Update basis_spec.txt
diff --git a/spec/basis_spec.txt b/spec/basis_spec.txt
index cae5af7..dd1068c 100644
--- a/spec/basis_spec.txt
+++ b/spec/basis_spec.txt
@@ -835,12 +835,19 @@
11.0 Alpha Channels in ETC1S Format Files
-----------------------------------------
-If the ETC1S .basis file has an alpha channel, basis_file_header::m_flags will be logically OR's with cBASISHeaderFlagHasAlphaSlices. Alpha channel ETC1S files will contain two slices for each mipmap level (or face, or video frame, etc.). The even slices will contain the RGB data, and the odd slices will contain the alpha data. A decoder can first decode the RGB data slice, then the next alpha channel slice, or it can decode them in parallel using multithreading.
+If the ETC1S .basis file has an alpha channel, basis_file_header::m_flags will be logically OR's with
+cBASISHeaderFlagHasAlphaSlices. Alpha channel ETC1S files will contain two slices for each mipmap level
+(or face, or video frame, etc.). The even slices will contain the RGB data, and the odd slices will contain
+the alpha data. A decoder can first decode the RGB data slice, then the next alpha channel slice, or it can
+decode them in parallel using multithreading.
12.0 Texture Video
------------------
-Both ETC1S and UASTC format files support texture video. Texture video files can be optionally mipmapped, and can contain optional alpha channels (stored as separate slices in ETC1S format files). Currently, the first frame is always an i-frame, and all subsequent frames are p-frames, but the file format and transcoder supports any frame being an i-frame (and the encoder will be enhanced to support this feature).
+Both ETC1S and UASTC format files support texture video. Texture video files can be optionally mipmapped, and
+can contain optional alpha channels (stored as separate slices in ETC1S format files). Currently, the first frame
+is always an i-frame, and all subsequent frames are p-frames, but the file format and transcoder supports any
+frame being an i-frame (and the encoder will be enhanced to support this feature).
Skip blocks always refer to the previous frame. i-frames cannot use skip blocks (encoded as endpoint predictor index 2).
