Blu ray movies can be converted to dvd-video format, but it is not always a simple process, and requires more tools than just AnyDVD HD and ImgBurn.
Blu ray format can use H264, VC-1 or Mpeg2 video codecs. The audio codecs that can be used are even more numerous, including regular AC3, DTS, LPCM, Dolby Digital Plus, DTS HD High Resolution Audio, DTS-HD MA, or Dolby True HD.
Video resolution in blu ray is 1920 x 1080 usually. The highest resolutions allowed in dvd video are either 720 x 480 (NTSC) or 720 x 576 (PAL). And the only audio allowed in dvd-video is DTS, AC3, LPCM, or in PAL video, MP2. The only video codec used in dvd-video is Mpeg2.
So you can see, the video and audio codecs don't always correspond, and the resolution and bitrate used in blu ray don't fit the necessary specifications of dvd-video.
Sometimes you can add the main m2ts file from the blu ray video into AVStoDVD and get a good dvd-video output. This works best if you start with a blu ray movie that is encoded with H264 or Mpeg2. But I've found that DTS-HD MA audio tracks tend to gum up the works, and if you start with VC-1 video codec in the blu ray, AVStoDVD won't do this conversion well, if at all.
For those difficult ones, it is best to use an AviSynth script and the HCenc encoder to work with the VC-1 video. I've used AvSP to make a simple script...something like this one where the source is a virtual drive H, mounted with an ISO of the blu ray movie:
LanczosResize (720, 480)
The main movie was in the 00010.m2ts file in this particular movie. It won't be the same in others.
For the audio, you can demux and convert to AC3 using ClownBD. Make sure to set output to AC3 audio that is compliant to dvd specifications....48khz and no more than 448kbps.