A method comprising: receiving a series of chunks of media content encoded according to an adaptive bitrate format, each chunk comprising a number of access units; setting a buffer utilization level of a compressed data buffer to a predetermined fraction of a maximum buffer size and feeding back the buffer utilization level to an upstream encoder; preprocessing each packet in a given chunk of the series of chunks of media content to provide a preprocessed chunk, the preprocessing comprising: evaluating the given chunk to provide chunk information characterizing the access units of the given chunk, the chunk information identifying respective timestamps associated with the access units of the given chunk; and adjusting at least one presentation or decode timestamp of each packet in the given chunk to be at an offset with respect to a clock reference value at the beginning of the given chunk based on the chunk information, the offset being a fixed offset value that is set based on the buffer utilization level, the preprocessed chunk including the adjusted timestamps for each packet; and streaming the preprocessed chunk in an output transport stream of concatenated chunks at a variable bitrate set according to a predetermined chunk presentation duration and based on the adjusted timestamps, whereby the adjusted timestamps and the buffer utilization value mitigate discontinuities between starting and ending compressed data buffer levels for the concatenated chunks, the variable bitrate maintaining a playout duration of each chunk equal to a corresponding chunk presentation duration thereof. receiving a series of chunks of media content encoded according to an adaptive bitrate format, each chunk comprising a number of access units; setting a buffer utilization level of a compressed data buffer to a predetermined fraction of a maximum buffer size and feeding back the buffer utilization level to an upstream encoder; preprocessing each packet in a given chunk of the series of chunks of media content to provide a preprocessed chunk, the preprocessing comprising: evaluating the given chunk to provide chunk information characterizing the access units of the given chunk, the chunk information identifying respective timestamps associated with the access units of the given chunk; and adjusting at least one presentation or decode timestamp of each packet in the given chunk to be at an offset with respect to a clock reference value at the beginning of the given chunk based on the chunk information, the offset being a fixed offset value that is set based on the buffer utilization level, the preprocessed chunk including the adjusted timestamps for each packet; and evaluating the given chunk to provide chunk information characterizing the access units of the given chunk, the chunk information identifying respective timestamps associated with the access units of the given chunk; and adjusting at least one presentation or decode timestamp of each packet in the given chunk to be at an offset with respect to a clock reference value at the beginning of the given chunk based on the chunk information, the offset being a fixed offset value that is set based on the buffer utilization level, the preprocessed chunk including the adjusted timestamps for each packet; and streaming the preprocessed chunk in an output transport stream of concatenated chunks at a variable bitrate set according to a predetermined chunk presentation duration and based on the adjusted timestamps, whereby the adjusted timestamps and the buffer utilization value mitigate discontinuities between starting and ending compressed data buffer levels for the concatenated chunks, the variable bitrate maintaining a playout duration of each chunk equal to a corresponding chunk presentation duration thereof.