  A giant solar filament was visible on the solar surface from 2011 Nov. 8-23.
The filament stretched over more than half a solar diameter. Multiwavelength
data from the SDO instrument AIA (171, 193, 304, and 211\AA) were used to
examine counter-streaming flows within the spine of the filament. H$\alpha$
images from the Kanzelh\"ohe Solar Observatory provided context information. We
apply local correlation tracking (LCT) to a two-hour time series on 2011 Nov.
16 of the AIA images to derive horizontal flow velocities of the filament. To
enhance the contrast of the AIA images, noise adaptive fuzzy equalization is
employed, which allows us to identify and quantify counter-streaming flows in
the filament. We detect counter-streaming flows in the filament, which are
visible in the time-lapse movies in all examined AIA wavelength bands. In the
time-lapse movies we see that these persistent flows lasted for at least two
hours. Furthermore, by applying LCT to the images we clearly determine
counter-streaming flows in time series of 171 and 193\AA\ images. In the
304\AA\ wavelength band, we only see minor indications for counter-streaming
flows with LCT, while in the 211\AA\ wavelength band the counter-streaming
flows are not detectable. The average horizontal flows reach mean flow speeds
of 0.5 km/s. The highest horizontal flow speeds are identified in the 171\AA\
band with flow speeds of up to 2.5 km/s. The results are averaged over a time
series of 90 min. Because the LCT sampling window has finite width, a spatial
degradation cannot be avoided leading to lower estimates of the flow velocities
as compared to feature tracking or Doppler measurements. The counter-streaming
flows cover about 15-20% of the whole area of the EUV filament channel and are
located in the central part of the spine. In conclusion, we confirm the
omnipresence of counter-streaming flows also in giant quiet-Sun filaments.
