Graphics Reference
In-Depth Information
B 3
B 4
B 7
B 8
B 2
B 6
P 0
I 1
P 5
leading pictures
IRAP
trailing pictures
Fig. 2.4
Leading pictures and trailing pictures
P 1
P 3
P 5
P 7
P 2
P 6
TSA
I 0
P 4
P 8
Fig. 2.5
TSA example
There are three types of trailing pictures in HEVC: temporal sub-layer access
(TSA) pictures, step-wise temporal sub-layer access (STSA) pictures, and ordinary
trailing pictures (TRAIL).
2.2.2.3
Temporal Sub-layer Access (TSA) Pictures
A TSA picture is a trailing picture that indicates a temporal sub-layer switching
point. The TSA picture type can only be used for a picture if it is guaranteed that
no picture that precedes the TSA picture in decoding order with a temporal ID that
is greater than or equal to the temporal ID of the TSA picture itself is used for
prediction of the TSA picture or any subsequent (in decoding order) pictures in the
same or higher temporal sub-layer as the TSA picture. For example, picture P 6 in
Fig. 2.5 can use the TSA picture type since only previous pictures in temporal sub-
layer 0 are used for prediction of the TSA picture itself and subsequent pictures in
decoding order.
When a decoder is decoding a subset of the temporal sub-layers in the bitstream
and encounters a TSA picture type of the temporal sub-layer just above the
maximum temporal sub-layer it is decoding, it is possible for the decoder to switch
up to and decode any number of additional temporal sub-layers. For the example in
Fig. 2.5 , a decoder that decodes only temporal sub-layer 0 can from the TSA picture
 
Search WWH ::




Custom Search