Results 1 to 9 of 9

Thread: nDVR Smooth Streaming recording

  1. #1

    Default nDVR Smooth Streaming recording

    Hi,

    I've got some questions regarding the format in which nDVR chunks are stored.

    I'm using the transcoder add-on and i want to record key-frame aligned mp4 files from those streams. Reading through different posts in the forum, i came up with some alternatives:
    • Live stream record add-on: correct me if i'm wrong, but this alternative could possibly generate mp4 files that aren't aligned, couldn't it?, even if i do it programmatically executing different threads?, i mean, i don't really know that much about mp4 files, but if the source streams are aligned, why wouldn't the mp4 files be?
    • Generate mp4 files out of the DVR ismv and isma: i've been reading a little bit about isma/v file format, and if i didn't get it wrong, WMS generates those files in 'wire' format, not 'disk format'. According to the thread http://www.wowza.com/forums/showthre...agments-to-mp4, WMS adds some custom parts to the isma/v files. Now, does this 'custom atoms' mean non-standard or are they just something i could parse from the isma/v files and discard it?

    I know this subject has been 'in the loop' for a while, and i'm trying to find a 'standard' solution to it.

    Thanks in advance!,
    Germán

  2. #2
    Join Date
    Dec 2007
    Posts
    22,013

    Default

    Try using StreamType "live-record" to record the transcoded streams. They should be aligned for vod. You might need more disks.

    Richard

  3. #3

    Default

    Quote Originally Posted by german View Post
    Hi,

    I've got some questions regarding the format in which nDVR chunks are stored.

    I'm using the transcoder add-on and i want to record key-frame aligned mp4 files from those streams. Reading through different posts in the forum, i came up with some alternatives:
    • Live stream record add-on: correct me if i'm wrong, but this alternative could possibly generate mp4 files that aren't aligned, couldn't it?, even if i do it programmatically executing different threads?, i mean, i don't really know that much about mp4 files, but if the source streams are aligned, why wouldn't the mp4 files be?
    • Generate mp4 files out of the DVR ismv and isma: i've been reading a little bit about isma/v file format, and if i didn't get it wrong, WMS generates those files in 'wire' format, not 'disk format'. According to the thread http://www.wowza.com/forums/showthre...agments-to-mp4, WMS adds some custom parts to the isma/v files. Now, does this 'custom atoms' mean non-standard or are they just something i could parse from the isma/v files and discard it?

    I know this subject has been 'in the loop' for a while, and i'm trying to find a 'standard' solution to it.

    Thanks in advance!,
    Germán
    I would use live stream record. If your source streams are aligned, so will your recorded mp4 files.

    For one thing the DVR's ismv and isma files are fragmented mp4, but contain custom atoms which would need to be removed. This is considered an internal file format so we will not support you in parsing these and restitching them together as an mp4 file. There's no guarantee these internal files won't be modified in future versions either. It's do-able, but you're on your own. I also think its a bit of work and live stream record is extremely easy to hook up.

  4. #4

    Default

    Richard, Scott:

    Thank you both for your answers!, i think i'll go with the stream record add-on because it's the easier to set-up, since i've an edge/origin configuration and setting Stream type to "live-record" would "break it".
    Is there any trouble using both nDVR and stream record add-ons for the same app and stream?

    Thanks again!,
    German

  5. #5
    Join Date
    Dec 2007
    Posts
    22,013

    Default

    German,

    For easy, use StreamType "liverepeater-origin-record" on the origin/transcoder. It should not break anything. If you use LiveStreamRecord addon you will have to coordination record start for each stream, which you can do with the API programatically, but with the addon it will be more difficult.

    Richard

  6. #6

    Default

    Richard:

    If i use the "liverepeater-origin-record", it'll record the stream constantly, so i won't have no control over it, i.e., i won't be able to start and stop the recording in any way. Am i right?

    Thanks!,
    Germán

  7. #7
    Join Date
    Dec 2007
    Posts
    22,013

    Default

    Yes, that's right: use LiveStreamRecord addon for more control. However, for multi-bitrate vod streaming I think you will want each version to start at exactly the same time, so you will probably want to use the LiveStreamRecord API in a Wowza module instead of the addon

    Richard

  8. #8

    Default

    Richard:

    Thanks again. I've never used the LiveStreamRecord API, the way i used to record one (just one) stream was sending a GET request to the HTTP Provider, and i was planning to do this in a 'threaded way' for each stream. I can see this could have as result that the recordings could not be of the same length. Is there any tutorial on how to use the LiveStreamRecord API?

    Regards,
    Germán

  9. #9
    Join Date
    Dec 2007
    Posts
    22,013

    Default

    There isn't a tutorial, but there is source code and API doc included in the addon that you can use for reference.

    Richard

Similar Threads

  1. nDVR Recording
    By ZeeJay in forum Wowza nDVR
    Replies: 1
    Last Post: 07-17-2014, 01:49 AM
  2. Parameters for Smooth recording
    By stream4life in forum General Forum
    Replies: 3
    Last Post: 02-21-2014, 06:41 AM
  3. Replies: 4
    Last Post: 11-06-2012, 07:09 AM
  4. nDVR playback is not smooth using flowplayer plugin
    By dpakrk in forum AddOn: Wowza nDVR
    Replies: 1
    Last Post: 08-06-2012, 10:54 AM
  5. nDVR not working with Smooth Streaming
    By german in forum AddOn: Wowza nDVR
    Replies: 1
    Last Post: 01-09-2012, 01:09 PM

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •