player code were based on the open source VLC Media Player, the last version of Google Video Player was not based on VLC, according to its readme file. However, it did include the OpenSSL cryptographic toolkit and some libraries from the Qt widget toolkit. Google Videos and the Google Video Player were ultimately phased out due to Google's acquisition of YouTube. GVI format and conversion Google Video Files (.gvi), and latterly its .avi files, are modified Audio Video Interleave (.avi) files that have an extra list containing the FourCC "goog" immediately following the header. Audio Video Interleaved (also Audio Video Interleave), known by its initials AVI, is a multimedia container format introduced by Microsoft in November 1992 as part of its Video for Windows technology. The list can be removed with a hex editor to avoid playback issues with various video players. The video is encoded in MPEG-4 ASP alongside an MP3 audio stream. MPEG-4 video players can render .gvi Google Video Files without format conversion (after changing the extension from .gvi to .avi, although this method of just renaming the file extension does not work with videos purchased with DRM to inhibit unauthorized copying). Among other software VirtualDub is able to read .gvi files and allows the user to convert them into different formats of choice. There are also privately developed software solutions, such as GVideo Fix, that can convert them to .avi format without recompression. MEncoder with "-oac copy -ovc copy" as parameters also suffices. AVI and MP4 Besides GVI and Flash Video, Google provided its content through downloadable Audio Video Interleave (.avi) and MPEG-4 (.mp4) video files. Not all formats are available through the website's interface, however, depending on the user's operating system. Where available, Google's "save as" function for Windows/Mac produced an .avi file, while the "save as" function for iPod and PSP produced an .mp4 file. This .avi file was not in standard AVI format. To play the file in a popular media player such as Winamp or Windows Media Player, the file had to first be modified, using a hex editor to delete the first LIST block in the file header, which started at byte 12 (000C hex, first byte in file is byte 0) and ended at byte 63 (003F hex). Optionally, the file length (in bytes 4 to 7, little endian) should also be amended, by subtracting 52 (3F hex – 0C