How good is the picture quality when a video-capable iPod is connected to a TV?

"Good" is a subjective term, and different people will have different opinions regarding the "picture quality" of the video that enabled iPods are capable of displaying on a television.

When the iPod 5th Gen (with Video) was introduced, it supported the following formats and resolutions:

H.264 Video: Up to 768 Kbps, 320 by 240 pixels, 30 frames per second, Baseline Profile up to Level 1.3 with AAC-LC up to 160 Kbps, 48 Khz, stereo audio in .M4V, .MP4 and .MOV file formats.

MPEG-4 Video: Up to 2.5 Mbps, 480 by 480 pixels, 30 frames per second, Simple Profile with AAC-LC up to 160 Kbps, 48 Khz, stereo audio in and .MOV file formats.

On September 12, 2006, Apple introduced the "Enhanced" iPod 5th Gen, and it continued to support H.264 (320x240), but also supported the much better:

H.264 video, up to 1.5 Mbps, 640 by 480 pixels, 30 frames per second, Baseline Low-Complexity Profile with AAC-LC audio up to 160 Kbps, 48 kHz, stereo audio in .m4v, .mp4, and .mov file formats.

MPEG-4 video, up to 2.5 Mbps, 640 by 480 pixels, 30 frames per second, Simple Profile with AAC-LC audio up to 160 Kbps, 48 kHz, stereo audio in .m4v, .mp4, and .mov file formats.

With a simple firmware update, the original iPod 5th Gen (with Video) supported the improved formats.

The iPod classic 6th Gen, iPod nano 3rd Gen/Fat through iPod nano 5th Gen (the iPod nano 6th Gen does not support video), and iPod touch, iPod touch 2nd Gen and iPod touch 3rd Gen models, support the previously supported formats as well as:

H.264 video, up to 2.5 Mbps, 640 by 480 pixels, 30 frames per second, Baseline Profile up to Level 3.0 with AAC-LC audio up to 160 Kbps, 48kHz, stereo audio in .m4v, .mp4, and .mov file formats.

The iPod touch 4th Gen/FaceTime and modestly updated iPod touch "4.5" Gen have significantly improved video capabilities and support:

H.264 video up to 720p, 30 frames per second, Main Profile level 3.1 with AAC-LC audio up to 160 Kbps, 48kHz, stereo audio in .m4v, .mp4, and .mov file formats.

MPEG-4 video, up to 2.5 Mbps, 640 by 480 pixels, 30 frames per second, Simple Profile with AAC-LC audio up to 160 Kbps per channel, 48kHz, stereo audio in .m4v, .mp4, and .mov file formats

All iPod 5th Gen models -- as well as the iPod classic models and the iPod nano 3rd Gen and iPod nano 4th Gen -- present video on the internal display at 320x240, whereas the iPod nano 5th Gen presents video at 240x376 and the iPod touch, iPod touch (2nd Gen) and iPod touch (3rd Gen) models present video on the internal display at 320x480. The iPod touch 4th Gen presents video on the internal display at 960x640. The iPod nano 6th Gen does not support video playback (although it will display the keyframe from the video and play the audio track).

In an in-depth review in ArsTechnica, the author connected the original iPod 5th Gen (with Video) to a "run-of-the-mill 27-inch SDTV" and reported that the 320x240 video:

Looked to my eyes exactly as they do during actual broadcasts. The colors were crisp and clear and the audio sounded decent over the television's built-in speakers. These experiences may or may not hold true for those of you who've got 50" DLPs and monster sound systems, but for me and what I suspect will be the majority of people buying this device, the video and audio quality will be more than acceptable.

Overall I was very pleased with the video output to my standard definition TV. I'm certain that some videophiles will be disappointed with the low video resolution the device offers, but I'm convinced that a majority of Apple iPod consumers will fail to notice or care about it very much.

The always superb iLounge covers the video quality of the iPod classic (2009), iPod nano 5th Gen, and iPod touch 3rd Gen, respectively, in a series of excellent reviews. The same site covers the video quality of the current iPod touch 4th Gen/4.5 Gen in an in-depth review as well.

Ultimately, if you have fairly modest expectations for average day-to-day use, you likely would be satisfied with the quality of video provided by most video-capable iPod models connected to a television (and the iPod touch 4th Gen/4.5 Gen plays true 720p video, most likely high enough quality to please all but the hardened videophile). Nevertheless, you might want to check one out in person before purchase for confirmation.