[rtmpdump] Why does --swfVfy require an argument?

Howard Chu hyc at highlandsun.com
Tue May 11 17:43:41 CEST 2010

David Woodhouse wrote:
> On Tue, 2010-05-11 at 06:45 -0700, Howard Chu wrote:
>> David Woodhouse wrote:
>>> Utilities like get_iplayer will already pass a --swfUrl argument; why do
>>> I need to provide it again?
>> The manpage says why.
>> The swfVfy option was intended to replace the swfUrl option.
> Unfortunately that's not massively practical. People who write tools
> like get_iplayer are too scared to include explicit references to
> rtmpdump and --swfVfy; they use flvstreamer instead and leave the task
> of actually making things _work_ to the end-user.
> If we could just enable SWF Verification (or have it default to being
> enabled) without having to re-provide the SWF URL, that would be a lot
> easier.

It's far too late to be questioning this now. The option has already been 
deployed through several versions.

Also, I was in close communication with the get_iplayer author when this 
option was added, he didn't have any problem with it. You seem to be putting 
words into other people's mouths.

There are good reasons not to leave SWF verification enabled all the time in 
the code. It changes the handshake version, and it frequently costs time both 
in making an HTTP connection to retrieve the SWF, and in computing the actual 
hash and response.

It was a good decision at the time. In retrospect it may not have been so 
great. In the new API swfVfy is a boolean option, but I don't see how to 
smoothly transition rtmpdump to the new API just yet.

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