[Ffmpeg-devel] Any pointers on how to connect to an MJPEG stream?

[Robert Harle]

Michel Bardiaux wrote:
> Robert Harle wrote:
>>
>>>> I have a camera that outputs an MJPEG stream to my network  
>>>> (connecting to http://camera_ip/mjpegstream).  I want to be able to 
>>>> obtain frames from the video using libavformat.  I can do this from 
>>>> a video file using av_open_input_file(), but I'm not sure how to 
>>>> convert to a stream.  At present I have:
>>>>
>>>> av_open_input_file(&formatctx, filename, NULL, 0, NULL);
>>>>
>>>> I see there is an av_open_input_stream() but I'm unsure as to the 
>>>> parameters to pass to it, or even if this is intended to do what I 
>>>> want.
>>>>
>>>> Can anyone offer a suggestion, or a resource to try?
>>>
>>> Try ffmpeg -i http://camera_ip/whatever -t 300 x.mpg , what happens?
>>
>> It fails, unable recognise the format.  I have to manually specify:
>
> My bad, which is why I wont take away points for not supplying the 
> full output messages :-)
>
>>
>>    ffmpeg -f mjpeg -i http://camera_ip/whatever -t 300 x.mpg
>>
>> and then it works fine.  Similarly, ffplay -f mjpeg <URL> works 
>> fine.  Reading between the lines of your request, is it that 
>> av_open_input_file() should take a URL and work, but the call fails 
>> because it can't recognise a format from the URL?
>>
> Exactly right. Now that you've got ffmpeg working, you can go in the 
> source and see how it does it. I may be a hard slog, but at least 
> you're sure you *will* find a solution.
>
> It is even possible that just giving the url an extension ".mjpg" will 
> do the trick!

And, indeed, this works!  Thank you so much! For the benefit of the 
archives I now pass my program "http://<ip 
address>/video?resolution=320x240,.mjpg" rather than "http://<ip 
address>/video?resolution=320x240" and it is happy to use 
av_open_input_file() again.

Cheers,
Robert.