Move planes order to the Components sections

No modification of text

Author: JeromeMartinez

ffv1.md

@@ -291,6 +291,15 @@ Background: in first implementations of FFV1 bitstream, the index for Cb and Cr
 
 FFV1 supports 1 Luma component, optionally 2 Chroma components, and optionally 1 Alpha component that can be used to code transparency data.
 
+The Cb and Cr planes are optional, but if used then MUST be used together. Omitting the Cb and Cr planes codes the frames in grayscale without color data. An FFV1 `Frame` using YCbCr MUST use one of the following arrangements:
+
+- Y
+- Y, Alpha
+- Y, Cb, Cr
+- Y, Cb, Cr, Alpha
+
+When FFV1 uses no Pixel transformation, the Y plane MUST be coded first. If the Cb and Cr planes are used then they MUST be coded after the Y plane. If an Alpha (transparency) plane is used, then it MUST be coded last.
+
 ## Pixel transformations
 
 Pixel transformations permit to modify the pixel data in a reversible way in order to improve the compression ratio, before being compressed. An example of usage is to compress RGB content which could have each component independently compressed but with a less optimal compression ratio.
@@ -301,15 +310,6 @@ Pixel transformation is indicated in the bitstream in order to permit the decode
 
 There is no Pixel transformation, the source content is directly compressed.
 
-The Cb and Cr planes are optional, but if used then MUST be used together. Omitting the Cb and Cr planes codes the frames in grayscale without color data. An FFV1 `Frame` using YCbCr MUST use one of the following arrangements:
-
-- Y
-- Y, Alpha
-- Y, Cb, Cr
-- Y, Cb, Cr, Alpha
-
-When FFV1 uses no Pixel transformation, the Y plane MUST be coded first. If the Cb and Cr planes are used then they MUST be coded after the Y plane. If an Alpha (transparency) plane is used, then it MUST be coded last.
-
 ### JPEG2000-RCT
 
 JPEG2000-RCT is a Reversible Color Transform that codes RGB (red, green, blue) planes losslessly in a modified YCbCr color space. Reversible Pixel transformations between YCbCr and RGB use the following formulae.