Free online FLV to FLAC converter

An FLV file may need to be converted when its soundtrack is required by an audio editor, music library, or archive that accepts FLAC but does not import FLV. The output contains audio only; video, subtitles, and other streams are discarded.

FLV and FLAC formats

FLV is the Flash Video container format, historically used for web video delivered through Adobe Flash Player. It is now mostly found in legacy web downloads, old screen recordings, and archives. An FLV file can contain audio encoded with MP3, AAC, Nellymoser, Speex, PCM, or other codecs, alongside video streams such as H.264, VP6, or Sorenson Spark.

FLAC is a lossless audio codec and file format. It compresses PCM audio without discarding samples, supports tags such as artist and album information, and is widely supported by desktop media players, audio editors, and many music devices. It does not contain video.

Converting MP3, AAC, or another lossy FLV soundtrack to FLAC prevents further lossy encoding, but it cannot restore audio detail removed by the original codec. The FLAC file can also be larger than the audio stream in the FLV because lossy audio is being decoded and saved as lossless audio.

Convert the file

To convert without installing software, upload the FLV to 101convert.com, select FLAC as the output format, start the conversion, and download the resulting file. Confirm that the downloaded FLAC has the expected duration; an FLV with no audio stream cannot produce usable audio output.

For local conversion or files with multiple streams, use FFmpeg. Inspect the file first:

ffprobe -hide_banner input.flv

Convert the first audio stream to FLAC:

ffmpeg -i input.flv -map 0:a:0 -c:a flac output.flac

-map 0:a:0 selects the first audio stream and excludes video. If the file has several audio tracks, use the stream listing from ffprobe to choose the required track. Add metadata when the source does not provide it:

ffmpeg -i input.flv -map 0:a:0 -c:a flac -metadata title="Track title" -metadata artist="Artist" output.flac

Quality and compatibility limits

Do not set a new sample rate or channel count for an archival conversion. Options such as -ar 44100 or -ac 2 resample audio or downmix channels, altering the decoded signal. Use them only when a specific player, editor, or device requires 44.1 kHz stereo output:

ffmpeg -i input.flv -map 0:a:0 -c:a flac -ar 44100 -ac 2 output.flac

Some older FLV files use uncommon codecs that a current player may not open. A current FFmpeg build usually supports more legacy codecs than consumer media applications. If FFmpeg reports that the audio codec is unsupported, changing FLAC settings will not solve the problem; the input audio must first be decoded by software that supports that codec.

FLAC support is strong in desktop software and modern media players, but some older portable players and in-car systems accept only MP3, AAC, or WAV. Check the target device before converting a large collection.