# VideoDecoder


## Overview

The VideoDecoder module provides the functions for video decoding.

\@syscap SystemCapability.Multimedia.Media.VideoDecoder

**Since**

9


## Summary


### Files

| Name| Description| 
| -------- | -------- |
| [native_avcodec_videodecoder.h](native__avcodec__videodecoder_8h.md) | Declares the native APIs used for video decoding.<br>**File to include**: <multimedia/player_framework/native_avcodec_videodecoder.h><br>**Library**: libnative_media_vdec.so | 


### Functions

| Name| Description| 
| -------- | -------- |
| \*[OH_VideoDecoder_CreateByMime](#oh_videodecoder_createbymime) (const char \*mime) | Creates a video decoder instance based on a Multipurpose Internet Mail Extension (MIME) type. This function is recommended in most cases.| 
| \*[OH_VideoDecoder_CreateByName](#oh_videodecoder_createbyname) (const char \*name) | Creates a video decoder instance based on a decoder name. To use this function, you must know the exact name of the decoder.| 
| [OH_VideoDecoder_Destroy](#oh_videodecoder_destroy) (OH_AVCodec \*codec) | Clears the internal resources of a video decoder and destroys the decoder instance.| 
| [OH_VideoDecoder_SetCallback](#oh_videodecoder_setcallback) (OH_AVCodec \*codec, OH_AVCodecAsyncCallback callback, void \*userData) | Sets an asynchronous callback so that your application can respond to events generated by a video decoder.| 
| [OH_VideoDecoder_SetSurface](#oh_videodecoder_setsurface) (OH_AVCodec \*codec, OHNativeWindow \*window) | Sets an output surface for a video decoder. This function must be called prior to **Prepare**.| 
| [OH_VideoDecoder_Configure](#oh_videodecoder_configure) (OH_AVCodec \*codec, OH_AVFormat \*format) | Configures a video decoder. Typically, you need to configure the video track description information that can be extracted from the container.| 
| [OH_VideoDecoder_Prepare](#oh_videodecoder_prepare) (OH_AVCodec \*codec) | Prepares internal resources for a video decoder. This function must be called after **Configure**.| 
| [OH_VideoDecoder_Start](#oh_videodecoder_start) (OH_AVCodec \*codec) | Starts a video decoder. This function can be called only after the decoder is prepared successfully.| 
| [OH_VideoDecoder_Stop](#oh_videodecoder_stop) (OH_AVCodec \*codec) | Stops a video decoder.| 
| [OH_VideoDecoder_Flush](#oh_videodecoder_flush) (OH_AVCodec \*codec) | Clears the input and output data in the internal buffer of a video decoder.| 
| [OH_VideoDecoder_Reset](#oh_videodecoder_reset) (OH_AVCodec \*codec) | Resets a video decoder.| 
| \*[OH_VideoDecoder_GetOutputDescription](#oh_videodecoder_getoutputdescription) (OH_AVCodec \*codec) | Obtains the description information about the output data of a video decoder.| 
| [OH_VideoDecoder_SetParameter](#oh_videodecoder_setparameter) (OH_AVCodec \*codec, OH_AVFormat \*format) | Sets dynamic parameters for a video decoder.| 
| [OH_VideoDecoder_PushInputData](#oh_videodecoder_pushinputdata) (OH_AVCodec \*codec, uint32_t index, OH_AVCodecBufferAttr attr) | Pushes the input buffer filled with data to a video decoder.| 
| [OH_VideoDecoder_RenderOutputData](#oh_videodecoder_renderoutputdata) (OH_AVCodec \*codec, uint32_t index) | Frees an output buffer of a video decoder and instructs the decoder to render the decoded data in the buffer on the output surface.| 
| [OH_VideoDecoder_FreeOutputData](#oh_videodecoder_freeoutputdata) (OH_AVCodec \*codec, uint32_t index) | Frees an output buffer of a video decoder.| 
| [OH_VideoDecoder_IsValid](#oh_videodecoder_isvalid) (OH_AVCodec \*codec, bool \*isValid) | Checks whether a video codec instance is valid.| 


## Function Description


### OH_VideoDecoder_Configure()

  
```
OH_AVErrCode OH_VideoDecoder_Configure (OH_AVCodec *codec, OH_AVFormat *format)
```

**Description**

Configures a video decoder. Typically, you need to configure the video track description information that can be extracted from the container.

This function must be called prior to **Prepare**.

\@syscap SystemCapability.Multimedia.Media.VideoDecoder

**Parameters**

| Name| Description| 
| -------- | -------- |
| codec | Pointer to an **OH_AVCodec** instance.| 
| format | Pointer to an **OH_AVFormat** instance, which provides the description information about the video track to be decoded.| 

**Returns**

Returns **AV_ERR_OK** if the operation is successful; returns an error code defined in [OH_AVErrCode](_core.md#oh_averrcode) otherwise.

**Since**

9


### OH_VideoDecoder_CreateByMime()

  
```
OH_AVCodec* OH_VideoDecoder_CreateByMime (const char *mime)
```

**Description**

Creates a video decoder instance based on a MIME type. This function is recommended in most cases.

\@syscap SystemCapability.Multimedia.Media.VideoDecoder

**Parameters**

| Name| Description| 
| -------- | -------- |
| mime | Pointer to a string that describes the MIME type. For details, see **AVCODEC_MIME_TYPE**.| 

**Returns**

Returns the pointer to an **OH_AVCodec** instance.

**Since**

9


### OH_VideoDecoder_CreateByName()

  
```
OH_AVCodec* OH_VideoDecoder_CreateByName (const char *name)
```

**Description**

Creates a video decoder instance based on a decoder name. To use this function, you must know the exact name of the decoder.

\@syscap SystemCapability.Multimedia.Media.VideoDecoder

**Parameters**

| Name| Description| 
| -------- | -------- |
| name | Pointer to a video decoder name.| 

**Returns**

Returns the pointer to an **OH_AVCodec** instance.

**Since**

9


### OH_VideoDecoder_Destroy()

  
```
OH_AVErrCode OH_VideoDecoder_Destroy (OH_AVCodec *codec)
```

**Description**

Clears the internal resources of a video decoder and destroys the decoder instance.

\@syscap SystemCapability.Multimedia.Media.VideoDecoder

**Parameters**

| Name| Description| 
| -------- | -------- |
| codec | Pointer to an **OH_AVCodec** instance.| 

**Returns**

Returns **AV_ERR_OK** if the operation is successful; returns an error code defined in [OH_AVErrCode](_core.md#oh_averrcode) otherwise.

**Since**

9


### OH_VideoDecoder_Flush()

  
```
OH_AVErrCode OH_VideoDecoder_Flush (OH_AVCodec *codec)
```

**Description**

Clears the input and output data in the internal buffer of a video decoder.

This function invalidates the indexes of all buffers previously reported through the asynchronous callback. Therefore, before calling this function, ensure that the buffers with the specified indexes are no longer required.

\@syscap SystemCapability.Multimedia.Media.VideoDecoder

**Parameters**

| Name| Description| 
| -------- | -------- |
| codec | Pointer to an **OH_AVCodec** instance.| 

**Returns**

Returns **AV_ERR_OK** if the operation is successful; returns an error code defined in [OH_AVErrCode](_core.md#oh_averrcode) otherwise.

**Since**

9


### OH_VideoDecoder_FreeOutputData()

  
```
OH_AVErrCode OH_VideoDecoder_FreeOutputData (OH_AVCodec *codec, uint32_t index)
```

**Description**

Frees an output buffer of a video decoder.

\@syscap SystemCapability.Multimedia.Media.VideoDecoder

**Parameters**

| Name| Description| 
| -------- | -------- |
| codec | Pointer to an **OH_AVCodec** instance.| 
| index | Index of an output buffer.| 

**Returns**

Returns **AV_ERR_OK** if the operation is successful; returns an error code defined in [OH_AVErrCode](_core.md#oh_averrcode) otherwise.

**Since**

9


### OH_VideoDecoder_GetOutputDescription()

  
```
OH_AVFormat* OH_VideoDecoder_GetOutputDescription (OH_AVCodec *codec)
```

**Description**

Obtains the description information about the output data of a video decoder. For details, see **OH_AVFormat**.

The caller must manually release the **OH_AVFormat** instance in the return value.

\@syscap SystemCapability.Multimedia.Media.VideoDecoder

**Parameters**

| Name| Description| 
| -------- | -------- |
| codec | Pointer to an **OH_AVCodec** instance.| 

**Returns**

Returns the pointer to an **OH_AVFormat** instance.

**Since**

9


### OH_VideoDecoder_IsValid()

  
```
OH_AVErrCode OH_VideoDecoder_IsValid (OH_AVCodec *codec, bool *isValid)
```

**Description**

Checks whether a video codec instance is valid.

\@syscap SystemCapability.Multimedia.Media.VideoDecoder

**Parameters**

| Name| Description| 
| -------- | -------- |
| codec | Pointer to an **OH_AVCodec** instance.| 
| isVaild | Output parameter. Pointer to an instance of the Boolean type. The value **true** means that the decoder instance is valid and **false** means the opposite.| 

**Returns**

Returns **AV_ERR_OK** if the operation is successful; returns an error code defined in [OH_AVErrCode](_core.md#oh_averrcode) otherwise.

**Since**

10


### OH_VideoDecoder_Prepare()

  
```
OH_AVErrCode OH_VideoDecoder_Prepare (OH_AVCodec *codec)
```

**Description**

Prepares internal resources for a video decoder. This function must be called after **Configure**.

\@syscap SystemCapability.Multimedia.Media.VideoDecoder

**Parameters**

| Name| Description| 
| -------- | -------- |
| codec | Pointer to an **OH_AVCodec** instance.| 

**Returns**

Returns **AV_ERR_OK** if the operation is successful; returns an error code defined in [OH_AVErrCode](_core.md#oh_averrcode) otherwise.

**Since**

9


### OH_VideoDecoder_PushInputData()

  
```
OH_AVErrCode OH_VideoDecoder_PushInputData (OH_AVCodec *codec, uint32_t index, OH_AVCodecBufferAttr attr)
```

**Description**

Pushes the input buffer filled with data to a video decoder.

The **OH_AVCodecOnNeedInputData** callback reports the available input buffer and the index.

After being pushed to the decoder, a buffer is not accessible until the buffer with the same index is reported again through the **OH_AVCodecOnNeedInputData** callback.

In addition, some decoders require the input of codec-specific data, such as PPS/SPS data in H.264 format, to initialize the decoding process.

\@syscap SystemCapability.Multimedia.Media.VideoDecoder

**Parameters**

| Name| Description| 
| -------- | -------- |
| codec | Pointer to an **OH_AVCodec** instance.| 
| index | Index of an input buffer.| 
| attr | Description information about the data in the buffer.| 

**Returns**

Returns **AV_ERR_OK** if the operation is successful; returns an error code defined in [OH_AVErrCode](_core.md#oh_averrcode) otherwise.

**Since**

9


### OH_VideoDecoder_RenderOutputData()

  
```
OH_AVErrCode OH_VideoDecoder_RenderOutputData (OH_AVCodec *codec, uint32_t index)
```

**Description**

Frees an output buffer of a video decoder and instructs the decoder to render the decoded data in the buffer on the output surface.

If no output surface is configured, calling this function only frees the output buffer.

\@syscap SystemCapability.Multimedia.Media.VideoDecoder

**Parameters**

| Name| Description| 
| -------- | -------- |
| codec | Pointer to an **OH_AVCodec** instance.| 
| index | Index of an output buffer.| 

**Returns**

Returns **AV_ERR_OK** if the operation is successful; returns an error code defined in [OH_AVErrCode](_core.md#oh_averrcode) otherwise.

**Since**

9


### OH_VideoDecoder_Reset()

  
```
OH_AVErrCode OH_VideoDecoder_Reset (OH_AVCodec *codec)
```

**Description**

Resets a video decoder. To continue decoding, you must call **Configure** to configure the decoder again.

\@syscap SystemCapability.Multimedia.Media.VideoDecoder

**Parameters**

| Name| Description| 
| -------- | -------- |
| codec | Pointer to an **OH_AVCodec** instance.| 

**Returns**

Returns **AV_ERR_OK** if the operation is successful; returns an error code defined in [OH_AVErrCode](_core.md#oh_averrcode) otherwise.

**Since**

9


### OH_VideoDecoder_SetCallback()

  
```
OH_AVErrCode OH_VideoDecoder_SetCallback (OH_AVCodec *codec, OH_AVCodecAsyncCallback callback, void *userData)
```

**Description**

Sets an asynchronous callback so that your application can respond to events generated by a video decoder.

This function must be called prior to **Prepare**.

\@syscap SystemCapability.Multimedia.Media.VideoDecoder

**Parameters**

| Name| Description| 
| -------- | -------- |
| codec | Pointer to an **OH_AVCodec** instance.| 
| callback | Callback function to set. For details, see **OH_AVCodecAsyncCallback**.| 
| userData | User-specific data.| 

**Returns**

Returns **AV_ERR_OK** if the operation is successful; returns an error code defined in [OH_AVErrCode](_core.md#oh_averrcode) otherwise.

**Since**

9


### OH_VideoDecoder_SetParameter()

  
```
OH_AVErrCode OH_VideoDecoder_SetParameter (OH_AVCodec *codec, OH_AVFormat *format)
```

**Description**

Sets dynamic parameters for a video decoder.

This function can be called only after the decoder is started. Incorrect parameter settings may cause decoding failure.

\@syscap SystemCapability.Multimedia.Media.VideoDecoder

**Parameters**

| Name| Description| 
| -------- | -------- |
| codec | Pointer to an **OH_AVCodec** instance.| 
| format | Pointer to an **OH_AVFormat** instance.| 

**Returns**

Returns **AV_ERR_OK** if the operation is successful; returns an error code defined in [OH_AVErrCode](_core.md#oh_averrcode) otherwise.

**Since**

9


### OH_VideoDecoder_SetSurface()

  
```
OH_AVErrCode OH_VideoDecoder_SetSurface (OH_AVCodec *codec, OHNativeWindow *window)
```

**Description**

Sets an output surface for a video decoder. This function must be called prior to **Prepare**.

\@syscap SystemCapability.Multimedia.Media.VideoDecoder

**Parameters**

| Name| Description| 
| -------- | -------- |
| codec | Pointer to an **OH_AVCodec** instance.| 
| window | Pointer to an **OHNativeWindow** instance. For details, see **OHNativeWindow**.| 

**Returns**

Returns **AV_ERR_OK** if the operation is successful; returns an error code defined in [OH_AVErrCode](_core.md#oh_averrcode) otherwise.

**Since**

9


### OH_VideoDecoder_Start()

  
```
OH_AVErrCode OH_VideoDecoder_Start (OH_AVCodec *codec)
```

**Description**

Starts a video decoder. This function can be called only after the decoder is prepared successfully.

After being started, the decoder starts to report the **NeedInputData** event.

\@syscap SystemCapability.Multimedia.Media.VideoDecoder

**Parameters**

| Name| Description| 
| -------- | -------- |
| codec | Pointer to an **OH_AVCodec** instance.| 

**Returns**

Returns **AV_ERR_OK** if the operation is successful; returns an error code defined in [OH_AVErrCode](_core.md#oh_averrcode) otherwise.

**Since**

9


### OH_VideoDecoder_Stop()

  
```
OH_AVErrCode OH_VideoDecoder_Stop (OH_AVCodec *codec)
```

**Description**

Stops a video decoder. After the encoder is stopped, you can call **Start** to start it again.

If you have passed codec-specific data in the previous **Start** for the decoder, you must pass it again.

\@syscap SystemCapability.Multimedia.Media.VideoDecoder

**Parameters**

| Name| Description| 
| -------- | -------- |
| codec | Pointer to an **OH_AVCodec** instance.| 

**Returns**

Returns **AV_ERR_OK** if the operation is successful; returns an error code defined in [OH_AVErrCode](_core.md#oh_averrcode) otherwise.

**Since**

9