Free online OGM to FLV converter

What the OGM format is

OGM, or Ogg Media, is an Ogg-based multimedia container commonly used for video with Vorbis audio and, in some files, Theora, MPEG-4, or other video codecs. Older encoding utilities, OGM tools, VirtualDubMod, and DVD-ripping workflows created many OGM files, so the format is most often encountered in archived anime, downloaded video, and older personal collections. OGM can contain multiple audio tracks, subtitles, and chapters, but support in current players and editors is limited compared with MP4 and Matroska.

What the FLV format is

FLV is a Flash Video container designed for web playback and older streaming systems. It commonly stores Sorenson Spark, VP6, or H.264 video with MP3 or AAC audio. FLV can be useful when a legacy Flash-based application, encoder, or media server explicitly requires that container; H.264/AAC FLV also provides reasonable compatibility with older video pipelines. Flash Player itself is obsolete, so FLV is generally unsuitable for new websites and modern device playback.

How to actually convert OGM to FLV

Using 101convert.com

Open the video converter on 101convert.com, add the .ogm file, select FLV as the output format, start the conversion, and download the resulting .flv file. This option requires no software installation, but it provides less control over stream selection and encoding settings than FFmpeg.

Using FFmpeg

1. Install a current FFmpeg build and place the source file in a convenient folder.

2. Inspect the streams before converting:

ffprobe input.ogm

3. Re-encode the video and audio into codecs supported by FLV:

ffmpeg -i input.ogm -map 0:v:0 -map 0:a:0? -c:v libx264 -pix_fmt yuv420p -crf 23 -c:a aac -b:a 128k -f flv output.flv

This selects the first video stream and, if present, the first audio stream. libx264 creates H.264 video, aac creates AAC audio, -crf 23 sets a moderate quality level, and -pix_fmt yuv420p improves compatibility with older FLV players. Use a lower CRF such as 18 for higher quality and a higher value such as 28 for a smaller file.

To convert a different audio track, replace -map 0:a:0? with the required stream number, such as -map 0:a:1?. Add another audio map only when the target workflow supports multiple tracks.

Quality, compatibility, and limitations

OGM's original video and audio codecs usually cannot be copied directly into FLV because FLV supports a narrower codec set. Re-encoding therefore causes some quality loss; retaining the original OGM is advisable for archival use. OGM subtitle streams, chapter data, and unusual metadata may not survive conversion, and FFmpeg generally does not embed OGM subtitles into FLV. If subtitles are required, extract them separately or burn them into the video during encoding.

For a file that already contains FLV-compatible H.264 video and AAC or MP3 audio, stream copying may work without re-encoding:

ffmpeg -i input.ogm -map 0:v:0 -map 0:a:0? -c copy -f flv output.flv

Use this only after checking the codecs with ffprobe; Theora, Vorbis, and other unsupported streams must be re-encoded. Test the output in the application that requires FLV because modern players may support the H.264/AAC streams while rejecting the obsolete container or its metadata.