Downloading FLVMeta 1.2.1 for Mac from the developer's website was possible when we last checked. We cannot confirm if there is a free download of this app available. FLVMeta for Mac is included in Audio & Video Tools. The actual developer of this free Mac application is Marc Noirot. Please check the Mac app with an antivirus before launch as it is downloaded from the developer's website, and we cannot ensure that it is safe.
From the developer:
flvmeta is a command-line utility aimed at manipulating Adobe(tm) Flash Video files (FLV). It has the ability to compute and inject a variety of values in the onMetaData event tag, including keyframe indices used by most video players to allow random-access seeking.
You may want to check out more software for Mac, such as MFilter, Aiseesoft WMV Converter for Mac or AkBrowser, which might be similar to FLVMeta.