Convert WTV to AMR — Free Online Tool
Convert WTV recorded TV files from Windows Media Center into AMR audio, extracting and re-encoding the audio track using the libopencore_amrnb codec optimized for speech. This is particularly useful for pulling voice-heavy broadcast content — news, talk shows, interviews — into a compact, mobile-friendly format.
to
FFmpeg Command
Copy this command to run the same conversion locally with FFmpeg on your desktop. Download FFmpeg
Drop your WTV file here
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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
WTV files are Windows Media Center DVR recordings that typically contain H.264 video alongside AAC or AC3 audio, plus embedded broadcast metadata. During this conversion, the video stream is completely discarded — only the audio track is extracted and re-encoded. The audio is transcoded from the source AAC/AC3 broadcast audio into AMR-NB (Adaptive Multi-Rate Narrowband) using the libopencore_amrnb codec at 12,200 bps — the highest AMR-NB bitrate. AMR-NB was designed specifically for speech encoding in GSM telephony, so it uses psychoacoustic modeling tuned to the human voice frequency range (300–3400 Hz). Music or sound effects in the original broadcast will sound noticeably degraded, but spoken dialogue will remain intelligible. The resulting .amr file will be dramatically smaller than the original WTV recording.
What Each Flag Does
| Flag | What it does |
|---|---|
ffmpeg
|
Invokes the FFmpeg tool. In this browser-based tool, FFmpeg runs locally via WebAssembly (FFmpeg.wasm), meaning your WTV file never leaves your device. |
-i input.wtv
|
Specifies the input WTV file — a Windows Media Center DVR recording that may contain H.264 video, AAC or AC3 broadcast audio, and embedded EPG metadata. |
-c:a libopencore_amrnb
|
Sets the audio encoder to libopencore_amrnb, which implements the AMR Narrowband codec used in GSM mobile telephony. This transcodes the broadcast audio from its original AAC/AC3 format into AMR-NB, automatically converting to mono at 8,000 Hz in the process. |
-b:a 12200
|
Sets the AMR-NB bitrate to 12,200 bits per second, the highest quality mode available in the AMR-NB standard. This is specified in raw bps (not kbps) because AMR bitrates are defined that way in the 3GPP standard. |
output.amr
|
Defines the output filename with the .amr extension, which tells FFmpeg to mux the encoded audio into an AMR container. The video stream from the WTV file is implicitly dropped because AMR is an audio-only format. |
Common Use Cases
- Extracting spoken dialogue from a recorded news broadcast or talk show to create a compact audio clip for mobile review
- Archiving voice-only content from Windows Media Center TV recordings onto older mobile phones or embedded systems that support AMR playback
- Pulling interview segments from a recorded TV program into AMR format for transcription workflows on tools that accept AMR input
- Reducing a large WTV recording to a tiny AMR file to test audio sync or speech content before committing to a heavier conversion
- Migrating speech recordings made via Windows Media Center (e.g., recorded radio programs) into a format compatible with VoIP or telephony pipelines
Frequently Asked Questions
No — AMR-NB is specifically engineered for speech in the 300–3400 Hz range, which matches human voice frequencies but not the full audio spectrum of broadcast content. Music, sound effects, and background ambiance in your WTV recording will sound muffled, tinny, and heavily compressed in the AMR output. If you need music or full-range audio to remain listenable, AMR is the wrong target format — consider MP3 or AAC instead.
AMR-NB was designed for GSM mobile telephony, where bandwidth was extremely constrained. Its bitrate options range from 4,750 bps to 12,200 bps — far below even the lowest MP3 quality. The WTV file's source audio (typically 128–384 kbps AAC or AC3) will be heavily downsampled during this conversion. The 12,200 bps default used here is the highest quality AMR-NB offers, but it still represents a massive reduction in audio fidelity compared to the original broadcast.
No. AMR is a bare audio container with virtually no metadata support. All of the rich broadcast metadata embedded in the WTV file — including program title, episode information, channel name, air date, and any EPG data — is lost during this conversion. If preserving that metadata matters to you, you should extract it from the WTV file separately before converting.
Replace the value after -b:a with a lower AMR-NB bitrate. Valid options are 4750, 5150, 5900, 6700, 7400, 7950, 10200, or 12200 (in bits per second, not kilobits). For example, use '-b:a 7950' for a moderate reduction in file size, or '-b:a 4750' for the absolute smallest output. Note that speech intelligibility degrades noticeably below about 7400 bps for typical broadcast dialogue.
By default, FFmpeg selects the first audio stream in the WTV file, which is typically the primary program audio (usually English). If your recording has multiple tracks — for example, a secondary language track or a secondary audio program (SAP) — you can target a specific one by adding '-map 0:a:1' (for the second audio track) before the output filename in the command. AMR does not support multiple audio tracks, so only one stream can be encoded into the output file.
The single-file command shown here can be adapted for batch processing using a shell loop. On Linux or macOS: 'for f in *.wtv; do ffmpeg -i "$f" -c:a libopencore_amrnb -b:a 12200 "${f%.wtv}.amr"; done'. On Windows Command Prompt: 'for %f in (*.wtv) do ffmpeg -i "%f" -c:a libopencore_amrnb -b:a 12200 "%~nf.amr"'. This processes each WTV file in the current directory and outputs a matching AMR file with the same base filename.
Technical Notes
The libopencore_amrnb encoder used in this conversion implements the AMR-NB standard (3GPP TS 26.071), which operates at a fixed sample rate of 8,000 Hz. This means FFmpeg will automatically downsample the WTV source audio — which is typically recorded at 44,100 Hz or 48,000 Hz — to 8 kHz, and also mix any multi-channel audio (stereo or surround) down to mono before encoding. These are hard constraints of the AMR-NB format, not optional settings. The output .amr file will always be mono, 8 kHz, regardless of the source. If your WTV file was recorded from an HD broadcast with Dolby Digital surround audio, expect the downmix to mono at 8 kHz to sound significantly different from the original. The libopencore_amrnb library must be present in your FFmpeg build — many default FFmpeg distributions include it, but some minimal builds omit it due to patent licensing history. The browser-based tool here handles this automatically via FFmpeg.wasm.