  With the availability of large-scale video datasets and the advances of
diffusion models, text-driven video generation has achieved substantial
progress. However, existing video generation models are typically trained on a
limited number of frames, resulting in the inability to generate high-fidelity
long videos during inference. Furthermore, these models only support
single-text conditions, whereas real-life scenarios often require multi-text
conditions as the video content changes over time. To tackle these challenges,
this study explores the potential of extending the text-driven capability to
generate longer videos conditioned on multiple texts. 1) We first analyze the
impact of initial noise in video diffusion models. Then building upon the
observation of noise, we propose FreeNoise, a tuning-free and time-efficient
paradigm to enhance the generative capabilities of pretrained video diffusion
models while preserving content consistency. Specifically, instead of
initializing noises for all frames, we reschedule a sequence of noises for
long-range correlation and perform temporal attention over them by window-based
function. 2) Additionally, we design a novel motion injection method to support
the generation of videos conditioned on multiple text prompts. Extensive
experiments validate the superiority of our paradigm in extending the
generative capabilities of video diffusion models. It is noteworthy that
compared with the previous best-performing method which brought about 255%
extra time cost, our method incurs only negligible time cost of approximately
17%. Generated video samples are available at our website:
http://haonanqiu.com/projects/FreeNoise.html.
