104 replies to this topic

[dweeb4]

As you all probably know, the 500 is weak in doing direct recording to external mounted disk - the recorded file has errors which can easily be seen if you run MPEG2Repair against the file. These errors can show as video or audio glitches when viewing the recording on the box. Other Dreambox models don't have this problem it is specific to the 500.

One method of minimising these errors is to use an image which allows display to be turned off during recording - below I include summary results of files recorded with display on & off. Although not completely error free the recording with display off is far better than with display on.

Anyway, up to now the only Enigma based image that had the display off option was the Punt@l image (which I never got working). Neutrino images seem to have had this option for a while. Now, the new Gemini V4.0 image has this option.

Why am I saying all this? Well I believe the PLi Helenite image would be near perfect if it included this feature. So this is just an attempt to try & get it included in the next release

"Display ON" recorded file analysis

File Size Processed: 834.71 MB, Play Time: 00h:31m:31s
720 x 576, 25.00 fps, 15.00 Mbps (3.13 Mbps Average).
Average Video Quality: 15.28 KB/Frame, 0.30 Bits/Pixel.
MPEG Audio.
256 of 47276 video frames found with errors.
0 of 0 audio frames found with errors.
166515 corrupted video bytes in file.

"Display OFF" recorded file analysis

File Size Processed: 706.17 MB, Play Time: 00h:26m:50s
720 x 576, 25.00 fps, 15.00 Mbps (3.11 Mbps Average).
Average Video Quality: 15.16 KB/Frame, 0.30 Bits/Pixel.
MPEG Audio.
9 of 40273 video frames found with errors.
0 of 0 audio frames found with errors.
19755 corrupted video bytes in file.

[dweeb4]

Here's another factor which might influence the direct recording quality on the 500 - "Neutrino also stops sections_sd while recording. I wonder if the Enigma based images could learn another trick there?"

[bib6666]

This is very interesting.
Some days ago i tested Pli Helinite, great image, but i had some problems in recoding (freezes, blocks)
I had in flash an "old" Gemini 3.20 and recording with cifs is fine, i tested Gemini 3.60 and even 4.00 (without the option to turn off the display, i did'n t kwon that) end recording in not fine... I have a Dm500 with Alps tuner

However i agree with you, Pli is very good best image(perhaps the best if you have not to record on pc), hope it will be fixed the problem in recording with lan..
I also noticed (but not sure )that the image quality (component out) of helinite is perhaps better than last Gemini 400

[dweeb4]

Good to hear somebody else's findings in this area.

As there have been 92 views but only your response, I might just start another thread to poll other PLi users experince with direct recording?

Edit: interesting Bib, that you say Gemini 3,20 recordings were error free! Are you sure these were direct recordings & done in the same way as your later Gemini images which were not error free?

[hemispherical1]

I used to run Gemini 6+ months ago and it seemed to provide better recording results. There was some pixelation, but the quality was better than most images I have tried recording with. I don't record often, but when I do, I've decided I have better luck using ngrab (actually sserver as I run Linux), than recording over cifs. I still see errors, but not nearly as many as recording directly to a share...

--
hemi

[bib6666]

Good to hear somebody else's findings in this area.

As there have been 92 views but only your response, I might just start another thread to poll other PLi users experince with direct recording?

Edit: interesting Bib, that you say Gemini 3,20 recordings were error free! Are you sure these were direct recordings & done in the same way as your later Gemini images which were not error free?

Well.. I did only a few tests, but the conditions were the same(direct recording started with timer)
Recording with Gemini 3.20 are not 100% errors free (MPEG2Repair found errors) but not noticeable when viewing recorded files ( some very little pixelation, let's say 1 or 2 during one hour recording but not always), and only when recording channels with very high bitrate.
i have not tried Gemini 3.3, 3.4 and 3.5 images

[dispatcher]

With PLi-Helenite Final on a DM500 I've just been busy (a few days ago) trying to record error Free on a CIFS share. But with no succes. The errors are plentyful, especially with high bitrate channels. Ofcourse I tried different settings, but none worked satisfactory.

That's why I'm using NGrab still. Not completely reliable, but at least one can record with it without (seeing) errors.

I would greatly appreciate an option in the next PLi release that disables the display while recording. And maybe the stopping of sections_sd while recording would also be a good addition (not sure here, because I only have experience with PLi images).

Apart from this issue I'm quite satisfied with PLi Helenite.

[th_gates9345]

Best video recording I've got was with old Pi2 image. No pixelation.

[bib6666]

Best video recording I've got was with old Pi2 image. No pixelation.

I see that you have a NAS disk.. Is there differences in recording quality between a Cifs mount on pc Hdd and a smbfs mount?
Thanks

[quilmore]

PLi Garnett was very good at recording
I've used it extensively and it always record to my share folder in a windows XP machine no problem
yes, some minor pixelation every now and then but nothing of importance

[th_gates9345]

I see that you have a NAS disk.. Is there differences in recording quality between a Cifs mount on pc Hdd and a smbfs mount?
Thanks

My first mounting for this image was cifs on a pc, now I only can get Samba on the landisk. I saw pixelation on PC mounting but I can't tell you exactly wich one has more.

[bib6666]

My first mounting for this image was cifs on a pc, now I only can get Samba on the landisk. I saw pixelation on PC mounting but I can't tell you exactly wich one has more.

Thanks!

[dweeb4]

Thanks for the replies, guys - it looks like I'll be trying server based recording if I can get it working to transport stream file recording instead of mpg files.

Can Ngrab do this does anyone know? I know that VLC can

[hemertje]

transport streams are mpg streams

[AriSuu]

I had a better recording when I killed gSUB before recording started. If running, it seems to do
something now and then which causes pixelation into recording. The older version of gSUB had
an option "suspend during recording" (or something) but this newer version doesn't have it.
Of course, everyone doesn't have to run gSUB at all.

Everyone seems to experiment with different wsize mount options, I did this before
but didn't get good recording (but that time I had not realized that gSUB is doing
something fishy....). I'll have to try again.

[th_gates9345]

I had a better recording when I killed gSUB before recording started.

What is gSUB? How do you kill it? Thanks.

[AriSuu]

I had a better recording when I killed gSUB before recording started.

What is gSUB? How do you kill it? Thanks.

gSUB is a plugin which displays subtitles.

[Sjaaky]

I checked some of my recordings with mpeg2repair.

Recording 1: (Pli Diamond)

File Size Processed: 1.84 GB, Play Time: 01h:00m:10s
704 x 576, 25.00 fps, 10.00 Mbps (3.75 Mbps Average).
Average Video Quality: 62.61 KB/Frame, 1.26 Bits/Pixel.
MPEG Audio.
238 of 26386 video frames found with errors.
0 of 0 audio frames found with errors.
237465 corrupted video bytes in file.

0,013% corrupted bytes; 0,9% frames with errors which is an error every 4 seconds. During playback I can see errors ones in a while , say ones a minute, but certainly not every 4 second. So although it contains errors, it's not that bad while viewing.

Recording 2: (Pli Helenite)

File Size Processed: 1.99 GB, Play Time: 01h:10m:53s
704 x 576, 25.00 fps, 10.00 Mbps (3.40 Mbps Average).
Average Video Quality: 16.60 KB/Frame, 0.34 Bits/Pixel.
MPEG Audio.
1 of 106341 video frames found with errors.
0 of 0 audio frames found with errors.
116 corrupted video bytes in file.

The video frame with the error is the last one, so this recording is flawless.

Recording 3: (Pli Helenite)

File Size Processed: 4.00 GB, Play Time: 01h:52m:53s
720 x 576, 25.00 fps, 15.00 Mbps (4.01 Mbps Average).
Average Video Quality: 19.62 KB/Frame, 0.39 Bits/Pixel.
Unknown Audio.
444 of 169059 video frames found with errors.
0 of 0 audio frames found with errors.
785089 corrupted video bytes in file.

0,019% corrupted bytes; 0,3% Frames with errors, but this recording has higher bitrates.

I don't trust the average video quality given by mpeg2repair. Given the playtime and filesize of recording 1 and 2, the quality should be about the same, which is backed by watching network troughput while watching the recordings in vlc on my pc. But mpeg2repair reports an almost 4x better avg video quality. 62KB/frame => 12 Mb/s, which is certainly not true.

I believe recordings will get better when tv output is disabled, because 2 filters on the same pid can put more strain on the demux. But when I stream with zapstream it is nearly perfect, so why can't a recording be just as good? Sure there's some overhead in cifs, but that should be no problem. I think there are some weak points in the recording code of enigma, but I have yet to find some time to improve it.

[quilmore]

Recording 1: (Pli Diamond)

which one is PLi Diamond?

Recording 2: (Pli Helenite)

File Size Processed: 1.99 GB, Play Time: 01h:10m:53s
704 x 576, 25.00 fps, 10.00 Mbps (3.40 Mbps Average).
Average Video Quality: 16.60 KB/Frame, 0.34 Bits/Pixel.
MPEG Audio.
1 of 106341 video frames found with errors.
0 of 0 audio frames found with errors.
116 corrupted video bytes in file.

The video frame with the error is the last one, so this recording is flawless.

how did you get a that recording?

[Sjaaky]

which one is PLi Diamond?

I don't know what you mean, but Pli Diamond is an old image and the first recording was done with Pli Diamond.

how did you get a that recording?

I always put the next lines in my rcS. The reason I put them there is not because it's better for performance, but because it's easier for me to prepare an image after I installed it with flash wizard pro.

echo 50 > /proc/sys/vm/dirty_writeback_centisecs
echo 200 > /proc/sys/vm/dirty_expire_centisecs

#extra cifs options
rmmod cifs
insmod /lib/modules/2.6.9/kernel/fs/cifs/cifs.ko CIFSMaxBufSize=64000

#mount /hdd
mount -t cifs -o user=jack,pass=pw,rsize=8192,wsize=8192,nobrl,forcedirectio //192.168.1.6/hdd /hdd

#mount dvds
mount 192.168.1.6:/mnt/dvd /hdd/dvd -o rw,soft,udp,nolock,rsize=4096,wsize=32768

I haven't done any benchmarks with CIFSMaxBufSize, dirty_writeback_centisecs or dirty_expire_centisecs, these are just some numbers I thought would be better. High bitrate recordings still contain errors, so I don't have the ultimate fix.