mplayer dvb dies after varying amounts of time

LeftyAce · 2015-01-28 05:41:45

Hi all,

I have a Hauppage WinTV 950Q usb tv tuner, and I use mplayer to watch broadcast TV:

mplayer -vo xv -framedrop -cache 8192 dvb://"CBS"

This works for between 2 and 30 minutes, but it inevitably fails. I start getting messages like this:

Cache empty, consider increasing -cache and/or -cache-min. [performance issue]
dvb_streaming_read, attempt N. 5 failed with errno 0 when reading 3260 bytes
dvb_streaming_read, attempt N. 4 failed with errno 0 when reading 1944 bytes
Cache empty, consider increasing -cache and/or -cache-min. [performance issue]
dvb_streaming_read, attempt N. 6 failed with errno 0 when reading 16260 bytes
dvb_streaming_read, attempt N. 5 failed with errno 0 when reading 15320 bytes
dvb_streaming_read, attempt N. 4 failed with errno 0 when reading 14944 bytes
dvb_streaming_read, attempt N. 3 failed with errno 0 when reading 14192 bytes
dvb_streaming_read, attempt N. 2 failed with errno 0 when reading 14004 bytes
dvb_streaming_read, attempt N. 1 failed with errno 0 when reading 13440 bytes

Apparently the cache is empty. Since this is a live broadcast, should I have (or need) a cache? Is there any way to force mplayer to just give up and move on when it loses a frame or two? (I thought that's what the -framedrop option was doing).

If I quit mplayer and restart it immediately, sometimes it works right away, other times I have to try a few times before it "catches." When it works right away, that means the signal is still there, right?
I've tried looking at the signal strength using femon -H, and here's what I get:

status SCVYL | signal  71% | snr   0% | ber 0 | unc 0 | FE_HAS_LOCK

The signal never moves from around 70%, at my house or if I take the whole setup over to a friend's house who lives really close to the TV towers. The SNR is always 0% (that doesn't seem accurate).

Any ideas why it dies?

Thanks,

Lefty

Darksoul71 · 2015-01-28 10:06:18

Hi there,

despite the cache message this really rather looks like your DVB devices stops working. I get similar messages from mplayer, when I have signal issues with my DVB-S2 box during heavy snow fall or rain.

I would take a closer look to your kernel log. Perhaps you see something suspicious. To my understanding a buffer usually is always needed for any access to devices / files simply because of the fact that reading and processing the date takes it time. It would be also interesting what happens, when you do not watch live broadcast but record it to file (-dumpstream -dumpfile <myfile.ts>).

HTH,
D$

LeftyAce · 2015-01-28 16:39:12

Thanks for the reply, Darksoul.

I know a buffer is always required, but mplayer's suggestion that I increase the cache size doesn't make sense, that seems like it would help if I had an unreliable stream AND I could request re-transmission of missed frames (so the cache would insulate me from that). In this case I can't request retransmission of missed information, so once it's gone it's gone, how does a larger cache help me?

Where should I go to look at these kernel logs? My /var/log folder contains no new information from the past few days (based on timestamps and ls -t).

Darksoul71 · 2015-01-29 06:47:43

You can typically get the last kernel messages / kernel ring buffer by typing dmesg in a terminal.
I would expect that you see at least some messages, when a hardware issue causes your DVB device to lock up.
But unfortunately sometimes nothing is logged although things go wrong.

In regard to the buffer / cache suggestion from mplayer, I would simply ignore this hint so far. An increase of the buffer / cache size usually helps when you have some performance issues different from a DVB device.

For example like in my case where I use SMPlayer to play back HD videos from an NTFS partitioned external HDD and (for some reason) get micro stuttering although enough resources are available. When I increase the buffer, those stutters go away.

Last edited by Darksoul71 (2015-01-29 08:36:18)

Arch Linux

#1 2015-01-28 05:41:45

mplayer dvb dies after varying amounts of time

#2 2015-01-28 10:06:18

Re: mplayer dvb dies after varying amounts of time

#3 2015-01-28 16:39:12

Re: mplayer dvb dies after varying amounts of time

#4 2015-01-29 06:47:43

Re: mplayer dvb dies after varying amounts of time

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