Category: Audio

Audio related stuff

DirectShow Spy: Filter Mapper Spy

DirectShow Filter Graph Spy was updated to add new functionality: spying over another DirectShow object – Filter Mapper. Filter Mapper object is used for filter registration purposes and also internally by DirectShow’s Intelligent Connect. IFilterMapper2 interface traces provide detailed description on steps DirectShow takes in order to connect and/or render filter pins. For example when…

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Windows Media Codec List

Windows Media Codec List utility uses IWMCodecInfo interface (see also IWMCodecInfo2, IWMCodecInfo3) lists installed Windows Media Codecs and their formats and presents the findings in a convenient way. The utility gives a quick idea what a programmer would obtain through IWMCodecInfo2/IWMCodecInfo3 interfaces and what well known format structures (WM_MEDIA_TYPE, AM_MEDIA_TYPE, WAVEFORMATEX, VIDEOINFOHEADER) correspond to particular…

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MediaTools: Tone Source Filter to generate reference audio feed, dual Audio Source Filter and Virtual Audio Capture Device

In order to obtain a reference audio source and especially useful for debugging purposes, including: audio input device unrelated to physical device, to avoid conditions when device is already in use by someone else non-zero audio signal which is independent of certain speaker or broadcasting service, including one that makes capture, transmission or rendering issues…

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I don’t have any idea who makes software nowadays, but how can it expected to be reliable? Intel DG33FBC motherboard, onboard Realtek ALC888 High Definition Audio. I am tracing AUDIO_STREAM_CONFIG_CAPS capabilities reported by onboard audio capture board, one of them: AM_MEDIA_TYPE: majortype {73647561-0000-0010-8000-00AA00389B71}, subtype {00000001-0000-0010-8000-00AA00389B71}, pUnk 0x00000000 bFixedSizeSamples 1, bTemporalCompression 0, lSampleSize 4 formattype {05589F81-C356-11CE-BF01-00AA0055595A},…

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Multichannel audio recording

There has been recently an interesting post “Problem playing back multi-channel wave file under vista” on DirectShow Development forum about certain hardware that is capable of recording 64 channels of audio in 24-bit per sample PCM quality, with a sample recorded .WAV file posted. I was curious what kind of hardware implements such recording. Google…

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FFDShow is getting more annoying

Surprisingly fast I got new problems having ffdshow installed as a part of K-Lite Codec Pack. No wonder though because let us take a look at registration information: Display Name: @device:sw:{083863F1-70DE-11D0-BD40-00A0C911CE86}\{0F40E1E5-4F79-4988-B1A9-CC98794E6B55} CLSID: {0F40E1E5-4F79-4988-B1A9-CC98794E6B55} Friendly Name: ffdshow Audio Decoder Path: C:\Program Files\K-Lite Codec Pack\ffdshow\ Merit: 0x3fffffff Nice merit, ain’t it? What is merit anyway? Let us…

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