# Enhancing Sign Language Recognition Performance Through Coverage-Based Dynamic Clip Generation
## 3 Methods
### Clip Generation
In the case where the total number of frames \(F_{total}\) exactly matches the number of frames required for a single clip \(F_{clip}\), the entire video is treated as a single clip. This clip is then duplicated \(N_{clip}\) times, with each clip containing all frames from 1 to \(F_{clip}\). * \(F_{total}<F_{clip}\): The total number of frames in the video is less than the number of frames required for a single clip. * When the total number of frames in the video is insufficient to create a complete clip, the available frames are used repeatedly. The operation \(j\) mod \(F_{total}\) is applied to cyclically repeat the frames, starting from the first frame of the video. As a result, each clip contains the same repeated frames, making all clips identical. The set \(L_{i}\), which represents the frame indices for the \(i\)-th clip, is defined as shown in Equation (5). \[L_{i}\leftarrow\{j\text{ mod }F_{total}\mid j=1,\ldots,F_{clip}\}\] (5)where each frame index is computed by cyclically repeating the available frames in the video. The modulo operation ensures that the frame indices remain within the valid range of \(F_{total}\). * The set \(L_{i}\) for each clip is then added to the overall set \(\mathbb{S}_{clip}\), as shown in Equation (6). \[\mathbb{S}_{clip}\leftarrow\mathbb{S}_{clip}\cup\{L_{i}\}\] (6) This ensures that each repeated-frame clip is included in the final set of clips. In this case, the total number of frames in the video is insufficient to create a complete clip. As a result, the video frames are repeated to fill each clip, making all clips identical. The modulo operation wraps the frame indices around when they exceed \(F_{total}\), creating a repeating cycle of frames. ```
1:Input:\(F_{total}\), \(F_{clip}\), \(N_{clip}\)\(\triangleright\) Total frames, frames per clip, number of clips
2:Output:\(\mathbb{S}_{clip}\)\(\triangleright\) Set of generated clips
3:if\(F_{total}>F_{clip}\)then\(\triangleright\) Case 1: Video is longer than the clip size
4:for\(i=0\) to \(N_{clip}-1\)do\(\triangleright\) Iterate over each clip
5:\(s_{i}\leftarrow\frac{F_{total}-F_{clip}}{N_{clip}-1}\times i\)\(\triangleright\) Start index for clip \(i\)
6:\(L_{i}\leftarrow\{s_{i}+j\mid j=1,2,\ldots,F_{clip}\}\)\(\triangleright\) Generate frame indices for clip
7:\(\mathbb{S}_{clip}\leftarrow\mathbb{S}_{clip}\cup\{L_{i}\}\)\(\triangleright\) Add clip to the output set
8:endfor
9:elseif\(F_{total}=F_{clip}\)then\(\triangleright\) Case 2: Video length equals clip size
10:for\(i=0\) to \(N_{clip}-1\)do
11:\(L_{i}\leftarrow\{1,\ldots,F_{clip}\}\)\(\triangleright\) Use all frames for each clip
12:\(\mathbb{S}_{clip}\leftarrow\mathbb{S}_{clip}\cup\{L_{i}\}\)\(\triangleright\) Add identical clips
13:endfor\(\triangleright\) Case 3: Video is shorter than the clip size
14:else
15:for\(i=0\) to \(N_{clip}-1\)do
16:\(L_{i}\leftarrow\{j\bmod F_{total}\mid j=1,\ldots,F_{clip}\}\)\(\triangleright\) Repeat frames using modulo
17:\(\mathbb{S}_{clip}\leftarrow\mathbb{S}_{clip}\cup\{L_{i}\}\)\(\triangleright\) Add repeated-frame clip
18:endfor
19:endif
20:return\(\mathbb{S}_{clip}\)\(\triangleright\) Return the complete set of clips
```  
**Algorithm 1** Clip Generation Algorithm  
Using the set \(\mathbb{S}_{clip}\) generated by the above clip generation algorithm, we calculate the coverage to evaluate how well the generated clips represent the entire video.