Apple has confirmed widespread reports complaining at the manner in which the iPod touch displays video with deep black areas, warning that some early units have "defective screens".

The company says this problem has affected "a small number of units and is being remedied," writes Walt Mossberg for the Wall Street Journal.

At issue are reports claiming that video playback on the iPod touch is significantly darker than on the iPhone, suggesting inferior screens are deployed on the former unit, and reducing the value of the video playback experience.

"The one I reviewed displayed video that was noticeably darker than that of my iPhone. For example, dark scenes in the classic Roman Polanski film, Chinatown, were really dark – lacking detail that the iPhone nicely detailed. The display also had a yellower cast than the iPhone. Dark images in photo albums similarly lacked detail," writes Christopher Breen on Macworld US.

Similar reports are emanating from other media outlets and from individual early iPod touch adopters.

Mossberg's otherwise glowing review observes, "my two test units displayer beautiful images".

It is not yet known how widespread a problem exists in those affected iPod touch units, nor is it yet known what remedial action Apple will offer customers in possession of affected units.