Question about 3gpp and appsrc usage.

[Jabra Havridi]

Hi, gstreamer community!

Sorry for my language skill in advance.

I have a task: capture sound on android tablet, encode it with amr-nb codec, and save it to 3pg-file.

I decided to capture sound and encode it with MediaCodec from Android API. Then i push it to gstreamer pipeline, that is responsible for recording 3gp-files from such stream.
I'm already done capture and encoding parts. Now my task is: push amr-nb stream to gstreamer pipeline through appsrc.

I use this pipeline to produce 3gp-files (this is equivalent for my code):
appsrc caps="audio/AMR,rate=8000,channels=1" stream-type=GST_APP_STREAM_TYPE_STREAM format=GST_FORMAT_TIME is-live=TRUE min-latency=0 do-timestamp=TRUE ! queue ! 3gppmux ! filesink location="/mnt/sdcard/temp/recording.3gp". 

Now i'm struggling with such a problem: resulting 3gp-file is wrong. This appears as playback problems: 
1) Timeline is not functional(current position on timeline stays at the begining all the playback time).
2) Some players can't play this files at all(VLC).
3) Recorded sound includes artefacts like a jitter.

To get deeper into the problem, i try to play my file and independent amr-nb-3gp-file without such problems(from http://download.wavetlan.com/SVV/Media/HTTP/http-3gp-audio.htm) 
with enhanced logging pipeline:

my file:
gst-launch-1.0.exe -ve --gst-debug=*:3,qtdemux:5 filesrc location="c:/temp/1461580323909-1461580384071.3gp" ! queue ! qtdemux ! amrnbdec ! directsoundsink 2>20160428_002_recorded_on_tablet_amr_3gp.log

Playback log for my file(also i have attached it to the letter): http://pastebin.com/JXxZzH5C


independent normal amr-3gp:
gst-launch-1.0.exe -ve --gst-debug=*:3,qtdemux:5 filesrc location="c:/temp/test1_AMR-NB_Mono_7.95kbps_8000Hz.3GP" ! queue ! qtdemux ! amrnbdec ! directsoundsink 2>20160428_001_normal_amr_3gp_from_web.log

Playback log for normal amr-3gp: http://pastebin.com/2bMzJJqC


Same problems appears while trying to stick together many amr buffers in different files using multifilesrc & 3gppmux:

gst-launch-1.0.exe -ve --gst-debug=*:3,qtdemux:5 filesrc location="c:/temp/touput_01.3gp" ! queue ! qtdemux ! amrnbdec ! directsoundsink 2>20160428_003_assembled_from_buffers_amr_3gp.log

Playback log for this case: http://pastebin.com/8q3vSrie


There is my questions:
 Is there any pitfalls with appsrc and 3gppmux usage within such a pipeline?
 Is there any tricks with 3gppmux and a pipeline timing?

Any useful advices will be greatly appreciated.


--------------------------
With best regards, Dmitriy Sereda.

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[Nicolas Dufresne-4]

Le mercredi 11 mai 2016 à 16:35 +0600, Jabra Havridi a écrit :
> I use this pipeline to produce 3gp-files (this is equivalent for my
> code):
> appsrc caps="audio/AMR,rate=8000,channels=1" stream-
> type=GST_APP_STREAM_TYPE_STREAM format=GST_FORMAT_TIME is-live=TRUE
> min-latency=0 do-timestamp=TRUE ! queue ! 3gppmux ! filesink
> location="/mnt/sdcard/temp/recording.3gp". 

The timestamps generated by appsrc (do-timestamp=TRUE) in this case
will be extremely approximate. You should probably timestamp the buffer
yourself, somewhere closer to the capture. Or even better, use
timestamp for your source.

Nicolas
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