sound dropouts with DVB

sound dropouts with DVB

[pinguin74]

Hello,

I use a Sundtek DVB-C stick with openSUSE 13.1 Linux.

Most of the time, TV is just fine. But sometimes the sound just drops
out, the sound disappears totally for up to 20 or 30 seconds. Usually
sound returns. When sound drops out, there is no error message.

Generally sound is fine, I use pulseaudio with KDE. The sound drop out
happens only when watching TV.

Is this a know issue with DVB? What could be the reason for the
dropouts? The DVB-C signal is strong, usually 100%.

Would be nice to get a hint.

Re: sound dropouts with DVB

[Markus Rechberger]

Hi,

On Thu, Mar 6, 2014 at 10:48 PM, pinguin74 <pinguin74@gmx.com> wrote:
> Hello,
>
> I use a Sundtek DVB-C stick with openSUSE 13.1 Linux.
>
> Most of the time, TV is just fine. But sometimes the sound just drops
> out, the sound disappears totally for up to 20 or 30 seconds. Usually
> sound returns. When sound drops out, there is no error message.
>
> Generally sound is fine, I use pulseaudio with KDE. The sound drop out
> happens only when watching TV.
>
> Is this a know issue with DVB? What could be the reason for the
> dropouts? The DVB-C signal is strong, usually 100%.
>

If you use mplayer, mplayer will show you if there's some stream corruption.
Other than that it could only be a codec issue.

Markus
> Would be nice to get a hint.
>
> --
> To unsubscribe from this list: send the line "unsubscribe linux-media" in
> the body of a message to majordomo@vger.kernel.org
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Re: sound dropouts with DVB

[pinguin74]

>> Most of the time, TV is just fine. But sometimes the sound just drops
>> out, the sound disappears totally for up to 20 or 30 seconds. Usually
>> sound returns. When sound drops out, there is no error message.
>>
> If you use mplayer, mplayer will show you if there's some stream corruption.
> Other than that it could only be a codec issue.

I will try with mplayer later. What does codec issue mean? I think the
audio stream in DVB-C is a digital stream that does not need to be
changed or encoded in any way? I thought DVB playback simply is a kind
of pass thru the digital streamt to the media player....

Re: sound dropouts with DVB

[Markus Rechberger]

On Fri, Mar 7, 2014 at 12:19 AM, pinguin74 <pinguin74@gmx.com> wrote:
>>> Most of the time, TV is just fine. But sometimes the sound just drops
>>> out, the sound disappears totally for up to 20 or 30 seconds. Usually
>>> sound returns. When sound drops out, there is no error message.
>>>
>> If you use mplayer, mplayer will show you if there's some stream corruption.
>> Other than that it could only be a codec issue.
>
> I will try with mplayer later. What does codec issue mean? I think the
> audio stream in DVB-C is a digital stream that does not need to be
> changed or encoded in any way? I thought DVB playback simply is a kind
> of pass thru the digital streamt to the media player....
>
>

The mediaplayer is using a codec for decoding/unpacking the compressed
digital stream.

Markus


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> To unsubscribe from this list: send the line "unsubscribe linux-media" in
> the body of a message to majordomo@vger.kernel.org
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Re: sound dropouts with DVB

[pinguin74]

Am 07.03.2014 00:36, schrieb Markus Rechberger:

>> I will try with mplayer later. What does codec issue mean? I think the
>> audio stream in DVB-C is a digital stream that does not need to be
>> changed or encoded in any way? I thought DVB playback simply is a kind
>> of pass thru the digital streamt to the media player....
> 
> The mediaplayer is using a codec for decoding/unpacking the compressed
> digital stream.

Oh yes, of course. Is this not also called "demuxing"? Or is demuxing
just the splitting of the stream?

I found out this may be an issue with the snd-hda-intel module.

When I use a different model option for this module, the siutation
changes, at least the bluetooth headphone does not lose connection, but
audio still drops out.

MPlayer reports I and B frame errors, but DVB works.

I now use
modprobe snd-hda-intel model=acer-aspire align_buffer_size=128000

I will try out VLC now with DVB to see if the VLC codecs work better
than Xine/kaffeine.

Thanx.

Re: sound dropouts with DVB

[pinguin74]

> The mediaplayer is using a codec for decoding/unpacking the compressed
> digital stream.

Oh, I just see my TV provider sends two video streams for each channel,
a H264 encoded video stream and an MPEG2 video stream, both in each
channel.

No matter if a channel is HD or not, there is always a H264 stream and
an MPEG2 video stream.

But I have no clue how to tell Xine or VLC to play either the H264
stream or the MPEG2 stream....

Thanks