[osg-users] Plugins errors for unsupported files

[Robert Osfield]

Hi Riccardo,

Just removing a code block might fix the problem you are seeing but
it'll break things for others so isn't an appropriate thing to do as
we'll just end up flip flopping between who's code we break today.

I haven't looked into the error itself yet, but my inclination would
be to see if is possible to improve the OSG's ffmpeg plugins' file
opening so that it handles the inability to read a file more
elegantly.

Robert.

On 19 October 2016 at 10:31, Riccardo Corsi <riccardo.corsi at kairos3d.it> wrote:
> Hi Robert,
>
> right, the ffmpeg plugin is trying to load files without knowing if they are
> of a supported format.
> The related code is here:
> https://github.com/openscenegraph/OpenSceneGraph/blob/master/src/osgPlugins/ffmpeg/ReaderWriterFFmpeg.cpp#L149
>
> The comment explains something related to videos served from internet.
> I'm wondering if it would be ok to move that code below, after having
> checked whether the filename contains a URL (performed a few lines below).
> This would stop the plugin to try loading every possible image and printing
> errors on the console.
>
> Thanks,
> Ricky
>
>
> On Tue, Oct 18, 2016 at 7:54 PM, Robert Osfield <robert.osfield at gmail.com>
> wrote:
>>
>> Hi Ricky,
>>
>> The OSG uses the Chain Of Responsibility Design Pattern for the
>> plugins - so it's the plugins themselves to decide what formats they
>> can load.  This enables them to handle multiple formats if they can
>> support it.  From the description it sounds like the ffmpeg isn't
>> doing a good enough at deciding what it can or cannot load.
>>
>> Robert.
>>
>> On 18 October 2016 at 18:18, Riccardo Corsi <riccardo.corsi at kairos3d.it>
>> wrote:
>> > Hi Robert and all,
>> >
>> > I'm currently using the ffmpeg plugin to load some movies - it works
>> > just
>> > fine but my application started generating a lot of errors on console
>> > like
>> > this:
>> >> FFmpegImageStream::open : av_open_input_file() failed : AVERROR_NOENT
>> > every time an image has to be loaded.
>> >
>> > You can reproduce the issue with the modified osgMovie example in
>> > attach,
>> > which also loads the textured cow model.
>> >
>> > Digging a bit I've seen that's because the file reading mechanism tries
>> > to
>> > read from all the already loaded plugins, reagardless of their
>> > extension(s)
>> > support.
>> > See here:
>> >
>> > https://github.com/openscenegraph/OpenSceneGraph/blob/master/src/osgDB/Registry.cpp#L1176
>> >
>> > I thought that the extension supported by each plugin was checked before
>> > trying to use it.
>> > Besides the annoying errors on the console, wouldn't it be more
>> > efficient?
>> >
>> > Thanks,
>> > Ricky
>> >
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