I have attached a raw annex-b h264 file that contains a 960x720 video. When using the sample decode on this file, the YUV output shows smeared artifacts as if it never found any good I-frames.
I have about 65-75% confidence in the validity of the dump itself, and I'll continue to pursue verifing it. The original source (MP4 avcc) has been confirmed to be correct and does not produce these artifacts.
I have used this same technique on other MP4 clips with success, but so far the two clips I've found that exhibit this symptom are cartoonish and most likely have a very high compression ratio.
So now it boils down to either the avcc->annexb conversion (in my code)has a bug, or if this dump is valid, there may be somenew stress presented to the decoder to exhibit symptom. I am hoping to pinpoint which it is by the end of the day. (I'll post back once I know)