How does the VLC player play the Audio/Video with timestamp

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pluto1027
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How does the VLC player play the Audio/Video with timestamp

Postby pluto1027 » 13 Mar 2017 09:11

Hi.

I tried to play my streaming file(VIDEO :MJPEG framerate 30, AUDIO: PCM SampleBits 44100, SampleRate 16, Channels 2) in my device as the RTSP server,
and it will connect to my iphone by RTP and play in the VLC player (as RTSP client)
But I can only see the video just run few seconds, and the audio always played the same sound.

I guessed it is the timestamp issue, so I did an experience:
I recorded a MJPEG video(remove audio), and sent one frame per second from my device.
And attached the pts increment to 2000 between every frame.

Send_time(sec) Frame_num pts timestamp
0 frame_0 0 2000000000
1 frame_1 2000 2000180000
2 frame_2 4000 2000360000
3 frame_3 6000 2000540000
...
29 frame_29 58000 2005220000

Because the VLC player should play the video according by the timestamp, and the payload type (m=video 0 RTP/AVP 26 => clock=90000).
I expect the video will show frame_0 in 0 sec, frame_1 in 2 sec, frame_2 in 4 sec, frame_3 in 6 sec, ... frame_29 in 58 sec.
But the real condition in my VLC player is frame_0 in 0 sec, frame_1 in 2 sec, frame_2 in 3 sec, frame_3 in 4 sec, ... frame-29 in 31 sec.
Could someone help me ? Thanks.

---------------------------------------------------------------
The following information is from my RTSP DESCRIBE:
i=MJPG
t=0 0
a=type:broadcast
a=control:*
a=range:npt=0-60.50
a=x-qt-text-nam:Motion JPEG.
a=x-qt-text-inf:MJPG
m=video 0 RTP/AVP 26
c=IN IP4 0.0.0.0
b=AS:12288
a=frmerate:30.0
a=control:track1

Rémi Denis-Courmont
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Joined: 07 Jun 2004 16:01
VLC version: master
Operating System: Linux
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Re: How does the VLC player play the Audio/Video with timestamp

Postby Rémi Denis-Courmont » 14 Mar 2017 18:51

This does not look like a valid SDP.
Rémi Denis-Courmont
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Private messages soliciting support will be systematically discarded

pluto1027
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Re: How does the VLC player play the Audio/Video with timestamp

Postby pluto1027 » 15 Mar 2017 02:19

Thanks for your reply.
Could you explain more detail?
Did you mean I lose some parameters form my RTSP DESCRIBE?

The following is the total information.
RTSP_DESCRIBE:
v=0
o=- 33520935 1 IN IP4 192.168.1.1
s=Motion JPEG. Streamed by live555.
i=MJPG
t=0 0
a=tool:iCatchTek
a=type:broadcast
a=control:*
a=range:npt=0-60.50
a=x-qt-text-nam:Motion JPEG. Streamed by live555.
a=x-qt-text-inf:MJPG
m=video 0 RTP/AVP 26
c=IN IP4 0.0.0.0
b=AS:12288
a=frmerate:30.0
a=control:track1
Last edited by pluto1027 on 15 Mar 2017 04:57, edited 1 time in total.

pluto1027
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Joined: 13 Mar 2017 08:15

Re: How does the VLC player play the Audio/Video with timestamp

Postby pluto1027 » 15 Mar 2017 04:27

There are actually two issues when I try to play RTP streaming.

1.
I tried to play my streaming file(VIDEO :MJPEG framerate 30, AUDIO: PCM SampleBits 44100, SampleRate 16, Channels 2) in my device as the RTSP server,
and it will connect to my iphone by RTP and play in the VLC player (as RTSP client)
But I can only see the video just run few seconds, and the audio always played the same sound.
=>This issue only happened in the VLC player on iphone & ipad, but it can play normally in the VLC play on my Windows PC.

2.
My experiment:I recorded a MJPEG video(remove audio), and sent one frame per second from my device.
And attached the pts increment to 2000 between every frame.
in my VLC player is frame_0 in 0 sec, frame_1 in 2 sec, frame_2 in 3 sec, frame_3 in 4 sec, ... frame-29 in 31 sec.
=>This issue happened in the VLC player on iphone, ipad and Windows PC.


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