> ## Documentation Index
> Fetch the complete documentation index at: https://devdocs.xbox.com/llms.txt
> Use this file to discover all available pages before exploring further.

# XAppCaptureReadScreenshotStream

> XAppCaptureReadScreenshotStream

# XAppCaptureReadScreenshotStream

Reads a screenshot stream.

## Syntax

```cpp theme={null}
HRESULT XAppCaptureReadScreenshotStream(  
         XAppCaptureScreenshotStreamHandle handle,  
         uint64_t startPosition,  
         uint32_t bytesToRead,  
         uint8_t* buffer,  
         uint32_t* bytesWritten  
)  
```

### Parameters

*handle*   \_In\_\
Type: XAppCaptureScreenshotStreamHandle

Screenshot stream handle returned by calling [XAppCaptureOpenScreenshotStream](/reference/system/xappcapture/functions/xappcaptureopenscreenshotstream).

*startPosition*   \_In\_\
Type: uint64\_t

Position in the stream to start reading.

*bytesToRead*   \_In\_\
Type: uint32\_t

Number of bytes in the stream to read.

*buffer*   \_Out\_writes\_to\_(bytesToRead,*bytesWritten)\
Type: uint8\_t*

Buffer to contain the bytes read by **XAppCaptureReadScreenshotStream**.

*bytesWritten*   \_Out\_\
Type: uint32\_t\*

Number of bytes actually written to the *buffer*.

### Return value

Type: HRESULT

Function result.

## Remarks

<Note>This function isn't safe to call on a time-sensitive thread. For more information, see [Time-sensitive threads](https://learn.microsoft.com/gaming/gdk/docs/gdk-dev/console-dev/overviews/threads/time-sensitive-threads).</Note>

Before reading a screenshot you must open a screenshot stream with [XAppCaptureOpenScreenShotStream](/reference/system/xappcapture/functions/xappcaptureopenscreenshotstream). This will produce the **XAppCaptureScreenshotStreamHandle** needed for the *handle* parameter. You may then call this function to read the screenshot. The *startPosition* and *bytesToRead* parameters will allow you to read a section of the screenshot, this is useful for reading a large stream a section at a time. You can get the total size of the stream from the *totalBytes* output parameter in [XAppCaptureOpenScreenShotStream](/reference/system/xappcapture/functions/xappcaptureopenscreenshotstream). The output parameters *buffer* and *bytesWritten* will help you accurately read the data returned from this function. After reading the screenshot data close the screenshot stream with [XAppCaptureCloseScreenshotStream](/reference/system/xappcapture/functions/xappcaptureclosescreenshotstream) in order to avoid a memory leak.

```cpp theme={null}
const int MAX_DATA = 1024;

XAppCaptureTakeScreenshotResult takeScreenshotResult = {0};
XAppCaptureScreenshotStreamHandle handle = nullptr;
XAppCaptureScreenshotFormatFlag screenshotFormat = XAppCaptureScreenshotFormatFlag::SDR;

BYTE buffer[MAX_DATA];
HANDLE file = INVALID_HANDLE_VALUE;
UINT64 totalBytesRead = 0;
UINT64 totalBytesToRead = 0;
bool hdrAvailable = false;

/* ... obtain takeScreenshotResult with XAppCaptureTakeScreenshot. Refer to corresponding documentation ... */

hdrAvailable = static_cast<bool>(takeScreenshotResult.availableScreenshotFormats & XAppCaptureScreenshotFormatFlag::HDR);

/* Note: It is optional to obtain the HDR screenshot, if HDR is available. You will need to call XAppCaptureOpenScreenshotStream twice to obtain both SDR and HDR screenshots */
if (hdrAvailable)
{
    screenshotFormat = XAppCaptureScreenshotFormatFlag::HDR;
}

if (FAILED_LOG(XAppCaptureOpenScreenshotStream(takeScreenshotResult.localId, screenshotFormat, &handle, &totalBytesToRead)))
{
    return;
}

/* T:\ is one example of a writeable local directory. Be aware that the T:\ drive can be invalidated on suspend or resume, and as such it's better to use Persistant Local Storage */
file = CreateFileA(hdrAvailable ? "T:\\MyScreenshot.jxr" : "T:\\MyScreenshot.png", GENERIC_READ | GENERIC_WRITE, 0, 0, CREATE_ALWAYS, FILE_ATTRIBUTE_NORMAL, 0);
if (file == INVALID_HANDLE_VALUE)
{
    /* You must always call XAppCaptureCloseScreenshotStream on an open XAppCaptureScreenshotStreamHandle to avoid a memory leak */
    FAILED_LOG(XAppCaptureCloseScreenshotStream(handle));
    return;
}

while (totalBytesRead < totalBytesToRead)
{
    uint32_t bytesRead = 0;
    uint32_t bytesWritten = 0;
    if (SUCCEEDED(XAppCaptureReadScreenshotStream(handle, totalBytesRead, sizeof(buffer), buffer, &bytesRead)))
    {
        WriteFile(file, buffer, bytesRead, &bytesWritten, NULL);

        totalBytesRead += bytesRead;
    }
    else
    {
        break;
    }
}

FAILED_LOG(XAppCaptureCloseScreenshotStream(handle));

CloseHandle(file);

```

## Requirements

**Header:** XAppCapture.h

**Library:** xgameruntime.lib

**Supported platforms:** Windows, XBOX One family consoles and XBOX Series consoles

## Conceptual documentation

* [Time-sensitive threads](https://learn.microsoft.com/gaming/gdk/docs/gdk-dev/console-dev/overviews/threads/time-sensitive-threads)

## See also

[GameDVR Overview](/build/console-features/game-dvr/gamedvr-broadcast)\
[XAppCapture Members](/reference/system/xappcapture/xappcapture_members)\
[XAppCaptureOpenScreenShotStream](/reference/system/xappcapture/functions/xappcaptureopenscreenshotstream)\
[XAppCaptureTakeScreenshot](/reference/system/xappcapture/functions/xappcapturetakescreenshot)\
[XAppCaptureCloseScreenshotStream](/reference/system/xappcapture/functions/xappcaptureclosescreenshotstream)


## Related topics

- [XAppCaptureScreenshotStream](/reference/system/xappcapture/structs/xappcapturescreenshotstream.md)
- [XAppCaptureTakeScreenshot](/reference/system/xappcapture/functions/xappcapturetakescreenshot.md)
- [XAppCapture](/reference/system/xappcapture/xappcapture_members.md)
- [Unity C# API wrappers for the GDK](/build/gdk-and-engines/unity/unity-api-wrappers.md)
- [XAppCaptureOpenScreenshotStream](/reference/system/xappcapture/functions/xappcaptureopenscreenshotstream.md)