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Posted by Kistent Waung - Contact Author

How to Free Convert FLV to MP4 without Re-encoding

This article will show you how to convert FLV to MP4 without re-encoding on Windows 10/11 with the best free FLV to MP4 converter - WinX HD Video Converter Deluxe for enjoying the YouTube FLV videos on Windows or portable devices.

For movies lovers, YouTube Video and Goolge Video are both great source. People can download videos from these sites without offending legal issues. But as you know, most online YouTube videos and Google videos are Flash Video files, or FLV files. They are not the popular video formats supported by the majority of portable devices. Instead, MP4 is the one accepted by almost every device and platform. That's why you're disposed to change FLV to MP4. And you don't plan to lose quality, you need to find one tool with "video copy" feature.

Table of Contents:

Way 1. Convert FLV to MP4 without Re-encoding with WinX

WinX HD Video Converter Deluxe is well-crafted with "Auto Copy" mode to let you 1:1 losslessly copy video, audio and subtitle tracks from FLV to MP4 container format without re-encoding, as long as your FLV and MP4 are kept with the same video codec H264. Of course, you can also use it to convert FLV H264 to MP4 H265 for smaller size. Yet, the quality would be slightly degraded, roughly 2% quality loss.

This tool also makes other video conversion simple and painless, including FLV to MOV, MKV to MP4, FLV to iPhone, YouTube to MP3, etc. with 420+ pre-programmed profiles. If you wanna download FLV from YouTube, Vimeo, it meets all your needs with 1000+ sites supported.

Tutorial: How to Remux FLV to MP4 without Re-encoding

After downloading and installing WinX Video Converter onto your computer, you only need 3 simple steps to get FLV transformed to MP4.

Free Download WinX HD Video Converter Deluxe for Windows 10/8/7
Free Download WinX HD Video Converter for macOS Big Sur and lower

Step 1. Add file

Click "+ Video" button from the interface to import the source FLV video.

Step2. Select output format

In the PC General Video list, choose "MP4 Video (AAC) or (MP3)" as the output video format. More preset profiles are available with MP4 format like Apple device, Android pad/mobile, Microsoft device, Sony device, game consoles, etc.

free copy FLV to MP4
Free copy FLV to MP4

Step 3. Tick Auto Copy

Manually tick "Auto Copy" option on the lower right corner of the main interface.

Enable Auto Copy
Enable Auto Copy

Step 4. Set output folder

Click Browse button to select a destination folder in the dialog box that opens, and click OK.

Step 5. Remux FLV

Hit "RUN" to remux FLV video to MP4 with the a conversion progress windows. Don't worry about the video conversion freezing or stuttering issues. With Intel QSV/Nvidia/AMD GPU hardware acceleration tech support, this video converting program can finish the FLV to MP4 container format conversion at 250-320FPS, up to 47x real-time faster. Your bulk FLV conversion can be done within seconds!

Video Tutorial: How to Transcode Any (FLV) Video to MP4 without Losing Quality

Way 2. How to Convert FLV to MP4 OBS without Decoding/Encoding

OBS Studio is a free open source for you to free record video to MP4 or FLV. See, it can directly shoot video and save it to MP4 file, but MP4 files will be corrupted if OBS crashes before MP4 recording is done. FLV doesn't have such problem. Therefore, FLV is a better option. Afterwards, if you're still prone to change video container format from FLV to MP4 without re-encoding, FFmpeg fits the bill. Providing you have FFmpeg installed on your Windows 10 or macOS, follow the below guide to remux FLV to MP4.

Step 1: Open a command prompt and head to the place of your video storage.

Step 2: Run the following command (In case ffmpeg is not located at your path, please type out its full path):
ffmpeg -i input.flv -c copy -copyts output.mp4. (For macOS users: the command is supposed to start with ./ffmpeg rather than ffmpeg)

Until now, the FLV to MP4 remuxing is done. You can check if your resulting MP4 file works normally. Load it to VLC player, transfer it to iPhone iPad Android, Xbox, PS5 to have a test. If the compatibility is okay, the resulting MP4 quality is extact 1:1 copy of FLV, zero loss. Try any free solution from the two options; both of them do the losslessly FLV to MP4 container format conversion without re-encoding.

Way 3. How to Convert FLV to MP4 Free Online with CloudConvert

Online video converter is preferred by many users who search for ways to convert FLV to MP4. CloudConvert is a popular web-based online video converter. It enables users to convert FLV to MP4 free online for up to 25 conversions per day. You also have options to change FLV video resolution, aspect ratio, video codec, audio codec, audio bit rate, etc. Use steps below to transcode FLV to MP4 free online using CloudConvert.

Step 1. Open CloudConvert flv to mp4 page. You should see the red "Select File" button. Click the Select File button, browse and choose the source FLV video file you'd like to convert to upload. Click the Convert button to start uploading the FLV video. You can add multiple FLV video at a time.

Step 2. After the upload video process completes, download the converted video to your computer. The uploading process may take a very long time. Online tools always deliver much slower FLV to MP4 conversion speed than desktop video converter programs do.

convert FLV to MP4
Enable Auto Copy

External Knowledge: FLV and MP4 Format

FLV: Flash Live Video file, is a preferred file format that is designed for web playback, offering high rates of compression to deliver video over the Internet using Adobe Flash Player.

FLV content cannot be played back directly. It must be embedded in (or linked from) an SWF file. You create (or download) a "container" SWF file from which to play the FLV file. The most common approach is to use an SWF file to function as a media player with screen and playback controls. Notable users of the FLV format include YouTube, Google Video, Reuters, Yahoo! Video and MySpace.

MP4: A video compression standard planned for late 1998. MPEG-4 extends the earlier MPEG-1 and MPEG-2 algorithms with synthesis of speech and video, fractal compression, computer visualisation and artificial intelligence-based image processing techniques.


author - Kistent Waung

Kistent Waung twitter icon

Graduated from Nanyang Technological University, Singapore, she employs herself in IT related content creation (since 2013) and happens to perfectly combine her major (computer & science) and her gusto (writing). She's seasoned at offering video audio conversion workarounds and always passionate about new trends, from hot HEVC, 4K to the new AV1 codec.

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