Comment 1 for bug 1238321

I have the same problem in 0.27 with missing audio after transcoding.

But.... sometimes I can transcode and audio still works. I think I've narrowed it down to the scenarios below.

WORKING AUDIO -
1. mythtranscode with lossless mpeg2 and honor cutlist
2. mythtranscode with mpeg4 and NO cutlist

==== output from avplay for transcoded file with audio working (mpeg2 trimmed by cutlist) ====
james@tvserver:/var/lib/mythtv/livetv$ avplay cutmpeg2.nuv
avplay version 0.8.8-4:0.8.8-0ubuntu0.12.04.1, Copyright (c) 2003-2013 the Libav developers
  built on Oct 22 2013 12:31:55 with gcc 4.6.3
[mpeg @ 0x7f04200008c0] max_analyze_duration reached
Input #0, mpeg, from 'cutmpeg2.nuv':
  Duration: 00:00:59.95, start: 0.310533, bitrate: 2869 kb/s
    Stream #0.0[0x1e0]: Video: mpeg2video (Main), yuv420p, 704x480 [PAR 10:11 DAR 4:3], 15000 kb/s, 29.97 fps, 29.97 tbr, 90k tbn, 59.94 tbc
    Stream #0.1[0x80]: Audio: ac3, 48000 Hz, stereo, s16, 192 kb/s
   1.10 A-V: -0.010 s:0.0 aq= 320KB vq= 3986KB sq= 0B f=0/0 f=0/0
=============================================================================

Note the audio stream above just says "stereo".

MISSING AUDIO -
1. mythtranscode with mpeg4 and honor cutlist

==== Output from avplay for transcoded file with no audio (mpeg4 trimmed by cutlist) ====
james@tvserver:/var/lib/mythtv/livetv$ avplay cutmpeg4.nuv
avplay version 0.8.8-4:0.8.8-0ubuntu0.12.04.1, Copyright (c) 2003-2013 the Libav developers
  built on Oct 22 2013 12:31:55 with gcc 4.6.3
[nuv @ 0x7fb2c00008c0] max_analyze_duration reached
[nuv @ 0x7fb2c00008c0] Estimating duration from bitrate, this may be inaccurate
Input #0, nuv, from 'cutmpeg4.nuv':
  Duration: 00:03:57.05, start: 0.033000, bitrate: 1411 kb/s
    Stream #0.0: Video: mpeg4, yuv420p, 1056x720, PAR 10:11 DAR 4:3, 30.30 fps, 29.97 tbr, 1k tbn, 1k tbc
    Stream #0.1: Audio: mp3, 48000 Hz, 2 channels, s16, 1411 kb/s
0.00 A-V: -1.969 s:0.0 aq= 0KB vq=15370KB sq= 0B f=0/0 f=0/0
=========================================================================

I can't seem to get avplay to admit that there is no audio. But nothing comes out.
The only difference between this output and one where audio works is the "max_analyze_duration reached" message and that the audio stream says it is "2 channels".

==== mythtranscode output when using mpeg4 and honor cutlist ====
james@tvserver:/var/lib/mythtv/livetv$ mythtranscode -i 2223_20131117010600.mpg -o cutmpeg4.nuv -p "High Quality" --honorcutlist
2013-11-16 20:13:12.990782 C mythtranscode version: fixes/0.27 [v0.27-75-g45459f9] www.mythtv.org
2013-11-16 20:13:12.990795 C Qt version: compile: 4.8.1, runtime: 4.8.1
2013-11-16 20:13:12.990802 N Enabled verbose msgs: general
2013-11-16 20:13:12.990809 N Setting Log Level to LOG_INFO
2013-11-16 20:13:13.001482 I Added logging to the console
2013-11-16 20:13:13.002141 I Setup Interrupt handler
2013-11-16 20:13:13.002154 I Setup Terminated handler
2013-11-16 20:13:13.002165 I Setup Segmentation fault handler
2013-11-16 20:13:13.002175 I Setup Aborted handler
2013-11-16 20:13:13.002185 I Setup Bus error handler
2013-11-16 20:13:13.002196 I Setup Floating point exception handler
2013-11-16 20:13:13.002206 I Setup Illegal instruction handler
2013-11-16 20:13:13.002221 I Setup Real-time signal 0 handler
2013-11-16 20:13:13.002265 N Using runtime prefix = /usr
2013-11-16 20:13:13.002278 N Using configuration directory = /home/james/.mythtv
2013-11-16 20:13:13.002357 I Assumed character encoding: en_US.UTF-8
2013-11-16 20:13:13.002766 N Empty LocalHostName.
2013-11-16 20:13:13.002775 I Using localhost value of tvserver
2013-11-16 20:13:13.002817 I Testing network connectivity to '192.168.1.4'
2013-11-16 20:13:13.004212 I Starting process manager
2013-11-16 20:13:13.004186 I Starting IO manager (read)
2013-11-16 20:13:13.004240 I Starting process signal handler
2013-11-16 20:13:13.004376 I Starting IO manager (write)
2013-11-16 20:13:13.103557 I New Client: (#1)
2013-11-16 20:13:13.118989 N Setting QT default locale to EN_US
2013-11-16 20:13:13.119076 I Current locale EN_US
2013-11-16 20:13:13.119127 N Reading locale defaults from /usr/share/mythtv//locales/en_us.xml
2013-11-16 20:13:13.126350 I Loading en_us translation for module mythfrontend
2013-11-16 20:13:13.128557 N Transcoding from 2223_20131117010600.mpg to cutmpeg4.nuv
2013-11-16 20:13:13.157261 I AFD: codec AC3 has 2 channels
2013-11-16 20:13:13.157620 I AFD: Opened codec 0x18aa000, id(AC3) type(Audio)
2013-11-16 20:13:13.160513 I AFD: Opened codec 0x18a95a0, id(MPEG2VIDEO) type(Video)
2013-11-16 20:13:13.160687 N AudioPlayer: Enabling Audio
2013-11-16 20:13:13.172275 I Honoring the cutlist while transcoding
2013-11-16 20:13:13.173138 I Cutlist : 0-2353,4150-11802
2013-11-16 20:13:13.173149 I Original Length: 11802 frames
2013-11-16 20:13:13.173154 I New Length : 1797 frames
2013-11-16 20:13:13.186324 I Resizing from 704x480 to 1056x720
2013-11-16 20:13:13.190327 I MythCoreContext: Connecting to backend server: 192.168.1.4:6543 (try 1 of 1)
2013-11-16 20:13:13.191959 I Using protocol version 77
2013-11-16 20:13:13.216344 I Copying Audio while transcoding Video
2013-11-16 20:13:13.223271 I Player(0): Fast-Forwarding from 0 to 2353
2013-11-16 20:13:25.233450 I Player(0): Fast-Forwarding from 4150 to 11802
2013-11-16 20:13:25.321820 N Transcoding 2223_20131117010600.mpg done
2013-11-16 20:13:25.321933 I Waiting for threads to exit.
Error: Not all threads were shut down properly:
Thread TFWSync is still running
Thread TFWWrite is still running
============================================================

Note the only error from mythtranscode is "Not all threads were shut down properly".

Here is the version I am using on the backend.
james@tvserver:~/mythtv/livetv$ apt-cache policy mythtv-backend
mythtv-backend:
  Installed: 2:0.27.0+fixes.20131108.45459f9-0ubuntu0mythbuntu2
  Candidate: 2:0.27.0+fixes.20131115.4ca9300-0ubuntu0mythbuntu2
  Version table:
     2:0.27.0+fixes.20131115.4ca9300-0ubuntu0mythbuntu2 0
        500 http://ppa.launchpad.net/mythbuntu/0.27/ubuntu/ precise/main amd64 Packages
 *** 2:0.27.0+fixes.20131108.45459f9-0ubuntu0mythbuntu2 0
        100 /var/lib/dpkg/status
     2:0.25.3+fixes.20130813.b5adf03-0ubuntu0mythbuntu2 0
        500 http://ppa.launchpad.net/mythbuntu/0.25/ubuntu/ precise/main amd64 Packages
     2:0.25.2+fixes.20120802.46cab93-0ubuntu1 0
        500 http://us.archive.ubuntu.com/ubuntu/ precise-updates/multiverse amd64 Packages
     2:0.25.0+fixes.20120410.1f5962a-0ubuntu1 0
        500 http://us.archive.ubuntu.com/ubuntu/ precise/multiverse amd64 Packages