Free online FLV to M2V converter

DVD-authoring applications and older MPEG-2 workflows may require an elementary video stream instead of a multiplexed FLV file. Converting produces an MPEG-2 video-only stream; any audio must be converted separately and multiplexed later.

What the FLV format is

FLV, or Flash Video, is a container designed for streaming video through Adobe Flash Player. Older video websites, Adobe Flash Media Server, Flash-based screen recorders, and legacy encoding tools commonly created FLV files. An FLV file can contain video encoded with Sorenson Spark, On2 VP6, or H.264 and may also contain AAC or MP3 audio.

FLV is a container, so its extension does not identify one fixed video codec. Check the streams before conversion if you need to preserve a particular frame size, frame rate, or interlacing mode.

What the M2V format is

M2V usually means an elementary MPEG-2 video stream stored without audio. DVD authoring software, older broadcast systems, and some MPEG-2 editing workflows use M2V because video and audio are supplied as separate streams and multiplexed into a final program stream later.

M2V can be more compatible with legacy authoring tools than FLV, but it is not normally a smaller format. If the FLV already contains H.264 or VP6, conversion to MPEG-2 requires re-encoding and may increase the file size while reducing quality. The resulting M2V contains no audio.

How to convert FLV to M2V

Using FFmpeg

FFmpeg is the most controllable desktop option. Install it, open a terminal in the folder containing the source file, and run:

ffmpeg -i input.flv -an -c:v mpeg2video -q:v 2 -f mpeg2video output.m2v

This command reads input.flv, discards audio with -an, encodes the video as MPEG-2, and writes an elementary stream through -f mpeg2video. The -q:v 2 setting gives high variable-quality output; use a higher value such as 4 or 6 for a smaller file with lower quality.

For DVD-compatible standard-definition output, set the required video standard explicitly. For NTSC:

ffmpeg -i input.flv -an -vf "scale=720:480:flags=lanczos,fps=30000/1001" -c:v mpeg2video -b:v 6000k -maxrate 8000k -bufsize 1835k -f mpeg2video output.m2v

For PAL:

ffmpeg -i input.flv -an -vf "scale=720:576:flags=lanczos,fps=25" -c:v mpeg2video -b:v 6000k -maxrate 8000k -bufsize 1835k -f mpeg2video output.m2v

DVD authoring also has constraints for aspect ratio, interlacing, GOP structure, audio format, and total bitrate. Let the authoring application encode or validate the stream if its specification differs from these settings.

Using a desktop converter

A graphical converter that supports FFmpeg can perform the same operation. Import the FLV, choose MPEG-2 Video or M2V as the output, disable audio, select the required frame size and frame rate, and export. Verify that the output is an elementary .m2v stream rather than an MPEG program stream with an incorrectly changed extension.

You can also convert the file for free on 101convert.com without installing software. Select FLV as the source format and M2V as the target, upload the file, start the conversion, and download the resulting stream.

Quality, compatibility, and limitations

• Converting H.264, VP6, or Sorenson video to MPEG-2 is a lossy re-encode. Keep the original FLV and avoid repeated conversions.
• M2V has no audio. Extract or convert the FLV audio separately, then use the DVD authoring or multiplexing application to combine it with the M2V stream.
• Do not use -c:v copy unless the FLV video is already MPEG-2 and the stream is compatible with the intended M2V consumer. Copying an H.264 or VP6 stream does not create valid MPEG-2 video.
• Use ffprobe input.flv to inspect the source codec, dimensions, frame rate, pixel format, and audio streams before choosing output settings.