# Copyright (c) 2020 PaddlePaddle Authors. All Rights Reserve. # #Licensed under the Apache License, Version 2.0 (the "License"); #you may not use this file except in compliance with the License. #You may obtain a copy of the License at # # http://www.apache.org/licenses/LICENSE-2.0 # #Unless required by applicable law or agreed to in writing, software #distributed under the License is distributed on an "AS IS" BASIS, #WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. #See the License for the specific language governing permissions and #limitations under the License. import math import paddle.fluid as fluid from paddle.fluid.layer_helper import LayerHelper from paddle.fluid.dygraph.nn import Conv2D, Pool2D, BatchNorm, Linear from paddle.incubate.hapi.model import Model from paddle.incubate.hapi.download import get_weights_path_from_url __all__ = ["TSM_ResNet", "tsm_resnet50"] # {num_layers: (url, md5)} pretrain_infos = { 50: ('https://paddlemodels.bj.bcebos.com/hapi/tsm_resnet50.pdparams', '5755dc538e422589f417f7b38d7cc3c7') } class ConvBNLayer(fluid.dygraph.Layer): def __init__(self, num_channels, num_filters, filter_size, stride=1, groups=1, act=None): super(ConvBNLayer, self).__init__() self._conv = Conv2D( num_channels=num_channels, num_filters=num_filters, filter_size=filter_size, stride=stride, padding=(filter_size - 1) // 2, groups=None, act=None, param_attr=fluid.param_attr.ParamAttr(), bias_attr=False) self._batch_norm = BatchNorm( num_filters, act=act, param_attr=fluid.param_attr.ParamAttr(), bias_attr=fluid.param_attr.ParamAttr()) def forward(self, inputs): y = self._conv(inputs) y = self._batch_norm(y) return y class BottleneckBlock(fluid.dygraph.Layer): def __init__(self, num_channels, num_filters, stride, shortcut=True, seg_num=8): super(BottleneckBlock, self).__init__() self.conv0 = ConvBNLayer( num_channels=num_channels, num_filters=num_filters, filter_size=1, act='relu') self.conv1 = ConvBNLayer( num_channels=num_filters, num_filters=num_filters, filter_size=3, stride=stride, act='relu') self.conv2 = ConvBNLayer( num_channels=num_filters, num_filters=num_filters * 4, filter_size=1, act=None) if not shortcut: self.short = ConvBNLayer( num_channels=num_channels, num_filters=num_filters * 4, filter_size=1, stride=stride) self.shortcut = shortcut self.seg_num = seg_num self._num_channels_out = int(num_filters * 4) def forward(self, inputs): shifts = fluid.layers.temporal_shift(inputs, self.seg_num, 1.0 / 8) y = self.conv0(shifts) conv1 = self.conv1(y) conv2 = self.conv2(conv1) if self.shortcut: short = inputs else: short = self.short(inputs) y = fluid.layers.elementwise_add(x=short, y=conv2, act="relu") return y class TSM_ResNet(Model): """ TSM network with ResNet as backbone Args: num_layers (int): ResNet layer number, only support 50 currently. Default 50. seg_num (int): segment number of each video sample. Default 8. num_classes (int): video class number. Default 400. """ def __init__(self, num_layers=50, seg_num=8, num_classes=400): super(TSM_ResNet, self).__init__() self.layers = num_layers self.seg_num = seg_num self.class_dim = num_classes if self.layers == 50: depth = [3, 4, 6, 3] else: raise NotImplementedError num_filters = [64, 128, 256, 512] self.conv = ConvBNLayer( num_channels=3, num_filters=64, filter_size=7, stride=2, act='relu') self.pool2d_max = Pool2D( pool_size=3, pool_stride=2, pool_padding=1, pool_type='max') self.bottleneck_block_list = [] num_channels = 64 for block in range(len(depth)): shortcut = False for i in range(depth[block]): bottleneck_block = self.add_sublayer( 'bb_%d_%d' % (block, i), BottleneckBlock( num_channels=num_channels, num_filters=num_filters[block], stride=2 if i == 0 and block != 0 else 1, shortcut=shortcut, seg_num=self.seg_num)) num_channels = int(bottleneck_block._num_channels_out) self.bottleneck_block_list.append(bottleneck_block) shortcut = True self.pool2d_avg = Pool2D( pool_size=7, pool_type='avg', global_pooling=True) stdv = 1.0 / math.sqrt(2048 * 1.0) self.out = Linear( 2048, self.class_dim, act="softmax", param_attr=fluid.param_attr.ParamAttr( initializer=fluid.initializer.Uniform(-stdv, stdv)), bias_attr=fluid.param_attr.ParamAttr( learning_rate=2.0, regularizer=fluid.regularizer.L2Decay(0.))) def forward(self, inputs): y = fluid.layers.reshape( inputs, [-1, inputs.shape[2], inputs.shape[3], inputs.shape[4]]) y = self.conv(y) y = self.pool2d_max(y) for bottleneck_block in self.bottleneck_block_list: y = bottleneck_block(y) y = self.pool2d_avg(y) y = fluid.layers.dropout(y, dropout_prob=0.5) y = fluid.layers.reshape(y, [-1, self.seg_num, y.shape[1]]) y = fluid.layers.reduce_mean(y, dim=1) y = fluid.layers.reshape(y, shape=[-1, 2048]) y = self.out(y) return y def _tsm_resnet(num_layers, seg_num=8, num_classes=400, pretrained=True): model = TSM_ResNet(num_layers, seg_num, num_classes) if pretrained: assert num_layers in pretrain_infos.keys(), \ "TSM-ResNet{} do not have pretrained weights now, " \ "pretrained should be set as False".format(num_layers) weight_path = get_weights_path_from_url(*(pretrain_infos[num_layers])) assert weight_path.endswith('.pdparams'), \ "suffix of weight must be .pdparams" model.load(weight_path) return model def tsm_resnet50(seg_num=8, num_classes=400, pretrained=True): """TSM model with 50-layer ResNet as backbone Args: seg_num (int): segment number of each video sample. Default 8. num_classes (int): video class number. Default 400. pretrained (bool): If True, returns a model with pre-trained model on COCO, default True """ return _tsm_resnet(50, seg_num, num_classes, pretrained)