While I don't consider OPlayer (HD) (AppStore links: iPhone; iPad) the best-performing or most versatile iOS video players out there, it still has some very strong and well-supported features like a very good MSMPEG4 and OGG Vorbis video decoder.
The just-released, new version boasts, among other things, support for volume boosting - something I really need when in a noisy environment or when needing as large a video playback volume as possible (see the annotated part of the screenshot; click it for a larger version):
I've tested audio boosting and found it only working during network streaming - just like movie flipping (the latter, so far, only being a unique feature of AVPlayer(HD), one of absolutely the best players.) No audio boost while playing back local files.
Hopefully the developers do allow for volume boosting when playing back local content as well - if you plan to play back local files, that is. Until then, stick with GoodPlayer (during only non-hardware-accelerated, that is, non-MOV / MP4 / M4V playback) or It's Playing (even hardware-accelerated playback; review) if you do need volume boost.
Very important to remember!
Also note that you must enable hardware MP4/M4V/MOV playback (it's disabled by default, enable at: Settings / Plugin / Use QuickTime)
Problems; how does the player compare to other players?
A mini-review follows: the biggest problems with the player are as follows:
- OPlayer is especially weak at playing back any kind of WMV3 (WMV1/WMV2 are OK) or MPEG-2 TS (aka DVB) files (see the WMV bible for more info)
- its H.264 decoder is definitely weaker than that of AVPlayerHD / ProPlayer at 1080p
- it has no nice features like video (brightness, contast, saturation etc.) DSP's, unlike It's Playing.
- its 1080p60 MTS support is definitely weaker than the best of the bunch)
NOTE: HERE, I've directly compared it to AVPlayer(HD). Worth a read for more info!