MPEG-TS Framerate Divider?
ccrisler at mutualink.net
Wed Apr 10 06:35:26 PDT 2013
Dropping H264 frames in general doesn't work. Most frames depend on
previous frames. So, when you drop one, all succeeding frames (until an
I-Frame) fail. Look at the Rx video on a lossy network. It is awful. Many
implementations have put a lot of work into forward error correction to
prevent that. If you want to change something, you have to transcode (yuk).
On Wed, Apr 10, 2013 at 2:48 AM, Edward Hervey <bilboed at gmail.com> wrote:
> One way or another you are going to have to demux the stream, modify
> the framerate and timestamps and remux it.
> * framerate : that information is present in the video elementary
> streams (i.e. not at the mpeg-ts level itself unlike other container
> formats) ... but a lot of decoders simply ignore it (and use the PTS/DTS
> instead for synchronization).
> * PTS/DTS : you will need to modify those. I'm not sure we can do this
> right now with the video parsers for example.
> Note that this is assuming that (for some weird reason) the provider
> of that stream encoded the video stream faster than the other streams.
> If you want to *drop* frames, you will have to either:
> * decode the stream, drop extra frames, re-encode
> * OR keep only I-frames ... but this might not work for all formats
> If you want to *insert* frames, you will have to decode, insert
> duplicate frames, re-encode.
> On Mon, 2013-04-08 at 10:57 -0700, Peter Witkowski wrote:
> > Hello,
> > I'm wondering if GStreamer has any way to lower the framerate of a
> > video stream inside a MPEG-2 TS without demuxing the TS. I'm provided
> > the MPEG-TS by a device and read out the bytes via a serial driver. I
> > currently have no say in terms of the framerate or size of the video.
> > The reason I ask is that there are other private data streams in the
> > TS that I want to preserve, and I only want to lower the framerate of
> > the video stream in the TS to lower the networking bandwidth
> > requirements of the TS.
> > Thank you in advance for the help!
> gstreamer-devel mailing list
> gstreamer-devel at lists.freedesktop.org
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