[FFmpeg-devel] [PATCH 4/4] avformat/udp: do not use thread cancellation when receiving data

[Marton Balint]

On Wed, 22 Jan 2020, Nicolas George wrote:

> Marton Balint (12020-01-16):
>> It is not supported by every threading implementation, and the only thing we
>> gain with it is an immediate shutdown of receiving packets on close and
>> avoiding the poll call before reading the data.
>>
>> I don't think it is a big issue if it takes 0.1 sec of delay to close an udp
>> stream. Back when this was introduced the delay was 1 sec, which was indeed
>> noticable.
>
> I don't like this. 0.1 s is less noticeable than 1 s for interactive
> human users, but for applications it may be way too much.

pthread_cancel is not implemented properly on Win32, also it is generally 
not considered a good practice. 0.1 sec delay is still the lesser evil 
than a lockup as shown in ticket #5717.

An alternate approach might be to call shutdown() from the main thread and 
hope that this interrupts the recvfrom() call in the receiver thread. It 
tends to work for linux, I am not sure how other platforms would react, 
what do you think?

Thanks,
Marton