Dyer told Camberwell Green Magistrates Court last week how he attacked the dog after it urinated on his trousers.
Andrew Wiles, prosecuting, said: "The vet said the dog's behaviour was very submissive and he was hand shy, which is evidence of the fact the dog was exposed to trauma.
"She said the dog would have been terrified and suffered mentally."
Dyer admitted causing unnecessary suffering to an animal and two counts of failing to ensure the welfare of an animal at a previous hearing and was ordered to do 200 hours unpaid work and pay £300 in court costs.
An RSPCA spokeswoman said the dog had now been seized, adding: "We are pleased the defendant has now been convicted in this horrific case.
"The footage speaks for itself about the cruelty here."
The maximum sentence for causing unnecessary suffering to an animal under the Animal Welfare Act 2006 is six months in prison or a fine of £20,000.