Hi Paras,
The PAL SDK is a very minimal library, designed to produce a nonce that can be attached to an Ad request, and allowing you to forward specific app interactions to Ad Manager. It does not handle parsing the returned VAST, VMAP, or Ads Playlist XML or stitching these ads into your video player. The PAL SDK is designed specifically for publishers who have developed (or need to develop) their own VAST-compatible ad solution, and wish to add support for Google Ad Manager programmatic ads.
The IMA SDK is our full-featured video ad library, which manages requests, stitching, playback, and signalling. We recommend that users only choose the PAL SDK if their use case is somehow incompatible with the IMA SDK.
Thanks,
Greg Schoppe
IMA SDK Team