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How to View
Many American Memory collections contain sound recordings, video, high-resolution images, and enhanced text that require special viewers. Most viewers can be downloaded free from vendor sites.
The links below explain the various formats used and how to access them.
Jump to:
Sound Recordings
| Sound Recording Formats | About the Format | Players |
|---|---|---|
| RealAudio (.ra, .ram) |
- Minimizes download time - If you have trouble using RealAudio, download the most recent version of RealPlayer |
Windows, Mac: RealPlayer |
| MP3 (MPEG 2, Layer 3, .mp3) |
- Offers high-quality sound - Downloads faster than WAV files |
- Windows: Media Player - Mac: QuickTime Additional MP3 Players |
| WAV (WaveForm, .wav) | - Higher-quality format - Must download completely before playing - Longer download time - Windows operating systems contain WAV players - Some browsers contain media players that play WAV files |
- Windows: Media Player - Mac: QuickTime |
Documents (Text and Page Images)
In general, no special viewers are required to view text in American Memory. Most images of historical documents, as well as transcriptions of documents, are displayed through your web browser.
Certain illustrations and higher-resolution images, however, require special formatting.
| Document Formats | About the Format | Viewers |
|---|---|---|
| TIFF (Tagged Image File Format, .tif, .tiff) |
Used for images of original pages | - TIFF viewers - Windows: Alternatiff - Mac OSX: Locate "Preview" on your computer |
| PCX (.pcx) |
Used for images of original illustrations | - Windows PCX viewers (pre-installed) Find "kodakimg.exe" MS Paintbrush. Find "mspaint.exe" - TIFF/PCX viewers Windows: IrfanView Windows: Quick View Plus Mac: Graphic Converter |
| PDF (Portable Document Format, .pdf) |
Used for page images | Adobe Acrobat Reader Adobe text-only download page |
| MrSID (Multi-resolution Seamless Image Database, .sid) |
- Used for page images - Wavelet compression technology - Decompresses only that portion of the image requested by the user |
MrSID viewer |
| SGML (Standard Generalized Markup Language, .sgm) |
- Enhanced search and browse features (including linked table of contents) - Viewing illustrations within SGML files requires the TIFF/PCX tools listed above. |
No current SGML viewer is available for download. Download an older, free SGML viewer for Windows from the Oasis XML Consortium. |
Maps
Maps in American Memory are presented as GIF files and require no special viewers, unless you choose to download and view maps offline.
Download and View Maps Offline
Maps are stored in MrSID format, developed by LizardTech. The company has discontinued this viewer and no longer offers technical support. The Library is providing access to this viewer until a suitable replacement is available, but cannot provide help or support for it.
| Map Format | About the Format | Viewer |
|---|---|---|
| MrSID (.sid) |
- Wavelet compression technology - Decompresses only that portion of the image requested by the user - Ideal for viewing maps, orthophotos, terrain models, and satellite data |
MrSID viewer |
View instructions for downloading, viewing, and printing maps with the MrSID viewer.
Prints and Photographs
Most prints and photographs in American Memory are displayed in GIF and JPEG formats and require no special viewers. Some images are also offered as TIFFs—higher-resolution images with larger file sizes that require additional software.
| Print, Photograph Formats | About the Format | Viewers |
|---|---|---|
| TIFF (Tagged Image File Format, .tif, .tiff) |
Used for images of original prints and photographs | - Windows TIFF viewers Alternatiff InterneTIFF IrfanView Quick View Plus - Mac TIFF viewers OSX: locate "Preview" on your computer Graphic Converter |
| MrSID (Multi-resolution Seamless Image Database, .sid) |
- Used for page images Wavelet compression technology - Decompresses only that portion of the image requested by the user |
MrSID viewer |
Video
American Memory video collections are available in the following formats:
| Motion Picture Formats | About the Format | Players |
|---|---|---|
| MPEG (Motion Picture Experts Group, .mpg, .mpeg) |
- Highest-quality files are in the MPEG format - Average file size is about nine megabytes for each minute of motion picture |
Windows: Media Player Mac: QuickTime Additional MPEG players |
| QuickTime (.mov) |
- QuickTime (Cinepak compression) - Offers smaller, downloadable files and allows films to be viewed on lower-end computers - Not as crisp as the MPEG format - Average file size is about five megabytes for each minute of motion picture - QuickTime 3 (Sorenson compression) - A streaming file format Enhanced image quality, higher resolution - Available in Dance Instruction Manuals collection - Average file size is about six megabytes for each minute of motion picture |
Windows, Mac: QuickTime Windows: Media Player |
| RealMedia (.rm, .ram) |
- A streaming file format - Useful for computers with slower Internet connections - Playback is slower (three to six frames per second) and may be affected by Internet traffic. |
Windows: Media Player Windows, Mac: RealPlayer |
More Information about Downloading and Viewing Video
Video clips longer than four minutes may have been segmented, thereby limiting maximum file size to approximately 40 MB. A typical 28.8 Internet connection achieves a theoretical maximum download rate of approximately 3.5 KB/sec (210 K/min) under ideal conditions. Therefore, a file of 40 MB would take approximately 190 minutes (three hours, ten minutes) under optimal conditions, depending on Internet traffic.