[gstreamer-bugs] [Bug 628548] New: [mpegtsmux][PATCH]Initialize PES packet before getting the header size

[GStreamer (bugzilla.gnome.org)]

https://bugzilla.gnome.org/show_bug.cgi?id=628548
  GStreamer | gst-plugins-bad | git

           Summary: [mpegtsmux][PATCH]Initialize PES packet before getting
                    the header size
    Classification: Desktop
           Product: GStreamer
           Version: git
        OS/Version: All
            Status: UNCONFIRMED
          Severity: normal
          Priority: Normal
         Component: gst-plugins-bad
        AssignedTo: gstreamer-bugs at lists.sourceforge.net
        ReportedBy: ylatuya at gmail.com
         QAContact: gstreamer-bugs at lists.sourceforge.net
      GNOME target: ---
     GNOME version: ---


Created an attachment (id=169291)
 View: https://bugzilla.gnome.org/attachment.cgi?id=169291
 Review: https://bugzilla.gnome.org/review?bug=628548&attachment=169291

Initialize PES packet before getting the header size

The PES header length is calculated before setting the dynamic flags, returning
   a wrong value. Small frames (audio ones) that should be sent in a single TS
packet are spawned to a new packet because of that error. For audio streams
where a single frame can cope in one TS packet it introduces a huge overhead.

In tsmux_write_stream_packet(), for a 100B packet, we prepare a TS packet with
a payload of(100+9)B. Then, we write the TS header using this value in
tsmux_write_ts_header(), and we call tsmux_stream_get_data(). The dynamic flags
where not set yet (get_data() does it), and now
tsmux_stream_pes_header_length() returns 14B instead of 9B. The payload of the
TS packet is 114B, 5B more than what was calculated. 109B are sent in a first
packet and the remaining 5B are sent in another one.

Using the following pipeline :
gst-launch audiotestsrc num-buffers=1000 ! ffenc_aac bitrate=30000 ! mpegtsmux
! filesink location=test.ts

:~gstreamer/head/gst-plugins-bad (mpegts)$ ls -al ts*
-rw-r--r-- 1 andoni andoni 263952 2010-09-01 22:01 /home/andoni/tspost.ts
-rw-r--r-- 1 andoni andoni 451764 2010-09-01 22:00 /home/andoni/tspre.ts

This is 58% less bandwith use, from 155kbps to 91kbps

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