220 26134 article Path: news.gmane.org!not-for-mail From: "'Jeffrey Yasskin' via ISO C++ Standard - Future Proposals" Newsgroups: gmane.comp.lang.c++.isocpp.proposals Subject: Re: Any interest to adding audio support to the std library? 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[2607:f8b0:4001:c06::22c]) by mx.google.com with ESMTPS id k7si226894ith.5.2016.06.03.08.43.41 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Fri, 03 Jun 2016 08:43:41 -0700 (PDT) Received-SPF: pass (google.com: domain of jyasskin@google.com designates 2607:f8b0:4001:c06::22c as permitted sender) client-ip=2607:f8b0:4001:c06::22c; Original-Received: by mail-io0-x22c.google.com with SMTP id k19so64685522ioi.3 for ; Fri, 03 Jun 2016 08:43:41 -0700 (PDT) X-Received: by 10.107.149.66 with SMTP id x63mr5927585iod.141.1464968620748; Fri, 03 Jun 2016 08:43:40 -0700 (PDT) Original-Received: by 10.64.225.228 with HTTP; Fri, 3 Jun 2016 08:43:21 -0700 (PDT) In-Reply-To: X-Original-Sender: jyasskin@google.com X-Original-Authentication-Results: mx.google.com; dkim=pass header.i=@google.com; spf=pass (google.com: domain of jyasskin@google.com designates 2607:f8b0:4001:c06::22c as permitted sender) smtp.mailfrom=jyasskin@google.com; dmarc=pass (p=REJECT dis=NONE) header.from=google.com X-Original-From: Jeffrey Yasskin Precedence: list Mailing-list: list std-proposals@isocpp.org; contact std-proposals+owners@isocpp.org List-ID: X-Spam-Checked-In-Group: std-proposals@isocpp.org X-Google-Group-Id: 399137483710 List-Post: , List-Help: , List-Archive: List-Subscribe: , List-Unsubscribe: , Xref: news.gmane.org gmane.comp.lang.c++.isocpp.proposals:26134 Archived-At: Is this based on an existing library? We're much more likely to adopt a proposal that's been used widely than one that was invented for the standard. On Fri, Jun 3, 2016 at 2:37 AM, wrote: > I have drafted some ideas on how I think the c++ std library could support > audio functionality. > > I know that audio functionality is a very operating specific problem, but > with the recent trend towards implementing a file-system library and > possibly a graphics library I believe that audio would not be too much of a > reach anymore. > > Here are some of the ideas I have so far. I have both some code examples of > the intended usage as well as a list of the types needed to implement the > given examples. > > Please keep in mind my drafts are still very rough. > > > CODE EXAMPLES > > //std::audio example 1 "single process" > void example_1(){ > double sample_rate = 44100; > std::size_t frame_size =2; > std::size_t buffer_size=128; > > std::audio_context > ctx{sample_rate,buffer_size,frame_size};//contruct from values > > std::astream_process proc(ctx,[](std::iastream const& input, > std::oastream& output){ > std::frame_buffer& buff = ctx.borrow_buffer();//borrow a > buffer from the context for usage > //prevents the need for dynamic allocation of a temporary buffer > input>>buff;//stream data into buffer for manipulation > for(auto&& frame: buff){ > frame=0.0;//do something with audio > } > output< });//dsp object > //uses implied routing equivilent to > //std::aout< // > > proc.start(); > //do other stuff > proc.stop(); > } > > //std::audio example 2 "process group" > void example_2(){ > > std::audio_context ctx;//default context created with > std::default_* values > > //version 1: capture context via lambda > std::astream_process proc1(ctx,[&ctx](std::iastream const& input, > std::oastream& output){ > std::frame_buffer& buff = ctx.borrow_buffer(); > input>>buff; > for(auto&& frame: buff){ > frame*=0.5; > } > output< });//dsp object > > //version 2: have context passed as argument > std::astream_process proc2(ctx,[](std::iastream const& input, > std::oastream& output,std::audio_context const& context){ > std::frame_buffer& buff = ctx.borrow_buffer(); > input>>buff; > for(auto&& frame: buff){ > frame*=2.0; > } > output< }); > > std::process_group pgroup;//a group of processes that will happen > consecutivley > pgroup.push(proc1);//add to group > pgroup.push(proc2);//add to group > > //configure stream relationships in terms of std::ain / std:aout > manually > //std::ain/std::aout are std::astream globals that refer to the default > audio inputs and outputs supplied by the context in use > //std::ain/std::aout will route the audio to the enpoint specified by > the context reference held by the process that is streaming the data > std::aout< //std::ain>>proc2>>proc1>>std::aout;//method 2 > > pgroup.start(); > //do other stuff > pgroup.stop(); > > } > > > //std::audio example 3 "audio files" > void example_3(){ > > std::audio_context ctx; > > std::astream_process proc(ctx,[](std::iafstream const& input, > std::oafstream& output){ > std::frame_buffer& buff = ctx.borrow_buffer(); > input>>buff; > for(auto&& frame: buff){ > frame=0.0; > } > output< });//dsp object > > std::iafstream audio_file1(ctx,"filename1.extension");//an audio file > handle > std::oafstream audio_file2(ctx,"filename2.extension");//an audio file > handle > > //routing > audio_file2< //audio_file1>>proc>>audio_file2;//equivilent syntax > proc.start(); > //do other stuff > proc.stop(); > } > > > //std::audio example 4 "combination routing" > void example_3(){ > > std::audio_context ctx; > //manually select hardware endpoints > std::size_t device_id = ctx.default_device_id(); > std::iastream input_device = > ctx.get_device(device_id); > std::oastream output_device = > ctx.get_device(device_id); > > std::astream_process proc(ctx,[](std::iastream const& input, > std::oastream& output, > std::iafstream const& > input_file, > std::oafstream& output_file){ > std::frame_buffer& buff = ctx.borrow_buffer(); > (input + input_file)>>buff;//add streams to perform sum before > writing to buffer > //or you could use seperate buffers > //like this > /* > std::frame_buffer buff1; > std::frame_buffer buff2; > > input>>buff1; > input_file>>buff2; > buff1+=buff2;//buffer arithmatic > */ > output< file out > output_file< }); > > std::iafstream audio_file1(ctx,"filename1.extension");//the actual files > to be used above > std::oafstream audio_file2(ctx,"filename2.extension"); > > //connect the files to the process > //connect the hardware device to the process > audio_file2< output_device< proc.start(); > //do other stuff > proc.stop(); > } > > > > REQUIRED LIBRARY MEMBERS > > > namespace std{ > inline namespace audio{ > //working context for audio flow > template > class audio_context; > /* > *The context in which all audio data is centered. > *Contains: sampling rate, buffer size, frame size, etc... > *The values of ain,aout,afin,afout refer to the endpoints defined by > the context, when applied to routing on a porocess tied to the context > *think of a context as the program level driver object > */ > > //audio streams (think like std::fstream and its friends) > class astream;//audio stream > class oastream;//output audio stream > class iastream;//input audio stream > class oafstream;//output audio file stream > class iafstream;//input audio file stream > > > //stream endpoints > class ain;//audio input endpoint > class aout;//audio output endpoint > class afin;//audio file input endpoint > class afout//audio file output endpoint > > //stream processing > template > class astream_process;//a dsp process applied to a stream > > template > class process_group;//a group of processes that will act as one > > //containers > template > class frame_buffer;//a sequence container that is resizeable at > runtime, but only with explicit resize calls. contains frames(see below) > /*Implementation note on frame_buffer > *frame_buffer is intended to hold N number of frames which > themselves can hold M number of samples > *meaning that the total size in samples if frame_buffer = N * M > *ideally frame_buffers representation of its sample data will be > continuous in memory > */ > > template > class frame;//a container that holds samples, thin array wrapper > > > //hardware representation > class device;//an audio device as recognized by the OS > class input_device;//an input device > class output_device;//an output device > > // audio file formats > enum class afformat{ > raw,//raw headerless audio bytes, interpreted only by the > settings of the context. > //best used for temporary storage within the life of a context > wav, > flac//etc... > } > } > } > > > > -- > You received this message because you are subscribed to the Google Groups > "ISO C++ Standard - Future Proposals" group. > To unsubscribe from this group and stop receiving emails from it, send an > email to std-proposals+unsubscribe@isocpp.org. > To post to this group, send email to std-proposals@isocpp.org. > To view this discussion on the web visit > https://groups.google.com/a/isocpp.org/d/msgid/std-proposals/f490fd21-cf07-4d7b-8936-c71c97a1ab9d%40isocpp.org. -- You received this message because you are subscribed to the Google Groups "ISO C++ Standard - Future Proposals" group. 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