FLV

FLV stands for Flash Live Video. The audio and video data within FLV files are encoded in the same manner as they are within SWF files. FLV was originally developed by Macromedia. In the early 2000s, Flash Video used to be the de facto standard for web-based streaming video (over RTMP). Notable users of it include Hulu, VEVO, Yahoo! Video, metacafe, Reuters.com, and many other news providers. Flash Video FLV files usually contain material encoded with codecs following the Sorenson Spark or VP6 video compression formats.

- - Wikipedia

M4A

Files with a .m4a extension are container files that store audio data. The audio data that is contained in the .m4a files is encoded using the MPEG4 Part 14 format. The .m4a file extension was created by Apple. It is very similar to the .mov and .mp4 file formats, except that .m4a files do not contain any video data. Like MP3 files, files with the .m4a extension are compressed, but the compression technology used to create .m4a files results in a higher quality of sound.

- - File.Org

Step-By-Step to Convert FLV to M4A

Interface

Step 1. Download and install the program, then double click it to run it, and then you'll see the main interface of the program.

Load Files

Step 2. Click "Add File(s)" button. Here you can select "Add Video" or "Add Folder" button to add files as you like.

Profile

Step 3. Click the drop-down arrow right beside the "Profile" column and select your desired video format from the drop-down list.

Edit

Step 4. Click "Edit" button to customize the output video like Effect, Trim, Crop, 3D Settings and Watermark.

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