On Fri, Jul 2, 2010 at 7:59 AM, Eli Billauer <[email protected]> wrote:
> That's an interesting point. I tried a YUV4MPEG stream with mplayer, which
> complained that it didn't recognize the stream tag C420jpeg (but played the
> clip OK). So this is a hint that a previous remark is probably correct about
> YUV4MPEG giving 4:2:0.
>
> Now I wonder why a 10 bits 4:4:4 file is needed. If it's a matter of image
> quality, you're going to lose it in the internal engine, which works in
> 8-bit space (I tried to edit Canon 500D footage under RGBA-FLOAT and got a
> black screen).
>
> But if we're at it, YUV4MPEG inherently includes a conversion from RGB to
> YUV (anyone here running YUV as the internal colorspace?) which the piped-to
> encoder may not take advantage of, and convert it again to something else.
> This is where bit resolution is slowly eroded. So if there's anything I
> would be glad to see in this field, it's the ability to render to an
> uncompressed RGB output (Maybe AVI?). Not that I'm sure whether encoders
> other than mencoder accept that.

I can't check now, but I believe I use RGB as the internal color space, so I
tried outputting to uncompressed RGB in the quicktime container. I have
not tried an AVI container but that would get rid of the mov atom problem.

Avidemux seems to be able to read the formats just fine. I have to add a
swap U and V filter to get the right colors, even though the input is really
uncompressed RGB. Quality is most important, and if it YUV4MPG is
actually 4:2:0, I may stay with uncompressed RGB. The Canon 7D video
is not perfect but some advantages it does have are the excellent
color at low light, not as good as the 5D Mk II probably, but way better
than consumer AVCHD cameras, and the good chroma resolution. For things
like light displays it does very well where some consumer AVCHD cameras turn
all the small colored lights white. What I am doing it pretty slow,
but it looks
very good.

Mark

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