Gemini Omni Flash references on Sume: 10 images, 3 videos of 3 s

Gemini Omni Flash 1.1 on Sume accepts up to 10 reference images and up to 3 reference videos, each at most 3 s long, so the most video reference one request can carry is 3 x 3 = 9 s. It does not accept audio references. You refer to the media in the prompt as <IMAGE_REF_0> and <VIDEO_REF_0>, counting from zero in list order.

The limits in one table

From the Sume Video Router page, read 2026-10-09. The model ID is gemini-omni-flash-1.1, and it is one catalog ID: Sume routes by the shape of your request, and you never choose an endpoint.

Cost of a referenced clip

References do not appear as a separate line in the catalog rates: Sume bills per output second by resolution. An 8-second referenced clip is 8 x $0.125 = $1.00 at 720p, $1.50 at 1080p and $3.00 at 4K. Native synced audio is always on, and the API rejects generate_audio: false.

Google's pricing page lists Omni Flash input, including video, at $1.50 per 1M tokens, but the Sume catalog rates this page uses are per output second, so do not add a token estimate on top of the Sume figure.

Prompt tags in practice

Tags follow list order and start at zero. If you send two images and one video, the images are <IMAGE_REF_0> and <IMAGE_REF_1> and the video is <VIDEO_REF_0>. A prompt such as the character in <IMAGE_REF_0> walks through the set shown in <IMAGE_REF_1>, moving like <VIDEO_REF_0> uses all three. Keep the order of the URL lists stable between retries so that the tags keep their meaning.

The 3-second ceiling on each reference video is the practical limit. A 12-second source must be trimmed to three clips of 3 s or fewer. Sume lists a trim endpoint at $0.02 per job for this kind of cut, so trimming a source costs two cents per cut before you spend on generation.

Common mistakes

Do not send video_url together with image_url, end_image_url or any reference_*_urls; video_url is the edit source, not a reference. Do not send reference_audio_urls: the model has no such input, and there is no bitrate_mode. If you need audio references, the Sume docs say the Seedance 2.x models, Wan 3.0, MiniMax H3 and H3 Max accept audio and video references; Omni does not.

Reference media must be reachable over public HTTPS. The errors page lists input_media_unreachable and image_not_fetchable for media Sume could not fetch.