NodeValid

Published video-model weights, licences and hardware notes

Open-Sora writes its length as a code rule

The repository states that candidate values for num_frames should be 4k+1 and less than 129. It is a rule about valid arguments rather than a duration, and it is the only length value in the register written that way. As of 2026-09-22.

Open-Sora in the length column, as publishedPublishing an argument constraint instead of a duration tells a reader exactly what the code will accept and nothing about what the result will look like.Length as publishednum_frames of 4k+1, under 129frames, seconds or bothFrames, as the constraintthe code enforcesOutput size256px and 768pxpixels per frameThe pair the 11B model isstated to supportMemory60.3GB peak at 768px on one GPUwhat holding them cost44.3GB across four or more,on H100 or H800One clip, as this release describes itA constraint, not a duration
Fig. 1 The length column filled with a validity rule from the implementation.
Open-Sora in the length column, with the columns that qualify it. Read from github.com/hpcaitech on 2026-09-22.
ColumnWhat the pages state
Length, in the vendor's own wordsnum_frames of 4k+1, under 129
The detail published beside itFrames, as the constraint the code enforces
Resolution, from the same pages256px and 768px
Hardware, from the same pages60.3GB peak at 768px on one GPU

Inclusion rule. The value this page is about, the detail the vendor attached to it, and the two columns that change how it should be read. A column the vendor left empty keeps its row and says so. Order. This column first, then its detail, then the two columns that qualify it.

1Developer documentation, precisely stated

4k+1 under 129 is unambiguous: 1, 5, 9 and so on up to 125. A reader writing a script knows exactly which values are legal, which is more than a stated maximum would give them.

It is also the least readable form for anyone asking how long a clip is. The rule encodes an architectural constraint rather than an output specification.

2Why the plus one matters

Frame counts of the form 4k+1 usually mean a first frame plus groups of four, which is a property of how the model compresses time. The rule is leaking the architecture, helpfully.

It also means the ceiling is 125 rather than 128, which a reader who rounded to the nearest power of two would get wrong.

3No rate, so no seconds

As with two other releases here, there is no frame rate, so 125 frames does not convert. At 24 FPS it is about five seconds and that figure is not on these pages.

The resolutions the model supports, 256px and 768px, are stated separately. The output space is therefore described by two rules and no example.

4Sources

Lengths above are in the unit the vendor chose, from github.com/hpcaitech on 2026-09-22, with no conversion applied. The full entry is at this family's page; frames against seconds is on length. Nearby: Four seconds, admitted, A minute, at a price.