How to play MP3 audio buffers

[s***@essential.com]

Hi,

I am developing a C++ only library (no java) using the NDK audio library.
One of the functionality I must support is to play MP3 audio buffers (not
files, I already done that).
I can't use mediacodec or another open source decoder (just ndk)

This documentation
(https://developer.android.com/ndk/guides/audio/opensl-for-android.html)
says that I can use the buffer api (Buffer queue data locator) to play PCM
data!
How do you go about playing MP3 audio buffers? Can you point me to a
documentation or an example code?

Thanks in advance.

Regards, Shahriar

P.S. I know this question has been asked before. But I haven't read a
concise answer yet.

['Don Turner' via android-ndk]

The NDK has its own extraction and decoding classes: NdkMediaExtractor and
NdkMediaCodec.

Docs
here: https://developer.android.com/ndk/reference/ndk_media_codec_8h.html
Sample code
here: https://github.com/googlesamples/android-ndk/blob/master/native-codec

You'll need to modify the sample code to decode MP3 rather than MP4
(video).

I would advise against using OpenSL ES for MP3 decoding since this
technique has some performance issues.

Post by s***@essential.com
Hi,
I am developing a C++ only library (no java) using the NDK audio library.
One of the functionality I must support is to play MP3 audio buffers (not
files, I already done that).
I can't use mediacodec or another open source decoder (just ndk)
This documentation (
https://developer.android.com/ndk/guides/audio/opensl-for-android.html)
says that I can use the buffer api (Buffer queue data locator) to play
PCM data!
How do you go about playing MP3 audio buffers? Can you point me to a
documentation or an example code?
Thanks in advance.
Regards, Shahriar
P.S. I know this question has been asked before. But I haven't read a
concise answer yet.

[s***@essential.com]

Hello,

Thanks for the replay. Looking at the header file (NdkMediaExtractor.h) the
API supports either a file or url as the source of data (not a buffer):

media_status_t AMediaExtractor_setDataSourceFd(AMediaExtractor*, int fd, off64_t offset, off64_t length);

/**
* Set the URI from which the extractor will read.
*/
media_status_t AMediaExtractor_setDataSource(AMediaExtractor*, const char *location); // TODO support headers



Shahriar

Post by 'Don Turner' via android-ndk
The NDK has its own extraction and decoding classes: NdkMediaExtractor and
NdkMediaCodec.
https://developer.android.com/ndk/reference/ndk_media_codec_8h.html
https://github.com/googlesamples/android-ndk/blob/master/native-codec
You'll need to modify the sample code to decode MP3 rather than MP4
(video).
I would advise against using OpenSL ES for MP3 decoding since this
technique has some performance issues.

Post by s***@essential.com
Hi,
I am developing a C++ only library (no java) using the NDK audio library.
One of the functionality I must support is to play MP3 audio buffers (not
files, I already done that).
I can't use mediacodec or another open source decoder (just ndk)
This documentation (
https://developer.android.com/ndk/guides/audio/opensl-for-android.html)
says that I can use the buffer api (Buffer queue data locator) to play
PCM data!
How do you go about playing MP3 audio buffers? Can you point me to a
documentation or an example code?
Thanks in advance.
Regards, Shahriar
P.S. I know this question has been asked before. But I haven't read a
concise answer yet.

[Celina Val]

Hi Shahriar,

Did you ever find the solution for your problem? I have the same problem.
The API that Don mentioned is only available for the beta ndk-17 and only
available for API Level 28+. :(

Thanks,
Celina

Post by s***@essential.com
Hello,
Thanks for the replay. Looking at the header file (NdkMediaExtractor.h)
media_status_t AMediaExtractor_setDataSourceFd(AMediaExtractor*, int fd, off64_t offset, off64_t length);
/**
* Set the URI from which the extractor will read.
*/
media_status_t AMediaExtractor_setDataSource(AMediaExtractor*, const char *location); // TODO support headers
Shahriar

Post by 'Don Turner' via android-ndk
The NDK has its own extraction and decoding classes: NdkMediaExtractor
and NdkMediaCodec.
https://developer.android.com/ndk/reference/ndk_media_codec_8h.html
https://github.com/googlesamples/android-ndk/blob/master/native-codec
You'll need to modify the sample code to decode MP3 rather than MP4
(video).
I would advise against using OpenSL ES for MP3 decoding since this
technique has some performance issues.

Post by s***@essential.com
Hi,
I am developing a C++ only library (no java) using the NDK audio
library. One of the functionality I must support is to play MP3 audio
buffers (not files, I already done that).
I can't use mediacodec or another open source decoder (just ndk)
This documentation (
https://developer.android.com/ndk/guides/audio/opensl-for-android.html)
says that I can use the buffer api (Buffer queue data locator) to play
PCM data!
How do you go about playing MP3 audio buffers? Can you point me to a
documentation or an example code?
Thanks in advance.
Regards, Shahriar
P.S. I know this question has been asked before. But I haven't read a
concise answer yet.