Frequently asked questions

All about streaming media, live streaming, transmuxing, http streaming, adaptive bit rate streaming and StreamZilla

Streaming

Do you have generic transcoding/encoding tips?

Flash live streaming settings

We strongly advise using the following encoding settings. If you use other settings, we cannot guarantee the stability, reliability or availability of your streams:

- video codec: H.264 (not VP6!)
- audio codec: AAC (not MP3!)
- frames per second: 25
- keyframes: every 2 seconds, in other words: every 50 frames
- audio sample rate: 48000 Hz

Windows Media live streaming settings

We advise using the following Windows Media Encoder settings:
- CBR (not VBR)
- Windows Media audio 9.2
- Windows Media video 9
- 25 Fps / keyframe 8 sec
- Buffer Size: 5
- Smoothness: 85
- Complexity: Auto

Smart Phones, iOS devices encoding settings

- video codec: H.264 baseline 3
- audio codec: AAC-LC
- frames per second: 25
- keyframes: every 2 seconds, in other words: every 50 frames
- audio sample rate: 48000
- aspect ratio: 16:9
- max bit rate streaming 3G: 250Kbps (audio + video)
- max bit rate streaming WiFi: 1Mbps (audio + video)

General tips

Encode at a decent bit rate. A low bit rate means low quality. A high bit rate means that users may experience buffering issues. European and some Asian customers may have high speed links that allow for HD quality content. But for other regions and for corporate viewers you must keep the encoding bit rate under 750Kbps.

Low quality videos are encoded at 320×240 at 250-500Kbps.

Medium size quality videos are encoded at 720×400 at 500-1000Kbps.

High quality videos are encoded at 720×400 at 1-2Mbps
High Definition videos are encoded at 1280×720 at 3-8Mbps.

Make sure that the video size fits the encoding bit rate. Do not encode a 320×240 movie at 2 Mbps. Do not encode a 1280×720 movie at 500 Kbps.

De-interlace your content before transcoding. The quality improves significantly.

Use 2-pass CBR (Constant Bit Rate) encoding for a high quality streamable file. VBR is not recommended for streaming.

Multiple Bit Rates

Encode your content into three to eight bit rates: 256, 512, 1000, 1500, 2000, 2500, 3000, 4000Kbps and upstream / upload these MP4s to the StreamZilla CDN. Group into one logical object and stream as adaptive bit rates to any device in RTMP, Apple HLS, Microsoft Smooth, Adobe HDS and MPEG DASH.

What is the difference between HTTP live streaming and True streaming?

HTTP live streaming is a relatively new technology.

Instead of pushing an actual stream over proprietary RTMP or RTSP protocols, HTTP live streaming chops streams into small segmented files which are downloaded in realtime by the client. The client then stitches these chunks back together into a fluent stream.

True streaming protocols offer QoS and can offer QoE as well. HTTP streaming cannot offer QoS, only QoE.

The first benefit is that HTTP live stream better passes through badly configured firewalls. StreamZilla has actually optimized our RTMP, MMS and RTSP services so they can be tunneled over HTTP as well. So this is not a real valid argument.

The second benefit is that HTTP streams better adapt to the actual available end users bandwidth. Although True streaming for Flash, 3GPP, Windows Media and Real have offered adaptive bit rate streaming features, HTTP adaptive bit rate streaming is faster and works in a more reliable way. This enhances the Quality of Experience for mobile and OTT users.

Some claims about HTTP adaptive bit rate streaming are however not true. They are not cheaper. Actually, HTTP adaptive bit rate streaming generates more overhead traffic than UDP based true streaming. HTTP adaptive bit rate streams are usually encoded with much higher bit rates, which generates more traffic.

StreamZilla invested heavily into making HTTP adaptive bit rate streaming easy. We parse, analyze and group assets so you don’t have to worry about objects and chunks and playlists. You just upload multiple bit rates of the same file and publish the stream. We transmux the stream in realtime offering multiple engines so you can deliver to a wide range of clients.

Many of our customers still stick with our ‘traditional’ true streaming services because it simply works. They don’t replace RTMP or RTSP or MMS streams with HTTP streams, they add HTTP streams to the mix, for instance to support Apple iOS devices. That is the power of StreamZilla: you are not limited but helped to use all these technologies: lower costs, less headaches, better reach, better performance.

Why is streaming better than progressive downloads?

End users experience no buffer under runs when you use our HTTP adaptive streaming services: all they may notice is that the quality of the stream sometimes changes.

Downloading generally generates more traffic than streaming. A progressive download is pushed at maximum speed to the viewers device. Even if a viewer watches for just one minute, the entire 10 minutes video could have been downloaded. Streaming only generates traffic during view time, plus a small buffer. The costs for streaming traffic can be 10 times lower than with progressive downloads!

A download is actually copied to the end users harddrive. A stream is not copied, only the audio and video data are sent. Only a small buffer is in the memory of the client device. The asset can not be copied and re-distributed, unless someone uses a specific stream ripper application.

Streaming offers better Quality of Service control, better traffic management, intelligent bursting and buffering, random access, better reporting and of course live streaming features.

Some CDN’s claim that they offer streaming support, but in reality they only offer progressive downloads to save costs. Some use intelligent download technologies to limit traffic, but these solutions never really match the benefits and efficiency of true streaming.

StreamZilla also offers legacy streaming via MMS, RTSP and RTMP, and offers progressive download support as well. With StreamZilla there is no operational cost difference between progressive download and streaming, but the benefits are huge, and you can save dramatically on traffic costs, so we advise to use streaming delivery whenever you can.

Are there downsides to streaming?

HTTP adaptive bit rate streaming combines the best of streaming technologies and http delivery. We strongly recommend to start using these delivery technologies. StreamZilla makes it very easy to switch from RTMP to HTTP.

If you need end users to keep a copy of your content, for instance for ringtones, podcasts and vodcasts, then downloading is the only option of course. For all other purposes we recommend streaming.

The downside of legacy streaming protocols (RTMP, MMS, RTSP) is that they could be blocked or frustrated by corporate firewalls. StreamZilla has enabled HTTP tunneling for all these protocols to bypass this issue.

What are the most popular media formats?

We advise to standardize on H.264+AAC because this enables us to deliver to iOS, Android, browsers, and virtually all devices out there.

For legacy players we advise: WMV for Windows Media and Silverlight. 3GPP for mobile content. FLV for legacy Flash players.

What are the most popular media players?

We support a wide range of media devices and software players. HTML5 is popular. Flash is popular. All other technologies are becoming less popular. We recommend to encode your content in H.264+AAC MP4 so we can deliver to the widest range of players. Most of our customers use FlowPlayer or JWPlayer.

Which on-demand streaming formats do the accounts support?

We support all popular streaming formats including MP4 (H.264+AAC), FLV, WMV, MP3, MOV, 3GP, M4V, F4V, ASF, WMA and ASF VOD streaming.

Which live streaming formats do the accounts support?

We offer integrated support for Apple HTTP Live Streaming, Microsoft HTTP Smooth Streaming, RTSP Windows Media Streaming, MPEG DASH (beta), RTMP Flash streaming, RTSP H.264, 3GPP, QuickTime streaming (legacy) and Icecast HTTP live streaming.

In our dashboard and through our API’s you can setup streaming publishing points for all these technologies. Our wizards let you setup and configure the publishing points and offer encoder setup details. We support a wide range of live encoders.

Which live encoders do the accounts support?

We support many encoders including Flash Media Encoder, Windows Media Encoder, Expression Encoder, FFmpeg, Wirecast and Icecast compliant encoders. Compliant hardware and software encoders may work as well, many customers have good experiences with Inlet, Digital Rapids and Envivio. You can also connect webcams such as AXIS (H.264 compliant) to our CDN. Wowza GoCoder is a great live encoding app for iOS devices.

Do the accounts support web delivery?

Yes, all our servers also offer support for HTTP downloadable delivery of content. You can upload any file type including web pages, images, documents, media, applications, configuration files and zip files. We do not offer PHP, ASP, database or other application support. The StreamZilla CDN is optimized for large objects delivery.

StreamZilla allows you to pre-ingest content into our CDN, and we also offer Remote Origin features so we can cache content off your origin servers, clouds and CDNs.

Do the accounts support progressive downloads?

Of course. You can progressively deliver any media file via our service. Upload the assets to the wwwroot. In addition, for FLV files we offer a advanced progressive download feature that lets the viewer skip through the video even if the video is not downloaded. Note that in general progressive download generates more traffic than with streaming delivery and that there is less QoS control and less exact reporting compared to streaming delivery. Use our true streaming service whenever you can.

Does the wwwroot support server side scripts?

The wwwroot is for static assets. You can upload any static asset type. You cannot run applications, execute PHP, ASP, CGI scripts or run databases. Please use your existing web server(s) for applications and use our CDN for web acceleration and streaming.

Which delivery protocols do the accounts support?

We offer integrated support for HTTP Adaptive bit rate streaming: Apple HTTP Live Streaming (Apple HLS), Adobe HTTP Dynamic Streaming (Adobe HDS), MPEG DASH and Microsoft Smooth Streaming.

We offer integrated support for true streaming protocols: Windows Media Streaming (MMS/RTSP) with advanced bursting, QuickTime, H.264 and 3GPP streaming (RTSP) with advanced bursting, Flash and H.264 streaming (RTMP) with advanced bursting.

We offer integrated support for advanced HTTP progressive download for MP4 files and HTTP progressive download for any file type.

Are the accounts optimized for firewalls and NAT?

Yes, all true streaming protocols are not just available on ports 554 (RTSP) and 1755 (RTMP) but also available on port 80 (the default port of HTTP) via TCP so streams are not blocked by firewalls or NAT routers.

If you still encounter issues with firewalls and proxies we advise to offer HTTP adaptive bit rate streams or a progressive download option next to the true streaming delivery options.

All HTTP live streaming protocols are by default available on port 80. For customers running in HTTPS environments, we offer HTTPS enabled request routing.

Does StreamZilla modify our content?

Absolutely not. We don’t change a single bit. We respect your content and your quality levels. You have complete control over your content quality, sizes and bit rates. You encode your content, upload to our CDN and we distribute. We do not downgrade your content by transcoding or modifying your content. We do offer powerful content analysis, parsing and management tools so you can immediately stream from one source to may devices.

Can I stream simultaneously VOD and Live?

Of course. Your account supports VOD and live streaming, and (progressive) download.

Can I stream multiple formats simultaneously?

Of course, you can mix multiple live and/or on-demand streams in any format.

Can I upstream/upload one format and you deliver in other formats?

We offer advanced transmuxing features: upload MP4 (H264+AAC) content and we deliver in all popular formats.

We do not transcode, downgrade or modify vod streams or live streams. You can upload and upstream and we serve it out exactly the way you offer it to us. If you want to offer content in multiple bit rates or multiple formats, you are free to upload or upstream all variants to us and offer these to your audience. We limit in no way and we do not degrade your content.

Can I stream one format to many clients?

Yes!

If you encode an MP4 live stream with H.264 video and AAC audio, then we can deliver this through multiple services to end users. We are capable of transmuxing the stream to RTMP, Apple HLS, RTSP, Adobe HDS, MPEG DASH and Smooth Streaming.

If you encode an MP4 file with H.264 video and AAC audio, then we can deliver this through multiple services to end users. We are capable of transmuxing the stream to RTMP, Apple HLS, RTSP, Adobe HDS, MPEG DASH and Smooth Streaming.

Our CDN service comes with integrated, free and powerful tools that analyse and manage ingested content. All you have to do is upload a number of bit rates of the same video. Our CDN recognizes this so you can group them into a logical asset and we can deliver HTTP adaptive streams in all popular formats.

Which transcoders do you advise?

Great transcoders are Handbrake, FFmpeg, Squeeze, Episode and FlipFactory.