Hikvision MP2L2 Audio Encoding Capability
  • The DS-2CD2632F-IS Hikvision camera has the option to select various formats for audio encoding. MP2L2 provides the best audio quality out of all the possibilities. Unfortunately, SecuritySpy only works with the old G.711 and G.726 encoding schemes, with very poor audio results. Is there any way that we could enable the MP2L2 audio stream to work with SecuritySpy?
  • Sorry, this format is currently unsupported by SecuritySpy (it's not widely used and there is no Apple API to decode it). If it becomes more popular, and Apple implement a decoder, then we will have another look at this. I'd suggest using G.711 as this is probably going to be better than G.726. It's a pity they don't support AAC, which is high-quality and widely supported.
  • Thank you for the insight.
  • I noticed that with video + G.711 audio recording the files are being saved in a MOV container rather than a m4v file. The problem which now occurs is that when attempting to view the saved footage through Safari or Chrome the browser throws out an error "Missing Plugin." It is attempting to play the file with the QuickTime plugin. However, even with the old plugin added the file does not play. The m4v (video only) files play just fine.
  • The solution is to enable the "Recompress audio data" option under Web -> Cameras -> Devices, and make sure that the audio compression format is set to AAC under Web -> Compression. Then you will get .m4v files that play back natively in web browsers.
  • In that case, if recompression is needed anyway, would be possible to add the ability to receive the higher quality MP2L2 audio stream and then recompresses it to AAC?
  • This would be the way to do it, and we'll consider this for the future when it becomes possible to do. However it would require significant development time for marginal benefit, and there are many more important things on our "to do" list for SecuritySpy that we have to prioritise.
  • Any updates on this feature? Will we able to use Hikvision with MP2L2 audio compression?
  • Sorry, nothing has changed. Even if we wanted to, we wouldn't be able to support this format, as Hikvision has not released any technical information or decoding library that we can use to process MP2L2 audio. It remains a proprietary Hikvision format that can be used with their software only.
  • VLC has been able to play the RTSP stream with MP2L2 audio for some time. I assume them must have some information about how to decode it.
  • Are you sure? MP2L2 is not listed as a supported audio format for VLC. It would be interesting if they are able to support it.
  • Yes, VLC audio has always worked for me. MP2L2 could just be a container for a common codec (e.g. MPEG-2).
  • When streaming the Media Information window says the audio is "MPEG audio layer 1/2 (mpga)"

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