[Live-devel] Streaming H264 elementary stream vs file
Simon Brown
sbrown at microvideo.co.uk
Tue Sep 8 06:53:56 PDT 2020
On Sep 8, 2020, at 12:52 AM, Simon Brown <sbrown at microvideo.co.uk> wrote:
>>> If I take our transport stream and convert it to raw H264 using
>>> FFmpeg with this command line:
>>>
>>> ffmpeg -i udp://:61110 -c:v copy -an -f h264 test.264
>>>
>>> and then ask testOnDemandRTSPServer to play it by asking for
>>> rtsp://192.168.1.13/h264ESVideoTest
>>>
>>> it plays fine.
>>>
>>> However, if I change the ffmpeg command to pipe out the raw 264
>>> data, and then the RTSP server to accept stdin as the file for
>>> h264ESVideoTest I get a single frame displayed and nothing more. Is
>>> there any reason for this?
>> Well, I’m sure there’s a reason for it; I just don’t know what that
>> reason is :-)
>>
>> I assume that you’ve already successfully tested:
>> your-modified-testOnDemandRTSPServer < test.264
>>
> Thanks - I asked for that. Yes, I have successfully tested that. It
> plays fine. One thing that puzzled me though, is that if I ask for
> the stream again it can start again at the beginning?
> I guess my understanding of pipes is poor, because I'd have thought
> that if it's taken the file in, it can't read it a second time.
> I'll try and record the stream with openRTSP in both instances and see
> what the difference is.
>
Some further testing yields slightly confusing results:
1) receive test.264 file with openRTSP, play out again on different
testOnDemand server and it plays fine.
2) receive live stream with openRTSP - it stops after 30 seconds or so
without me asking it to. If I play it out again using
testOnDemandRTSPServer then it plays in VLC, but at half the speed.
3) if I play that live file with ffplay however it plays it at normal speed.
4) if I now try and play the rtsp stream from the original source with
ffplay it says it "could not find codec parameters for stream 0 (Video:
264, none): unspecified size.
Regards,
Simon
--
Microvideo
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