HD 4:2:2 to 4:2:0

[ssuave]

Hi,
I wonder what methods are in use for this conversion in case of HD videos?
4:2:2 to 4:2:0

[Guest]

You have to re-encode.

[ssuave]

You have to re-encode.
Can you elaborate?

[Guest]

Say you have an MPEG2 stream in your HD video and that stream is encoded 4:2:2. To make it 4:2:0 you have to decode the MPEG2 stream and then re-encode it with an MPEG2 encoder configured for 4:2:0 output. Then you have to mux that video stream with the original audio stream.

That's all very obvious. Better that you should elaborate on your problem!

[ssuave]

Say you have an MPEG2 stream in your HD video and that stream is encoded 4:2:2. To make it 4:2:0 you have to decode the MPEG2 stream and then re-encode it with an MPEG2 encoder configured for 4:2:0 output. Then you have to mux that video stream with the original audio stream.

That's all very obvious. Better that you should elaborate on your problem!

thanks.
I was looking for ways to convert an original (captured from camera by H.264 intra-frame coding with no further processing in 4:2:2 color space) found in avi format to 4:2:0 color space.
1 way I know is to use ffmpeg like this:
->ffmpeg -i s_10_scorenarrow.avi -vcodec rawvideo -pix_fmt yuv420p s_10_scorenarrow.yuv

I was just wondering if there are some opinions on this method or better alternatives.

[Guest]

That's outputting raw video, which is not very useful by itself. Presumably you'd want to re-encode and remux, wouldn't you?