Encoder Buffer - 2023.1 English

The buffer memory controller of the encoder block manages the read and write access to the encoder buffer, which stores pixel data from the reference frames. It pre-fetches data blocks from the reference frames in the system memory and stores them in the encoder buffer. The encoder buffer stores Luma and Chroma pixels from the reference frames so that they are present in the buffer when needed by the encoder. The encoder buffer must be one contiguous memory access (CMA) buffer and should be aligned to a 32-byte boundary. Refer to the Zynq UltraScale+ MPSoC Data Sheet: Overview (DS891) to see the device memory available per EV device.

Calculate the system bandwidth in total derated based on memory controller efficiency for the required access pattern. Enable the Encoder Buffer if the calculated bandwidth is insufficient.

The optional encoder buffer can be used to reduce the memory bandwidth. This option can slightly reduce the video quality. See the CacheLevel2 in Table 1 for more information. Aside from the size, there are no user controls for tuning the Encoder buffer usage.

gst-launch-1.0 videotestsrc ! omxh265enc prefetch-buffer=true ! fakesink

The required encoder buffer memory size for 4:2:0 and 4:2:2 sampling formats are shown in the following tables.