Slidecasting is a new multimedia format from SlideShare - you can play any slidedeck synchronized with an audio file. To create a slidecast, you need to upload slides to SlideShare. Your audio file, however, can be hosted anywhere on the web- any server, file storage, or podcasting service. You link the slides & audio together using our synchronization tool. Now every time you play the Slidecast, the audio is streamed from its location and plays with the slides.

You can think Slidecasts as a mashup of slideshare with podcasts.

Slidecasting is also different from webcasting (or screencasting). Unlike webcasts or screencasts, slidecasts does not require complex recording or streaming technology. Instead it allows you to take existing media (slides and audio) and link them together using a free, web based interface. Additionally, webcasts are usually bandwidth hogs, difficult to create and annoyingly sluggish to view. A slidecast, on the other hand, can be setup in a jiffy, has a much faster experience. And yes, SlideCasting is completely free.

For Slidecasting, we just require the URL of a streamable mp3 file. This could be on a webserver, a media server, any podcasting service or a file repository. It could be free or on paid basis for you- we don't get in there. Only requirement is that the audio file should be freely downloadable (without permissions or passwords). Once a Slidecast is made, the audio will be streamed from its location to play alongside the slides. If anytime the audio streaming is stopped, or the URL becomes inaccessible (e.g. audio server is down), the Slidecast will get disrupted.

Once you create the Slidecast, the mp3 will be streamed from its location to play alongside the slides. If for any reason, the mp3 file is unavailable (e.g., audio server is down), then the Slidecast will not play.

No, SlideShare does not host audio files at present. Though we might do so in future, stay tuned. There are hundreds of places on the web that allow audio hosting, for you to choose from. Please use only those audio files (or URLs) for which you have the required copyright permissions.

Slidecasting is the ability to synchronize slides with media. The creative possibilities are endless. So let your imagination roam. There are all sorts of slideshows (look on SlideShare!) and audio files can also be just about anything- songs, musicals, recorded talks, voice narrations, instrumental music, talk shows, podcast interviews, news bulletins, speeches, advertising jingles et al. Put them together and you can have a large variety of Slidecasts.

Some quick examples that come to mind :

• your talk recorded with a portable mp3 player (or cellphone) synchronized to your powerpoint slides
• nursery rhymes synchronized to a picture slideshow
• a podcast interview as a voice over with some slides
• a love song for your beloved (pictures and song together)
• an advertising jingle accompanying some branding snapshots
• picture storybooks (a visual storytelling sessions for your child or grandchild)

No, SlideShare does not copy or transfer the audio file to its servers. It simply streams it from its original location. If the streaming stops for any reason, the Slidecast will get disrupted but SlideShare shall not have access to that file. No, the audio file will not be downloadable from SlideShare.

There are three ways to create a Slidecast.

• You can synchronize each slide with a point in the audio file
• You can divide audio equally between the slides (suitable for musical slideshows).
• Or choose the I'm feeling lazy option. The audio will still show up under the slides, but there will be no synchronization.

There are three parts to the tool

• Slide selector: you can select and navigate the slides here. You can see three slides at a time.
• Synchronization workspace: this contains the audio waveform. This is where the actual synchronization between slides & audio is done.
• Audio selector: this is where you navigate the audio using the draggable window

Divide audio equally is a quick way to create a Slidecast. If you choose this option, your audio file will get divided into equal parts and get synchronized among all the slides. For example, if your mp3 is 4 mins long and your slideshow has 20 slides. If you click "Divide audio equally" your slides will change every 12 seconds (divide 4 minutes or 240 seconds by 20 slides).

This option is useful if you simply want to play a audio track (a song or album) along with your slides. Or you can use this option to start with a rough synchronization and fine tune it later.

Undo synchronization option removes all marks. You can use this to begin again. If you don't make any more marks, then the audio will still show up beneath the slides, but there will be no synchronization.

Select Slide 5 in the slide selector by clicking on it. You will notice two blue markers in the workspace, one saying Slide 5 begin and the other saying "slide 5 end". Drag these markers to appropriate position in the audio and the slides will get marked. Change the position of the markers as often as you want.

Note that marking the end of Slide 5 also marks beginning of Slide 6. Similarly marking beginning of Slide 5 also marks end of Slide 4.

Its easy! In the audio selector area there is a Draggable window. You can use this to select different parts of the audio in the synchronization workspace.

If you want to remove audio, go to Edit Slidecast and click Remove link to mp3. The audio synchronization will be removed and the slides will be on their own again.

Save saves your current work but does not make it available for public viewing. Only when you Save & Publish your work, does it get pushed out for public viewing on SlideShare.

That's easy. There is a red playhead in the audio selector as well as in the synchronization workspace. Just click on it and it will start playing from its current position. You can drag the playhead to play any section of the audio.

The red dot shows the slide where the audio (the red playhead) is currently playing.

All slides that have been synchronized are marked with a green check mark at the bottom.

You can convert your audio file from .wav format to .mp3 format using any one of the many freely available audio encoders. Details here.