Using AVPlayer for Audio Playback (C/C++)

The AVPlayer is used to play raw media assets in an end-to-end manner. In this topic, you will learn how to use the AVPlayer to play a complete piece of music.

The full playback process includes creating an AVPlayer instance, setting the media asset to play, setting playback parameters (volume, speed, and focus mode), controlling playback (play, pause, seek, and stop), resetting the playback configuration, and releasing the instance.

During application development, you can use the callback function of the AVPlayer to obtain the playback process information. If the application performs an operation when the AVPlayer is not in the given state, the system may throw an exception or generate other undefined behavior.

Figure 1 Playback state transition

For details about the states, see AVPlayerState. When the AVPlayer is in the prepared, playing, paused, or completed state, the playback engine is working and a large amount of RAM is occupied. If your application does not need to use the AVPlayer, call OH_AVPlayer_Reset() or OH_AVPlayer_Release() to release the instance.

How to Develop

Link the dynamic library in the CMake script.

target_link_libraries(sample PUBLIC libavplayer.so)

You can use C/C++ APIs related to audio playback by including the header files avplayer.h, avpalyer_base.h, and native_averrors.h. Read AVPlayer for the API reference.

1. Call OH_AVPlayer_Create() to create an AVPlayer instance. The AVPlayer is the idle state.

2. Call OH_AVPlayer_SetPlayerCallback() to set the events to listen for, which will be used in the full-process scenario. The table below lists the supported events.

3. Call OH_AVPlayer_SetURLSource() to set the media asset URL. The AVPlayer enters the initialized state.

4. Call OH_AVPlayer_Prepare() to switch the AVPlayer to the prepared state. In this state, you can obtain the duration of the media asset to play and set the volume.

5. Call OH_AVPlayer_Play(), OH_AVPlayer_Pause(), OH_AVPlayer_Seek(), and OH_AVPlayer_Stop() to perform audio playback control as required.

6. (Optional) Call OH_AVPlayer_Reset() to reset the AVPlayer. The AVPlayer enters the idle state again and you can change the media asset URL.

7. Call OH_AVPlayer_Release() to switch the AVPlayer to the released state. Now your application exits the playback.

Sample Code

#include "napi/native_api.h"
#include <multimedia/player_framework/avplayer.h>
#include <multimedia/player_framework/avplayer_base.h>
#include <multimedia/player_framework/native_averrors.h>
void OnInfo(OH_AVPlayer *player, AVPlayerOnInfoType type, int32_t extra)
{
    const char *url;
    int32_t ret;
    switch (type) {
        case AV_INFO_TYPE_STATE_CHANGE:
            switch (extra) {
                case AV_IDLE: // This state is reported upon a successful callback of OH_AVPlayer_Reset().
                    *url = "/data/test/mp3_48000Hz_64kbs_mono.mp3"
                    ret = OH_AVPlayer_SetURLSource (player, url); // Set the URL.
                    if (ret != AV_ERR_OK) {
                    // Exception processing.
                    }
                    break;
                case AV_INITIALIZED: 
                    ret = OH_AVPlayer_Prepare(player); // This state is reported when the AVPlayer sets the playback source.
                    if (ret != AV_ERR_OK) {
                    // Exception processing.
                    }
                    break;
                case AV_PREPARED:  
                    ret = OH_AVPlayer_Play(player); // Call OH_AVPlayer_Play() to start playback.
                    if (ret != AV_ERR_OK) {
                    // Exception processing.
                    }
                    break;
                case AV_PLAYING:  
                    ret = OH_AVPlayer_Pause(player); // Call OH_AVPlayer_Pause() to pause the playback.
                    if (ret != AV_ERR_OK) {
                    // Exception processing.
                    }
                    break;
                case AV_PAUSED:  
                    ret = OH_AVPlayer_Play(player); // Call OH_AVPlayer_Play() again to start playback.
                    if (ret != AV_ERR_OK) {
                    // Exception processing.
                    }break;
                case AV_STOPPED:  
                    ret = OH_AVPlayer_Reset(player); //Call OH_AVPlayer_Reset() to reset the AVPlayer state.
                    if (ret != AV_ERR_OK) {
                    // Exception processing.
                    }
                    break;
                case AV_COMPLETED:  
                    ret = OH_AVPlayer_Stop(player);// Call OH_AVPlayer_Stop() to stop the playback.
                    if (ret != AV_ERR_OK) {
                    // Exception processing.
                    }
                    break;
                default:
                    break;
            }
            break;
        case AV_INFO_TYPE_POSITION_UPDATE:
        // do something
            break;
        default:
            break;
    }
}

void OnError(OH_AVPlayer *player, int32_t errorCode, const char *errorMsg)
{
    // do something
}

int main()
{
    // Create an AVPlayer instance.
    OH_AVPlayer *player = OH_AVPlayer_Create();
    AVPlayerCallback callback;
    callback.onInfo = OnInfo;
    callback.onError = OnError;
    // Set the callback to listen for process information.
    int32_t ret = OH_AVPlayer_SetPlayerCallback(player, callback);
    if (ret != AV_ERR_OK) {
    // Exception processing.
    }
    const char *url = "/data/test/mp3_48000Hz_64kbs_mono.mp3";
    ret = OH_AVPlayer_SetURLSource (player, url); // Set the URL.
    if (ret != AV_ERR_OK) {
    // Exception processing.
    }
}