The lines blur though when you start keeping state between batches, and a lot of batch processing ends up requiring that (joins, deduplication, etc).
Batching is, by definition, the gathering of data records into a collection before you send it. Streaming does not do that, which is the entire point. What happens after transmission occurs, on reception, is entirely irrelevant to whether the data transfer mode is "streaming."
An audio stream can easily be defined as a series of records, where each record is a sample spanning N seconds, probably as provided by the hardware. Similarly, a video frame can also be considered a record. As soon as a record becomes available, it is sent. Thus, streaming.
Optimizing to fully utilize network frames can generally be considered a low level transport optimization, and thus not relevant to the discussion.