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  • Audio not there for many Shmoocon 2022 videos

    Many videos under Shmoocon 2022 does not have audio.
  • Answer selected by ghost_pepper108 at June 9, 2022, 18:40.

    New ShmooCon torrent added ghost_pepper108 The new one is about a gig larger but it has audio 😁

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    • #2
      Originally posted by ghost_pepper108 View Post
      Many videos under Shmoocon 2022 does not have audio.
      Would you provide links to example videos which have no audio? I would expect DT would reply, but due to time zone complications and other stuff, he may not be able to reply as quickly as me.
      I'm pretty sure the first question he would ask, would be which videos, so it can be investigated.

      Also, if you have a link to a Schmoocon video in 2022 which *does* work, that could help us compare to find differences and identify possible causes.

      Thanks!
      Last edited by number6; June 8, 2022, 09:56.

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      • #3
        Example

        https://infocon.org/cons/ShmooCon/Sh...0go%20here.mp4

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        • #4
          should be encoded with Opus, do other videos have audio?

          I’ll check the source files.
          PGP Key: https://defcon.org/html/links/dtangent.html

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          • #5
            Originally posted by ghost_pepper108 View Post
            Thanks!

            I found and tested URL1 = https://infocon.org/cons/ShmooCon/Sh...0The%20Con.mp4 (URL1 changed to 2019 video not 2022 since it was posted) vs the video link you provided URL2 = https://infocon.org/cons/ShmooCon/Sh...0go%20here.mp4

            In using VLC player, I can see both URL1 and URL2 each have a video track and an audio track.
            Both use HEVC video codes, and Opus audio in an MP4 container.
            However, VLC produces zero audio output in URL2, while working in URL1. (There is an audio track in the MP4 container, but it seems to have no playable data)
            This suggests there is just no audio data in the existing audio track/stream of URL2 to play.
            At this point, I don't think this problem is in your use of your media player if audio works in URL1, but does not work in URL2
            It could be a problem with the source file or the encoding or a bug in the re-encoder. Dark Tangent would be able to examine this issue to see if the larger source file has problems, and try to diagnose the problem with this. I have tagged Dark Tangent here to draw his attention to this.



            (Below this point, nothing related to the issue you posted, but commentary on other issues people may see.)

            I've tested this and other videos with a few media players (Xine, mplayer, vlc, (Both windows attempts direct to installing $0.99 HEVC codec library (video), but with a little searching there might be a free option for MS Windows: https://apps.microsoft.com/store/det...hl=en-us&gl=US (including this link is not advice to use it or claim of how well it works) Adding the video codec did not help with audio play-back: Windows "Media Player", "Windows Media Player" etc.)

            These appear to be MP4 container using Opus for audio encoding. Some media players appear to have problems when opus audio is included in MP4 containers, but are happy to play Opus audio in MKV containers. (For mplayer and similar, a possible work-around where there is audio saved in opus format in MP4 container: https://unix.stackexchange.com/quest...-mp4-container ... Though the link to the proposed codecs.conf file appears to be an unofficial repo/copy from svn to github:
            https://github.com/sherpya/MPlayer/b...tc/codecs.conf) Other players may have similar work-arounds.

            For testing audio with your favorite media player, try to play https://infocon.org/cons/ShmooCon/Sh...0the%20Con.mp4 as I have confirmed it has video and an audio track with audio which can play in VLC showing video and playing audio content.
            Last edited by number6; June 8, 2022, 12:36.

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            • #6
              Thanks number6 for looking into it. Yes, both the URLs do not play any audio in VLC player. It does have some noises at random places but just that , no usable audio. Video is fine. My VLC runs on mac so I don't think I need additional codecs.
              Dark Tangent - Most of the mp4 in ShmooCon 2022 has this issue.

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              • #7
                Originally posted by ghost_pepper108 View Post
                Thanks number6 for looking into it. Yes, both the URLs do not play any audio in VLC player. It does have some noises at random places but just that , no usable audio. Video is fine. My VLC runs on mac so I don't think I need additional codecs.
                Dark Tangent - Most of the mp4 in ShmooCon 2022 has this issue.
                Sorry, I copied the wrong link (same name for file, different video)
                https://infocon.org/cons/ShmooCon/Sh...0The%20Con.mp4
                This one from 2019: does audio work for you?
                (Not the one from 2022)

                Also, which media player (implied VLC) are you using on which platform?
                TIA
                Last edited by number6; June 8, 2022, 12:54.

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                • #8
                  Yes, the link you provided from 2019 works and many others work (that is both video and audio work) since I regularly use this site. Here is a link from Shmoocon 2022 that works https://infocon.org/cons/ShmooCon/Sh...20Patching.mp4

                  I am using VLC on Mac.

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                  • number6
                    number6 commented
                    Editing a comment
                    Thanks! That is consistent with what I found. The rest will probably be for DT to provide in reply. Good luck!

                • #9
                  Problem verified. The source material is using .m4a AAC encoding, and for some reason ffmpg doesn't like it. I'll try updating to whatever the latest ffmpg is and if that doesn't fix it I'll have to just copy the audio stream.

                  Either way I'll reencode and regenerate the torrent.

                  Thanks for pointing out the problem ghost_pepper108
                  PGP Key: https://defcon.org/html/links/dtangent.html

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                  • #10
                    Yep, so ffmpg update didn't fix it so just copying the audio stream. It makes the files bigger, but better than no audio.
                    PGP Key: https://defcon.org/html/links/dtangent.html

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                    • #11
                      New ShmooCon torrent added ghost_pepper108 The new one is about a gig larger but it has audio 😁
                      PGP Key: https://defcon.org/html/links/dtangent.html

                      Comment


                      • #12
                        Thank you Dark Tangent. The videos are fine now.
                        Thanks number6 for initial tests.

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