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Reordering audio overview doc

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Trying to put more common use cases earlier in the
list of implementation details.

Change-Id: I11195d5d2f7846dec3342d43fe3917fb13374daa
Reviewed-by: Ling Hu <ling.hu@nokia.com>
Reviewed-by: Dmytro Poplavskiy <dmytro.poplavskiy@nokia.com>
This commit is contained in:
Angus Cummings
2012-05-18 11:24:18 +10:00
committed by Qt by Nokia
parent 2564dbec68
commit f11c5c83a0
1 changed files with 49 additions and 49 deletions
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doc/src/audiooverview.qdoc
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@@ -40,6 +40,55 @@ See that documentation for more information.
\section1 Audio Implementation Details
\section2 Playing compressed audio
For playing media or audio files that are not simple, raw audio, you can
use the \l QMediaPlayer C++ class, or the \l {Audio} and \l {MediaPlayer} QML types.
The QMediaPlayer class and associated QML types are also capable of playing
\l{multimedia-playing-video}{video}, if required. The compressed audio formats supported does depend
on the operating system environment, and also what media plugins the user
may have installed.
Here is how you play a local file using C++:
\snippet doc/src/snippets/multimedia-snippets/media.cpp Local playback
You can also put files (even remote URLs) into a playlist:
\snippet doc/src/snippets/multimedia-snippets/media.cpp Audio playlist
\section2 Recording audio to a file
For recording audio to a file, the \l {QAudioRecorder} class allows you
to compress audio data from an input device and record it.
\snippet doc/src/snippets/multimedia-snippets/media.cpp Audio recorder
\section2 Low latency sound effects
In addition to the raw access to sound devices described above, the QSoundEffect class (and
\l {SoundEffect} QML type) offers a slightly higher level way to play
sounds. These classes allow you to specify a WAV format file which can
then be played with low latency when necessary. Both QSoundEffect and
SoundEffect have essentially the same API.
You can adjust the number of \l {QSoundEffect::loops}{loops} a sound effect is played, as well as
the \l {QSoundEffect::setVolume()}{volume} (or \l {QSoundEffect::setMuted()}{muting}) of the effect.
For older, Qt 4.x based applications \l QSound is also available. Applications
are recommended to use QSoundEffect where possible.
\section2 Monitoring audio data during playback or recording
The \l QAudioProbe class allows you to monitor audio data being played or
recorded in the higher level classes like \l QMediaPlayer, \l QCamera and
\l QAudioRecorder. After creating your high level class, you can simply
set the source of the probe to your class, and receive audio buffers as they
are processed. This is useful for several audio processing tasks, particularly
for visualization or adjusting gain. You cannot modify the buffers, and
they may arrive at a slightly different time than the media pipeline
processes them.
Here's an example of installing a probe during recording:
\snippet doc/src/snippets/multimedia-snippets/media.cpp Audio probe
\section2 Low level audio playback and recording
Qt Multimedia offers classes for raw access to audio input and output
facilities, allowing applications to receive raw data from devices like
@@ -65,35 +114,6 @@ In \c push mode, the audio device provides a QIODevice instance that
can be written or read to as needed. Typically this results in simpler
code but more buffering, which may affect latency.
\section2 Low latency sound effects
In addition to the raw access to sound devices described above, the QSoundEffect class (and
\l {SoundEffect} QML type) offers a slightly higher level way to play
sounds. These classes allow you to specify a WAV format file which can
then be played with low latency when necessary. Both QSoundEffect and
SoundEffect have essentially the same API.
You can adjust the number of \l {QSoundEffect::loops}{loops} a sound effect is played, as well as
the \l {QSoundEffect::setVolume()}{volume} (or \l {QSoundEffect::setMuted()}{muting}) of the effect.
For older, Qt 4.x based applications \l QSound is also available. Applications
are recommended to use QSoundEffect where possible.
\section2 Playing compressed audio
For playing media or audio files that are not simple, raw audio, you can
use the \l QMediaPlayer C++ class, or the \l {Audio} and \l {MediaPlayer} QML types.
The QMediaPlayer class and associated QML types are also capable of playing
\l{multimedia-playing-video}{video}, if required. The compressed audio formats supported does depend
on the operating system environment, and also what media plugins the user
may have installed.
Here is how you play a local file using C++:
\snippet doc/src/snippets/multimedia-snippets/media.cpp Local playback
You can also put files (even remote URLs) into a playlist:
\snippet doc/src/snippets/multimedia-snippets/media.cpp Audio playlist
\section2 Decoding compressed audio to memory
In some cases you may want to decode a compressed audio file and do further
processing yourself (like mix multiple samples, or some custom digital signal
@@ -108,26 +128,6 @@ Here's an example of decoding a local file:
Note: This API is preliminary at this time - the API may change or be
removed before the final 5.0 release.
\section2 Recording audio to a file
For recording audio to a file, the \l {QAudioRecorder} class allows you
to compress audio data from an input device and record it.
\snippet doc/src/snippets/multimedia-snippets/media.cpp Audio recorder
\section2 Monitoring audio data during playback or recording
The \l QAudioProbe class allows you to monitor audio data being played or
recorded in the higher level classes like \l QMediaPlayer, \l QCamera and
\l QAudioRecorder. After creating your high level class, you can simply
set the source of the probe to your class, and receive audio buffers as they
are processed. This is useful for several audio processing tasks, particularly
for visualization or adjusting gain. You cannot modify the buffers, and
they may arrive at a slightly different time than the media pipeline
processes them.
Here's an example of installing a probe during recording:
\snippet doc/src/snippets/multimedia-snippets/media.cpp Audio probe
\section1 Examples
There are both C++ and QML examples available.