Here a simple django model:

class SomeModel(models.Model):title = models.CharField(max_length=100)video = models.FileField(upload_to='video')

I would like to save any instance so that the video's file name would be a valid file name of the title.

For example, in the admin interface, I load a new instance with title "Lorem ipsum" and a video called "video.avi". The copy of the file on the server should be "Lorem Ipsum.avi" (or "Lorem_Ipsum.avi").

Thank you :)

If it just happens during save, as per the docs, you can pass a function to upload_to that will get called with the instance and the original filename and needs to return a string to be used as the filename. Maybe something like:

from django.template.defaultfilters import slugify
class SomeModel(models.Model):title = models.CharField(max_length=100)def video_filename(instance, filename):fname, dot, extension = filename.rpartition('.')slug = slugify(instance.title)return '%s.%s' % (slug, extension) video = models.FileField(upload_to=video_filename)