In some video coding applications, it is desirable to reduce the complexity of the video encoder at the expense of a more complex decoder. Distributed Video (DV) Coding is a new paradigm that aims at achieving this. To allocate a proper number of bits to each frame, most DV coding algorithms use a feedback channel (FBC). However, in some cases, a FBC does not exist. In this paper, we therefore propose a rate allocation (RA) algorithm for pixel-domain distributed video (PDDV) coders without FBC. Our algorithm estimates at the encoder the number of bits for every frame without significantly increasing the encoder complexity. For this calculation we consider each pixel of the frame individually, in contrast to our earlier work where the whole frame is treated jointly. Experimental results show that this pixel-based approach delivers better estimates of the adequate encoding rate than the frame-based approach. Compared to the PDDV coder with FBC, the PDDV coder without FBC has only a small loss in RD performance, especially at low rates.