[PATCH videoproto] Xvproto: fix xvEncodingInfo to match actual wire protocol

Daniel Martin consume.noise at gmail.com
Tue Jun 11 00:13:17 PDT 2013


On 10 June 2013 11:55, Julien Cristau <jcristau at debian.org> wrote:
> On Mon, Jun 10, 2013 at 11:41:00 +0200, Daniel Martin wrote:
>
>> On 9 June 2013 19:00, Julien Cristau <jcristau at debian.org> wrote:
>> > The padding is *before* the rate field, so the rate is placed on a 32bit
>> > boundary.  This change adds explicit padding between height and rate,
>> > and removes extraneous padding after the rate field, which the server
>> > never sent and xlib never read.
>> >
>> > This changes sizeof(xvEncodingInfo).  Hopefully that's not a big deal as
>> > clients only see the Xlib structure XvEncodingInfo.
>>
>> (Hopefully, I'm right with that):
>> I think that's an ABI change and a bit more difficult. Think about an X
>> server, which is compiled against a xvproto version without that change
>> and the lib compiled against xvproto with that change. In that case the
>> lib would start to read the encoding info, where the X server just sended
>> those extraneous pad bytes.
>>
> No.  As said in the commit message, the server never sent the extraneous
> pad bytes, so this patch doesn't change either the server or libXv
> behaviour.  Both it and libXv use sz_xvEncodingInfo, which is ok.

Sorry, after putting it side by side on a paper I clearly saw it. With
that it's:
    Reviewed-by me.


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