Comments on: Smooth Streaming Architecture http://alexzambelli.com/blog/2009/02/10/smooth-streaming-architecture/ Silverlight, streaming media, Windows Media, VC-1, H.264, Smooth Streaming Fri, 30 Jul 2010 23:31:36 -0700 http://wordpress.org/?v=2.9.1 hourly 1 By: Alex Zambelli http://alexzambelli.com/blog/2009/02/10/smooth-streaming-architecture/comment-page-1/#comment-12274 Alex Zambelli Fri, 25 Jun 2010 07:31:33 +0000 http://alexzambelli.com/blog/?p=36#comment-12274 @Alon: The physical fragment on disk can contain both audio and video (as is the case with content encoded with Expression Encoder for example), but the HTTP client request must be made separately for each so the fragment that gets sent over the wire only contains either audio or video. The video and audio fragments are allowed to have different durations (especially since audio fragments tend to be smaller than video fragments) because the A/V samples don't need to be multiplexed before they're handed off to the decoder. @Alon: The physical fragment on disk can contain both audio and video (as is the case with content encoded with Expression Encoder for example), but the HTTP client request must be made separately for each so the fragment that gets sent over the wire only contains either audio or video.
The video and audio fragments are allowed to have different durations (especially since audio fragments tend to be smaller than video fragments) because the A/V samples don’t need to be multiplexed before they’re handed off to the decoder.

]]> By: Alon http://alexzambelli.com/blog/2009/02/10/smooth-streaming-architecture/comment-page-1/#comment-12183 Alon Wed, 16 Jun 2010 23:07:18 +0000 http://alexzambelli.com/blog/?p=36#comment-12183 Thanks for this excellent explanation. Looking at the client manifest file example in the link above I noticed that the video framents and audio fragments are not aligned (different durations). Does this imply each fragment contains just video or just audio or is that simply due to some "non uniform interleaving" of video and audio data within mdat of each fragment? Can you clarify? Thanks, Alon Thanks for this excellent explanation.
Looking at the client manifest file example in the link above I noticed that the video framents and audio fragments are not aligned (different durations).
Does this imply each fragment contains just video or just audio or is that simply due to some “non uniform interleaving” of video and audio data within mdat of each fragment?
Can you clarify?
Thanks,
Alon

]]> By: gperetz http://alexzambelli.com/blog/2009/02/10/smooth-streaming-architecture/comment-page-1/#comment-11704 gperetz Mon, 17 May 2010 11:11:35 +0000 http://alexzambelli.com/blog/?p=36#comment-11704 Hi Alex. Maybe you can help me. I am trying to simulate a live smooth streaming client. I'm having probelms in calculating the time of the fragments that do not appear in the manifest. I was trying to analyze the fragment moof box to get the duration, and add it the fragment time. The problem is it appears to be incorrect (or maybe should be used in a different manner) for the audio stream. The video stream duration brings me to the next fragment just fine. However, with the audio stream it often misses the time (by a very small difference, sometimes just 1 increment) and so the server returns 404. I don't see that behaviour with the silverlight client - it always gets status 200 from the server, and requests the manifest only at the beginning of the play. More details: I am getting a moof box - indise the traf box I check the tfhd box and trun box. the tfhd box (defaults) has no values in it. the turn box has SampleSize, SampleFlags and SampleDuration present, and shows 6 or 7 samples. What I did was to sum the SampleDuration of the samples, and got the fragment duration. Did I miss anything? Hi Alex. Maybe you can help me.
I am trying to simulate a live smooth streaming client. I’m having probelms in calculating the time of the fragments that do not appear in the manifest. I was trying to analyze the fragment moof box to get the duration, and add it the fragment time. The problem is it appears to be incorrect (or maybe should be used in a different manner) for the audio stream. The video stream duration brings me to the next fragment just fine. However, with the audio stream it often misses the time (by a very small difference, sometimes just 1 increment) and so the server returns 404. I don’t see that behaviour with the silverlight client – it always gets status 200 from the server, and requests the manifest only at the beginning of the play. More details: I am getting a moof box – indise the traf box I check the tfhd box and trun box. the tfhd box (defaults) has no values in it. the turn box has SampleSize, SampleFlags and SampleDuration present, and shows 6 or 7 samples. What I did was to sum the SampleDuration of the samples, and got the fragment duration. Did I miss anything?

]]> By: Mark http://alexzambelli.com/blog/2009/02/10/smooth-streaming-architecture/comment-page-1/#comment-11490 Mark Thu, 06 May 2010 21:20:13 +0000 http://alexzambelli.com/blog/?p=36#comment-11490 Hi Alex, This is a very usefull documentation that covers the the VOD and partial the LIVE part of the smooth stream Thank you, this is verry usefull. The problem for me is that i can't find documentation for the LIVE part where the the encoder is pushing data to the IIS. When testing the "IIS Smooth Streaming Player Development Kit - Beta 2" i see that the pushencoder is sending manifests for each stream. It's that all? send manifest before streaming the stream with the specification that you posted here? How do i find the place to post the specific stream? is random string? "http://localhost/live/stream.isml/Streams(4996-stream5)" This is very vague. There is no documentation for that. It would be wonderfull if you can help me understand how it works. Kind Regards, Mark Hi Alex,

This is a very usefull documentation that covers the the VOD and partial the LIVE part of the smooth stream

Thank you, this is verry usefull.

The problem for me is that i can’t find documentation for the LIVE part where the the encoder is pushing data to the IIS.

When testing the “IIS Smooth Streaming Player Development Kit – Beta 2″ i see that the pushencoder is sending manifests for each stream. It’s that all? send manifest before streaming the stream with the specification that you posted here? How do i find the place to post the specific stream? is random string? “http://localhost/live/stream.isml/Streams(4996-stream5)”

This is very vague. There is no documentation for that.

It would be wonderfull if you can help me understand how it works.

Kind Regards,
Mark

]]> By: Alex Zambelli http://alexzambelli.com/blog/2009/02/10/smooth-streaming-architecture/comment-page-1/#comment-11162 Alex Zambelli Sat, 17 Apr 2010 03:04:03 +0000 http://alexzambelli.com/blog/?p=36#comment-11162 GZIP compression in IIS is dynamic - you don't need to manually zip/unzip anything. The entire process ought to be completely transparent. Just enable Dynamic Compression in IIS7 (you must remember to install the feature - it's not a default feature) and then use Fiddler2 or HTTPWatch to monitor your Silverlight player's HTTP traffic. The headers in the outgoing HTTP requests should contain "Accept-Encoding: gzip, deflate" and the headers in the HTTP server responses should contain "Content-Encoding: gzip". If you don't see compression applied to video and audio MP4 chunks, don't worry, gzip compression on compressed video/audio data isn't very useful anyway since the content is already highly compressed. The true benefit is in client manifest compression, since uncompressed client manifests can often exceed 500 kbytes for long content. GZIP compression in IIS is dynamic – you don’t need to manually zip/unzip anything. The entire process ought to be completely transparent. Just enable Dynamic Compression in IIS7 (you must remember to install the feature – it’s not a default feature) and then use Fiddler2 or HTTPWatch to monitor your Silverlight player’s HTTP traffic. The headers in the outgoing HTTP requests should contain “Accept-Encoding: gzip, deflate” and the headers in the HTTP server responses should contain “Content-Encoding: gzip”. If you don’t see compression applied to video and audio MP4 chunks, don’t worry, gzip compression on compressed video/audio data isn’t very useful anyway since the content is already highly compressed. The true benefit is in client manifest compression, since uncompressed client manifests can often exceed 500 kbytes for long content.

]]> By: David http://alexzambelli.com/blog/2009/02/10/smooth-streaming-architecture/comment-page-1/#comment-11148 David Fri, 16 Apr 2010 03:25:19 +0000 http://alexzambelli.com/blog/?p=36#comment-11148 Hi Alex, I'm trying to use gzip compression in IIS smooth streaming. I have configured compression function on IIS 7.0, and add according HTTP response header. But I'm still a little confused that if I need prepare compressed files on IIS7. How to do with manifest file? You know, the client request the manifest file by the URL "http://host/program.ism/manifest", but actually there is not a file named manifest, but program.ismc instead. So do I need compress the program.ismc as program.ismc.gzip on IIS7? Or IIS7 can do the compressing work on demond? Hi Alex, I’m trying to use gzip compression in IIS smooth streaming. I have configured compression function on IIS 7.0, and add according HTTP response header. But I’m still a little confused that if I need prepare compressed files on IIS7. How to do with manifest file? You know, the client request the manifest file by the URL “http://host/program.ism/manifest”, but actually there is not a file named manifest, but program.ismc instead. So do I need compress the program.ismc as program.ismc.gzip on IIS7? Or IIS7 can do the compressing work on demond?

]]> By: Sushil http://alexzambelli.com/blog/2009/02/10/smooth-streaming-architecture/comment-page-1/#comment-10073 Sushil Fri, 19 Feb 2010 09:18:04 +0000 http://alexzambelli.com/blog/?p=36#comment-10073 Yes I meant about on-demand content. My only point was, as player is pulling video & audio chunks based on bandwidth, cpu & seek-poistion etc, it could have helped me to serve metadata based on clients' capabilities. And the way to do it was to generate the text stream dynamically. Thanks anyways. Yes I meant about on-demand content.
My only point was, as player is pulling video & audio chunks based on bandwidth, cpu & seek-poistion etc, it could have helped me to serve metadata based on clients’ capabilities. And the way to do it was to generate the text stream dynamically.
Thanks anyways.

]]> By: Alex Zambelli http://alexzambelli.com/blog/2009/02/10/smooth-streaming-architecture/comment-page-1/#comment-10013 Alex Zambelli Tue, 16 Feb 2010 17:07:56 +0000 http://alexzambelli.com/blog/?p=36#comment-10013 Are you still talking about on-demand video, or live video too? If you don't know what ads/comments you will need to insert ahead of time, then insert markers which correspond to some lookup scheme (e.g. DoubleClick calls). Are you still talking about on-demand video, or live video too?

If you don’t know what ads/comments you will need to insert ahead of time, then insert markers which correspond to some lookup scheme (e.g. DoubleClick calls).

]]> By: Sushil http://alexzambelli.com/blog/2009/02/10/smooth-streaming-architecture/comment-page-1/#comment-9984 Sushil Mon, 15 Feb 2010 12:53:19 +0000 http://alexzambelli.com/blog/?p=36#comment-9984 Hi Alex, Thanks for your answer. I got the method you were explaining but in my scenario, if I don't know what announcements/ads to place in advance and also what position (e.g. I need to put markers for user comments in text stream which are stored in a db) what should I do? I basically need a way in which everytime user starts a video I should be able to create text-stream dynamically. At the same time I dont want to generate the entire ismc file at runtime. Please help. Hi Alex,

Thanks for your answer.
I got the method you were explaining but in my scenario, if I don’t know what announcements/ads to place in advance and also what position (e.g. I need to put markers for user comments in text stream which are stored in a db) what should I do?

I basically need a way in which everytime user starts a video I should be able to create text-stream dynamically. At the same time I dont want to generate the entire ismc file at runtime.

Please help.

]]> By: Alex Zambelli http://alexzambelli.com/blog/2009/02/10/smooth-streaming-architecture/comment-page-1/#comment-9965 Alex Zambelli Sun, 14 Feb 2010 14:40:45 +0000 http://alexzambelli.com/blog/?p=36#comment-9965 Hi Sushil, I recommend you look at http://www.codeplex.com/Wikipage?ProjectName=smf because the Silverlight Media Framework is already enabled for interpreting ad insert metadata. If you'd like to insert ad markers into pre-encoded content, you could do it by appending ad stream metadata to the client manifest (*.ismc), like this: <img src="http://alexzambelli.com/images/ad-insert.png" alt="" /> The string within the F tags is just a base64 encoded string formatted in a way that makes sense to your client. Hi Sushil,

I recommend you look at http://www.codeplex.com/Wikipage?ProjectName=smf because the Silverlight Media Framework is already enabled for interpreting ad insert metadata.

If you’d like to insert ad markers into pre-encoded content, you could do it by appending ad stream metadata to the client manifest (*.ismc), like this:

The string within the F tags is just a base64 encoded string formatted in a way that makes sense to your client.

]]>