Rec. ITU-T H.265 v3 (04/2015) Some Definitions

broken link: 

A location in a bitstream at which it is indicated that some subsequent pictures in decoding order may contain serious visual artefacts due to unspecified operations performed in the generation of the bitstream. 

这是一个比特流中的位置，表明在解码顺序上的子序列图像也许会含有一系列的由于在比特流生成中采取的非特定操作而造成的人工视觉效果，

broken link access (BLA) access unit: 

An access unit in which the coded picture with nuh_layer_id equal to 0 is a BLA picture. 

BLA编码图像（nuh_layer_id = 0）中的一个访问单元

broken link access (BLA) picture: 

An IRAP picture for which each VCL NAL unit has nal_unit_type equal to BLA_W_LP, BLA_W_RADL, or BLA_N_LP. NOTE – A BLA picture contains only I slices, and may be the first picture in the bitstream in decoding order, or may appear later in the bitstream. Each BLA picture begins a new CVS, and has the same effect on the decoding process as an instantaneous decoding refresh (IDR) picture. However, a BLA picture contains syntax elements that specify a non-empty RPS. When a BLA picture for which each VCL NAL unit has nal_unit_type equal to BLA_W_LP, it may have associated random access skipped leading (RASL) pictures, which are not output by the decoder and may not be decodable, as they may contain references to pictures that are not present in the bitstream. When a BLA picture for which each VCL NAL unit has nal_unit_type equal to BLA_W_LP, it may also have associated RADL pictures, which are specified to be decoded. When a BLA picture for which each VCL NAL unit has nal_unit_type equal to BLA_W_RADL, it does not have associated RASL pictures but may have associated random access decodable leading (RADL) pictures. When a BLA picture for which each VCL NAL unit has nal_unit_type equal to BLA_N_LP, it does not have any associated leading pictures. 

当每个VCL NAL单元的nal_unit_type = BAL_W_LP, BLA_W_RADL, or BLA_N_LP时的IRAP图像

注：一个BAL图像仅仅包含I slice， 它可以使解码算顺序上比特流中的第一张图像，或者出现在后面的比特流中。每一个BLA图像开始一个新的CVS，这跟解码过程中的IDR帧一样效果。然而，一个BLA图像包含的语法元素（指定一个非空RPS）。当一个BLA图像（每个VCL单元的nal_unit_type = BLA_W_LP）时，它拥有关联RASL图像（解码器不输出且不可解码）。当BLA图像（每个VCL单元的nal_unit_type = BLA_W_RADL），它没有关联RASL图像，但是有关联的RADL图像。当BLA图像（每个VCL单元的nal_unit_type = BLA_N_LP），它没有任何关联图像。