I think the VLC media player supports HLS on multiple platforms. On Fri, Apr 20, 2012 at 4:56 AM, Ruediger Rolf <[email protected]>wrote:
> After one week I have to add 2 more findings to my H.264 experiments: > - When rescaling you should be aware that the dimensions of your video > must stay even numbers. If you use the ffmpeg option "-vf scale=200:-1" you > might be unlucky that your hight can get an odd number. > - streaming of h.264 files to mobile devices will require multiple > streaming techniques [4]. > > And now for me the interesting question would be, who has more experience > with these different streaming techniques: > - RTMP worked very reliable for us for several years now with FLV videos. > Additional to any desktop PC that has Flash installed it works in our > Android and iOS app [5]. Unfortunately it does not work with H.264 on iOS > (but on Android). > - HTTP Dynamic Streaming (HDS) is Adobes approach to http-streaming. I > never used it yet, and again it does not work on iOS. I have not tried it > on other plattforms yet. > - HTTP Live Streaming (HLS) is Apples approach on http-streaming. This now > works for iOS only and the latest Mac OS version. You cannot use it on > Windows, Linux, Android, Mac OS 10.6 (try it yourself [6]). So I'm > wondering why such a bad supported format is currently so highly requested. > Does anyone here have experience with HLS yet? > > I'm currently considering to switch back to FLV as everything seemed much > easier with this format. > > Regards > Rüdiger > > [4] > http://forums.adobe.com/**message/4100805<http://forums.adobe.com/message/4100805> > [5] > http://vm193.rz.uni-**osnabrueck.de/matterhorn2go/**index_en.html<http://vm193.rz.uni-osnabrueck.de/matterhorn2go/index_en.html> > [6] > https://developer.apple.com/**resources/http-streaming/**examples/<https://developer.apple.com/resources/http-streaming/examples/> > > On 16.04.2012 17:05, Ruediger Rolf wrote: > >> Dear fellow Matterhorn users, >> >> as we start to use our Matterhorn 1.3 in these days, I wanted to improve >> our workflow definitions. I decided that I wanted to use H.264 only, as we >> luckly updated to a Wowza Media Server [1] that allows us to stream H.264 >> [2]. >> >> So I created some MP4 encoding profiles, updated the multi-quality >> workflow definition and created a HD-workflow definition based on >> multi-quality. These updates are documented here [3]. >> >> In creating the MP4 encodings I recognized that MP4 behaves quite >> different from FLV. I don't know how much I like these changes and I must >> say that FLV had some great features that I currently miss. So what has to >> be considered when encoding MP4: >> 1. If you want synchronous playback of two streams the two videos for >> presenter and presentation need to have the same framerate and GOP >> structure. If this is not given the videos can be out of sync for several >> seconds. >> 2. The Engage Player can only jump to key-frames. These are usually set >> every 300 frames. That means every 10s on NTSC, 12s on PAL. If you reduce >> the framerate to save bandwith the intervall may become even greater. You >> can try to set the key frame interval manually, but the presets may >> overwrite these changes. The consequence is that when you jump to a chapter >> in the Matterhorn engage player you will not jump to the exact second but >> to the last keyframe, that may be several seconds earlier. FLV did not have >> this problem as the format somehow stores the reference to the keyframes in >> the metadata. >> 3. At least in the engage player there seems to be a problem that the >> h.264 videos are not always lip sync, which means that the delay of audio >> and video is more than 80ms. >> 4. There are several "profiles" for H.264. I have not understood the >> differences between these profiles in depth. The advantage of baseline >> profile is that it should run on the most devices and is probably hardware >> accelerated. So at least one of you profiles should be a basline profile. >> From my subjective tests the lip-sync issues is not that recognizeable on >> main and high profiles somehow. >> 5. There are several encoding presets (from ultrafast to veryslow) for >> x264. There is a dublication of presets ffmpeg has its own which are called >> with the "-vpre" option and the presets from the x264 codec itself which >> can be called with the "-preset" option. The vpre-settings create a MP4 >> that is not playable in Flash, so I recommend to use the x264 presets that >> all seem to work fine. In my tests ultrafast was more than 10x faster than >> veryslow. From my test-encodings I decided to use the medium setting (2-3x >> the encoding time of ultrafast), as the video-quality seemed okay for me >> than, but I might adjust this with more test videos around. (In general the >> baseline profile encoded 30% in my examples than the other profiles). >> >> I hope my findings are helpful to others, as it seemed to me that there >> was quite a lot chatting on IRC about using H.264. >> >> Rüdiger >> >> >> [1] A guide on how to setup Wowza with Matterhorn can be found here: >> http://opencast.jira.com/wiki/**display/MHDOC/Wowza+Media+**Server+3+v1.3<http://opencast.jira.com/wiki/display/MHDOC/Wowza+Media+Server+3+v1.3> >> [2] Red5 does not allow seeking in MP4 files somehow. >> [3] http://opencast.jira.com/wiki/**display/MH/HD-Video+%28720p%** >> 29+with+H.264+encoding+only<http://opencast.jira.com/wiki/display/MH/HD-Video+%28720p%29+with+H.264+encoding+only> >> >> > ______________________________**_________________ > Matterhorn-users mailing list > Matterhorn-users@**opencastproject.org<[email protected]> > http://lists.opencastproject.**org/mailman/listinfo/**matterhorn-users<http://lists.opencastproject.org/mailman/listinfo/matterhorn-users> > -- Hank Magnuski Direct: +1-408-541-9230 x205 Cell: +1-650-714-2409 Skype: hank.magnuski www.ncast.com
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