llm-multimodal 1.4.0

Multimodal processing for vision and other modalities
Documentation 
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141

use std::collections::HashMap;

use serde_json::{json, Value};

use crate::{
    registry::{ModelMetadata, ModelProcessorSpec, ModelRegistryError, RegistryResult},
    types::{FieldLayout, Modality, PromptReplacement, TokenId},
    vision::image_processor::PreprocessedImages,
};

pub(super) struct QwenVLVisionSpec;

impl QwenVLVisionSpec {
    fn pad_token_id(metadata: &ModelMetadata) -> RegistryResult<TokenId> {
        metadata
            .config_u32(&["vision_token_id"])
            .map(|v| v as TokenId)
            .ok_or_else(|| ModelRegistryError::MissingConfigField {
                field: "vision_token_id".to_string(),
            })
    }

    fn start_token_id(metadata: &ModelMetadata) -> RegistryResult<TokenId> {
        metadata
            .config_u32(&["vision_start_token_id"])
            .map(|v| v as TokenId)
            .ok_or_else(|| ModelRegistryError::MissingConfigField {
                field: "vision_start_token_id".to_string(),
            })
    }
}

impl ModelProcessorSpec for QwenVLVisionSpec {
    fn name(&self) -> &'static str {
        "qwen_vl"
    }

    fn matches(&self, metadata: &ModelMetadata) -> bool {
        metadata.model_id.to_ascii_lowercase().contains("qwen")
            && metadata.model_id.to_ascii_lowercase().contains("vl")
    }

    fn placeholder_token(&self, _metadata: &ModelMetadata) -> RegistryResult<String> {
        Ok("<image>".to_string())
    }

    fn placeholder_token_id(&self, metadata: &ModelMetadata) -> RegistryResult<TokenId> {
        // Must match pad_token_id (vision_token_id) — this is the repeated token
        // in the expanded sequence. image_token_id is a distinct token in Qwen2-VL.
        Self::pad_token_id(metadata)
    }

    fn modality_limits(
        &self,
        _metadata: &ModelMetadata,
    ) -> RegistryResult<HashMap<Modality, usize>> {
        Ok(HashMap::from([(Modality::Image, 10)]))
    }

    fn processor_kwargs(&self, _metadata: &ModelMetadata) -> RegistryResult<Value> {
        Ok(json!({}))
    }

    fn prompt_replacements(
        &self,
        metadata: &ModelMetadata,
        preprocessed: &PreprocessedImages,
    ) -> RegistryResult<Vec<PromptReplacement>> {
        let start_token_id = Self::start_token_id(metadata)?;
        let pad_token_id = Self::pad_token_id(metadata)?;
        let placeholder_token = self.placeholder_token(metadata)?;
        Ok(preprocessed
            .num_img_tokens
            .iter()
            .map(|&num_tokens| {
                let mut tokens = Vec::with_capacity(num_tokens + 1);
                tokens.push(start_token_id);
                tokens.extend(std::iter::repeat_n(pad_token_id, num_tokens));
                PromptReplacement::sequence(Modality::Image, &placeholder_token, tokens)
            })
            .collect())
    }

    fn field_layouts(&self) -> HashMap<String, FieldLayout> {
        // pixel_values is patchified: [total_patches, patch_features].
        // patches_per_image tells how many patches belong to each image.
        // image_grid_thw is [num_images, 3].
        HashMap::from([
            (
                "pixel_values".to_string(),
                FieldLayout::flat("patches_per_image"),
            ),
            ("image_grid_thw".to_string(), FieldLayout::Batched),
            ("patches_per_image".to_string(), FieldLayout::Batched),
        ])
    }

    fn keep_on_cpu_keys(&self) -> Vec<String> {
        vec!["image_grid_thw".to_string()]
    }
}

#[cfg(test)]
mod tests {
    use serde_json::json;

    use crate::{
        registry::{test_helpers::*, ModelMetadata, ModelRegistry},
        types::ImageSize,
    };

    #[test]
    fn qwen_vision_uses_config_token_ids() {
        let tokenizer = TestTokenizer::new(&[("<image>", 999)]);
        let config = json!({
            "model_type": "qwen2_vl",
            "vision_start_token_id": 151652,
            "vision_token_id": 151654,
            "image_token_id": 151655,
            "vision_config": {"patch_size": 14}
        });
        let metadata = ModelMetadata {
            model_id: "Qwen2-VL-7B",
            tokenizer: &tokenizer,
            config: &config,
        };
        let registry = ModelRegistry::new();
        let spec = registry.lookup(&metadata).expect("qwen spec");
        // 448/14 = 32 grid, merge_size=2 => (32*32)/4 = 256 tokens
        let replacements = spec
            .prompt_replacements(
                &metadata,
                &test_preprocessed_with_tokens(&[ImageSize::new(448, 448)], &[256]),
            )
            .unwrap();
        // 256 pad tokens + 1 start token = 257
        assert_eq!(replacements[0].tokens.len(), 257);
        assert_eq!(replacements[0].tokens[0], 151652);
        assert_eq!(replacements[0].tokens[1], 151654);
    }
}