[FFmpeg-devel] [PATCH 4/4] lavf/concatdec: support seeking.

[Nicolas George]

Le quartidi 4 ventôse, an CCXXI, Stefano Sabatini a écrit :
> > +    if (cat->avf)
> > +        avformat_close_input(&cat->avf);
> Is this related?

Yes: this patch introduces several calls to open_file(), so I moved the
closing of the previously opened file there instead of putting it in the
call site.

> http://pubs.opengroup.org/onlinepubs/009604599/functions/xsh_chap02_03.html
> 
> [ESPIPE]
> Invalid seek. An attempt was made to access the file offset associated with a pipe or FIFO.
> 
> so no it doesn't seem very suitable to me (no pipe of FIFO here).

The description is misleading: we will get ESPIPE also for sockets (that is
written in the spec for lseek) and unseekable devices. ESPIPE is the error
code for the kernel to say "seeking is not supported on this kind of file
descriptor". The name was badly chosen, but it is the correct code.

My question was about portability, in fact.

> What we used in other cases:
> [ENOSYS]
> Function not implemented. An attempt was made to use a function that is not available in this implementation.
> 
> but even this use is quite stretched, and honestly I don't know what
> to suggest.
> 
> A generic AVERROR with an explaining log message may be useful in this
> case.

I do not think it is acceptable to output log messages in this circumstance.

Regards,

-- 
  Nicolas George
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