Codec troubleshooting procedure

[dmegatool]

I have some problems with DVDs that I encode with Handbrake OSX (h264 - AAC). They play pretty well with the 2 audio track being recognize but I sometimes get bad keyframes or something. I get artifacts at some points and they go away when a new scene is shown. It happened 4 times on a 2h20 movie.

The videos plays perfect in every other player (VLC, Quicktime, WMP). I'm trying to figure out what it causing this and how to solve it.

What's the procedure to troubleshoot something like this ?

I changed the h264 codec within Sage audio / video menu and they all do the same thing. Only Arcsoft decoder gave me different artifacts (a little bit less but included green squares). I tried CoreAVC / Cyberlink 8 / Arcsoft / FFDShow MPEG-4.

[dmegatool]

More infos :

I tried "SageTV Player" instead of DirectShow and the video plays perfectly. But the audio isn't... at all.

My videos have 2 audio track, english and french version. Both encoded in AAC. The SageTV Player seems to be ignoring a track or whatever cause the track labeled english is silent and the one labeled french plays the english track...

[Taddeusz]

Do you have a particular reason for converting the audio? What happens if you do an AC3-passthrough of the audio rather than converting it to AAC?

What version of Handbrake are you using? You may give one of the daily builds a try. At least on Windows they have become quite a bit better as far as H.264 standards than 0.9.4 is.

[dmegatool]

Originally Posted by Taddeusz

Do you have a particular reason for converting the audio? What happens if you do an AC3-passthrough of the audio rather than converting it to AAC?

What version of Handbrake are you using? You may give one of the daily builds a try. At least on Windows they have become quite a bit better as far as H.264 standards than 0.9.4 is.

I'm using 0.9.4

As for AC3 vs AAC... I don't have particular reason. I'm not really obsess on the audio quality. An AAC/160kpbs is fine enough for me so it keep the file size a little bit smaller. At least I think so. I think I'll give the AC3 a spin to see what happen.

Meanwhile, I've found a solution... kind of. If I use more keyframe, the problem go away. I tried the parameter keyint=12 and it worked perfectly. At 24, the glitch was still there but lasted only for a fraction of a second.

EDIT: Just tried the AC3 Passthrough and I get the same bug. English track's empty and french's playing the english track.

[Taddeusz]

Originally Posted by dmegatool

I'm using 0.9.4

As for AC3 vs AAC... I don't have particular reason. I'm not really obsess on the audio quality. An AAC/160kpbs is fine enough for me so it keep the file size a little bit smaller. At least I think so. I think I'll give the AC3 a spin to see what happen.

Meanwhile, I've found a solution... kind of. If I use more keyframe, the problem go away. I tried the parameter keyint=12 and it worked perfectly. At 24, the glitch was still there but lasted only for a fraction of a second.

EDIT: Just tried the AC3 Passthrough and I get the same bug. English track's empty and french's playing the english track.

What do you mean by key frames? H.264 doesn't have key frames. At least as far as the Handbrake settings are concerned it has only reference frames and B-frames. Reference frames should be kept reasonable. While, depending on the H.264 level you're shooting for you can have an insanely high number of reference frames a lot of decoders have trouble with those videos because they are more processor intensive to decode. It's best to keep the reference frames to a sane level such as 3 or 4. B-frames are the same. They should be kept to about 3 or 4. Unless you're shooting for just completely insane quality but even then you start hitting a wall of negative returns. You spend more processing time cranking on the video while giving you less improvements in quality.

Correction: I realized after I posted that H.264 does in fact have key frames. Handbrake doesn't directly expose those settings. You have to put those in as custom settings. By default I believe Handbrake sets the key frame interval to the frame rate of the video.

[dmegatool]

Originally Posted by Taddeusz

Correction: I realized after I posted that H.264 does in fact have key frames. Handbrake doesn't directly expose those settings. You have to put those in as custom settings. By default I believe Handbrake sets the key frame interval to the frame rate of the video.

Exactly. That's what keyint is.

As for the default, I didn't find anything about it. Seems like it's even bigger than the frame rate video because the artifacts lingers for several seconds. If I manually set it to 24, it's wayyyy shorter.

I tried other settings to see if it would make any difference without success. I turned off B-Frames, Reference frames, CABAC, ... I didn't change anything.

[Taddeusz]

Originally Posted by dmegatool

Exactly. That's what keyint is.

As for the default, I didn't find anything about it. Seems like it's even bigger than the frame rate video because the artifacts lingers for several seconds. If I manually set it to 24, it's wayyyy shorter.

I tried other settings to see if it would make any difference without success. I turned off B-Frames, Reference frames, CABAC, ... I didn't change anything.

Ok, just looked at one of my videos. Yes, Handbrake uses the framerate to set keyint and keyint_min. Basically keyint becomes 10xframerate and keyint_min becomes the framerate. So I suppose that H.264 actually uses variable key framing. Which is probably determined by the I, P, and B frames being used.

I would highly recommend trying the latest Handbrake daily. The latest videos I have created with build 3380 have no problems during playback. The ones I created under 0.9.4 will not play properly on my SageTV Client and actually give me a black screen.

[dmegatool]

Originally Posted by Taddeusz

I would highly recommend trying the latest Handbrake daily. The latest videos I have created with build 3380 have no problems during playback. The ones I created under 0.9.4 will not play properly on my SageTV Client and actually give me a black screen.

Never thought it could make such a difference. I'll give it a try today and see what happen. Thanks for the suggestion.

[dmegatool]

Just tried the latest build (3429). It's a better but still glitchy.

How do I use graphEdit to see what Sage is using ? I've seen a lot of people use it to troubleshoot. I can open the file directly and I can see what is being use. What about Sage ? Can I see what is being used to decode ?

[Taddeusz]

Originally Posted by dmegatool

Just tried the latest build (3429). It's a better but still glitchy.

How do I use graphEdit to see what Sage is using ? I've seen a lot of people use it to troubleshoot. I can open the file directly and I can see what is being use. What about Sage ? Can I see what is being used to decode ?

The best way to do that is to enable the debug log. I don't remember the lines off the top of my head but in the log when you play a video it will give you a rundown of all the DX filters used. However, the difference is generally that SageTV likes to force it's own splitter in the graph rather than using the system default.

I don't believe I've asked but what version of SageTV are you running and what version of Windows?

[dmegatool]

I'm on Windows 7 and Sage beta 7 (.09)... I know that 0.11 is out so maybe I should get it.

I can't tell if it was working on V6.

[Taddeusz]

Originally Posted by dmegatool

I'm on Windows 7 and Sage beta 7 (.09)... I know that 0.11 is out so maybe I should get it.

I can't tell if it was working on V6.

Since you're on Windows 7 have you tried the Microsoft Decoder? At least between it and the Arcsoft decoder I've found that it is the most compatible. I've had very few problems using it. And in fact have had quite a few problems when I've selected to use Arcsoft.

Also, what settings are you using? What video renderer and audio decoder are you using? For Windows 7 EVR is the best as it's going to give you hardware acceleration for both MPEG2 and H.264 video. I can't recall off the top of my head which I'm using but I can recommend either the Microsoft audio decoder or AC3Filter. For the AAC audio you also want to make sure you have a good dx filter, but I believe that as of Windows 7 you get one "out of the box."

[dmegatool]

Originally Posted by Taddeusz

For Windows 7 EVR is the best as it's going to give you hardware acceleration for both MPEG2 and H.264 video.

EVR doesn't work well for me. The video skip some frames every 5 seconds or so. It's annoying as hell. Overlay works the best for me.

That's sad cause with EVR, playing a HDPVR file, I get around 3% of CPU usage. With overlay and CoreAVC, it's around 40%.

[Taddeusz]

First, you should upgrade to the latest beta version.

Also, what video card are you using and are you running the latest drivers?

[Taddeusz]

Originally Posted by dmegatool

EVR doesn't work well for me. The video skip some frames every 5 seconds or so. It's annoying as hell. Overlay works the best for me.

The only place I ever notice any kind of jumpiness is when playing HDPVR recordings. Everything else plays smooth.