[gst-devel] How do get the number of frames in a video file?

[Nick Haddad]

I understand how to get the duration in nanonseconds after pausing a  
pipeline,  that is working fine in my code.  But asking for frames is  
a little trickier, especially for variable frame rate files,  which I  
would like to support.

Should I be trying to ask the decodebin for the duration in frames?   
Is the file source a better element to ask?

Thanks for your help,
-nick


On Feb 21, 2008, at 9:57 AM, Wim Taymans wrote:

>
> On Thu, 2008-02-21 at 09:49 -0500, Nick Haddad wrote:
>> Anyone else have ideas on how to best do this?
>
> Go to PAUSED, wait for paused to happen by listening to the ASYNC_DONE
> message or by polling or by doing a blocking gst_element_get_state().
> Then you can get all the info.
>
> Wim
>
>>
>> Thanks,
>> -Nick
>>
>> On Feb 20, 2008, at 9:53 AM, Nick Haddad wrote:
>>
>>> I really need to get this information before playback starts.  I  
>>> want
>>> to present the user with the frame count after they open a file.
>>>
>>> If there is no generalized way to do do this (by asking the decode
>>> bin?) Is there a way seek through by frames without decoding the  
>>> video
>>> in the files?  If there is then I can do a quick walk through  
>>> frame by
>>> frame to do my count.
>>>
>>> Thanks,
>>> -Nick
>>>
>>> On Feb 20, 2008, at 5:54 AM, Felipe Contreras wrote:
>>>
>>>> On Feb 19, 2008 11:48 PM, Nick Haddad <nhaddad at mathworks.com>  
>>>> wrote:
>>>>> I want to retrieve the duration of a video file in frames, but  
>>>>> can't
>>>>> figure out the best way to do this.
>>>>>
>>>>> Calling...
>>>>>
>>>>> GstFormat fmt = GST_FORMAT_DEFAULT;
>>>>> gst_element_query_duration( _pipeline, &fm, &numFrames)
>>>>>
>>>>> ...doesn't work.  I'm assuming because the pipeline doesn't know
>>>>> about
>>>>> the "default format" (GST_FORMAT_TIME works fine).
>>>>>
>>>>> Which element in my pipeline should I query for the number of  
>>>>> video
>>>>> frames?  Is this even possible.  Currently I am building a  
>>>>> pipeline
>>>>> using decodebin.
>>>>
>>>> Do you need it at any point in time or would it be OK at the end of
>>>> the playback?
>>>>
>>>> -- 
>>>> Felipe Contreras
>>>
>>>
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