Fixing HEVC based TS file

Begonnen von freebits, September 15, 2015, 18:29:04

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freebits

#15
Thank you so much, Cypheros. It's been working great for several large recording files.

But I have additional questions about TS-Doctor before buying it.

1. Can I skip audio detail scan? It takes very long time to scan PCR switching position and audio scan adds additional time to get the final fix if the recording is very long? It would be best if another option to on/off the audio detail scan is added so I can save some time fixing the recordings.

2. Auto cut does not work? We have some midprogram advertisings in the UHD channel but TS-Doctor doesn't ask if I'd like to cut them automatically or not. I think the problematic TS sample I shared had also the commercial for your test.

Thanks!

Cypheros

Hi, audio scan is needed to find changes in the format to detect commercials.

Commercials are detected with different methodes like audio or video format changes. Not every channel has such format changes. But we are working on a new version using video analysis to detect video changes and channel logos to distinguish movies from commercials.

Djfe

is it desired behaviour, that a dialogue is shown, that has to be ignored?

or is this case unlikely in comparison and there is no other way to show the right dialogue first?

Cypheros

That would break other fixes. Sometimes streams are so scrambled or damaged, it's better to stop processing such files in an early stage.

freebits

#19
Thank you.

Understood your point.

Btw, I see some recordings fixed by TS-Doctor have slight audio sync issue (Audio is slightly faster than video) and some are good in sync.

This fix does not touch anything regarding to Audio sync stuff and is it purely because of recording error or signal strength when audio is out of sync?

Cypheros

The fix doesn't change the synch because all timers (audio, video, subtitles, etc. ) are changed with the same value. Most sync problems are caused by errors during remuxing to other container formats like MKV, MP4, ...
If you have a transport stream with lost packets due to reception problems, remuxers tend to ignore missing audio parts and you'll get an audio stream that is shorter that the video stream. That causes the sync problems. As you stay with transport stream format, any part of the stream has it's own timers to keep audio and video in sync, even if some audio or video packets get lost during transmission.

freebits

Zitat von: Cypheros am September 19, 2015, 19:15:39
The fix doesn't change the synch because all timers (audio, video, subtitles, etc. ) are changed with the same value. Most sync problems are caused by errors during remuxing to other container formats like MKV, MP4, ...
If you have a transport stream with lost packets due to reception problems, remuxers tend to ignore missing audio parts and you'll get an audio stream that is shorter that the video stream. That causes the sync problems. As you stay with transport stream format, any part of the stream has it's own timers to keep audio and video in sync, even if some audio or video packets get lost during transmission.

Thank you.

I meant the fixed TS stream not the remuxed mkv or mp4.
I thought the attached log is from the relative very clean TS recording and I saw audio is slight ahead of video during the whole play.

Can the delay below found in the log affect the audio/video sync?

Video PCR to PTS difference -912 ms
$01A1: Delay to video stream = -494ms

Can I add audio delay in millisecond when cutting/fixing the file to have better sync?

Mam

Zitat von: Cypheros am September 19, 2015, 19:15:39
any part of the stream has it's own timers to keep audio and video in sync, even if some audio or video packets get lost during transmission.
It would not a too bad idea for the Doctor to insert dummy (silence) audio packets as fillers during the "repair run"... Many many reported problems would have been vaporized instantly. This is not too complicated for MPEG and Dolby tracks, AAC and MP3 are not so easy to handle because they are compressed.
But for the people it would be enough to be able to keep an MPEG track in synch whiles losing an AAC one. Better ANY working track than NONE...

Derrick

ZitatThis is not too complicated for MPEG and Dolby tracks, AAC and MP3 are not so easy to handle because they are compressed.
All types you've enumerated are compressed  8)

freebits

Cypheros,

Another observation is I don't get message like 'PCR error is detected and you can "Virtually cut and reopen' in a larger recordings.

The only files that I got such message was rather smaller recordings like 1gb or so.

When I get the message?

Mam

Zitat von: Derrick am September 20, 2015, 00:10:52
All types you've enumerated are compressed  8)
Sometimes people mix up "multiplexed" or "encoded" with "compressed"...


Cypheros

Zitat von: freebits am September 20, 2015, 04:36:43
Another observation is I don't get message like 'PCR error is detected and you can "Virtually cut and reopen' in a larger recordings.
When I get the message?

At the beginning of the analysis the start an the end of the file is checked for PCR erratic fluctuations. I guess the problem file has commercials at the start or end, where many PCR jumps are detected.

freebits

Okay. Then can I adjust the audio delay from the fixed recording?

Cypheros

The delay between audio and video you can find in the log is no error, that's OK for transport streams. It will be automatically corrected during playback.

I checked your samples and audio video sync is OK. Please be aware that playback of UHD will bring your computer to the limits. If CPU usage is at maximum, the system is not able to keep audio and video in perfect sync.
Try to playback with a H.265 capable hardware decoder like Samsung UHD TV and you'll see that audio and video is in sync.

freebits

Zitat von: Cypheros am September 21, 2015, 14:27:40
The delay between audio and video you can find in the log is no error, that's OK for transport streams. It will be automatically corrected during playback.

I checked your samples and audio video sync is OK. Please be aware that playback of UHD will bring your computer to the limits. If CPU usage is at maximum, the system is not able to keep audio and video in perfect sync.
Try to playback with a H.265 capable hardware decoder like Samsung UHD TV and you'll see that audio and video is in sync.

I test those clips via 4K UHD media player supporting hw acceleration of HEVC stream and saw the audio sync issue from it. Anyway, will test it again after remuxing it with some delay using ffmpeg or so..


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