:
attr_list.append('Read-Only')
if attrs & win32con.FILE_ATTRIBUTE_HIDDEN:
attr_list.append('Hidden')
if attrs & win32con.FILE_ATTRIBUTE_SYSTEM:
attr_list.append('System')
return ', '.join(attr_list) or 'None'
def _get_version_info(self):
"""Extract version information from DLL."""
try:
info = win32api.GetFileVersionInfo(self.filepath, '\\')
return {
'FileVersion': f"{info['FileVersionMS'] >> 16}.{info['FileVersionMS'] & 0xFFFF}.{info['FileVersionLS'] >> 16}.{info['FileVersionLS'] & 0xFFFF}",
'CompanyName': win32api.GetFileVersionInfo(self.filepath, '\\StringFileInfo\\040904b0\\CompanyName') or 'Unknown',
'FileDescription': win32api.GetFileVersionInfo(self.filepath, '\\StringFileInfo\\040904b0\\FileDescription') or 'DirectShow Filter'
}
except:
return {}
def _has_digital_signature(self, pe):
"""Check if the file has a digital signature."""
return bool(pe.OPTIONAL_HEADER.DATA_DIRECTORY[pefile.DIRECTORY_ENTRY['IMAGE_DIRECTORY_ENTRY_SECURITY']].VirtualAddress)
def _guess_filter_type(self):
"""Heuristic to guess filter type based on filename (e.g., Msnp.ax, Mpeg2data.ax)."""
filename = Path(self.filepath).stem.lower()
if 'mpeg' in filename:
return 'Parsing Filter (likely MPEG-related)'
elif 'render' in filename:
return 'Rendering Filter'
else:
return 'Unknown Filter Type'
def write_properties(self, output_filepath):
"""Write properties to a new .AX file (copy of original)."""
try:
with open(self.filepath, 'rb') as src, open(output_filepath, 'wb') as dst:
dst.write(src.read())
print(f"Properties written to {output_filepath}")
except Exception as e:
print(f"Error writing file: {e}")
def print_properties(self):
"""Print all properties to console."""
for key, value in self.properties.items():
print(f"{key}: {value}")
# Example usage
if __name__ == "__main__":
ax_file = AXFileHandler("example.ax")
ax_file.read_properties()
ax_file.print_properties()
ax_file.write_properties("output.ax")
Notes:
- Requires
pywin32(pip install pywin32) andpefile(pip install pefile) for DLL metadata. - The
write_propertiesmethod creates a copy of the .AX file, as modifying the internal structure is not feasible without proprietary specs. - The
Filter Typeis a heuristic guess, as exact filter roles are not exposed in public documentation.
3. Java Class for .AX File Handling
import java.io.*;
import java.nio.file.*;
import java.nio.file.attribute.*;
import java.util.*;
import com.sun.jna.platform.win32.*;
public class AXFileHandler {
private String filepath;
private Map<String, String> properties;
public AXFileHandler(String filepath) {
this.filepath = filepath;
this.properties = new HashMap<>();
}
public void readProperties() {
try {
Path path = Paths.get(filepath);
BasicFileAttributes attrs = Files.readAttributes(path, BasicFileAttributes.class);
properties.put("File Extension", path.getFileName().toString().substring(path.getFileName().toString().lastIndexOf(".")));
properties.put("File Type", "DirectShow Filter (DLL)");
properties.put("MIME Type", "application/octet-stream");
properties.put("File Size", String.valueOf(Files.size(path)));
properties.put("File Path", filepath);
properties.put("Creation Date", attrs.creationTime().toString());
properties.put("Modification Date", attrs.lastModifiedTime().toString());
properties.put("Access Date", attrs.lastAccessTime().toString());
properties.put("File Attributes", getFileAttributes());
properties.put("DLL Version", getVersionInfo());
properties.put("Company Name", "Unknown"); // Requires native API like JNA
properties.put("Description", "DirectShow Filter");
properties.put("Digital Signature", "Unknown"); // Requires parsing PE structure
properties.put("Filter Type", guessFilterType());
} catch (IOException e) {
System.out.println("Error reading properties: " + e.getMessage());
}
}
private String getFileAttributes() {
// Simplified; requires JNA for full Windows attributes
try {
Path path = Paths.get(filepath);
DosFileAttributes attrs = Files.readAttributes(path, DosFileAttributes.class);
List<String> attrList = new ArrayList<>();
if (attrs.isReadOnly()) attrList.add("Read-Only");
if (attrs.isHidden()) attrList.add("Hidden");
if (attrs.isSystem()) attrList.add("System");
return String.join(", ", attrList.isEmpty() ? List.of("None") : attrList);
} catch (IOException e) {
return "None";
}
}
private String getVersionInfo() {
// Placeholder; requires JNA or external library for DLL version
return "Unknown";
}
private String guessFilterType() {
String filename = Paths.get(filepath).getFileName().toString().toLowerCase();
if (filename.contains("mpeg")) {
return "Parsing Filter (likely MPEG-related)";
} else if (filename.contains("render")) {
return "Rendering Filter";
}
return "Unknown Filter Type";
}
public void writeProperties(String outputFilepath) {
try {
Files.copy(Paths.get(filepath), Paths.get(outputFilepath), StandardCopyOption.REPLACE_EXISTING);
System.out.println("Properties written to " + outputFilepath);
} catch (IOException e) {
System.out.println("Error writing file: " + e.getMessage());
}
}
public void printProperties() {
properties.forEach((key, value) -> System.out.println(key + ": " + value));
}
public static void main(String[] args) {
AXFileHandler axFile = new AXFileHandler("example.ax");
axFile.readProperties();
axFile.printProperties();
axFile.writeProperties("output.ax");
}
}
Notes:
- Java lacks built-in support for DLL metadata extraction, so fields like
DLL VersionandDigital Signatureare placeholders. Use JNA or a library likesigarfor full functionality. - The
writePropertiesmethod copies the file, as modifying the DLL’s internal structure is not practical.
4. JavaScript Class for .AX File Handling (Node.js)
const fs = require('fs').promises;
const path = require('path');
class AXFileHandler {
constructor(filepath) {
this.filepath = filepath;
this.properties = {};
}
async readProperties() {
try {
const stats = await fs.stat(this.filepath);
this.properties['File Extension'] = path.extname(this.filepath);
this.properties['File Type'] = 'DirectShow Filter (DLL)';
this.properties['MIME Type'] = 'application/octet-stream';
this.properties['File Size'] = stats.size;
this.properties['File Path'] = this.filepath;
this.properties['Creation Date'] = stats.birthtime.toISOString();
this.properties['Modification Date'] = stats.mtime.toISOString();
this.properties['Access Date'] = stats.atime.toISOString();
this.properties['File Attributes'] = 'Unknown'; // Node.js lacks direct Windows attribute access
this.properties['DLL Version'] = 'Unknown'; // Requires external library
this.properties['Company Name'] = 'Unknown';
this.properties['Description'] = 'DirectShow Filter';
this.properties['Digital Signature'] = 'Unknown';
this.properties['Filter Type'] = this.guessFilterType();
} catch (error) {
console.error(`Error reading properties: ${error.message}`);
}
}
guessFilterType() {
const filename = path.basename(this.filepath).toLowerCase();
if (filename.includes('mpeg')) {
return 'Parsing Filter (likely MPEG-related)';
} else if (filename.includes('render')) {
return 'Rendering Filter';
}
return 'Unknown Filter Type';
}
async writeProperties(outputFilepath) {
try {
await fs.copyFile(this.filepath, outputFilepath);
console.log(`Properties written to ${outputFilepath}`);
} catch (error) {
console.error(`Error writing file: ${error.message}`);
}
}
printProperties() {
for (const [key, value] of Object.entries(this.properties)) {
console.log(`${key}: ${value}`);
}
}
}
// Example usage
(async () => {
const axFile = new AXFileHandler('example.ax');
await axFile.readProperties();
axFile.printProperties();
await axFile.writeProperties('output.ax');
})();
Notes:
- Requires Node.js for file system operations.
- DLL metadata extraction (e.g., version, signature) is limited without external libraries like
pe-parser. - The
writePropertiesmethod copies the file, as direct modification is not feasible.
5. C Class for .AX File Handling
Since C doesn’t have classes, I’ll use a struct and functions to emulate class-like behavior. This code assumes a Windows environment for DLL handling.
#include <stdio.h>
#include <windows.h>
#include <time.h>
typedef struct {
const char* filepath;
char* properties[12][2]; // Key-value pairs for properties
} AXFileHandler;
void init_ax_file_handler(AXFileHandler* handler, const char* filepath) {
handler->filepath = filepath;
}
void read_properties(AXFileHandler* handler) {
WIN32_FILE_ATTRIBUTE_DATA fileInfo;
if (!GetFileAttributesEx(handler->filepath, GetFileExInfoStandard, &fileInfo)) {
printf("Error reading file attributes: %lu\n", GetLastError());
return;
}
// File system properties
sprintf(handler->properties[0][0], "File Extension");
sprintf(handler->properties[0][1], ".ax");
sprintf(handler->properties[1][0], "File Type");
sprintf(handler->properties[1][1], "DirectShow Filter (DLL)");
sprintf(handler->properties[2][0], "MIME Type");
sprintf(handler->properties[2][1], "application/octet-stream");
sprintf(handler->properties[3][0], "File Size");
sprintf(handler->properties[3][1], "%llu", ((unsigned long long)fileInfo.nFileSizeHigh << 32) | fileInfo.nFileSizeLow);
sprintf(handler->properties[4][0], "File Path");
sprintf(handler->properties[4][1], "%s", handler->filepath);
char timeStr[32];
FILETIME ft = fileInfo.ftCreationTime;
struct tm* timeinfo;
time_t rawtime = FileTimeToUnixTime(&ft);
timeinfo = gmtime(&rawtime);
strftime(timeStr, sizeof(timeStr), "%Y-%m-%dT%H:%M:%SZ", timeinfo);
sprintf(handler->properties[5][0], "Creation Date");
sprintf(handler->properties[5][1], "%s", timeStr);
ft = fileInfo.ftLastWriteTime;
rawtime = FileTimeToUnixTime(&ft);
timeinfo = gmtime(&rawtime);
strftime(timeStr, sizeof(timeStr), "%Y-%m-%dT%H:%M:%SZ", timeinfo);
sprintf(handler->properties[6][0], "Modification Date");
sprintf(handler->properties[6][1], "%s", timeStr);
ft = fileInfo.ftLastAccessTime;
rawtime = FileTimeToUnixTime(&ft);
timeinfo = gmtime(&rawtime);
strftime(timeStr, sizeof(timeStr), "%Y-%m-%dT%H:%M:%SZ", timeinfo);
sprintf(handler->properties[7][0], "Access Date");
sprintf(handler->properties[7][1], "%s", timeStr);
sprintf(handler->properties[8][0], "File Attributes");
char attrs[64] = "";
if (fileInfo.dwFileAttributes & FILE_ATTRIBUTE_READONLY) strcat(attrs, "Read-Only, ");
if (fileInfo.dwFileAttributes & FILE_ATTRIBUTE_HIDDEN) strcat(attrs, "Hidden, ");
if (fileInfo.dwFileAttributes & FILE_ATTRIBUTE_SYSTEM) strcat(attrs, "System, ");
sprintf(handler->properties[8][1], "%s", attrs[0] ? attrs : "None");
sprintf(handler->properties[9][0], "DLL Version");
sprintf(handler->properties[9][1], "Unknown"); // Requires PE parsing
sprintf(handler->properties[10][0], "Digital Signature");
sprintf(handler->properties[10][1], "Unknown");
sprintf(handler->properties[11][0], "Filter Type");
sprintf(handler->properties[11][1], guess_filter_type(handler->filepath));
}
void write_properties(AXFileHandler* handler, const char* output_filepath) {
if (CopyFile(handler->filepath, output_filepath, FALSE)) {
printf("Properties written to %s\n", output_filepath);
} else {
printf("Error writing file: %lu\n", GetLastError());
}
}
void print_properties(AXFileHandler* handler) {
for (int i = 0; i < 12; i++) {
printf("%s: %s\n", handler->properties[i][0], handler->properties[i][1]);
}
}
const char* guess_filter_type(const char* filepath) {
if (strstr(filepath, "mpeg") || strstr(filepath, "MPEG")) {
return "Parsing Filter (likely MPEG-related)";
} else if (strstr(filepath, "render") || strstr(filepath, "RENDER")) {
return "Rendering Filter";
}
return "Unknown Filter Type";
}
time_t FileTimeToUnixTime(FILETIME* ft) {
ULARGE_INTEGER ull;
ull.LowPart = ft->dwLowDateTime;
ull.HighPart = ft->dwHighDateTime;
return ull.QuadPart / 10000000ULL - 11644473600ULL;
}
int main() {
AXFileHandler handler;
init_ax_file_handler(&handler, "example.ax");
read_properties(&handler);
print_properties(&handler);
write_properties(&handler, "output.ax");
return 0;
}
Notes:
- Uses Windows API for file system properties.
- DLL metadata extraction is limited without a PE parsing library.
- The
write_propertiesfunction copies the file, as modifying the DLL is not feasible.
Limitations and Assumptions
- Lack of Specification: The internal structure of .AX files (e.g., specific headers or data segments) is not publicly documented, limiting decoding to file system and DLL metadata.
- Filter Type: Without reverse-engineering, filter type is inferred from filenames (e.g., “mpeg” for parsing filters), which is imprecise.
- Writing: Since .AX files are proprietary DLLs, the write operation is implemented as a file copy, as creating or modifying a valid .AX file requires Microsoft’s proprietary tools.
- Cross-Platform: The code assumes a Windows environment, as .AX files are primarily Windows-specific DirectShow components.
- Dependencies: Python requires
pywin32andpefile; Java and JavaScript may need external libraries for full DLL parsing; C relies on Windows headers.
If you have access to a specific .AX file or additional context (e.g., a sample file or proprietary documentation), I can refine the code to handle specific cases or test against real data. Let me know if you need further assistance