Texas Instruments Codec Engine Server manual More About the groupId Field, Server.algs.groupId

Creating a Codec Server

How you define the groupId field can affect performance or whether a codec can be created at all. For detailed information on shared scratch memory, see the Framework Components documentation. You may save some time by reading the commentary for the server configuration script in the video_copy example, which is in <CE_install_dir>/examples /ti/sdo/ce/examples/servers/video_copy/video_copy.cfg.

What is true for sharing memory is also true for sharing DMA resources among codecs. Again, for details, please check the Framework Components documentation or the commentary regarding the theory and practice of DMA configuration in the video_copy configuration example in the script referenced above.

2.2.3.3More About the groupId Field

Note that although both the Server.algs[] and Engine.algs[] array have an optional groupId field, there is a distinction between the Server.algs[] and Engine.algs[] arrays. This makes sense, if you consider that DSP-based algorithms on a DM644x (DSP+ARM) are configured into a Server, while the same DSP-based algorithms on a DM643x (DSP only) are configured into an Engine.

Server.algs[].groupId

For each algorithm in the respective algs[] array, if the optional groupId is uninitialized, the algorithm will be configured into a group with other algorithms that have their groupId field uninitialized and run at the same priority. If no algorithms have both of these attributes, it will be in a unique groupId.

Exactly which groupId it will be assigned into is non-deterministic. Therefore, it's not possible to configure scratch resources (for example, DSKT2 scratch memory and DMAN3 DMA resources) for this non- deterministic groupId. It's important therefore, that if the system integrator intends for an algorithm's resources to be shared, the groupId field should be appropriately configured.

Also, if the groupId is non-deterministically assigned, and the algorithm requests scratch resources, these resources will be granted from (likely non-configured) resource pools!

For example, in DSKT2-based systems, DSKT2 grants such memory

requests using the (likely non-configured) DSKT2.DARAM_SCRATCH_SIZES[<nondeterministic-groupId>] and DSKT2.SARAM_SCRATCH_SIZES[<nondeterministic-groupId>] memory blocks. This can lead to strange system behavior, including algorithms that sometimes can be created but other times fail.

Configuring a Codec Server 2-13