[mythtv-users] no sound after transcoding to MPEG4

Joachim Gehweiler post at joachim-gehweiler.de
Tue Oct 21 00:47:45 EDT 2003


Joseph A. Caputo wrote:
> Joachim Gehweiler wrote:
> 
>> Nearly everything is working fine, but there is still some big problem 
>> left: If I record some TV show, I can watch it as long as I did NOT 
>> transcode it, that means everything is ok with the original recording 
>> (video as Hardware MJPEG; sound as MP3 or uncompressed). But after 
>> transcoding to MPEG4, the video is ok, but there is no sound! I tried 
>> various combinations of the MPEG4 settings and the audio settings, but 
>> in all cases the sound was missing.
> 
> If you have your recording profile set as 'Hardware MJPEG', that might 
> be part of your problem.  The PVR-250 is a Hardware MPEG (*not* MJPEG) 
> encoder.  The codec is MPEG-2.  It sounds like you have the card 
> configured properly (or you wouldn't be getting good recordings), but if 
> you've mis-configured your recording profiles, it might explain why your 
> transcodings are screwed up.
> 
> -JAC

How would my recording profiles be correct? The database looks like:

mysql> select * from recordingprofiles;
+----+-----------+----------------+------------+
| id | name      | videocodec     | audiocodec |
+----+-----------+----------------+------------+
|  1 | Default   | Hardware MJPEG | MP3        |
|  2 | Live TV   | Hardware MJPEG | MP3        |
|  3 | Transcode | MPEG-4         | MP3        |
+----+-----------+----------------+------------+
3 rows in set (0.00 sec)

mysql> select * from codecparams;
+---------+--------------------------+-------+
| profile | name                     | value |
+---------+--------------------------+-------+
|       1 | width                    | 720   |
|       1 | height                   | 576   |
|       1 | rtjpegquality            | 170   |
|       1 | rtjpeglumafilter         | 0     |
|       1 | rtjpegchromafilter       | 0     |
|       1 | mpeg4bitrate             | 2200  |
|       1 | mpeg4maxquality          | 2     |
|       1 | mpeg4minquality          | 15    |
|       1 | mpeg4qualdiff            | 3     |
|       1 | mpeg4scalebitrate        | 1     |
|       1 | mpeg4optionvhq           | 0     |
|       1 | mpeg4option4mv           | 0     |
|       1 | hardwaremjpegquality     | 100   |
|       1 | hardwaremjpeghdecimation | 4     |
|       1 | hardwaremjpegvdecimation | 4     |
|       1 | samplerate               | 48000 |
|       1 | mp3quality               | 7     |
|       2 | width                    | 720   |
|       2 | height                   | 576   |
|       2 | rtjpegquality            | 170   |
|       2 | rtjpeglumafilter         | 0     |
|       2 | rtjpegchromafilter       | 0     |
|       2 | mpeg4bitrate             | 2200  |
|       2 | mpeg4maxquality          | 2     |
|       2 | mpeg4minquality          | 15    |
|       2 | mpeg4qualdiff            | 3     |
|       2 | mpeg4scalebitrate        | 1     |
|       2 | mpeg4optionvhq           | 0     |
|       2 | mpeg4option4mv           | 0     |
|       2 | hardwaremjpegquality     | 100   |
|       2 | hardwaremjpeghdecimation | 4     |
|       2 | hardwaremjpegvdecimation | 4     |
|       2 | samplerate               | 48000 |
|       2 | mp3quality               | 7     |
|       3 | width                    | 720   |
|       3 | height                   | 576   |
|       3 | rtjpegquality            | 170   |
|       3 | rtjpeglumafilter         | 0     |
|       3 | rtjpegchromafilter       | 0     |
|       3 | mpeg4bitrate             | 2200  |
|       3 | mpeg4maxquality          | 2     |
|       3 | mpeg4minquality          | 15    |
|       3 | mpeg4qualdiff            | 3     |
|       3 | mpeg4scalebitrate        | 1     |
|       3 | mpeg4optionvhq           | 1     |
|       3 | mpeg4option4mv           | 1     |
|       3 | hardwaremjpegquality     | 100   |
|       3 | hardwaremjpeghdecimation | 4     |
|       3 | hardwaremjpegvdecimation | 4     |
|       3 | samplerate               | 48000 |
|       3 | mp3quality               | 7     |
+---------+--------------------------+-------+
51 rows in set (0.00 sec)


Indeed, 'Hardware MJPEG' is something different as 'MPEG-2 Hardware 
Encoder', but in the setup I can only choose between

RTJPEG
Hardware MJPEG
MPEG-4

It simply doesn't offer 'MPEG-2 Hardware Encoder'!!!

Somewhere in the mail archives, I found people talking on a similar problem:

http://www.gossamer-threads.com/perl/mailarc/gforum.cgi?post=82847;search_string=recording%20profile%20ivtv;guest=1390560&t=search_engine#82847

and they mailed their databased contents, which are totally different 
from mine; in fact, in my database, there is simply not table called 
'profilegroups', only one called 'recordingprofiles'.

I manually changed the database such that it looked like:

mysql> select * from recordingprofiles;
+----+-----------+-------------------------+-------------------------+
| id | name      | videocodec              | audiocodec              |
+----+-----------+-------------------------+-------------------------+
|  1 | Default   | MPEG-2 Hardware Encoder | MPEG-2 Hardware Encoder |
|  2 | Live TV   | MPEG-2 Hardware Encoder | MPEG-2 Hardware Encoder |
|  3 | Transcode | MPEG-4                  | MP3                     |
+----+-----------+-------------------------+-------------------------+
3 rows in set (0.00 sec)

but this didn't change anything either; furthermore the backend output 
make one belief it would have worked:

Input #0, mpeg, from 
'/home/mythtv/recordings/1049_20031020223600_20031020224100
.nuv':
   Stream #0.0: Video: mpegvideo, 720x576, 25.00 fps, 16000 kb/s
   Stream #0.1: Audio: mp2, 48000 Hz, stereo, 384 kb/s
Transcoding from 
/home/mythtv/recordings/1049_20031020223600_20031020224100.nuv
to /home/mythtv/recordings/1049_20031020223600_20031020224100.nuv.tmp
Position map found
Transcoding 
/home/mythtv/recordings/1049_20031020223600_20031020224100.nuv done

but it still did NOT work - there is no sound this time again.

Do you have another idea what might go wrong or where I should start 
looking for it?

Is my database correct? If not, what should a correct database look like?

Best,
   Joachim



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