Johannes,

MLT can not use that patch because it relies upon FFmpeg to do the demuxing, whereas gmerlin-avdecoder provides its own. There was a guy named Ivan Schreter who submitted a lot of patches towards improving AVCHD in FFmpeg. The comments by ArtInvent reflect that effort. I recently updated FFmpeg to a June snapshot on one of my machines, and I agree it is working much better - usually good enough. However, Ivan's last patch basically overhauls the seeking in FFmpeg and will require updating many of the FFmpeg components (demuxers and decoders). Therefore, it was not accepted yet, and he has lost interest.

I might someday provide a gmerlin-avdecoder backend in MLT. MLT can use multiple backends at the same time. However, first, I have to get it (gmerlin) working and evaluate it. So far, I have been failing. I mean I get something to work, but with very little encoded audio/video support. Needs more time, but I might reject it if I feel it will be more trouble than its worth.

Ultimately, Kdenlive is not the only project interested in AVCHD with accurate seek support in FFmpeg. So, just because I am not willing to work on it at the moment does not mean no one is. Also, buying me a AVCHD camera does mean I can drop everything else related to MLT and Kdenlive just to work on better AVCHD. There are other important bugs and the needs of the distro packagers that I must address as well - not to mention a better deinterlacer. Unfortunately, I am getting little time for much else at the moment. That's really the crux of the problem for me. To address this would require so much reading of the specs and analysis that in order to stay focused on that, I can really only do that.

I can see much activity on the FFmpeg devel mailing list about AVCHD and I am sure a better support will be achieved quickly.

Hi Dan,

I haven't lost interest, I just got a baby daughter :-). So I don't have time to work on it now. I'm still following the development, though. I've already tried some modifications in MPEG-TS code in order to support seeking properly, however, my efforts so far have failed to achieve workable results, so I didn't post it anywhere.

But I see that Baptiste from FFmpeg group is working now somewhat more intensively on MPEG-TS and H.264 (although in different area), so I'm thinking of getting in touch directly with him.

Regards,

Ivan

Baptiste wrote me privately that he would like to work on hardware decoding also. He thinks this is achievable. So don't hesitate to discuss this issue too ...

@ddennedy: I totally understand you. I am myself a software developer, although in a completely different field and regularly get requests for things that cannot be (easily) done. I just wnated to make sure I had undrstood right what was going on. If I can summarize, it currently looks like this:

- Someone is trying to make VDPAU work in ffmpeg, which would automatically translate into it also working in MLT and kdenlive. This would mean that most people with a modern NVIDIA card would be able to playback and use AVCHD at native speed.

- Someone else might be looking at better software rendering which would include something called PTS/DTS and which would make huge changes to the entire ffmpeg source tree. This should help the rest.

(The presentation of the second point clearly shows I have no clue what I'm talking about.)

Now I was currently looking into buying a new notebook to be able to edit the video, as my current Macbook seems to be too slow for anything. It's one of those using the Intel rather an NVDIA card. But then it hit me: when I run it in Mac OS X and use Final Cut somehow the machine can play the AVCHD footage in the preview window before I even import it into Final Cut (it converts it to Apple's native format during import). First I thought it would just be doing some tricks whereby it would use the camera to play it back, but the same also works if I import from a copied BDMV-folder on an external harddrive.

So I guess my question is this: Is most of the notebook-hardware upgrade we all seem to have to go through now rather pointless in light of it just being the current iteration of ffmpeg/the software that makes it go so slow? Would one expect that once the DTS/PTS stuff goes into ffmpeg, that it will have the same playback quality/speed as the preview of Final Cut on Mac OS X?

from my point of view, it's not a good thing to link fonctionnality and particular hardware ...

nyme

Hi,

for the very brave, my pre-pre-alpha patches for head FFmpeg and head MLT to edit AVCHD files directly in kdenlive (frame-exact seeking support).

Note: current MLT patch will most probably break (at least some of) other formats.

I've tested it with files from my camcorder (Panasonic), other camcorders may have issues (e.g., I know Canon has some issues, so your mileage may vary).

Regards,

Ivan

This is great, thanks!

>> Why don't we just all pitch in and buy Dennedy a new camcorder? :)

> However, I would be willing to pitch €100 towards a AVCHD camera for Dan, if he thinks it will improve
> his motivation for working with AVCHD. Note: one can't ask him to commit to this, only ask if he thinks it will help!

I would also pitch €100 toward such a cause.

@johanneswilm : mlt framework moved to git at http://mltframework.org/gitweb/mlt.git

do not use svn any more, now the current stable version is mlt 0.4.4 (which includes mlt++ by default).

Hey and thanks a lot!

The ffmpeg patches compile very cleanly. I had no idea that MLT and kdenlive had switched source repositories though. But when I figured it out also the mlt patch applied cleanly.

When running it looked good at first with seeking working. Playback was still slow, but I guess that's just the processing power. After a few minutes of playing with it it however didn't want to play any more. I instead tried to render just a clip from the timeline to a flv. The resulting flv plays the sound at normal speed but seems to play the video at double speed. That's funny, because it always used to play it at half speed. I wonder if whatever is speeding it up is doing that twice by coincidence.

My camera is a Sony HDR-SR12.

Nice job anyways!

@sunab: yes I now noticed that. Pretty stupid of me.

@jmpoure ++: Should I post my results as mentioned two posts above somewhere in your database? Should I compile ffmpeg or mlt with debugging enabled and see what makes it crash and post that somewhere? If nobody is going to use it for anything, I won't bother.

@johanneswilm .Yes, please go ahead. This is free software, you can get involved at any setp.

We have some hot issues that need development. Testing AVCHD patch, VDPAU in MLT, fixing mlt for Mac OS PPC, trying a way to integrate showfo for color and light management. If you can help in any way, go ahead:

* AVCHD patch needs modifications. The was not reviewed yet by FFmpeg members. Dan may be reviewing the MLT patch only after 15th July.
* If you want, you may work on VDPAU decoding in MLT. This is on Dan's radar, but it would help him a lot. If you want some information, I can forward you some private emails describing how to achieve this.
* I am stuck on MLT on Mac OS X 10.5. MLT dies after 5 to 7 frames. Also, the MLT display needs to be embedded. There is an SDL problem. If you would like to debug, please send me your SSH key at jm <> poure dot com and I will open you a remote SSH access on our shared Mac. A good Mac support is important.
* There is also a huge work on color and light management, including studying possible solution, even if showfo seems a resonable solution.

Thanks a lot for your help.
Jean-Michel

Hi all,

since there were no objections from FFmpeg since a week, I've just committed my seeking patches to FFmpeg repository (revision 19681). MPEG-TS (and thus also AVCHD) seeking now works, at least for AVCHD movies from my Panasonic camcorder. I know that Canon camcorders had some issues with proper key frame detection (files are missing appropriate SEI messages), so they might still have a problem.

As for MLT, I've updated my patch for the newest MLT revision (as of today, 2009-08-22). I didn't test it too much, though, but here it is attached. So feel free to test it.

MPEG-PS movies (e.g., DVD VOB) don't work correctly with MLT patch only. Two patches for FFmpeg are still needed, one which introduces proper seeking for MPEG-PS, one to fix a bug in mpegvideo parser. These patches are not yet accepted by FFmpeg, but I attached them here. They also cause seeking regression (patch NOT attached).

Regards,

Ivan