user16050: (Total beginner) Trying to process an MP4 file using an AviSynth script, as follows:
    DirectShowSource(inputFile, fps=25, convertfps=true, logfile=logFile)
Error message: "DirectShowSource: couldn't open file SomeFile.mp4. Cannot play back the file. The format is not supported."
The file is valid, i.e. it can be played in a video player.
Using Windows 10 64-bit, and AviSynth 2.60
How can I process this file using AviSynth?

user16050: In the end, I made it work just as posted above, by installing the Haali Media Splitter. I have seen posts by people who say that this software is needed to process MP4 files.

16050: <p>(Total beginner) Trying to process an MP4 file using an AviSynth script, as follows:
    DirectShowSource(inputFile, fps=25, convertfps=true, logfile=logFile)</p>

<p>Error message: "DirectShowSource: couldn't open file SomeFile.mp4. Cannot play back the file. The format is not supported."</p>

<p>The file is valid, i.e. it can be played in a video player.</p>

<p>Using Windows 10 64-bit, and AviSynth 2.60</p>

<p>How can I process this file using AviSynth?</p>
 16050: <p>In the end, I made it work just as posted above, by installing the Haali Media Splitter. I have seen posts by people who say that this software is needed to process MP4 files.</p>
