Page 1 of 2 12 LastLast
Results 1 to 10 of 13

Thread: Incorrect program duration

  1. #1
    Join Date
    Aug 2010
    Posts
    34

    Default Incorrect program duration

    I've recently upgraded my media server to an i7, upgraded Mezzmo to v5 and retired Windows Media Centre in favour of Media Portal TV Server.
    The previous server was too slow to transcode on the fly so I wrote a C++ utility to interrogate WMC every hour and repackage any new recordings from .wmv to MPEG program streams so that my Sony devices could play them natively. This worked well for years.

    The new server is quick enough to transcode the transport streams coming from MediaPortal in real time so I've retired the utility. This is generally working very well.

    However, I've noticed that occasionally Mezzmo is reporting incorrect program durations. I had a closer look at one of them and found that ffmpeg reports the correct duration (in this case 1 hr 17 min), VideoRedo reports correctly as does Windows Explorer and Windows Media Player. Mezzmo however, displays the duration as 15 minutes. When I try to play the program, the TV also reports 15 minutes and plays erratically. If I manually run up VideoRedo and do a Quickstream Fix on the recording, all is OK.

    I've also noticed some other programs reporting as over 10 hours in Mezzmo when, in fact, they're only an hour or so.

    It's only a minor issue but has anyone else noticed this behaviour with MPEG transport streams recorded from TV?

    Thanks,
    Paul.

  2. #2
    Join Date
    Aug 2013
    Posts
    139

    Default

    Hi,

    I have also had this occasionaly, along with ffmpeg not being able to detect the video width so the show fails to add

    I have put it down to slight corruption in the file while the recording is in place, i tested mine on another dlna server that uses ffmpeg and it shows the same problem

    Like you, playback of the file is fine when using local apps, just ffmpeg cant detect the info, a quick mpeg fix program corrects it

    I can go weeks without seeing it, then get this a few times in a few days

  3. #3
    Join Date
    Jun 2012
    Posts
    720

    Default

    Quote Originally Posted by paul49 View Post
    I've recently upgraded my media server to an i7, upgraded Mezzmo to v5 and retired Windows Media Centre in favour of Media Portal TV Server.
    The previous server was too slow to transcode on the fly so I wrote a C++ utility to interrogate WMC every hour and repackage any new recordings from .wmv to MPEG program streams so that my Sony devices could play them natively. This worked well for years.

    The new server is quick enough to transcode the transport streams coming from MediaPortal in real time so I've retired the utility. This is generally working very well.

    However, I've noticed that occasionally Mezzmo is reporting incorrect program durations. I had a closer look at one of them and found that ffmpeg reports the correct duration (in this case 1 hr 17 min), VideoRedo reports correctly as does Windows Explorer and Windows Media Player. Mezzmo however, displays the duration as 15 minutes. When I try to play the program, the TV also reports 15 minutes and plays erratically. If I manually run up VideoRedo and do a Quickstream Fix on the recording, all is OK.

    I've also noticed some other programs reporting as over 10 hours in Mezzmo when, in fact, they're only an hour or so.

    It's only a minor issue but has anyone else noticed this behaviour with MPEG transport streams recorded from TV?

    Thanks,
    Paul.
    If you go into the Mezzmo GUI and then look at Properties --> Video does it show the correct values there ? If not try the Get Properties from File option. If that fixes it then a likely culprit is that Mezzmo tried to discover the file automatically while it was still being copied or transcoded.

  4. #4
    Join Date
    Aug 2010
    Posts
    34

    Default

    Quote Originally Posted by paulsalter View Post
    I can go weeks without seeing it, then get this a few times in a few days
    That's my experience as well.

  5. #5
    Join Date
    Aug 2010
    Posts
    34

    Default

    Quote Originally Posted by jbinkley60 View Post
    If you go into the Mezzmo GUI and then look at Properties --> Video does it show the correct values there ? If not try the Get Properties from File option. If that fixes it then a likely culprit is that Mezzmo tried to discover the file automatically while it was still being copied or transcoded.
    Thanks jbinkley60. That fixed the file which Mezzmo reported as 15 minutes but not the ones which it reported as over 10 hours. Interestingly ffmpeg shows the incorrect duration for these as well but the other programs are correct.

  6. #6
    Join Date
    Jun 2012
    Posts
    720

    Default

    Quote Originally Posted by paul49 View Post
    Thanks jbinkley60. That fixed the file which Mezzmo reported as 15 minutes but not the ones which it reported as over 10 hours. Interestingly ffmpeg shows the incorrect duration for these as well but the other programs are correct.
    So for the 10 hour ones the Mezzmo Properties show the file length as 10 hrs ? If so the Mezzmo folks will need to help here.

  7. #7
    Join Date
    Aug 2010
    Posts
    34

    Default

    Quote Originally Posted by jbinkley60 View Post
    So for the 10 hour ones the Mezzmo Properties show the file length as 10 hrs ? If so the Mezzmo folks will need to help here.
    I suspect the problem lies with ffmpeg rather than Mezzmo. I assume that Mezzmo uses ffmpeg to read the program duration and ffmpeg is reporting it incorrectly. All my other tools (including plain old Windows Explorer) report it correctly.

    There are quite a few tickets (one is recent) opened against ffmpeg regarding similar issues. When I get a chance, I'll do some reading and testing. I quickly ran ffmpeg with -analyzeduration and it's still wrong.

    Hardly a show stopper - I can manually fix it in a couple of minutes. Thank you for your suggestions - as you said, it seems likely that Mezzmo might have added the (15 minute file) while it was still recording. That's easy to fix if it happens again.

  8. #8
    Join Date
    Aug 2010
    Posts
    34

    Default

    I just had a look though my various Mezzmo folders and found quite a large number of programs all with around 10 hours reported and they're all from the same TV channel. But not all programs are wrong and even when there are multiple episodes of the same series, some are correct and some are not. The recordings from the other channels are correct in each case.

    The channel in question has comparatively poor signal strength and quality and the recordings on this channel experience dropouts quite frequently.

    Quote Originally Posted by paulsalter View Post
    I have put it down to slight corruption in the file while the recording is in place
    Agree - maybe it's just corrupt timestamps and, for whatever reason, ffmpeg can't recover? I've never really had a reason to study ffmpeg's command line options in any great detail. If I get bored one day, I'll do some further research.
    Last edited by paul49; 01-28-2017 at 10:02 AM.

  9. #9
    Join Date
    Aug 2013
    Posts
    139

    Default

    Just been looking back from when i was looking into this before

    Here is an example of one of mine with issues (this data was taken from Mediainfo program)
    From what i could gather (thought dont fully understand) is that the ones with problems have this GOP setting, the ones that work have Variable for this
    Not sure if this is somehow the broadcaster sending data slightly differently to reduce bitrates, or the bitrates are reduced automatically for some reason (less frames per second) which is throwing ffmeg off

    This is one that looks ok at 30 mins, but Mezzmo (and tested on Serviio which uses ffmeg also), both of these the show is reported as 5 mins
    Unfortunately i have long since deleted this file so cannot do any more test with it

    Video
    ID : 101 (0x65)
    Menu ID : 4169 (0x1049)
    Format : MPEG Video
    Format version : Version 2
    Format profile : Main@Main
    Format settings, BVOP : Yes
    Format settings, Matrix : Custom
    Format settings, GOP : M=3, N=24
    Format settings, picture structure : Frame
    Codec ID : 2
    Duration : 29 min 58 s
    Bit rate mode : Variable
    Bit rate : 2 333 kb/s
    Maximum bit rate : 15.0 Mb/s
    Width : 704 pixels
    Height : 576 pixels
    Display aspect ratio : 16:9
    Active Format Description : Letterbox 16:9 image, with alternative 14:9 center
    Frame rate : 25.000 FPS
    Standard : PAL
    Color space : YUV
    Chroma subsampling : 4:2:0
    Bit depth : 8 bits
    Scan type : Interlaced
    Scan order : Top Field First
    Compression mode : Lossy
    Bits/(Pixel*Frame) : 0.230
    Stream size : 500 MiB (80%)
    Last edited by paulsalter; 01-28-2017 at 10:33 PM.

  10. #10
    Join Date
    Aug 2010
    Posts
    34

    Default

    Quote Originally Posted by paulsalter View Post
    is that the ones with problems have this GOP setting, the ones that work have Variable for this
    I just checked a series I recorded where 5 episodes had the incorrect duration and 2 were correct and, unfortunately, there is no correlation with the GOP information.

    I know a lot more about (still) image compression and formats (it used to be my job) than I do about video but GOP looks like it roughly corresponds (in a much more complex way) to what happens in a CCITT Group 3-2D image - individual frames in a GOP are used to store "difference" data referring to previous frames (saving on data) and there is a fully encoded frame at the beginning of each GOP.

    I'm becoming more interested in finding out what's happening here, even though we couldn't do much if an answer is found. Perhaps someone from Mezzmo may wish to comment after the weekend.

Similar Threads

  1. Aspect ratios incorrect on TV
    By dehalley in forum Mezzmo Questions and Support
    Replies: 31
    Last Post: 03-29-2016, 09:51 AM
  2. Forcing DTS to AC3/DD5.1 breaks ffwd/rewind and gives incorrect duration
    By cjstepinraazor in forum Mezzmo Questions and Support
    Replies: 4
    Last Post: 01-02-2015, 08:07 PM
  3. Howto repair an invalid video duration
    By Hogi in forum Mezzmo Questions and Support
    Replies: 5
    Last Post: 05-31-2013, 07:42 AM
  4. Some .mkvs show no duration and stop playing after 10 minutes.
    By mcutugno in forum Mezzmo Questions and Support
    Replies: 3
    Last Post: 06-27-2011, 10:11 AM
  5. Random incorrect resolution
    By saear in forum Mezzmo Questions and Support
    Replies: 1
    Last Post: 11-03-2010, 09:50 AM

Tags for this Thread

Bookmarks

Posting Permissions

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