From Brian Willoughby Sent Wed, Jan 10th 2018, 00:34
From Brian Willoughby Sent Wed, Jan 10th 2018, 00:34
Another issue is that I don=E2=80=99t think it=E2=80=99s possible to = create a Dolby 5.1 stream on the fly from discrete channels. The link = you shared is for Compressor, which is authoring software that converts = from one file format to another. Compressor is not designed for live = playback and mixing of multiple channels like a regular DAW. It=E2=80=99s = generally used as an offline step in the workflow. Since I have external Dolby 5.1 decoder hardware in my home theatre = setup, I=E2=80=99ve been curious for decades as to whether it would be = possible to create a compatible stream within some audio software and = then use my external decoder to separate the channels into 5.1 surround. = I learned enough to discover which audio interfaces can be put into a = non-mixed mode where a single application can make private use of the = interface to pass a digital bitstream through from software to external = decoder, but I never found any DAW or software support for creating a = Dolby 5.1 stream on the fly. The options seem to be limited to playing = back a pre-mastered Dolby 5.1 soundtrack from DVD media (or similar), or = converting files using software like Compressor to go from discrete, = uncompressed tracks to a combined, compressed bitstream. By the way, all = of my research was focused on laptop based software, but CoreAudio is = largely the same between macOS and iOS. For my laptop, I ended up getting an Emagic EMI 2|6 interface, which = supports 6 outputs at 48 kHz (or 2 outputs at 96 kHz). Luckily, my home = theatre setup has 6 RCA inputs that will accept 5.1 audio. This hardware = setup was compatible with all of the DAW software (and my custom = software) that needed multiple channels. By the way, all audio on an iPad (or any iOS device) is CoreAudio. So, = if you=E2=80=99re hearing sound, then something inside (app) is talking = CoreAudio. The only question is whether the software looks for CoreAudio = devices with multiple channels, and whether it allows access to channels = beyond the default first two that are used for stereo. I=E2=80=99m = assuming that there are many DAW apps for iOS that support multichannel. = I=E2=80=99ve briefly used Cubasis while working for a client, and I = recall that it fully supports multiple channels. So, there=E2=80=99s at = least one option. Brian On Jan 9, 2018, at 4:17 PM, annika morgan <xxxxxx.x.xxxxxx@xxxxx.xxx> = wrote: > Yeah, I was reading more about core audio last night and realized that = you=E2=80=99d need something inside (app) and outside (DAW) the IPad = that can talk core audio. >=20 > On Tue, Jan 9, 2018 at 6:12 PM Brian Willoughby = <xxxxxx@xxxxxxxxxxxx.xxx> wrote: >> On Jan 8, 2018, at 4:38 AM, annika morgan <xxxxxx.x.xxxxxx@xxxxx.xxx> = wrote: >> > Dolby 5.1 is what you need. Then you can assign audio to each dolby = 5.1 channel. >> > >> > https://support.apple.com/kb/PH21206?locale=3Den_US >>=20 >> Careful. In many cases, Dolby 5.1 is not what you want. It is = basically always compressed in a lossy manner, so you certainly = wouldn=E2=80=99t want to be recording a new album this way. >>=20 >> Support for Dolby 5.1 is intended for playback of pre-mastered = surround soundtracks, and this mode allows for interfaces which can pass = the proprietary Dolby bitstream through the device and on to outboard = surround decoders via digital audio interconnects. In addition, some = audio interfaces will decode the bitstream, but those are rare in = comparison to the ones that pass through the data for external decoding. >>=20 >> What you need is to use the CoreAudio features that support = multi-channel outputs without compression. This is obviously not = available in a simple stereo playback application like iTunes, but the = iOS DAW software should support multichannel without restricting the = data to Dolby. Many interfaces will support 8 discrete, full-range, = uncompressed outputs, or more. >>=20 >> Brian Willoughby