Supported Formats - Design Guidelines and Considerations for Building Windows Certified Network Media Devices

Supported Formats
The following sections describe the formats that are supported for each content type, including the associated file name extension and Multipurpose Internet Mail Extensions (MIME) type. The NSS does not expose content for which the MIME type cannot be determined. For a device to play a format that NSS supports, the device must also support the codec that is appropriate for the format. Note that various codecs can be used for some formats such as WAV, MPEG-4, and audio video interleave (AVI).
Music /Audio
The Windows 7 Network Sharing Service supports audio formats shown in Table 1.
Table . Supported Audio Formats
Format
|
File name extension
|
MIME type
|
WMA
|
.wma
|
audio/x-ms-wma
|
MPEG-1 Layer 3
|
.mp3
|
audio/mpeg
|
WAV
|
.wav
|
audio/wav
|
PCM
|
Not applicable
|
audio/L16
|
AAC
|
.AAC
|
Audio/vnd.dlna.adts
|
M4A
|
.M4A
|
Audio/mp4
|
Photos / Pictures
The Windows 7 NSS supports the picture formats shown in Table 2.
Table . Supported Picture Formats
Format
|
File name extension
|
MIME type
|
Joint Photographic Experts Group (JPEG)
|
.jpg
|
image/jpeg
|
Portable network graphics (PNG)
|
.png
|
image/png
|
RAW
|
(codec specific)
|
(codec specific)
|
For more information about RAW format support, see “Additional Formats” later in this paper.
Video
The Windows 7 NSS supports the video formats shown in Table 3.
Table . Supported Video Formats
Format
|
File name extension
|
MIME type
|
WMV
|
.wmv
|
video/x-ms-wmv
|
MPEG-2
|
.mpeg, .mpg
|
video/mpeg
|
MPEG-1
|
.mpeg, .mpg
|
video/mpeg
|
AVI
|
.avi
|
video/avi
|
MPEG2 TS
|
.TS, .TTS
|
video/vnd.dlna.mpeg-tts
|
MPEG 4 Video
|
.MP4, .M4V, .MP4V,
|
Video/mp4
|
Recorded TV
The Windows 7 NSS also supports the following video formats of recorded TV shown in Table 4.
Table . Supported Recorded TV Formats
Format
|
File name extension
|
MIME type
|
Digital video recorder-Microsoft (DVR-MS)
|
.dvr-ms
|
Video/x-ms-dvr
|
Windows TV (WTV)
|
.wtv
|
Video/wtv
|
Playlists
The Windows 7 NSS supports the playlist formats shown in Table 5.
Table . Supported Playlist Formats
Format
|
File name extension
|
MIME type
|
Windows Media Playlist
|
.wpl, .asx
|
Not applicable
|
M3U
|
.m3u
|
Not applicable
| Additional Formats
Format support in Windows Media Player is extensible. You can add media formats to Windows Media Player by installing the appropriate codec and creating the appropriate registry keys on the system that is running Windows Media Player. Formats that are supported in Windows Media Player are also supported by the Windows 7 NSS. For more information, see “Resources” at the end of this paper.
Supported Streaming Protocols
The NSS in Windows 7 and Windows Vista® supports HTTP and Real-Time Streaming Protocol (RTSP)/RTP protocols for delivering content to devices. The NSS in Windows XP supports streaming only over HTTP.
Format Transcoding
The Windows 7 NSS uses the Media Delivery Engine to deliver transcoded media content—content that is converted from one format to another—to the requesting device.
When the Windows 7 NSS exposes a media file to a device, it provides multiple resource elements for the content. One resource element specifies a URL for the content in its original format. The subsequent resource elements each specify a URL for a transcoded version of the content. A device can choose a resource element for which it has a codec to play back, and the NSS automatically transcodes the original format to the requested format. Formats supported for transcode by the Windows 7 NSS are listed in Table 6.
For an example showing multiple resource elements for transcoded content, see Appendix 2.
Table . Supported Transcoding Formats by Content Type
Content type
|
Destination format
|
Music / Audio
|
PCM
WMA
MP3
|
Photos / Pictures
|
YUV
JPG
|
Video
|
MPEG2 (phase alternating line—PAL)
MPEG2 (National Television System Committee—NTSC)
WMV
|
As mentioned earlier, Windows Media Player supports transcoding most supported input media formats to the preceding destination formats. This support means that digital media devices that implement the DMP and DMR role are not required to support all codecs to deliver a great playback experience. For example, if a user has video files that are all XVID, the Windows 7 NSS exposes the native XVID file to DMPs and DMRs, and also exposes a transcoded WMV and MPEG2 stream. This means that, even though the DMP and DMR do not support XVID, they still can provide a great playback experience for the consumer by requesting the WMV or MPEG2 format, where Windows automatically transcodes the XVID content.
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