AppSource: avoid reading the whole media

[gianks]

Hi all,
implementing my own multifilereader via AppSource i'm stucked trying to avoid the need-data signal to be emitted until the EOS.
I need to play sequences of really short files (4-6 seconds), each of them are playbackable and of same format (mpegts). I don't understand why the pipeline is triggering the need-data signal continously forcing me to provide the next file repeatedly until they are finished.

After few reads of 4096 bytes the typefind element works as expected but the pipeline playback starts just after some files (many reads) while the appsource proceeds up to the end as fast as possible

I tried to set the max-bytes property to 1 MB and to set the StreamType to AppStreamTypeStream but the source is still attempting to read all the data instead of being pulled as needed for the live playback.

The Pipeline is the following:

APPSRC ! TYPEFIND ! QUEUE   APPSINK

The TypeFind Callback adds a demuxer and a muxer and via the new_pad callback the correct parser is added per each individual stream with its queue to the pipeline, connected to the the demuxer and the muxer. The muxer is finally connected to the appsink. It becomes (video only):

APPSRC ! TYPEFIND ! QUEUE ! TSDEMUX ! H264PARSE ! QUEUE ! MPEGTSMUX !  APPSINK

Below the log of my app during the pipeline startup. As expected the first read of 4Kb is enough to detect the type video/mpegts but even if the demuxer is still detecting the two multimedia streams the need-data is called without pause.

Thanks for the help!

<pre>
@@@@@@@@@@@@@ ASYNC @@@@@@@@@@@@
NeedData  4096  Bytes with buffer 4096
TypeFound:  "video/mpegts, systemstream=(boolean)true, packetsize=(int)188"
AfterTypeFound:  "video/mpegts, systemstream=(boolean)true, packetsize=(int)188"
Demuxer added, waiting for pads...
NeedData  4096  Bytes with buffer 4096
NeedData  4096  Bytes with buffer 4096
NeedData  4096  Bytes with buffer 4096
NeedData  4096  Bytes with buffer 4096
NeedData  4096  Bytes with buffer 4096
NeedData  4096  Bytes with buffer 4096
New Pad available for:  QGst::Caps("video/x-h264, stream-format=(string)byte-stream, alignment=(string)nal")  ||
NeedData  4096  Bytes with buffer 4096
NeedData  4096  Bytes with buffer 4096
NeedData  4096  Bytes with buffer 4096
NeedData  4096  Bytes with buffer 4096
NeedData  4096  Bytes with buffer 4096
NeedData  4096  Bytes with buffer 4096
NeedData  4096  Bytes with buffer 4096
NeedData  4096  Bytes with buffer 4096
NeedData  4096  Bytes with buffer 4096
NeedData  4096  Bytes with buffer 4096
NeedData  4096  Bytes with buffer 4096
NeedData  4096  Bytes with buffer 4096
NeedData  4096  Bytes with buffer 4096
NeedData  4096  Bytes with buffer 4096
NeedData  4096  Bytes with buffer 4096
NeedData  4096  Bytes with buffer 4096
NeedData  4096  Bytes with buffer 4096
NeedData  4096  Bytes with buffer 4096
New Pad available for:  QGst::Caps("audio/mpeg, mpegversion=(int)2, stream-format=(string)adts")
NeedData  4096  Bytes with buffer 4096
NeedData  4096  Bytes with buffer 4096
NeedData  4096  Bytes with buffer 4096
... ....
... ....
NeedData  4096  Bytes with buffer 4096
Still needing  1700  bytes
Opening File:  "/tmp/rec/LS_1182112391924859463589265238/video000000003.avi"
Opening success, size  450824
NeedData  1700  Bytes with buffer 4096
NeedData  4096  Bytes with buffer 4096
NeedData  4096  Bytes with buffer 4096
... ....
... ....
</pre>

[gianks]

Hi,
i've finally discovered that a non necessary queue on the pipeline was causing the unwanted behaviour.
It's fixed.

Thanks