[streaming] Re: Trying to emulate VLC streaming in a test equipment, but failing

[Jean-Paul Saman]

Chhaya, Harshal wrote:
> Hi,
> 
> I found some more details and so am following up to my earlier
> post in the hope that this additional information can help
> someone diagnose the problem and suggest a solution.
> 
> I analysed the messages generated in each case and I found
> that when I stream using VLC or when I stop and re-start the
> client when streaming from the test equipment, the client 
> displays this:
> 
> ts debug: pid[68] unknown
> ts debug: PATCallBack called
> ts debug: new PAT ts_id=31975 version=23 current_next=1
> ts debug:   * number=1 pid=66
> ts debug: PMTCallBack called
> ts debug: new PMT program number=1 version=25 pid_pcr=68
> ts debug:   * es pid=68 type=3 fcc=mpga
> 
> but when I stream from my test equipment in a loop, the 
> client displays only:
> 
> ts debug: PATCallBack called
> ts debug: PMTCallBack called
> ts warning: discontinuity received 0x0 instead of 0x4 (pid=69)
> mpgatofixed32 debug: libmad error: bad main_data_begin pointer
> main warning: buffer is 71700 in advance, triggering downsampling
> mpeg_audio debug: emulated startcode (no startcode on following frame)
> main warning: backward_pts != dts (40000)
> main warning: backward_pts != dts (40000)
> 
> There is no "new PAT..." or "new PMT..." line.
> 
> What causes the client to detect a new PAT and PMT? Is it
> something that the server sends?
> 
The test equipment should update the version numbers of the PAT and PMT 
if they change. And set the discontinuity bit in the TS header. 
Basically your test equipment isn't following MPEG2-TS specifications.

> How can I ensure that the client VLC detects when the video
> stream has looped around?
> 
Follow the spec.

> BTW, I found the 'use sequential numbers instead of 
> timestamps' option in vlc 0.8.6 and enabled it but it didn't 
> make any difference.
> 
> FWIW, mplayer can play the stream even from the test equipment
> but the video quality gets progressively worse. It also can't
> play the audio which is in mp3 format.

VLC uses the specifications and MPLayer doesn't. So when a file can be 
played with mplayer it doesn't mean the stream is according to 
specification. Only that mplayer is less stringent.

> Thanks for any and all suggestions.

Gtz,
Jean-Paul Saman.

-- 
This is the streaming mailing-list, see http://www.videolan.org/streaming/
To unsubscribe, please read http://www.videolan.org/support/lists.html