Subaru 2014 Legacy/Outback Owner's Manual page 250

Visual Operations
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Supported MP4 standards
• Supported extensions:
MP4, M4V (single-byte characters only, not case-sensitive)
• Maximum number of directory layers:
8 layers (including the root folder)
• Number of folders that can be stored in the USB memory:
255 (including the root folder)
• Number of files that can be stored in the USB memory:
9999
• Codec support:
Complies with MPEG1 Windows Media standards
MPEG4 MPEG-4 Simple Profile
• Maximum resolution:
720×480 (30 fps), 720×576 (25 fps)
• Supported audio codec:
MP3, AC3
- Supported sampling frequencies (kHz):
AC3: 32 - 320
* For the other audio codec, see "About USB Devices" on Page 235.
- Supported channel modes:
Stereo, Monaural
248 Audio and Visual