This guide explains how to use the Paraformer audio file recognition Android SDK to convert speech to text.
User guide: For an introduction to the models and for selection advice, see Audio file recognition.
Getting started
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Obtain an API key: Obtain and configure an API key. For security, configure the API key as an environment variable.
NoteYou can use a temporary API key to grant temporary access permissions or to strictly control risky operations, such as accessing or deleting sensitive data. A temporary API key is valid for 60 seconds by default and must be retrieved again after it expires.
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Download the SDK and run the sample code:
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Unzip the package. In the
app/libsdirectory, find the SDK in AAR format and add it to your project dependencies.For Android C++ integration, use theandroid_libsandandroid_includedirectories in the ZIP package to obtain the dynamic libraries and header files. -
Open the project in Android Studio. The sample code is located in
DashParaformerFileTranscriberActivity.java. Replace the API key and test the feature.
Invocation steps
Synchronous mode
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Initialize the SDK.
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Configure the parameters as needed.
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You can start a synchronous recognition task by calling
<a baseurl="t3168966_v1_0_0.xdita" data-node="6187600" data-root="85177" data-tag="xref" href="#7d33691bdb32v" id="f23a108d4eg1l">startFileTranscriber</a>withasync_requestset tofalse. -
In the
<a baseurl="t3168966_v1_0_0.xdita" data-node="6187600" data-root="85177" data-tag="xref" href="#163c1ef871tqt" id="923fb7c245i2i">onFileTransEventCallback</a>interface, you can listen for theEVENT_FILE_TRANS_RESULTevent to obtain the final recognition result. -
You can call
<a baseurl="t3168966_v1_0_0.xdita" data-node="6187600" data-root="85177" data-tag="xref" href="#44bf12ed9a4g9" id="487820766d8bm">release</a>to release SDK resources.
Asynchronous mode
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Initialize the SDK.
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Configure the parameters as needed.
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Call
<a baseurl="t3168966_v1_0_0.xdita" data-node="6187600" data-root="85177" data-tag="xref" href="#7d33691bdb32v" id="22ebcd76aarja">startFileTranscriber</a>to start the recognition task (setasync_requesttotrue). -
Call
<a baseurl="t3168966_v1_0_0.xdita" data-node="6187600" data-root="85177" data-tag="xref" href="#047417083bahi" id="11274e5cb48za">queryFileTranscriber</a>to query the recognition progress or results. -
In the
<a baseurl="t3168966_v1_0_0.xdita" data-node="6187600" data-root="85177" data-tag="xref" href="#163c1ef871tqt" id="7969c3e863mt7">onFileTransEventCallback</a>interface, listen for theEVENT_FILE_TRANS_QUERY_RESULTevent to retrieve the current query result. -
In the
<a baseurl="t3168966_v1_0_0.xdita" data-node="6187600" data-root="85177" data-tag="xref" href="#163c1ef871tqt" id="8c05913f40chf">onFileTransEventCallback</a>interface, listen for theEVENT_FILE_TRANS_RESULTevent to obtain the final recognition result. -
Call
<a baseurl="t3168966_v1_0_0.xdita" data-node="6187600" data-root="85177" data-tag="xref" href="#44bf12ed9a4g9" id="93441cc422u5v">release</a>to release the SDK resources.
Request parameters
Connection and control parameters
To configure these settings, pass a JSON string to the parameters parameter of the initialize interface.
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Example: The following JSON string is an example that does not list all available parameters. Add parameters as needed.
{ "url": "wss://dashscope.aliyuncs.com/api-ws/v1/inference", "apikey": "st-****", "device_id": "my_device_id", "service_mode": "1" } -
Parameter descriptions
Parameter
Type
Required
Description
urlStringYes
The endpoint. This is fixed at
wss://dashscope.aliyuncs.com/api-ws/v1/inference.apikeyStringYes
The API key. Use a more secure temporary API key with a short validity period to reduce the risk of leaking a long-term key.
service_modeStringYes
The operating mode. For audio file recognition, this is fixed at
"1".device_idStringYes
A unique string that identifies the end user. You can set this to an in-app user ID or a unique device identifier generated by the client. This ID is mainly used for log tracking and troubleshooting.
debug_pathStringNo
The storage path for log files.
This parameter is effective only if you set
save_logto true when you call the initialize interface. In this case, you must specify a log file path. Otherwise, an error occurs.A maximum of two log files are kept locally.
max_log_file_sizeintNo
Sets the maximum size of a log file in bytes.
This parameter is effective only if you set
save_logto true when you call the initialize interface.Default value: 104857600 (100 × 1024 × 1024 bytes, or 100 MiB).
log_track_levelintNo
Controls the filtering level of log content sent externally through the log callback (
<a baseurl="t3168966_v1_0_0.xdita" data-node="6187600" data-root="85177" data-tag="xref" href="#9c10968457gc6" id="af05028057sjq">onFileTransLogTrackCallback</a>).Default value: 2.
Valid values:
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0: LOG_LEVEL_VERBOSE
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1: LOG_LEVEL_DEBUG
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2: LOG_LEVEL_INFO
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3: LOG_LEVEL_WARNING
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4: LOG_LEVEL_ERROR
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5: LOG_LEVEL_NONE (disables this feature)
Note:
log_track_levelandlevel(set through the initialize interface) together determine which logs are sent to the callback. A log's level value must be greater than or equal to both thelog_track_levelandlevelvalues to trigger the callback. For example, if you setlog_track_levelto 2 (INFO) andlevelto 3 (WARNING), only logs at the WARNING level or higher (value >= 3) trigger the callback. -
Speech recognition effect parameters
Use the setParams interface to configure the nls_config parameter. You can also use the startFileTranscriber interface to configure all speech recognition effect parameters.
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Example: The following JSON string is an example that does not list all available parameters. Add parameters as needed.
{ "file_urls": [ "https://dashscope.oss-cn-beijing.aliyuncs.com/samples/audio/paraformer/hello_world_female2.wav" ], "async_request": false, "nls_config": { "model":"paraformer-v2", "disfluency_removal_enabled":false, "timestamp_alignment_enabled": false } } -
Parameter descriptions
Parameter
Type
Required
Description
file_urlsarray[string]Yes
A list of URLs for the audio or video files to transcribe. The HTTP and HTTPS protocols are supported. A single request supports only 1 URL.
If your audio files are stored in OSS, the SDK does not support temporary URLs that start with the oss:// prefix.
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Audio formats:
aac,amr,avi,flac,flv,m4a,mkv,mov,mp3,mp4,mpeg,ogg,opus,wav,webm,wma,wmvImportantBecause of the many audio and video formats and their variations, it is not technically possible to test all of them. The API cannot guarantee that all formats are recognized correctly. Test your files to verify that you get normal speech recognition results.
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Audio sampling rate
Varies by model:
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paraformer-v2 supports any sample rate.
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paraformer-v1 supports any sample rate.
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paraformer-8k-v2 supports only the 8 kHz sample rate.
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paraformer-8k-v1 supports only the 8 kHz sample rate.
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paraformer-mtl-v1 supports sample rates of 16 kHz and higher.
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Audio file size and duration: The audio file cannot exceed 2 GB. The duration must be within 12 hours.
If you want to process a file that exceeds these limits, you can pre-process the file to reduce its size. For best practices on file pre-processing, see Pre-process video files to improve transcription efficiency (for audio file recognition scenarios).
async_requestbooleanNo
Specifies whether the speech recognition is an asynchronous request.
Default value:
false.Valid values:
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true: asynchronous request
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false: synchronous request
apikeystringNo
If the
apikeyin the Connection and control parameters is a temporary API key, you can update it here to prevent it from expiring.nls_configobjectYes
The core configuration object for speech recognition. It includes key parameters such as model selection and recognition effect control.
nls_config.modelstringYes
The speech recognition model.
nls_config.language_hintsarray[string]No
Specifies the language codes of the speech to be recognized. This parameter applies only to the paraformer-v2 model.
Default value:
["zh", "en"].Supported language codes:
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zh: Chinese
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en: English
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ja: Japanese
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yue: Cantonese
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ko: Korean
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de: German
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fr: French
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ru: Russian
nls_config.disfluency_removal_enabledbooleanNo
Specifies whether to filter disfluent words, such as "um" and "ah".
Default value: false.
Valid values:
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true: filter
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false: do not filter
nls_config.timestamp_alignment_enabledbooleanNo
Specifies whether to enable the timestamp alignment feature.
Default value: false.
Valid values:
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true: enable
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false: disable
nls_config.special_word_filterobjectNo
Specifies the sensitive words to process during speech recognition and supports different processing methods for different sensitive words.
If this parameter is not passed, the system enables the built-in sensitive word filtering logic. Words in the recognition result that match the Alibaba Cloud Model Studio sensitive word list are replaced with an equal number of asterisks (
*).If you pass this parameter, you can implement the following sensitive word processing policies:
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Replace with
*: Replaces matching sensitive words with an equal number of asterisks (*). -
Direct filtering: Removes matching sensitive words from the recognition result completely.
The value of this parameter should be a JSON object with the following structure:
{ "filter_with_signed": { "word_list": ["test"] }, "filter_with_empty": { "word_list": ["start", "happen"] }, "system_reserved_filter": true }JSON field descriptions:
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filter_with_signed-
Type: object.
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Required: No.
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Description: Configures the list of sensitive words to be replaced with
*. Matching words in the recognition result are replaced with an equal number of asterisks (*). -
Example: Using the JSON above, the speech recognition result for "Help me test this piece of code" will be "Help me **** this piece of code".
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Internal fields:
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word_list: A string array that lists the sensitive words to be replaced.
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filter_with_empty-
Type: object.
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Required: No.
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Description: Configures the list of sensitive words to be removed (filtered) from the recognition result. Matching words in the recognition result are completely deleted.
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Example: Using the JSON above, the speech recognition result for "Is the game about to start?" will be "Is the game about to?".
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Internal fields:
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word_list: A string array that lists the sensitive words to be completely removed (filtered).
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system_reserved_filter-
Type: Boolean value.
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Required: No.
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Default value: true.
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Description: Specifies whether to enable the system's preset sensitive word rules. If set to
true, the system's built-in sensitive word filtering logic is also enabled. Words in the recognition result that match the Alibaba Cloud Model Studio sensitive word list are replaced with an equal number of asterisks (*).
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nls_config.channel_idarray[integer]No
Specifies the indexes of the audio tracks in a multi-track audio file to recognize. The index starts from 0. For example, [0] indicates that only the first track is recognized, and [0, 1] indicates that both the first and second tracks are recognized. If you omit this parameter, the first track is processed by default.
ImportantEach specified audio track is billed separately. For example, a request for [0, 1] for a single file incurs two separate charges.
Default value:
[0]nls_config.diarization_enabledbooleanNo
Automatic speaker diarization. This feature is disabled by default.
This feature is applicable only to mono audio. Multi-channel audio does not support speaker diarization.
When this feature is enabled, the recognition results will display a
speaker_idfield to distinguish different speakers.NoteIf you enable speaker diarization, keep the audio duration under 2 hours. Exceeding this limit may cause recognition failures or timeouts.
For an example of
speaker_id, see Recognition result description.nls_config.speaker_countintegerNo
A reference value for the number of speakers. To use this feature, set
diarization_enabledtotrue.By default, the number of speakers is automatically determined. If you configure this parameter, it only helps the algorithm try to output the specified number of speakers. It does not guarantee that the exact number will be output.
Value range:
[2, 100]. This feature is used to distinguish multiple speakers, so you must set it to at least 2.nls_config.vocabulary_idstringNo
The ID of the hotword vocabulary, used to improve the recognition accuracy of specific words. This parameter applies to v2 and later models. For information on how to use hotwords, see Customize hotwords.
nls_config.resourcesarray[object]No
Hotword resource configuration for v1 models. The function is the same as
vocabulary_id, but the configuration method is different:resourcesis an array of objects. Each element contains aresource_idfield and aresource_typefield:-
resource_id:stringtype, the hotword ID. -
resource_type:stringtype, the value is the fixed string "asr_phrase".
Example:
{ "nls_config": { "resources": [ { "resource_id": "xxxxxxxxxxxx", "resource_type": "asr_phrase" } ] } }For information on how to use hotwords, see Customize and manage Paraformer speech recognition hotwords.
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Key interfaces
NativeNui
initialize
Initializes the speech recognition SDK instance. The SDK uses the singleton pattern. Do not initialize it again before you call release.
This method is blocking and must be called from a non-UI thread.
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Method signature
public synchronized int initialize(final INativeFileTransCallback callback, String parameters, final Constants.LogLevel level, final boolean save_log) -
Parameter descriptions
Parameter
Type
Description
callback<a baseurl="t3168966_v1_0_0.xdita" data-node="6187600" data-root="85177" data-tag="xref" href="#8b030fec74e01" id="45ea99a0b0619">INativeFileTransCallback</a>The implementation of the event and data callback interface.
parametersStringA JSON string that contains authentication, connection, and debugging parameters. See Connection and control parameters.
levelConstants.LogLevelControls the logging level of the SDK itself.
save_logbooleanSpecifies whether to save binary logs. If
true, you must specify a path usingdebug_pathin the Connection and control parameters. You can also set the file size usingmax_log_file_size. -
Return value description
Returns an error code. For more information, see Error codes.
setParams
You can use this method to set or update the nls_config parameter independently. You do not need to call this method if all parameters are provided at once in startFileTranscriber.
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Method signature
public synchronized int setParams(String params); -
Parameter descriptions
Parameter
Type
Description
paramsStringThe
nls_configparameter from Speech recognition effect parameters. Parameters other thannls_configcannot be set using this method.Example:
{ "nls_config": { "model":"paraformer-v2", "disfluency_removal_enabled":false, "timestamp_alignment_enabled": false } } -
Return value description
Returns an error code. For more information, see Error codes.
startFileTranscriber
Starts recognition.
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Method signature
public synchronized int startFileTranscriber(String params, byte[] task_id) -
Parameter descriptions
Parameter
Type
Description
paramsStringSpeech recognition effect parameters.
Example:
{ "file_urls": [ "https://dashscope.oss-cn-beijing.aliyuncs.com/samples/audio/paraformer/hello_world_female2.wav" ], "async_request": false, "nls_config": { "model":"paraformer-v2", "disfluency_removal_enabled":false, "timestamp_alignment_enabled": false } }task_idbyte[]The task ID. The SDK internally generates a random string. You can get the task_id after this method is called successfully.
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Return value description
Returns an error code. For more information, see Error codes.
queryFileTranscriber
You can use this method to query the current status and result of an asynchronous task. After a successful call, the result is returned in the <a baseurl="t3168966_v1_0_0.xdita" data-node="6187600" data-root="85177" data-tag="xref" href="#163c1ef871tqt" id="d8e4560affcnl">onFileTransEventCallback</a> callback through the EVENT_FILE_TRANS_QUERY_RESULT event.
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Method signature
public synchronized int queryFileTranscriber(String task_id) -
Parameter descriptions
Parameter
Type
Description
task_idbyte[]The ID of the task to query.
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Return value description
Returns an error code. For more information, see Error codes.
cancelFileTranscriber
Immediately cancels the current task.
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Method signature
public synchronized int cancelFileTranscriber(String task_id) -
Parameter descriptions
Parameter
Type
Description
task_idbyte[]The ID of the task to cancel.
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Return value description
Returns an error code. For more information, see Error codes.
release
Releases all internal resources of the SDK. After this method is called, the SDK instance becomes unavailable. To use the SDK again, you must call initialize.
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Method signature
public synchronized int release(); -
Return value description
Returns an error code. For more information, see Error codes.
GetVersion
Retrieves the current SDK version information.
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Method signature
public synchronized String GetVersion(); -
Return value description
The current SDK version information.
INativeFileTransCallback: Listener callback
onFileTransEventCallback: Listen for events and speech recognition results
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Method signature
void onFileTransEventCallback(NuiEvent event, final int resultCode, final int arg2, AsrResult asrResult, String taskId); -
Parameter descriptions
Parameter
Type
Description
eventNuiEventThe callback event.
resultCodeintThe error code. This is valid when an EVENT_ASR_ERROR event occurs.
asrResultAsrResultThe speech recognition result.
taskIdStringThe task ID.
arg2intA reserved parameter.
onFileTransLogTrackCallback: Listen for trace logs
You can use this callback to receive detailed internal logs from the SDK for troubleshooting and debugging.
default void onFileTransLogTrackCallback(Constants.LogLevel level, String log)
NuiEvent: Event types
|
Event |
Description |
|
EVENT_FILE_TRANS_CONNECTED |
Successfully connected to the service. |
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EVENT_FILE_TRANS_UPLOADED |
Successfully uploaded the audio file for recognition. |
|
EVENT_FILE_TRANS_QUERY_RESULT |
The result of a task query. |
|
EVENT_FILE_TRANS_RESULT |
The final recognition result. |
|
EVENT_ASR_ERROR |
An error occurred during speech recognition. |