Thomson PDP 2225 bugs


  1. Purpose
  2. mp3PRO playback at highest bitrate
    1. Sample files
    2. How to reproduce
    3. Firmware
  3. No mp3PRO sync for first frame
  4. Volume limitation
  5. ID3 high-bit characters
  6. Author

1 Purpose

This page is created to demonstrate bugs in the Thomson Lyra PDP 2225 MP3 player (also known as RCA Lyra RC1080). The intention is to help the engineers reproduce the bugs and hopefully fix them in future firmware upgrades.

2 mp3PRO playback at highest bitrate

When playing back mp3PRO files at 96 kbps, the audio often drops out for a brief moment. I've found out that this only happens when the volume reaches a certain level. With my Lyra it's reproducible for specific songs at different volume levels. This leads me to believe that the DSP can't keep up with the stream -- which may or may not be related to the volume limitation algorithm, or perhaps just lack of power. The last guess is probably the least likely one, since the device almost certainly uses a switchmode power supply, and because the bug occurs consistently.

Figure 1: Output from the Lyra when the drop-out occurs.

The illustration above shows the range 8,535s - 8,698s (0,163s) in a sample output from the Lyra. The drop-out lasts for about 23 ms.

2.1 Sample files

2.2 How to reproduce

Download the encoded samples and play back the 96 kbps mp3PRO version on the Lyra at the highest volume. Try to lower the volume or play one of the other two encoded versions to observe the absent of the bug. With my Lyra the bug occurs at volume level 42 with this specific sample - turn it down to 41, and it disappears. Hopefully this bug can be fixed by optimizing the mp3PRO/SBR decoder a tiny bit, or by removing the volume limitation algorithm and applying simple clipping instead.

2.3 Firmware

Only tested with version 4.11 - US/European version

3 No mp3PRO sync for first frame

Occationally the Lyra won't pick up the mp3PRO sync at the first frame, although it's perfectly fine (i.e. not ruined by bad ID3v2 taggers or something like that). (No details or samples on this one yet)

4 Volume limitation

Instead of clipping the waveform when it peaks, the volume is limited until the end of the song. This is quite unusual and annoying. (No details or samples on this one yet)

5 ID3 high-bit characters

For ID3 tags (at least ID3v2) the Latin-1 (ISO 8859-1) character set should be assumed - see the specs. The Lyra doesn't seem to support the high-bit characters, thus every non-ascii character is displayed wrong:

Figure 2: Display showing wrong characters for "זרו".

6 Author

This report was written by Jacob Laursen. I can be contacted at: