MIME Type and Codec Fingerprinting

Media format support varies by platform and configuration. BotBrowser normalizes codec responses to protect platform identity.

Prerequisites

BotBrowser installed. See Installation Guide.
A profile file (.enc for production).

Quick Start


chromium-browser \
  --bot-profile="/path/to/profile.enc"

Start with this launch to establish a clean baseline before adding extra overrides.

Overview

Every browser reports which media formats it can play. The combination of supported MIME types and codecs varies by operating system, installed libraries, hardware decoders, and browser build configuration. BotBrowser normalizes these responses at the browser engine level so that reported media capabilities match the loaded profile’s platform identity.

How BotBrowser Normalizes Codec Responses

BotBrowser controls MIME type and codec responses at the browser engine level to ensure they match the target profile’s platform identity.

Configuration

The default configuration uses expand mode, which prioritizes local decoders while extending the list with profile-defined types. This can be configured via the --bot-config-media-types flag:


# expand (default): profile types + local decoders
chromium-browser \
  --bot-profile="/path/to/profile.enc" \
  --bot-config-media-types=expand
 
# profile: use only profile-defined media types
chromium-browser \
  --bot-profile="/path/to/profile.enc" \
  --bot-config-media-types=profile
 
# real: use actual system media types
chromium-browser \
  --bot-profile="/path/to/profile.enc" \
  --bot-config-media-types=real

All media type and codec query APIs return platform-consistent results matching the profile. Responses remain identical across all execution contexts (main page, Workers, Service Workers, iframes).

Common Scenarios

Capture a baseline result using the Quick Start setup.
Change one relevant setting at a time and compare the new output.
Keep your final launch command documented so future checks are reproducible.

Troubleshooting / FAQ

Problem	Solution
Observed value does not match the profile expectation	Verify profile path, active overrides, and any framework-injected settings.
Same setup behaves differently on another machine	Compare BotBrowser build, profile version, host OS target, and full launch args.
Test results fluctuate between runs	Keep proxy, locale/timezone, and runtime load stable during comparison tests.

Next Steps

CLI Flags Reference. Complete list of all available flags.
DRM Fingerprinting. How DRM capabilities interact with codec reporting.

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