[vlc] Re: [HOWARD JOHNSON <hwjohnso at adtran.com>] Dropping audio on high def clips

Tue May 17 19:42:43 CEST 2005

Jean,

Thanks for responding.  Yes it also happens on unicast.  And yes, the 
audio is enabled.  Every other "play" of the clip has the audio coming 
through on the client.

Best Regards,
Howard Johnson

Jean-Paul Saman wrote:

> Does this also occur in the case of using unicast?
>
> And could you check on the VLC client when this happens if the audio 
> is enabled? I have seen situations where VLC defaults to disabled 
> audio on looping.
>
> Greetings,
> Jean-Paul Saman.
>
> System administration wrote:
>
>> ----- Forwarded message from HOWARD JOHNSON <hwjohnso at adtran.com> -----
>>
>> From: HOWARD JOHNSON <hwjohnso at adtran.com>
>> Date: Wed, 11 May 2005 15:35:26 -0500
>> To: vlc at videolan.org
>> Subject: Dropping audio on high def clips
>> X-Spam-Status: No, score=1.2 required=5.0 tests=HTML_20_30,HTML_MESSAGE,
>>     HTML_TAG_EXIST_TBODY,HTML_TITLE_EMPTY,MAILTO_LINK,SIGNATURE_DELIM,
>>     SUPERLONG_LINE autolearn=no version=3.0.2
>>
>> I am having consistent, reproducible problems using VLC as server and 
>> client with streaming/playing a looped MPEG-2 high definition video clip
>>
>> with A/52 audio encoding.  In a nutshelI, when looping this type of 
>> video, every other iteration of the video looses sound for the entire 
>> length of the clip.  So the 1st, 3rd, 5th, 7th etc... iterations play 
>> fine for both audio and video but the 2nd, 4th, 6th etc... iterations 
>> play only the video.  It seems as though the problem is with the 
>> client.  If you stop the VLC client on an even number iteration and 
>> restart the client then both audio and video play.
>>
>> The first set of messages captured show the A/52 audio stream 
>> detected and the audio module a52 is selected.  The second set of 
>> messages shows what happens with the 1st iteration ends and the 2nd 
>> begins.  For some reason the audio stream is not detected.  And like 
>> I said, on the 3rd iteration, the client re-dectects the A/52 audio 
>> and loads the a52 module and then both audio and video play normally.
>>
>> The server is invoked as follows:
>>    "vlc Route_66.mpg  --sout-keep --loop --sout udp:224.1.1.1 --ttl 12"
>>
>> And the client is invoked as follows:
>>    "vlc -vout x11 --nofullscreen udp://@224.1.1.1"
>>
>> This anomaly is happening on two different client machines running 
>> vlc-0.8.1 but running different Linux distributions.
>>
>> Any ideas would be appreciated.
>>
>> main debug: looking for decoder module
>> main debug: probing 19 candidates
>> main debug: using decoder module "libmpeg2"
>> a52: A/52 channels:2 samplerate:48000 bitrate:384000
>> main debug: looking for audio output module
>> main debug: probing 4 candidates
>> main debug: thread 229386 (decoder) created at priority 0 
>> (src/input/decoder.c:157)
>> ts warning: first packet for pid=76 cc=0xf
>> ts warning: discontinuity received 0x3 instead of 0xc
>> alsa debug: opening ALSA device `default'
>> libmpeg2 debug: 1920x1088, aspect 768000, 29.971 fps
>> main warning: dts != current_pts (-2808074)
>> main debug: thread 245766 (aout) created at priority 0 (alsa.c:603)
>> main debug: using audio output module "alsa"
>> main debug: output 'fl32' 48000 Hz Stereo frame=1 samples/8 bytes
>> main debug: mixer 'fl32' 48000 Hz Stereo frame=1 samples/8 bytes
>> main debug: no need for any filter
>> main debug: looking for audio mixer module
>> main debug: probing 3 candidates
>> main debug: using audio mixer module "trivial_mixer"
>> main debug: input 'a52 ' 48000 Hz Stereo frame=1536 samples/1536 bytes
>> main debug: filter(s) 'a52 '->'fl32' 48000 Hz->48000 Hz Stereo->Stereo
>> main debug: looking for audio filter module
>> main debug: probing 22 candidates
>> main debug: using audio filter module "a52tofloat32"
>> main debug: found a filter for the whole conversion
>> main debug: filter(s) 'fl32'->'fl32' 52800 Hz->48000 Hz Stereo->Stereo
>> main debug: looking for audio filter module
>> main debug: probing 22 candidates
>> main debug: using audio filter module "bandlimited_resampler"
>> main debug: found a filter for the whole conversion
>> main warning: vout synchro warning: pts != current_date (-33355)
>> main warning: late picture skipped (-10547)
>> main debug: stream periodicity changed from B[1] to B[2]
>> a52 debug: emulated sync word (no sync on following frame)
>> main warning: buffer is 69723 in advance, triggering downsampling
>> ts warning: discontinuity received 0xb instead of 0x1
>> ts warning: discontinuity received 0xc instead of 0x8
>>
>> ...snip
>>
>> ts debug: PMTCallBack called
>> ts debug: new PMT program number=1 version=6 pid_pcr=78
>> ts debug:   * es pid=78 type=129 fcc=a52
>> ts debug:    * descriptor : unknown (0x5)
>> ts debug:    * descriptor : unknown (0xa)
>> main debug: unlocking module "a52"
>> main debug: thread 213001 joined (src/input/decoder.c:189)
>> main debug: killing decoder fourcc `a52 ', 49 PES in FIFO
>> main debug: unlocking module "a52tofloat32"
>> main debug: unlocking module "bandlimited_resampler"
>> main debug: thread 245766 joined (alsa.c:655)
>> main debug: unlocking module "alsa"
>> main debug: unlocking module "trivial_mixer"
>> main debug: unlocking module "libmpeg2"
>> main debug: thread 229386 joined (src/input/decoder.c:189)
>> main debug: killing decoder fourcc `mpgv', 60 PES in FIFO
>> ts debug: PMTCallBack called
>> ts debug: new PMT program number=1 version=7 pid_pcr=79
>> ts debug:   * es pid=78 type=129 fcc=a52
>> ts debug:    * descriptor : unknown (0x5)
>> ts debug:    * descriptor : unknown (0xa)
>> ts debug:   * es pid=79 type=2 fcc=mpgv
>> main debug: looking for decoder module
>> main debug: probing 19 candidates
>> main debug: using decoder module "libmpeg2"
>> main debug: thread 262150 (decoder) created at priority 0 
>> (src/input/decoder.c:157)
>> ts warning: first packet for pid=78 cc=0xf
>> ts warning: discontinuity received 0x2 instead of 0xb
>> libmpeg2 debug: 1920x1088, aspect 768000, 29.971 fps
>> main warning: dts != current_pts (-2807333)
>> main warning: late picture skipped (74948)
>> main warning: vout synchro warning: pts != current_date (-33355)
>> main debug: stream periodicity changed from B[1] to B[2]
>> main debug: stream periodicity changed from P[5] to P[4]
>> main debug: decoded 70/105 pictures
>>
>>  
>>
>

-- 
This is the vlc mailing-list, see http://www.videolan.org/vlc/
To unsubscribe, please read http://www.videolan.org/support/lists.html