code/policy_models/module/Video_Former.py

# This code is referenced from https://github.com/dhansmair/flamingo-mini

import torch
from einops import rearrange, repeat
from einops_exts import rearrange_many
from torch import einsum, nn
import torch.nn.functional as F

from policy_models.module.transformers.utils import feed_forward_layer

class Attention(nn.Module):
    def __init__(
            self,
            dim: int,
            num_heads: int = 8,
            use_cross_attn=False,
            y_dim=512,
            qkv_bias: bool = False,
            qk_norm: bool = False,
            attn_drop: float = 0.,
            proj_drop: float = 0.,
            norm_layer: nn.Module = nn.LayerNorm,
            attn_mask = None,
    ) -> None:
        super().__init__()
        assert dim % num_heads == 0, 'dim should be divisible by num_heads'
        self.num_heads = num_heads
        self.head_dim = dim // num_heads
        self.scale = self.head_dim ** -0.5
        self.fused_attn = True

        self.qkv = nn.Linear(dim, dim * 3, bias=qkv_bias)
        self.q_norm = norm_layer(self.head_dim) if qk_norm else nn.Identity()
        self.k_norm = norm_layer(self.head_dim) if qk_norm else nn.Identity()
        self.attn_drop = nn.Dropout(attn_drop)
        self.proj = nn.Linear(dim, dim)
        self.proj_drop = nn.Dropout(proj_drop)
        self.attn_mask = attn_mask
        self.use_cross_attn=use_cross_attn
        if self.use_cross_attn:
            #print('use_cross_attn')
            self.y_kv = nn.Linear(y_dim, dim * 2, bias=qkv_bias)
            self.y_k_norm = norm_layer(self.head_dim) if qk_norm else nn.Identity()
            self.gate = nn.Parameter(torch.zeros([self.num_heads]))

    def forward(self, x: torch.Tensor, y=None, attn_mask=None) -> torch.Tensor:
        B, N, C = x.shape
        qkv = self.qkv(x).reshape(B, N, 3, self.num_heads, self.head_dim).permute(2, 0, 3, 1, 4)
        q, k, v = qkv.unbind(0)
        q, k = self.q_norm(q), self.k_norm(k)

        # TODO: whether to use attn_mask
        if self.fused_attn:
            runtime_mask = None
            if attn_mask is not None:
                runtime_mask = attn_mask.to(x.device)
            elif self.attn_mask is not None:
                runtime_mask = self.attn_mask.to(x.device)[:q.shape[2],:k.shape[2]]
            x = F.scaled_dot_product_attention(
                q, k, v,
                dropout_p=self.attn_drop.p if self.training else 0.,
                attn_mask=runtime_mask
            )
        else:
            q = q * self.scale
            attn = q @ k.transpose(-2, -1)
            attn = attn.softmax(dim=-1)
            attn = self.attn_drop(attn)
            x = attn @ v

        if self.use_cross_attn:
            #print('y_shape:',y.shape)
            N_y = y.shape[1]
            y_kv = self.y_kv(y).reshape(B, N_y, 2, self.num_heads, self.head_dim).permute(2, 0, 3, 1, 4)
            y_k, y_v = y_kv.unbind(0)
            y_k = self.y_k_norm(y_k)
            y_out = F.scaled_dot_product_attention(
                q, y_k, y_v,
                dropout_p=self.attn_drop.p if self.training else 0.,
            )
            #print('y_out_shape:', y_out.shape)
            y_out = y_out*self.gate.tanh().view(1, -1, 1, 1)
            x = x + y_out

        x = x.transpose(1, 2).reshape(B, N, C)
        x = self.proj(x)
        x = self.proj_drop(x)
        return x

class PerceiverAttentionLayer(nn.Module):
    """Perceiver Attention Layer"""

    def __init__(self, dim: int, dim_head: int = 64, heads: int = 8):
        super().__init__()
        self.scale = dim_head**-0.5
        self.heads = heads
        self.dim_head = dim_head
        inner_dim = dim_head * heads

        # trainable components of PerceiverAttentionLayer
        self.norm_media = nn.LayerNorm(dim)
        self.norm_latents = nn.LayerNorm(dim)

        self.to_q = nn.Linear(dim, inner_dim, bias=False)
        self.to_k = nn.Linear(dim, inner_dim, bias=False)
        self.to_v = nn.Linear(dim, inner_dim, bias=False)
        self.to_out = nn.Linear(inner_dim, dim, bias=False)

    def forward(self, features, latents):
        """Latent vectors are cross-attending to the visual features x

        Args:
            features: Batch of visual features with shape (batch_size, n_features, dim)
            latents: Latent learnt vectors which are used to compute queries with shape (batch_size, n_latents, dim)

        Returns:
            Attention score with shape (batch_size, n_latents, dim)
        """
        assert features.ndim == 3
        assert latents.ndim == 3
        assert features.shape[0] == latents.shape[0]
        assert features.shape[2] == latents.shape[2]

        n_heads = self.heads
        n_batch, n_features, dim = features.shape
        n_queries = latents.shape[1]

        # Layer normalization
        x = self.norm_media(features)
        latents = self.norm_latents(latents)

        # Compute the queries from the latents, for all attention heads simultaneously
        q = self.to_q(latents)
        q = rearrange(q, 'b q (h d) -> b h q d', h=n_heads)
        assert q.shape == torch.Size([n_batch, n_heads, n_queries, self.dim_head])

        # Keys and values for all attention heads
        kv_input = torch.cat((x, latents), dim=-2)
        n_features_latents = n_features + n_queries
        k = self.to_k(kv_input)
        v = self.to_v(kv_input)

        k, v = rearrange_many((k, v), 'b f (h d) -> b h f d', h=n_heads)
        assert v.shape == torch.Size([n_batch, n_heads, n_features_latents, self.dim_head])

        q = q * self.scale

        # Attention scores
        sim = einsum('b h q d, b h f d -> b h q f', q, k)
        sim = sim - sim.amax(dim=-1, keepdim=True).detach()
        alphas = sim.softmax(dim=-1)

        out = einsum('b h q f, b h f v -> b h q v', alphas, v)
        out = rearrange(out, 'b h q v -> b q (h v)')

        return self.to_out(out)

class TempAttentionLayer(nn.Module):
    """Perceiver Attention Layer"""

    def __init__(self, dim: int, dim_head: int = 64, heads: int = 8):
        super().__init__()
        self.scale = dim_head**-0.5
        self.heads = heads
        self.dim_head = dim_head
        inner_dim = dim_head * heads

        # trainable components of PerceiverAttentionLayer
        self.norm_media = nn.LayerNorm(dim)

        self.to_q = nn.Linear(dim, inner_dim, bias=False)
        self.to_k = nn.Linear(dim, inner_dim, bias=False)
        self.to_v = nn.Linear(dim, inner_dim, bias=False)
        self.to_out = nn.Linear(inner_dim, dim, bias=False)

    def forward(self, features):
        """Latent vectors are cross-attending to the visual features x

        Args:
            features: Batch of visual features with shape (batch_size, n_features, dim)
            latents: Latent learnt vectors which are used to compute queries with shape (batch_size, n_latents, dim)

        Returns:
            Attention score with shape (batch_size, n_latents, dim)
        """
        assert features.ndim == 3

        n_heads = self.heads
        n_batch, n_features, dim = features.shape
        n_queries = features.shape[1]

        # Layer normalization
        x = self.norm_media(features)

        # Compute the queries from the latents, for all attention heads simultaneously
        q = self.to_q(x)
        q = rearrange(q, 'b q (h d) -> b h q d', h=n_heads)
        assert q.shape == torch.Size([n_batch, n_heads, n_queries, self.dim_head])

        # Keys and values for all attention heads
        n_features_latents = n_features
        k = self.to_k(x)
        v = self.to_v(x)

        k, v = rearrange_many((k, v), 'b f (h d) -> b h f d', h=n_heads)
        assert v.shape == torch.Size([n_batch, n_heads, n_features_latents, self.dim_head])

        q = q * self.scale

        # Attention scores
        sim = einsum('b h q d, b h f d -> b h q f', q, k)
        sim = sim - sim.amax(dim=-1, keepdim=True).detach()
        alphas = sim.softmax(dim=-1)

        out = einsum('b h q f, b h f v -> b h q v', alphas, v)
        out = rearrange(out, 'b h q v -> b q (h v)')

        return self.to_out(out)


class Video_Former_3D(nn.Module):
    """Perceiver Resampler with multi-head attention layer"""

    def __init__(
            self,
            dim: int,
            depth: int,
            condition_dim: int = 1280,
            dim_head: int = 64,
            heads: int = 8,
            num_latents: int = 64,
            num_frame: int = 14,
            num_time_embeds: int = 4,
            ff_mult: int = 4,
            activation: str = 'gelu',
            trainable: bool = True,
            use_temporal: bool = False,
    ):
        super().__init__()

        self.dim = dim
        self.num_queries = num_latents
        self.num_frame = num_frame
        self.condition_dim = condition_dim
        self.use_temporal = use_temporal
        self.input_mask_mode = 'zero' # 'none' | 'zero' | 'gaussian' | 'learnable'

        self.goal_emb = nn.Sequential(
            nn.Linear(condition_dim, dim * 2),
            nn.GELU(),
            nn.Linear(dim * 2, dim)
        )
        # self.goal_emb = nn.Sequential(
        #     nn.Linear(condition_dim, dim),
        #     nn.LayerNorm(dim),
        # )
        frame_seq_len = num_latents // num_frame
        self.latents = nn.Parameter(torch.randn(self.num_frame, frame_seq_len, dim))  # type: ignore[reportPrivateUsage]
        self.time_pos_emb = nn.Parameter(torch.randn(num_time_embeds, 1, dim))  # type: ignore[reportPrivateUsage]
        attn_mask = torch.ones((num_frame, num_frame))
        #attn_mask = torch.tril(attn_mask).bool()

        self.layers = nn.ModuleList([])

        if self.use_temporal:
            for _ in range(depth):
                self.layers.append(
                    nn.ModuleList(
                        [
                            PerceiverAttentionLayer(dim=dim, dim_head=dim_head, heads=heads),
                            #TempAttentionLayer(dim=dim, dim_head=dim_head, heads=heads),
                            Attention(dim, num_heads=heads, qkv_bias=True, use_cross_attn=False,
                                      y_dim=512, attn_mask=attn_mask),
                            feed_forward_layer(dim=dim, mult=ff_mult, activation=activation),
                        ]
                    )
                )
        else:
            for _ in range(depth):
                self.layers.append(
                    nn.ModuleList(
                        [
                            PerceiverAttentionLayer(dim=dim, dim_head=dim_head, heads=heads),
                            feed_forward_layer(dim=dim, mult=ff_mult, activation=activation),
                        ]
                    )
                )

        # Layer normalization takes as input the query vector length
        self.norm = nn.LayerNorm(dim)

        self._update_trainable_state(trainable)

        # learnable frame token (used when input_mask_mode == 'learnable')
        if self.input_mask_mode == 'learnable':
            # shape: (1, 1, n_features, dim) after goal_emb
            self.learnable_mask_token = nn.Parameter(torch.zeros(1, 1, 1, dim))

    def _update_trainable_state(self, trainable: bool = True):
        for param in self.parameters():
            param.requires_grad = trainable

    def forward(self, x_f: torch.Tensor, mask: torch.BoolTensor = None, extra : torch.Tensor = None, frame_mask_prob: float = 0.0, language: torch.Tensor = None):
        """Run perceiver resampler on the input visual embeddings

        Args:
            x_f: Input visual embeddings of shape (batch_size, n_frames, n_features, d_visual)
            mask: Mask for the input visual embeddings of shape (batch_size, n_frames)
            extra: Extra tensor for concatenation
            frame_mask_prob: Probability of masking each frame during training (0.0 = no masking)
            language: Language embeddings of shape (batch_size, 1, lang_dim)

        Returns:
            Resampler features of shape (batch_size, num_queries, d_visual)
        """
        assert x_f.ndim == 4

        batch_size, max_length, _, dim = x_f.shape

        # Generate per-batch frame mask (True=keep, False=mask) with non-uniform probability centered at index 6
        frame_mask = None
        if frame_mask_prob > 0.0 and self.training:
            # per-frame mask probabilities p_i: highest at center_idx=6, decays with distance
            center_idx = 6 if max_length == 14 else (max_length // 2)
            frame_indices = torch.arange(max_length, device=x_f.device).float()
            distances = (frame_indices - float(center_idx)).abs()
            sigma = 2.0
            # Gaussian decay: p_i = frame_mask_prob * exp(-0.5 * (d/sigma)^2)
            per_frame_p = frame_mask_prob * torch.exp(-0.5 * (distances / sigma) ** 2)
            # broadcast to batch and sample Bernoulli per (b, t)
            rand_vals = torch.rand(batch_size, max_length, device=x_f.device)
            # True=keep, False=mask
            frame_mask = rand_vals > per_frame_p.unsqueeze(0)
            # ensure at least one frame kept per sample
            needs_fix = frame_mask.sum(dim=1) == 0
            if needs_fix.any():
                idx = torch.nonzero(needs_fix, as_tuple=False).squeeze(-1)
                rand_cols = torch.randint(0, max_length, (idx.numel(),), device=x_f.device)
                frame_mask[idx, rand_cols] = True

        # Mask the position embeddings for the padded frames
        time_pos_emb = (
            self.time_pos_emb[:max_length].unsqueeze(0).expand(batch_size, -1, -1, -1)
        )  # [batch_size, max_length, 1, dim]
        if mask is not None:
            time_pos_emb = time_pos_emb * mask.unsqueeze(-1).unsqueeze(-1)

        # Apply the position embeddings
        x_f = self.goal_emb(x_f)
        # Frame-level input masking before adding positional encoding
        if frame_mask is not None:
            bsz = batch_size
            T = max_length
            n_features = x_f.shape[2]
            d = x_f.shape[3]
            mask_expand = frame_mask.unsqueeze(-1).unsqueeze(-1).expand(bsz, T, n_features, d)
            if self.input_mask_mode == 'zero':
                x_f = torch.where(mask_expand, x_f, torch.zeros_like(x_f))
            elif self.input_mask_mode == 'gaussian':
                noise = torch.randn_like(x_f)
                x_f = torch.where(mask_expand, x_f, noise)
            elif self.input_mask_mode == 'learnable':
                token = self.learnable_mask_token
                token = token.expand(bsz, T, n_features, d)
                x_f = torch.where(mask_expand, x_f, token)
            # 'none' -> do nothing
        if extra is not None:
            extra = repeat(extra, 'b q d -> b T q d', T=max_length)
            x_f = torch.cat([x_f, extra],dim = 2)
        x_f = x_f + time_pos_emb

        # Flatten the frames
        x_f = rearrange(x_f, 'b T n d -> (b T) n d')

        # Copy the latents for every element in the batch
        x = repeat(self.latents, 'T q d -> b T q d', b=batch_size)
        x = rearrange(x, 'b T q d -> (b T) q d')

        # Apply attention and feed forward layer
        if self.use_temporal:
            for attn, Temp_attn, ffw in self.layers:
                x = x + attn(x_f, x)
                x = rearrange(x, '(b T) q d -> (b q) T d', b = batch_size)
                # build per-batch temporal attention mask if frame_mask is provided
                runtime_temporal_mask = None
                if frame_mask is not None:
                    # frame_mask: (b, T) True=keep, False=mask
                    keep = frame_mask  # (b, T)
                    # expand along batch for each latent query: current batch for attention is (b * q)
                    q_per_frame = x.shape[0] // batch_size
                    # construct (b, 1, 1, T) -> (b*q, 1, 1, T)
                    mask_bt = keep.unsqueeze(1).unsqueeze(2)  # (b,1,1,T)
                    runtime_temporal_mask = mask_bt.repeat_interleave(q_per_frame, dim=0)  # (b*q,1,1,T)
                    # convert to additive mask with 0 for keep and -inf for masked
                    runtime_temporal_mask = runtime_temporal_mask.to(x.dtype)
                    runtime_temporal_mask = torch.where(
                        runtime_temporal_mask > 0,
                        torch.zeros_like(runtime_temporal_mask),
                        torch.full_like(runtime_temporal_mask, -1e9)
                    )
                x = x + Temp_attn(x, attn_mask=runtime_temporal_mask)
                x = rearrange(x, '(b q) T d -> (b T) q d', b = batch_size)
                x = x + ffw(x)
        else:
            for attn, ffw in self.layers:
                x = x + attn(x_f, x)
                x = x + ffw(x)

        #x = rearrange(x, 'l q d -> b T q d', b=batch_size)
        x = x.reshape(batch_size, -1 ,x.shape[1],x.shape[2])
        x = rearrange(x, 'b T q d -> b (T q) d')
        assert x.shape == torch.Size([batch_size, self.num_queries, self.dim])
        norm = self.norm(x)

        return norm

class Video_Former_2D(nn.Module):
    """Perceiver Resampler with multi-head attention layer"""

    def __init__(
            self,
            dim: int,
            depth: int,
            condition_dim: int = 1280,
            dim_head: int = 64,
            heads: int = 8,
            num_latents: int = 64,
            num_frame: int = 16,
            num_time_embeds: int = 4,
            ff_mult: int = 4,
            activation: str = 'gelu',
            trainable: bool = True,
    ):
        super().__init__()

        self.dim = dim
        self.num_queries = num_latents
        self.num_frame = num_frame
        self.condition_dim = condition_dim

        self.goal_emb = nn.Sequential(
            nn.Linear(condition_dim, dim * 2),
            nn.GELU(),
            nn.Linear(dim * 2, dim)
        )
        seq_len = num_latents // num_frame
        self.latents = nn.Parameter(torch.randn(num_frame, seq_len, dim))  # type: ignore[reportPrivateUsage]
        self.time_pos_emb = nn.Parameter(torch.randn(num_time_embeds, 1, dim))  # type: ignore[reportPrivateUsage]

        self.layers = nn.ModuleList([])
        for _ in range(depth):
            self.layers.append(
                nn.ModuleList(
                    [
                        PerceiverAttentionLayer(dim=dim, dim_head=dim_head, heads=heads),
                        feed_forward_layer(dim=dim, mult=ff_mult, activation=activation),
                    ]
                )
            )

        # Layer normalization takes as input the query vector length
        self.norm = nn.LayerNorm(dim)

        self._update_trainable_state(trainable)

    def _update_trainable_state(self, trainable: bool = True):
        for param in self.parameters():
            param.requires_grad = trainable

    def forward(self, x_f: torch.Tensor, mask: torch.BoolTensor = None):
        """Run perceiver resampler on the input visual embeddings

        Args:
            x_f: Input visual embeddings of shape (batch_size, n_frames, n_features, d_visual)
            mask: Mask for the input visual embeddings of shape (batch_size, n_frames)

        Returns:
            Resampler features of shape (batch_size, num_queries, d_visual)
        """
        assert x_f.ndim == 4

        batch_size, max_length, _, dim = x_f.shape

        assert dim == self.condition_dim

        # Mask the position embeddings for the padded frames
        time_pos_emb = (
            self.time_pos_emb[:max_length].unsqueeze(0).expand(batch_size, -1, -1, -1)
        )  # [batch_size, max_length, 1, dim]
        if mask is not None:
            time_pos_emb = time_pos_emb * mask.unsqueeze(-1).unsqueeze(-1)

        # Apply the position embeddings
        x_f = self.goal_emb(x_f)
        x_f = x_f + time_pos_emb

        # Flatten the frames
        x_f = rearrange(x_f, 'b T n d -> (b T) n d')

        # Copy the latents for every element in the batch
        x = repeat(self.latents, 'T q d -> b T q d', b=batch_size)
        x = rearrange(x, 'b T q d -> (b T) q d')

        # Apply attention and feed forward layer
        for attn, ffw in self.layers:
            x = x + attn(x_f, x)
            x = x + ffw(x)

        #x = rearrange(x, 'l q d -> b T q d', b=batch_size)
        x = x.reshape(batch_size, -1 ,x.shape[1],x.shape[2])
        x = rearrange(x, 'b T q d -> b (T q) d')
        assert x.shape == torch.Size([batch_size, self.num_queries, self.dim])
        norm = self.norm(x)

        return norm



class Video_Former_3D_vggt(nn.Module):
    """Perceiver Resampler with multi-head attention layer"""

    def __init__(
            self,
            dim: int,
            depth: int,
            condition_dim: int = 1280,
            dim_head: int = 64,
            heads: int = 8,
            num_latents: int = 64,
            num_frame: int = 14,
            num_time_embeds: int = 4,
            ff_mult: int = 4,
            activation: str = 'gelu',
            trainable: bool = True,
            use_temporal: bool = False,
    ):
        super().__init__()

        self.dim = dim
        self.num_queries = num_latents
        self.num_frame = num_frame
        self.condition_dim = condition_dim
        self.use_temporal = use_temporal
        self.input_mask_mode = 'zero' # 'none' | 'zero' | 'gaussian' | 'learnable'

        self.goal_emb = nn.Sequential(
            nn.Linear(condition_dim, dim * 2),
            nn.GELU(),
            nn.Linear(dim * 2, dim)
        )
        frame_seq_len = num_latents // num_frame
        self.latents = nn.Parameter(torch.randn(self.num_frame, frame_seq_len, dim))  # type: ignore[reportPrivateUsage]
        self.time_pos_emb = nn.Parameter(torch.randn(num_time_embeds, 1, dim))  # type: ignore[reportPrivateUsage]
        attn_mask = torch.ones((num_frame, num_frame))
        attn_mask2 = torch.ones((256, 256))
        #attn_mask = torch.tril(attn_mask).bool()

        self.layers = nn.ModuleList([])

        self.vggt_emb = nn.Sequential(
            nn.Linear(dim, 2048),
            nn.GELU(),
            nn.Linear(2048, 2048)
        )


        self.spatial_attn = Attention(dim, num_heads=heads, qkv_bias=True, use_cross_attn=False,
                                y_dim=512, attn_mask=attn_mask2)
        self.temporal_attn = Attention(dim, num_heads=heads, qkv_bias=True, use_cross_attn=False,
                                y_dim=512, attn_mask=attn_mask)
        self.feature_ffw = feed_forward_layer(dim=dim, mult=ff_mult, activation=activation)

        if self.use_temporal:
            for _ in range(depth):
                self.layers.append(
                    nn.ModuleList(
                        [
                            PerceiverAttentionLayer(dim=dim, dim_head=dim_head, heads=heads),
                            Attention(dim, num_heads=heads, qkv_bias=True, use_cross_attn=False,
                                      y_dim=512, attn_mask=attn_mask),
                            feed_forward_layer(dim=dim, mult=ff_mult, activation=activation),
                        ]
                    )
                )
        else:
            for _ in range(depth):
                self.layers.append(
                    nn.ModuleList(
                        [
                            PerceiverAttentionLayer(dim=dim, dim_head=dim_head, heads=heads),
                            feed_forward_layer(dim=dim, mult=ff_mult, activation=activation),
                        ]
                    )
                )

        # Layer normalization takes as input the query vector length
        self.norm = nn.LayerNorm(dim)
        self.norm_g = nn.LayerNorm(dim)

        self._update_trainable_state(trainable)

        # learnable frame token (used when input_mask_mode == 'learnable')
        if self.input_mask_mode == 'learnable':
            # shape: (1, 1, n_features, dim) after goal_emb
            self.learnable_mask_token = nn.Parameter(torch.zeros(1, 1, 1, dim))

    def _update_trainable_state(self, trainable: bool = True):
        for param in self.parameters():
            param.requires_grad = trainable

    def forward(self, x_f: torch.Tensor, mask: torch.BoolTensor = None, extra : torch.Tensor = None, frame_mask_prob: float = 0.0, language: torch.Tensor = None):
        """Run perceiver resampler on the input visual embeddings
        Args:
            x_f: Input visual embeddings of shape (batch_size, n_frames, n_features, d_visual)
            mask: Mask for the input visual embeddings of shape (batch_size, n_frames)
            extra: Extra tensor for concatenation
        Returns:
            Resampler features of shape (batch_size, num_queries, d_visual)
        """
        assert x_f.ndim == 4

        batch_size, max_length, _, dim = x_f.shape

        # Mask the position embeddings for the padded frames
        time_pos_emb = (
            self.time_pos_emb[:max_length].unsqueeze(0).expand(batch_size, -1, -1, -1)
        )  # [batch_size, max_length, 1, dim]
        if mask is not None:
            time_pos_emb = time_pos_emb * mask.unsqueeze(-1).unsqueeze(-1)

        # Apply the position embeddings
        x_f = self.goal_emb(x_f)
        
        if extra is not None:
            extra = repeat(extra, 'b q d -> b T q d', T=max_length)
            x_f = torch.cat([x_f, extra],dim = 2)
        x_f = x_f + time_pos_emb

        # Flatten the frames
        x_f = rearrange(x_f, 'b T n d -> (b T) n d')

        # Copy the latents for every element in the batch
        x = repeat(self.latents, 'T q d -> b T q d', b=batch_size)
        x = rearrange(x, 'b T q d -> (b T) q d')

        x_g = x_f + self.spatial_attn(x_f)
        x_g = rearrange(x_g, '(b T) q d -> (b q) T d', b = batch_size)
        x_g = x_g + self.temporal_attn(x_g)
        x_g = rearrange(x_g, '(b q) T d -> (b T) q d', b = batch_size)
        x_g = x_g + self.feature_ffw(x_g)

        # x_f = torch.cat([x_f, x_g], dim = 1)
        x_f = x_g

        # Apply attention and feed forward layer
        for attn, Temp_attn, ffw in self.layers:
            x = x + attn(x_f, x)
            x = rearrange(x, '(b T) q d -> (b q) T d', b = batch_size)
            x = x + Temp_attn(x)
            x = rearrange(x, '(b q) T d -> (b T) q d', b = batch_size)
            x = x + ffw(x)

        #x = rearrange(x, 'l q d -> b T q d', b=batch_size)
        x = x.reshape(batch_size, -1 ,x.shape[1],x.shape[2])
        x = rearrange(x, 'b T q d -> b (T q) d')
        assert x.shape == torch.Size([batch_size, self.num_queries, self.dim])
        norm = self.norm(x)
        x_g = rearrange(x_g, '(b T) q d -> b T q d', b = batch_size)

        return norm, self.vggt_emb(self.norm_g(x_g))