[r0lZ]

I'm not sure I understand that profile and level concepts correctly. I did some tests with different presets (CRF 23, profile auto and level not defined), of course always with the same input file, and obviously the profile and levels depend of the input file, that's right, but also of the preset. For example, I got the Baseline profile when I have encoded the video with the Ultrafast preset, and profile high level 5.1 when the same video has been encoded with the Placebo preset, without any other change. Since my TV refuses to display level 5.0 or higher, I NEED to specify --level 4.1 if I use a slow preset.

Therefore, if I can agree that the characteristics of the input file are important to determine the profile and level used by default by x264, I notice that the preset is at least as important, and I must disagree when you say that "setting --level manually is almost always a bad idea". IMO, setting level to 4.1 (or max 4.2) is essential if you need a good compatibility with most hardware players, and you want to encode with a slow preset. (I wonder if it make sense to use a very slow preset like Placebo and in the same time limit the encoder with --profile high --level 4.1, but it's another question.)