Trim an irrelevant clause.

This is true, but not important to understanding the limitation.

doc/draft-ietf-codec-oggopus.xml

@@ -972,9 +972,8 @@ This is of course a very extreme packet, consisting of 255 streams, each
  containing 120 ms of audio encoded as 2.5 ms frames, each frame
  using the maximum possible number of octets (1275) and stored in the least
  efficient manner allowed (a VBR code 3 Opus packet).
-Even in such a packet, most of the data will be zeros, as 2.5 ms frames,
- which are required to run in the MDCT mode, cannot actually use all
- 1275 octets.
+Even in such a packet, most of the data will be zeros as 2.5 ms frames
+ cannot actually use all 1275 octets.
 The largest packet consisting of entirely useful data is
  (15,326*N - 2) octets, or about 15 kB per stream.
 This corresponds to 120 ms of audio encoded as 10 ms frames in either