I dowloaded ti-dvsdk_dm3730-evm_4_02_00_06 and tested mpeg2 decoder on beagleboard xM rev. C with 640x360 mpeg1 stream. I found the following issues.
1. Vdec2_create(Engine_Handle hEngine, Char *codecName, VIDDEC2_Params *params, VIDDEC2_DynamicParams *dynParams) failed if maxWidth and maxHeight are set to 640 and 360 respetively in *params. It is O.K. if set to 1280x720 or 720X480. In terms of its user guide, it should work from 128x96 to 1280x720
2. It doesn't work with 640x360 mpeg1. Following the first issue, maxWidth and maxHeight are set to 1280X720, Vdec2_create works. But decoder output is green strip at the bottom of screen. I tested it with ffmpeg, it works. Then I tested davinci 720x480 mpeg2 test stream, it works. Its user data document says it supports mpeg1 as well.
Thanks.