The opus encoder and decoder do not need to have matched sampling rates or channel counts. It is recommended to always just decode at the highest rate the hardware supports (e.g. 48kHz stereo) so the user gets the full quality of whatever the far end is sending.
If libopus is built with -DNONTHREADSAFE_PSEUDOSTACK (instead of VAR_ARRAYS, or USE_ALLOCA), it will use a user-provided block of heap instead of stack for many things, resulting in much lower stack usage.This makes the resulting library non-threadsafe and is not recommended on anything except limited embedded platforms.
Opus Aec 10
Computing the duration directly from the file contents allows files to be written in a single pass, without any seeking, which is necessary for live streaming. Chaining also simplifies live streaming, as you can just pipe multiple files into the same network connection, with all associated metadata updates, etc., and the results are still valid .opus files (contrast with the hacks used to add metadata to MP3 streams).
Opening a typical .opus file, which is not multiplexed and not chained, and computing the duration over the network requires just one extra HTTP request, which can proceed in parallel with the buffering in the main request. This is the behavior you will get from libopusfile's HTTP backend by default.
Enumeration of chain boundaries can be expensive in files with many links, but in our testing libopusfile used nearly an order of magnitude fewer seeks to do this than some other media frameworks (at the time). Storing a duration in a header wouldn't solve this, since every link in a chain has its own, independent headers. If the cost of chain enumeration is a problem, the best way to avoid it is to store the links in separate files (i.e., don't use chaining).
libopusfile includes fallbacks to prevent pathological worst-case behavior when its guesses are repeatedly wrong. Weighted bisection can degrade to a linear scan, but libopusfile's worst case is within a constant factor of naive bisection (i.e., logarithmic). We have only ever observed such pathological behavior in files we manually constructed to trigger it.
libopusfile also takes shortcuts when the target location is near the current position, to make small seeks cheaper. In the best case it can loop forever over very short files whose data is contained in a single page (e.g., less than 1 second long with default encoder settings) without any seeking at all.
As with file durations, an index at the beginning of the file is incompatible with live streaming. It also means more data has to be fetched before a file can start playing over the network, because you must read past the index even when you don't intend to seek. The index could be stored at the end (which even still allows encoding the file in a single pass), but this requires one (or more) extra seeks to read the index (especially if its exact location at the end is not known), either on file open or on first seek. Unlike the final timestamp, which is small and fixed in size, an index grows with the file duration, and can have unbounded size. It is also easy for an index to become out of sync with a file that has been edited or damaged, in which case seeking will simply fail. By contrast, you can seek in a truncated .opus download without issues.
In practice, bisection seeking on VBR audio achieves performance that is very nearly as good as seeking with an index, without any of the drawbacks of an index. libopusfile provides a test program called seeking_example which can be used to benchmark the performance on your files.
manual completo de opus 2010, maneja paso a paso el procedimiento y uso del programa asi como tambien viene con imagenes de cada paso. Descargado:146vecesAgregado por:alex rodriguez (La reputación del usuario esExcelente)Fecha:Mon, 30 May 2016Licencia:Descarga Gratispara usuarios registrados. El registro es gratis.Tamaño de descarga:25849401bytes Calificación:8.62/10Votos:13Califícalo
I recently ran an update and some of my audio and video settings in config.js stopped working. I figured out what happened in the audio. I was using the settings that enable HD audio, but the update overrides any disableAEC: TRUE. I turned off the stereo and maxopusbitrate, so AEC is back on. 2ff7e9595c
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