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How to Record Losslessly Using x264vfw
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Before getting started, you must install the x264 codec in advance. If you do not know how to install it, please refer to the Help section.
Click the Codec menu in oCam, then click the External Codec menu item.
Select Use External Codec, choose the x264vfw codec, and then click the Settings button.
Using the default x264vfw settings as a base, change the parts highlighted in the yellow box in the image below as shown.
The following settings need to be changed.
Preset - Ultrafast ( Set this to improve encoding speed. The file size may become larger, but if you choose other options, significant lag may occur. )
Profile - High 4:4:4 ( The default profile may cause quality loss, so change it to High 4:4:4 for lossless encoding. )
Keep input colorspace - Keeps the color space of the internally received input buffer. ( If you use other options, encoding may fail. )
Rate control - Single pass - lossless - Change this for lossless encoding.
Click the OK button to apply the settings.
When recording 64-bit games, the settings are applied to x264vfw64 for 64-bit, so run x264vfw - Configure x264vfw64 from the Start menu and configure it in the same way as shown above.
If you record with the above settings, the video will be recorded losslessly. One important point is that if you want to play back the lossless video without quality loss, you must change the settings in your video player.
Below is how to check a lossless video using PotPlayer.
Run PotPlayer, then click Preferences ( F5 ).
In the Preferences window,
click Video - Color Space/Attributes on the left, then in the Color Space group box on the right, select Convert manually if possible - Default output color space. ( If you do not configure this, even if the recording is lossless, the screen colors may still be altered during playback. )
Click OK, then play the video recorded losslessly.
At this point, press Ctrl + F1 in PotPlayer. As shown below, the output format of the video codec must be displayed as RGB(32 Bits).
Also, in the playback information under the File Information tab, the following properties must match as shown below.
Format profile : High 4:4:4 Predictive@L3
Color space : RGB
Color range : Full
Matrix coefficients : RGB
Please note that Windows Media Player does not play this properly, and preview thumbnails will not be displayed in Windows Explorer.
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Another helpful tip
What to Do If the "Failed to av_image_alloc" Error Appears When Starting Recording
While using oCam, this error message may appear in very rare cases. This error is usually caused by insufficient available memory on the Windows system. Below is a detailed explanation of how to resolve this issue.
The first solution is to reduce memory usage. To do this, close other programs that are currently running to free up system memory, then try recording again with oCam. The more programs you have running, the more system resources are divided, so closing unnecessary programs can help reduce memory shortage issues.
The second method is to reduce the size of the recording area. If the recording area is set too large, memory usage can increase. In oCam, try reducing the recording area using the mouse or shortcut keys (such as Shift + arrow keys) before recording. This can lower memory usage and help prevent the error.
Third, this issue can also occur if oCam's video resolution setting is too high. For example, if recording is set to a high resolution such as 8K, it can place a heavy load on system memory. To fix this, follow the steps below:
1. In the oCam main window, click 'Tools' in the top menu, then select 'Options'.
2. In the Settings window, go to the 'Recording' tab.
3. In the 'Resize' section, find the 'Video Resize' option and check the currently configured resolution.
4. Change the resolution to a lower value, such as 1080p or 720p, and save the setting.
5. Restart oCam and try recording again.
Applying the methods above can resolve errors caused by insufficient memory and allow you to record more reliably in oCam. If the problem continues, consider checking your system's memory status or updating oCam to the latest version.