Tuesday, August 16, 2011
DPP Solutions: AV File Formats
As you get into multimedia, the alphabet soup of file formats can be confusing. Here’s a quick reference guide to common file types.
The following is an annotated list of the data file types you may encounter while working with audio/video recorders and editing systems.
Uncompressed Audio Files
WAV: Flexible PCM file based on the Resource Interchange File Format (RIFF) and capable of storing virtually any combination of bit rates and sample frequencies; ideal format for data interchange and storage/archiving; BWF, or Broadcast WAV, adds standardized metadata and timecode references for sample-accurate AV synchronization within recorders and workstations.
AIFF (Apple Interchange File Format): A PCM file similar in structure to WAV; directly compatible with Mac OS, but capable of being read by and output to most audio and video workstations and related applications.
Compressed Audio Files
Audio Codecs: Encoding/decoding schemes capable of producing data-reduced versions of 16/24-bit audio files at variable sample frequencies, either lossy or lossless in format; includes MP3 (Motion Picture Experts Group | Layer 3), QuickTime, Microsoft Windows Media Audio, Apple Advanced Audio Coding (AAC) and MPEG-4 variants, including m4p, a proprietary version of AAC in MP4 format with Apple-developed digital rights management.
Compressed Video Files
AVCHD (Advanced Video Codec High Definition): A high-end consumer format developed by Panasonic and Sony for HD systems; uses MPEG-4 H.264 encoding.
AVI (Audio Video Interleave): Interface format developed by Microsoft and compatible with RIFF; contains multiple streams to accommodate different data types, including control of separate AV material; format creates compressed files that are moderately large, but that retain high image and sound quality.
DivX: An open-source video-compression software scheme jointly developed by DivX Networks, intended primarily for program distribution, rather than postproduction.
FLV (Flash Video Format): Developed by Adobe and used for Internet delivery of data-compressed media files.
H.26L Series: A series of flexible AV codecs developed by Video Coding Experts Group (VCEG) and MPEG and used as a capture format for digital cameras and editing workstations; designed as two distinct layers—a video coding layer (VCL) and a network adaptation layer (NAL) responsible for packaging the coded data based on the specific characteristics of the network or data channel being used; one of the codec standards for Blu-ray discs and widely used for Internet streaming and cable broadcast, satellite TV services and videoconferencing; often referred to as AVC and MPEG-4 part 10.
MOV: A proprietary QuickTime format developed by Apple for encoding digital video, digital audio and images; supported by Apple's Final Cut Studio and Logic Studio, and licensed to many other vendors for image-capture and AV editing; a plug-in architecture supports additional third-party codecs.
MPEG: A digital-video format standardized by the Moving Picture Experts Group, incorporating both MPEG-1 and MPEG-2 audio/video compression at various image sizes and compression schemes; includes MPEG-4/MP4 format (.mp4 extension) used both for storage and online delivery of audio and visual media with low bit-rate encoding schemes and support of digital rights management; separate data compression for multichannel audio and video material (video with MPEG-4 video encoding and audio using AAC compression; replayed with Apple QuickTime Player).
WMV (Windows Media Video): Format developed by Microsoft for Internet streaming and data storage.