Larry Mason informed us that our most recent episodes of Endurance Radio would not play on the Emprex MP1003 MP3 player he had just recently purchased at Frys. This concerned me, because I know that often many different brands of MP3 players use the same chipset, and if it was a chipset problem, and not an embedded software problem, there could be many MP3 players out there that would not play our content.

I was unable to find this MP3 player at our local Frys, but was able to find it at Frys online partner/portal Outpost.com. Once delivered, I set out to find what was wrong with our MP3s that was causing them not to play on the Emprex.

My first shot was to remove all the ID3 tags from the MP3, and see what happened. Lo and behold, this stripped-down MP3 played correctly on the Emprex. Going back to the original MP3, and pulling various tags out of the MP3, I discovered it was the embedded GIF file we were using in the ID3v2 album art tag that was causing the problem. Once I removed just the album art, the MP3 played properly on the Emprex.

Referring to the ID3v2 specification, I noted that they say ‘The “image/png” or “image/jpeg” picture format should be used when interoperability is wanted.’ I inserted a JPG image as album art, and the file played properly. Next, I inserted a different GIF image, and this file also played properly, so it was not just a GIF/JPG problem. Interestingly, I noted that iTunes would not show the GIF album art, but would show the JPG album art (I was inserting the album art via TagScanner, not iTunes). Interoperability indeed.

The takeaways from this experiment are:

1) Always use JPGs as album art.
2) There is something in the GIF image in this program that causes the Emprex MP3 player to choke. Perhaps there is a common set of bytes in the image that the Emprex interpreted as MP3 data? This still remains to be investigated further.