In one embodiment, a network device analyzes an encoded video stream using black detection before splicing video into the encoded video stream. When black data is detected, the network device determines whether insertion of a black intra frame with the spliced video will improve viewing upon decoding. The network device may also determine whether a splicing boundary indication included in the encoded video stream is accurate based on an observed transition between the detected black data and other data, and compensate the video splice accordingly.