Category: Audio

Audio related stuff

Windows Media Player encountered a problem while playing ASF/WMV file with multiple audio tracks

This is not really obvious: Windows Media Player refuses to open a Windows Media (ASF) file with an undescriptive error message: “Windows Media Player encountered a problem while playing the file”. The problem, however, is that the file is actually good, more or less. The file plays well in DirectShow and Media Foundation APIs. There…

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Audio playback at non-standard rates in DirectShow

DirectShow streaming and playback in particular offers flexible playback rates for scenarios where playback is requested to take place slower or faster than real time. For a DirectShow developer, the outer interface is pretty straightforward:IMediaPosition::put_Rate┬átakes playback rate and that’s it. Playback rate. Must not be zero. The playback rate is expressed as a ratio of…

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Sample: Simultaneous Audio Playback via Waveform Audio (waveOut) API

The minimalistic sample demonstrates support of [deprecated] Waveform Audio API for multiple playback streams. Depending on command line parameters, the application starts threads to open audio hardware using separate waveOutOpen call and stream one or more generated sine waves: 1,000 Hz sine wave as 22,050 Hz, Mono, 16-bit PCM (command line parameter “a”) 5,000 Hz…

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Adobe Flash Media Live Encoder 3.1

It is the first time ever – because probably I am not as experienced as Geraint – I witness availability of IMediaSample interface without availability of IMediaSample2. One might be curious what kind of software could provide such a weirdo in 2010? It is latest and greatest Adobe Flash Media Live Encoder 3.1. Additionally to…

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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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