ASF to 3G2 Converter

ASF to 3G2: Windows Media Into a CDMA Handset Format

ASF is Microsoft's Advanced Systems Format — the container behind Windows Media, released proprietarily in 1996 and published in 1998. The .asf, .wmv and .wma extensions all name the same container; the different names exist to signal what is inside, not to describe a different file structure. It usually holds Windows Media Video with Windows Media Audio, and it does not specify how the streams are encoded, only how they are packaged.

3G2 is the 3GPP2 file format, specified in C.S0050-B, built for CDMA2000 networks. It is small, tightly constrained and designed for handsets. Converting ASF to 3G2 means shrinking a desktop-era Windows file down to something a legacy CDMA phone, an MMS gateway or an old in-vehicle unit will accept — which makes the codec and resolution choices on this page the whole story.

How to Convert ASF to 3G2

1. Upload Your ASF File: Drag the .asf onto the page or click "Add Files" to browse. Several files can be queued and converted with the same settings.
2. Choose a Video Codec: Video Codec offers four entries — H.263, H.264 (which the page opens on), MPEG-4 and Xvid. H.264 is the modern choice; H.263 is the one the oldest handsets expect, and it changes the frame size in a way described below.
3. Choose an Audio Codec and a Resolution: Audio Codec lists AAC, AMR Narrow Band and AMR Wide Band — pick one deliberately, because the page does not preselect any of the three for you. Video resolution opens on Keep original; use Width x Height for a genuine handset frame such as 176 x 144, or Preset Resolutions for 240p and 144p.
4. Convert and Download: Click Convert and save the .3g2. Files are uploaded over an encrypted connection, re-encoded on our servers, and deleted automatically after a few hours — no sign-up, no watermark.

Walk-through: H.263 Rewrites Your Resolution, H.264 Does Not

This is the single behaviour that catches people on this page, and it depends entirely on the codec you pick.

If you select H.263, the frame size is snapped to the largest legal H.263 size that fits inside your source, chosen from a fixed list: 128 x 96 (SQCIF), 176 x 144 (QCIF), 352 x 288 (CIF), 704 x 576 (4CIF) and 1408 x 1152 (16CIF). That snap overrides whatever you selected under Video resolution, and it does not preserve the aspect ratio. A 1920 x 1080 ASF becomes 704 x 576 — a 16:9 picture squashed into a 4:3 frame. This is not a bug so much as a consequence of the codec: H.263 defines a closed set of picture sizes and refuses anything else, and the pipeline picks a legal one for you rather than failing outright.

If you leave it on H.264, none of that applies. Your resolution choice is honoured, aspect ratio and all. The same is true of MPEG-4 and Xvid, which snap to a multiple of 4 and 2 respectively rather than to a fixed list.

So the decision runs like this:

• Targeting a pre-2008 CDMA flip phone: H.263 plus AMR Narrow Band, with Width x Height at 176 x 144. This is the most universally accepted 3G2 combination, and at that size the H.263 snap lands exactly where you wanted anyway.
• Targeting a later CDMA smartphone, roughly 2008-2012: leave the codec on H.264, pair it with AAC or AMR Narrow Band, and set 320 x 240 (QVGA). It plays on most of that generation and looks noticeably better.
• Unsure what the device is: start with H.264 plus AMR Narrow Band at 320 x 240. If it refuses to play, fall back to H.263 plus AMR Narrow Band at 176 x 144.
• Feeding software rather than hardware: H.264 plus AAC at whatever resolution suits. Nothing about .3g2 requires you to stay small; the constraints came from the network and the handsets, not the container.

One more thing the page cannot do for you: the CDMA-native speech codecs the 3GPP2 specification names — EVRC, EVRC-B, EVRC-WB, 13K (QCELP), SMV and VMR-WB — are decoded on playback devices but are not offered as encode options here. A 3G2 produced on this page always carries AAC, AMR-NB or AMR-WB audio.

ASF and 3G2 at a Glance

Audio Codec Choices, and What They Cost

Both AMR modes are mono by design, so a stereo ASF is downmixed when you pick one. That is usually the right trade for a feature-phone target — AMR-NB was built for voice and produces very small tracks — but it is the wrong choice for music. If the ASF you are converting is a music video or a recorded concert, choose AAC and accept that the oldest handsets will not play it.

Common Errors and How to Fix Them

• "My widescreen video came out squashed." You selected H.263, which snapped the frame to a legal H.263 size without preserving the aspect ratio. Switch to H.264, or set Width x Height to a 4:3 shape deliberately so nothing surprises you.
• "The resolution I chose was ignored." Same cause. The H.263 snap overrides the Video resolution selection entirely. Only H.264, MPEG-4 and Xvid honour your setting.
• "The old phone refuses to play the file." The codec is probably too modern. Re-convert with Video Codec set to H.263 and Audio Codec set to AMR Narrow Band, at 176 x 144.
• "The audio came out mono when the source was stereo." Both AMR modes are mono-only. Choose AAC if you need two channels.
• "The picture is much worse than the ASF." A 3G2 target implies a small frame and a low bitrate, and this is a second lossy generation on a Windows Media source that was already compressed. Raise the Quality Preset, or set a higher Constant Bitrate, and do not downscale further than the device requires.
• "The ASF will not upload or convert at all." Some Windows Media files are DRM-protected, and no converter can decode those. A file that plays only in Windows Media Player with a licence check is not going to convert anywhere.

When This Doesn't Work

If your destination is anything made in the last decade, 3G2 is the wrong target — its whole design brief was CDMA bandwidth and two-inch screens, and the networks it served no longer exist. ASF to MP4 gives you H.264 in a container that plays on phones, browsers, televisions, editors and media servers with none of the codec archaeology this page requires. If you need the GSM-network sibling rather than the CDMA one, ASF to 3GP writes that instead. And if what you actually want is a smaller Windows Media file rather than a different format, ASF to WMV keeps the same container family under the conventional extension.

Frequently Asked Questions

What is the difference between 3GP and 3G2?

They are siblings, not the same format. 3GP was defined by 3GPP for GSM and UMTS networks in ETSI 3GPP TS 26.244; 3G2 was defined by 3GPP2 for CDMA2000 networks in C.S0050-B. The video codec lists are essentially the same — MPEG-4 Part 2, H.263 and H.264 — but 3G2 additionally allows the CDMA speech codecs EVRC, EVRC-B, EVRC-WB, 13K (QCELP), SMV and VMR-WB, while excluding HE-AAC v2 and AMR-WB+ that 3GP permits. Target a CDMA device and you want 3G2; target a GSM device and ASF to 3GP is the page.

Why did my resolution setting get ignored?

Because you chose H.263. That codec defines a closed set of picture sizes — 128 x 96, 176 x 144, 352 x 288, 704 x 576 and 1408 x 1152 — and refuses anything else, so the pipeline snaps your frame to the largest legal size that fits inside the source and encodes that. It overrides the Video resolution selection and it does not preserve the aspect ratio, which is why a 1080p source lands at 704 x 576. Select H.264 instead and your resolution choice is honoured exactly.

Which audio codec is preselected on this page?

None of them dependably. The list is AAC, AMR Narrow Band and AMR Wide Band, and the page's underlying default value does not correspond to any of those three entries, so treat the audio codec as something you must choose. For a legacy handset pick AMR Narrow Band; for anything newer, or for music, pick AAC. Making the choice explicit also removes any doubt about what ended up in the file.

Are .asf and .wmv actually different formats?

No. Both are Advanced Systems Format files, and so is .wma. Microsoft introduced the separate names so that the extension would signal the content — .wma for audio-only, .wmv for video, .asf for the generic case — and the MIME types differ accordingly, but the container structure is identical. That is why an .asf holding video behaves exactly like a .wmv in every player, and why the two convert identically here.

Can I put QCELP or EVRC audio in the output?

Not from this page. Those CDMA-native speech codecs are named in the 3GPP2 file format specification and legacy handsets decode them, but they are not offered as encode options here — the audio list is AAC, AMR Narrow Band and AMR Wide Band. In practice AMR-NB is the closest substitute for a speech-heavy clip aimed at an old handset, and the great majority of devices that decode QCELP also decode AMR-NB.

Why will my ASF not convert at all?

The likeliest reason is DRM. ASF is the container Windows Media DRM was built around, and a protected file cannot be decoded without its licence, so no converter will open it — this one included. If the file plays only inside Windows Media Player after a licence check, that is what you are dealing with. The other common cause is a rarer Windows Media Video profile that the decoder does not handle; try opening the file in VLC first to see whether the problem is the file or the conversion.

What frame size should I use for an old CDMA phone?

176 x 144 (QCIF) is the safe answer, set through Width x Height. That was the workhorse size for camera phones through roughly 2007 and essentially every 3G2-capable handset decodes it. For a later CDMA smartphone, 320 x 240 (QVGA) is a reasonable step up. Going above 352 x 288 for a genuine feature phone is the most common reason a device lists the file but refuses to play it.

Does the Windows Media audio survive the conversion?

No — it is re-encoded. Windows Media Audio is not on the 3G2 audio list, so the track is decoded and compressed again into whichever of AAC, AMR-NB or AMR-WB you selected. The video is re-encoded too, even if you pick a codec close to what the source used; there is no pass-through mode on this page. Expect a second lossy generation on both streams.

How are my files handled?

Your .asf is uploaded over an encrypted connection, decoded and re-encoded on our servers, and both the upload and the resulting .3g2 are deleted automatically after a few hours. Files are never shared or made public, and there is no sign-up, no watermark and no account required.