"I have a 1080p video and I want to play it on a medium configured PC running Windows 8.1. Since the system doesn't have enough resources, the videos sometimes stall, or play in a slow motion. Is there any software/tool/method to convert HD video to SD?"
Yes, there is. FonePaw Video Converter Ultimate can help you convert HD videos such as H.264/ AVC, AVCHD (*.m2ts, *.mts), MPEG-2 (*.ts) and 4K to SD videos in batches. It also supports to convert videos to the format specifically set up for end devices, including iPad, iPhone, Apple TV, PSP, HTC, Samsung, Xbox and other popular devices. Here's how to use it:
1. Download the trial version of this HD converter
Here are both Windows and Mac OS versions are available, please choose the right one to download.
2. Add files to the program
After downloading, install and run the program on your computer. Then, click "Add File" on the toolbar. A dialog will pop up for choosing video files to the program. Just import the HD files you want to convert.
3. Choose profile, destination and settings
Click "Profile" > "General Video" to choose the formats (AVI, MP4, MOV, FLV, SWF, etc.) you need. Then, click "Browse" and find a folder to place your converted files. You can also go to Settings panel and do some settings for video conversion.
4. Convert HD to SD
Click "Convert" button to start HD to SD conversion process. A few minutes later, you can transfer the converted video files to your portable devices like iPad, iPhone, iPod, PSP, etc.
Apart from converting HD to SD, FonePaw Video Converter Ultimate can also helps you convert SD to HD or HD to HD. Just download it and have a try.