[mythtv-users] Encoding to h264 Some Recordings Have No Sound

[Ian Barton]

belcampo wrote:
> Ian Barton wrote:
>> I have been transcoding stuff to h264 for months. However recently 
>> some transcodes are producing videos with no sound. I can't seem to 
>> find the reason for this. I am using ffmpeg built from svn. I have 
>> reverted to a version of ffmpeg that I know worked before with no luck.
>>
>> This happens even with different series recorded from the same 
>> channel, which I would expect to have the same video profile. Here is 
>> a sample showing my ffmpeg encoding and its output. I have tried 
>> tweaking the various audio output params to no effect:
>>
>> /usr/bin/nice -19 ffmpeg -y -i /home/mythmedia/1020_20091217095900.mpg 
>> -f mp4 -vcodec libx264 -r 30 -s 320x240 -qcomp 0.6 -qmin 11 -qmax 51 
>> -qdiff 4 -flags +loop -cmp +chroma -subq 7 -refs 6 -g 250 -keyint_min 
>> 25 -rc_eq "blurCplx^(1-qComp)" -sc_threshold 40 -me_range 12 
>> -i_qfactor 0.71 -directpred 3 -f mp4 -threads 4 -acodec libfaac -ar 
>> 22050 -ab 64k -ac 2 -async 1 -crf 26 -aspect 4:3 
>> /media/recordings/mythtv/pda/nokia/The_Outer_Limits_Last_Supper_2009-12-17_09-59.mp4 
>>
>>
>>
>> Input #0, mpeg, from '/home/mythmedia/1020_20091217095900.mpg':
>>   Duration: 00:30:44.04, start: 0.360000, bitrate: 1680 kb/s
>>     Stream #0.0[0x1e0]: Video: mpeg2video, yuv420p, 544x576 [PAR 24:17 
>> DAR 4:3], 15000 kb/s, 25 fps, 25 tbr, 90k tbn, 50 tbc
>>     Stream #0.1[0x1c0]: Audio: mp2, 48000 Hz, 1 channels, s16, 64 kb/s
>>     Stream #0.2[0x1c1]: Audio: mp2, 48000 Hz, 2 channels, s16, 128 kb/s
>> [libx264 @ 0x1549190]using SAR=1/1
>> [libx264 @ 0x1549190]using cpu capabilities: MMX2 SSE2Slow
>> [libx264 @ 0x1549190]profile Baseline, level 1.3
>> Output #0, mp4, to 
>> '/media/recordings/mythtv/pda/nokia/The_Outer_Limits_Last_Supper_2009-12-17_09-59.mp4': 
>>
>>     Stream #0.0: Video: libx264, yuv420p, 320x240 [PAR 1:1 DAR 4:3], 
>> q=11-51, 200 kb/s, 30 tbn, 30 tbc
>>     Stream #0.1: Audio: aac, 48000 Hz, 1 channels, s16, 64 kb/s
>> Stream mapping:
>>   Stream #0.0 -> #0.0
>>   Stream #0.1 -> #0.1
>> Press [q] to stop encoding
>> frame= 1509 fps= 70 q=28.0 Lsize=    2216kB time=60.05 bitrate= 
>> 302.3kbits/s
>> video:2160kB audio:17kB global headers:0kB muxing overhead 1.824322%
>> [libx264 @ 0x1549190]frame I:18    Avg QP:23.71  size:  6385
>>
>> Ian.
>> _______________________________________________
>> mythtv-users mailing list
>> mythtv-users at mythtv.org
>> http://mythtv.org/cgi-bin/mailman/listinfo/mythtv-users
> Maybe adding -map 0:0 -map 0:2 makes a difference ?
> This way you choose the second audio channel.
> _______________________________________________
>

Thanks that worked.

Ian.