Convert MPG to 3G2 — Free Online Tool
Convert MPG video files (MPEG-1/2 standard, commonly from VCD, DVD, or broadcast sources) to 3G2 format optimized for CDMA mobile networks, re-encoding the video with H.264 (libx264) and audio with AAC — dramatically reducing file size while maintaining watchable quality on mobile devices.
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FFmpeg Command
Copy this command to run the same conversion locally with FFmpeg on your desktop. Download FFmpeg
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Note: Browser-based encoding uses approximate quality targets. For precise CRF compression, copy the FFmpeg command above and run it on your desktop.
Estimated output:
Conversion Complete!
DownloadHow It Works
MPG files typically carry MPEG-2 video and MP2 audio, codecs designed for broadcast and optical disc playback rather than mobile delivery. Because 3G2 requires codecs suited for low-bandwidth CDMA transmission, this conversion cannot simply remux the streams — both video and audio must be fully re-encoded. The MPEG-2 video stream is decoded and re-encoded into H.264 using libx264 with a CRF of 23, which applies perceptual compression far more efficiently than MPEG-2 at equivalent visual quality. The MP2 audio is decoded and re-encoded into AAC at 128k, which offers better quality-per-bit than MP2 at mobile-friendly bitrates. The -movflags +faststart flag reorganizes the file's metadata to the beginning of the output, enabling progressive playback on mobile devices before the file has fully downloaded.
What Each Flag Does
| Flag | What it does |
|---|---|
ffmpeg
|
Invokes the FFmpeg command-line tool. In this browser-based tool, FFmpeg runs locally via WebAssembly (FFmpeg.wasm) — no files leave your device. The same command can be run on your desktop if you have FFmpeg installed, which is especially useful for MPG files larger than 1GB. |
-i input.mpg
|
Specifies the input file — your source MPG video containing MPEG-1 or MPEG-2 video and typically MP2 audio. FFmpeg automatically detects the MPEG container and demuxes the video and audio streams for re-encoding. |
-c:v libx264
|
Re-encodes the video stream using libx264, the H.264 encoder. This replaces the MPEG-2 video from the MPG source with H.264, which achieves significantly higher compression efficiency — essential for producing a 3G2 file suitable for CDMA mobile delivery. |
-c:a aac
|
Re-encodes the audio stream using AAC, replacing the MP2 audio typical of MPG files. AAC is the required audio codec for 3G2 mobile video and provides better audio quality than MP2 at the lower bitrates used in mobile streaming contexts. |
-crf 23
|
Sets the Constant Rate Factor for the H.264 encode to 23, which is the libx264 default and represents a good balance between visual quality and file size for standard-definition MPG source material. Lower values (e.g., 18) yield higher quality and larger 3G2 files; higher values (e.g., 28) yield smaller files with more visible compression. |
-b:a 128k
|
Sets the AAC audio bitrate to 128 kilobits per second. This is appropriate for mono or stereo audio in a 3G2 file intended for mobile consumption, offering a significant improvement over the MP2 audio bitrates commonly found in MPG files while keeping the output compact. |
-movflags +faststart
|
Moves the MP4/3G2 container's metadata (moov atom) to the beginning of the output file. This is critical for 3G2 files intended for mobile streaming over CDMA networks, as it allows the device to begin playback before the entire file has been downloaded. |
output.3g2
|
Specifies the output filename with the .3g2 extension, which tells FFmpeg to wrap the H.264 video and AAC audio into the 3G2 container format developed for 3GPP2 CDMA mobile standards. |
Common Use Cases
- Converting archived VCD or DVD-ripped MPG files for playback on older CDMA smartphones or feature phones that only support 3G2 media
- Shrinking large MPEG-2 broadcast recordings captured from a TV tuner card into compact 3G2 clips for sharing over 3G mobile networks with limited data plans
- Preparing MPG video content for compatibility with legacy CDMA multimedia messaging (MMS) systems that require the 3G2 container
- Converting MPG home video archives originally authored for DVD into a mobile-friendly format for viewing on CDMA-based devices without access to a desktop player
- Reducing the file size of MPEG-2 video footage from broadcast or surveillance sources so it can be stored or transferred on older mobile devices with limited storage
- Producing 3G2 video clips from MPG source files for use in retro or compatibility testing workflows involving CDMA network infrastructure
Frequently Asked Questions
Yes, some quality loss is inevitable because this is a transcode between two lossy formats — your MPEG-2 video is decoded and re-encoded into H.264, and your MP2 audio is decoded and re-encoded into AAC. However, H.264 at CRF 23 is generally very efficient, and the output quality is typically quite watchable for standard-definition MPG content. The most perceptible difference may be in fine detail or fast motion compared to the original MPEG-2 source. If quality is critical, you can lower the CRF value (e.g., to 18) in the FFmpeg command for a higher-quality, larger output file.
MPG files using MPEG-2 video are inherently large because MPEG-2 was designed for high-bitrate broadcast and disc storage, not efficient compression. H.264 (used in 3G2) achieves the same or better perceived visual quality at roughly half the bitrate of MPEG-2, thanks to more advanced compression techniques like smaller block sizes and better motion estimation. Additionally, AAC audio at 128k is more efficient than MP2 at typical bitrates. The combination of these two more modern codecs in the 3G2 container explains the significant file size reduction.
FFmpeg will preserve the display aspect ratio encoded in the MPG source during the H.264 re-encode. However, DVD-sourced MPEG-2 content is often interlaced (fields rather than full frames), and this tool does not automatically apply deinterlacing. If your source MPG is interlaced, the 3G2 output may show combing artifacts on fast-moving content. For interlaced source material, you would want to add a deinterlace filter such as -vf yadif to the FFmpeg command before converting.
No. The 3G2 container as used in this conversion does not support subtitle streams or multiple audio tracks, and neither does the MPG format in this context. If your MPG source contains multiple audio tracks (e.g., from a DVD-rip), only the first audio stream will be encoded into the 3G2 output. Any subtitle data in the source will be discarded during conversion.
To adjust video quality, change the -crf value: lower numbers (e.g., -crf 18) produce higher quality and larger files, while higher numbers (e.g., -crf 28) produce smaller files with more compression artifacts. The range is 0 (lossless) to 51 (lowest quality), with 23 as the default balance. To change audio quality, replace -b:a 128k with a higher bitrate like -b:a 192k for better audio fidelity, keeping in mind that 3G2 was designed for low-bandwidth mobile delivery so very high audio bitrates may be impractical for the format's intended use case.
Yes. On Linux or macOS, you can loop over files in a directory with a shell command such as: for f in *.mpg; do ffmpeg -i "$f" -c:v libx264 -c:a aac -crf 23 -b:a 128k -movflags +faststart "${f%.mpg}.3g2"; done. On Windows Command Prompt, use: for %f in (*.mpg) do ffmpeg -i "%f" -c:v libx264 -c:a aac -crf 23 -b:a 128k -movflags +faststart "%~nf.3g2". The browser-based tool processes one file at a time, so the FFmpeg command is especially useful for batch processing large collections of MPG files.
Technical Notes
This conversion involves a full transcode of both streams: MPEG-2 video (the dominant codec in MPG files for DVD and broadcast) is re-encoded to H.264 via libx264, and MP2 audio (the standard companion audio codec in MPEG-1/2 systems) is re-encoded to AAC. The 3G2 container is a close relative of MP4 and QuickTime's MOV, based on the ISO Base Media File Format (MPEG-4 Part 12), which is why the -movflags +faststart flag applies here — it moves the moov atom to the front of the file for streaming compatibility over CDMA networks. Note that 3G2 has limited codec flexibility compared to modern containers: only H.264 and MJPEG are supported for video, and only AAC and MP3 for audio in this implementation. MPG files do not carry rich metadata, chapter markers, or subtitle streams, so none of those are lost in this particular conversion — the formats are similarly limited in that regard. If your source MPG was encoded at a very low resolution (e.g., VCD-standard 352x240 or 352x288), the H.264 re-encode will preserve that resolution; no upscaling is applied. The output 3G2 file will be significantly smaller than the source MPG in most cases due to H.264's superior compression efficiency over MPEG-2.