[Live-devel] How does Fastforward/Rewind work on a stream ?

Glen Gray glen at lincor.com
Tue Oct 18 15:02:22 PDT 2005 

Follow up on the previous email.

As an experiment, I've changed all the playMediaSession and
playMediaSubsession functions to pass in a scale value of 12.0.

That way, it'll just ask the server for a stream with a scale of 12.0

That aspect seems to work as I can see vlc print out the following RTSP
communications. As you can see below, that all looks ok, and on the
server I can see it accepting a play request for the stream at speed 12
(in /usr/mbase/logs/cla_playout.log)

VLC then creates all it's playback threads and looses the connection
somehow. VLC logs follow the RTSP OUTPUT.


******* RTSP OUTPUT *******
Received OPTIONS response: RTSP/1.0 200 OK
CSeq: 1
Message: OPTIONS Successful
Public: OPTIONS, DESCRIBE, SETUP, PLAY, PAUSE, SET_PARAMETER,
GET_PARAMETER, SET_PLAYMODE, TEARDOWN
Date: Tue, 18 Oct 2005 12:42:10 GMT

Sending request: DESCRIBE rtsp://vod/TahitiDreams2 RTSP/1.0
CSeq: 2
Accept: application/x-rtsp-mh, application/sdp
User-Agent: VLC Media Player (LIVE555 Streaming Media v2005.10.05)

status change: ( New input: rtsp://vod/TahitiDreams2 )
status change: ( audio volume: 256 )
status change: ( play state: 1 )
Received DESCRIBE response: RTSP/1.0 200 OK
CSeq: 2
Date: Tue, 18 Oct 2005 12:42:10 GMT
Server: Kasenna MediaBase version 7.2
Content-type: application/x-rtsp-mh
Content-Length: 455

Need to read 455 extra bytes
Read 455 extra bytes: <MediaDescription>
<MediaContainer
NumStreams = 1
>
<MediaStreams>
<MediaStream
StreamID = 0
MimeType = application/x-sgimb
MaxBitRate = 4500001
Height = 480
Width = 704
FramesPerSecond = 29.969999
AspectRatio = 0.673500
FramesToIFramesRatio = 12.000000
AudioHeader = 0
Duration = 384065978
StartTime = 0
PlayModes = 7
NumTrickSpeed = 3
TrickSpeeds = 2,6,12
TypeSpecificData = MPEG-2
VideoPid = 4131
AudioPid = 4130
</MediaStreams>
</MediaDescription>

Kasenna Content Type: MPEG-2
[00000249] livedotcom demuxer debug: sdp=v=0
o=NoSpacesAllowed 1 1 IN IP4 192.168.2.12
s=rtsp://vod/TahitiDreams2
c=IN IP4 192.168.2.12
t=0 0
a=control:*
a=range:npt=0-384
m=video 1554 RAW/RAW/UDP 33
a=control:trackID=4131

[00000249] livedotcom demuxer debug: RTP subsession 'video/MP2T'
Sending request: SETUP rtsp://vod/TahitiDreams2/ RTSP/1.0
CSeq: 3
Transport: RAW/RAW/UDP;unicast;client_port=1554-1555
User-Agent: VLC Media Player (LIVE555 Streaming Media v2005.10.05)

Received SETUP response: RTSP/1.0 200 OK
CSeq: 3
Transport:
RAW/RAW/UDP;destination=192.168.2.220;port=1554;client_port=1554;source=192.168.2.12
Session: 1129622200

Sending request: PLAY rtsp://vod/TahitiDreams2 RTSP/1.0
CSeq: 4
Session: 1129622200
Scale: 12.000000
Range: npt=0.000-
User-Agent: VLC Media Player (LIVE555 Streaming Media v2005.10.05)

Received PLAY response: RTSP/1.0 200 OK
CSeq: 4
Date: Tue, 18 Oct 2005 12:42:11 GMT
Scale: 12.000000
***** END RTSP OUTPUT ********


********* VLC OUTPUT ***********
[00000250] main private debug: thread 85883824 (stream out) created at
priority 0 (src/input/demux.c:335)
[00000013] main module debug: using access_demux module "livedotcom"
[00000248] main input debug: `rtsp://vod/TahitiDreams2' successfully
opened
[00000250] main private debug: creating demux: access='' demux='ts'
path=''
[00000251] main demuxer debug: looking for demux2 module: 1 candidate
[00000151] main module debug: using demux2 module "ts"
[00000251] ts demuxer debug: PATCallBack called
[00000251] ts demuxer debug: new PAT ts_id=1 version=0 current_next=1
[00000251] ts demuxer debug:   * number=1 pid=1280
libdvbpsi error (PSI decoder): TS discontinuity (received 15, expected
0)
[00000251] ts demuxer debug: PMTCallBack called
[00000251] ts demuxer debug: new PMT program number=1 version=31
pid_pcr=4131
[00000251] ts demuxer debug: PMTCallBack called
[00000251] ts demuxer debug: new PMT program number=1 version=0
pid_pcr=4131
[00000251] ts demuxer debug:  * descriptor : unknown (0x17)
[00000251] ts demuxer debug:   * es pid=4131 type=2 fcc=mpgv
[00000248] main input debug: selecting program id=1
[00000253] main decoder debug: looking for decoder module: 20 candidates
[00000094] main module debug: using decoder module "libmpeg2"
[00000253] main decoder debug: thread 109239216 (decoder) created at
priority 0 (src/input/decoder.c:159)
[00000251] ts demuxer debug:   * es pid=4130 type=3 fcc=mpga
[00000258] main decoder debug: looking for decoder module: 20 candidates
[00000097] main module debug: using decoder module "mpeg_audio"
[00000258] main decoder debug: thread 119729072 (decoder) created at
priority 0 (src/input/decoder.c:159)
[00000251] ts demuxer warning: first packet for pid=4131 cc=0xf
libdvbpsi error (PSI decoder): TS discontinuity (received 0, expected 1)
[00000251] ts demuxer debug: PATCallBack called
libdvbpsi error (PSI decoder): TS discontinuity (received 0, expected 1)
[00000251] ts demuxer debug: PMTCallBack called
[00000248] main input warning: clock gap, unexpected stream
discontinuity
[00000253] libmpeg2 decoder debug: 704x480, aspect 576000, 29.971 fps
[00000253] main decoder debug: no usable vout present, spawning one
[00000270] main video output debug: looking for video output module: 6
candidates
[00000270] xvideo video output debug: adaptor 0, port 56, format
0x32315659 (YV12) planar
[00000270] xvideo video output debug: Window manager supports NetWM
[00000270] xvideo video output debug: Window manager supports
_NET_WM_STATE_FULLSCREEN
[00000270] xvideo video output debug: Window manager supports
_NET_WM_STATE_ABOVE
[00000270] xvideo video output debug: Window manager supports
_NET_WM_STATE_BELOW
[00000236] main module debug: using video output module "xvideo"
[00000270] main video output debug: waiting for thread completion
[00000270] main video output debug: got 8 direct buffer(s)
[00000270] main video output debug: picture in 704x480 (0,0,704x480),
chroma I420, ar 4:3, sar 10:11
[00000270] main video output debug: picture user 704x480 (0,0,704x480),
chroma I420, ar 4:3, sar 10:11
[00000270] main video output debug: picture out 704x480, chroma I420, ar
4:3, sar 10:11
[00000270] main video output debug: direct render, mapping render
pictures 0-6 to system pictures 1-7
[00000270] main video output debug: thread 149044144 (video output)
created at priority 0 (src/video_output/video_output.c:494)
[00000271] main private debug: Registering subpicture channel, ID: 2
[00000271] main private debug: Registering subpicture channel, ID: 3
[00000271] main private debug: Registering subpicture channel, ID: 4
[00000271] main private debug: Registering subpicture channel, ID: 5
[00000258] main decoder debug: thread 119729072: secret message
triggered at src/misc/block.c:227 (Connection timed out)
[00000250] main private debug: thread 85883824: secret message triggered
at src/misc/block.c:227 (Connection timed out)
[00000253] main decoder debug: thread 109239216: secret message
triggered at src/misc/block.c:227 (Connection timed out)
************ END OF VLC OUTPUT**************

-- 
Glen Gray <glen at lincor.com>              Digital Depot, Thomas Street
Senior Software Engineer                            Dublin 8, Ireland
Lincor Solutions Ltd.                          Ph: +353 (0) 1 4893682

More information about the live-devel mailing list