Memory management techniques involve establishing a memory pool having an amount of sharable memory, and dynamically allocating the sharable memory to concurrently manage multiple sets of sequenced units of digital data. In an exemplary scenario, the sets of sequenced units of digital data are sets of time-ordered media samples forming clips of media content, and the techniques are applied when media samples from two or more clips are simultaneously presentable to a user as independently-controlled streams. Variable amounts of sharable memory are dynamically allocated for preparing upcoming media samples for presentation to the user. In one possible implementation, a ratio of average data rates of individual streams is calculated, and amounts of sharable memory are allocated to rendering each stream based on the ratio. Then, the sharable memory allocated to rendering individual streams is reserved as needed to prepare particular upcoming media samples for presentation to the user.