When the video bit-rate is greater than the available network bandwidth, the video stream suffers from packet loss due to packets that need to be dropped. A streaming server (or a network proxy) can implement a proactive packet filtering strategy, which is to voluntarily block (not forward) some packets in the event of such bandwidth mismatch. The challenge is to decide which packets to block so that the quality of the video at the client side is maximized with regards to the available bandwidth. Previous proposals aimed to use meta-information from the video encoding or to pre-process the multimedia data. Our goal is to design a lightweight strategy, which only uses video metadata available from the video file container. We demonstrate on a set of HEVC videos that out lightweight packet filtering algorithm performs as well as more complex strategies. Moreover, the video quality remains high despite a large number of blocked packets, while a random selection of dropped packet leads to a significant quality drop.