Transcoding in VLC 0.8.5 and earlier

[Guest]

Transcoding a DivX or XviD with MPEG audio (not mp3) in an AVI format into an MP2v with MPG2a in a MPEG-TS or PS format Test 3 crashes VLC after stopping or finishing the transcode. Have also tried MPGa.

Doing this in earlier versions of VLC did not crash the player. The end result is a .ts or .mpeg file that plays audio only and the same is true for another player like MPC. So it seems fairly obvious that the pins for the MP2v video filter in transcoding are not connecting. But why? Both of these are standard forms.

I never have understood the difference between MP2a and MPGa other than possible variances sampling frequency. But in early 0.8.5 Sampling=<frequency> was introduced, unfortunately not many users seem to be aware of this because it is not part of the options. This gets confusing and difficult to remember when and how to use it, beside having to add it manually.

Next I tried a DivX and an XviD copy into MPEG-TS and PS. While this does appear to work in VLC, MPC plays audio only. I'm not real surprised at this one because it's not a standard form.

Next was the great attempt to find a compatible copy or transcode for these types of files. The first attempt was OGG as this is a reasonably standard form. So we are just exchanging containers. VLC plays the file but MPC gives an error message (see below) and plays Video only.

Stream 0
Ogg Splitter

Media Type 0:
--------------------------
AM_MEDIA_TYPE:
majortype: MEDIATYPE_Audio {73647561-0000-0010-8000-00AA00389B71}
subtype: Unknown GUID Name {00005500-0000-0010-8000-00AA00389B71}
formattype: FORMAT_WaveFormatEx {05589F81-C356-11CE-BF01-00AA0055595A}
bFixedSizeSamples: 1
bTemporalCompression: 0
lSampleSize: 1
cbFormat: 30

WAVEFORMATEX:
wFormatTag: 0x5500
nChannels: 2
nSamplesPerSec: 48000
nAvgBytesPerSec: 16000
nBlockAlign: 1
wBitsPerSample: 0
cbSize: 12 (extra bytes)


Please note that the filter being called is the stock MPEG audio handler just as before except now the audio pins will not connect. I have verified this with GraphEdit. This does appear to be a VLC problem because these standard forms do normally play in MPC.

Next I tried to copy video and transcode audio using Vorbis, still in OGG. I didn't expect this to work for timing constraints between the audio and video IE possible interleave problems. But it worked in both VLC and MPC. However if the file is given a OGM extension Windows explorer will crash. Both OGG and OGM will show thumbnails and the common extension for this file type would be OGM. The only way you can get back into the directory without crashing explorer is to do it from DOS and delete the file. This is truly disgusting and has not been encountered with any other type of OGM file. So once again VLC's transcode functions appear to be the problem. I have read threads on this forum regarding the Haali splitter causing problems. This is not installed on this machine. The original Tobias filter set is being used for Direct Show. Also please note that while DivX does work, XviD does not work in MPC unless it is transcoded into DivX, however VLC will play both forms and media information shows the correct form. This also is not a problem within the XviD Direct Show Filters but instead a problem within VLC using these standard forms.

Giving up on OGG/OGM I decided to move to the ASF container, this was first attempted (DivX source) as a straight copy as before. The resultant file (.asf) will play in both VLC and MPC however the file is recognized as an MP43 in both players. Transcoding to DivX made no difference as the result was the same. Using XviD for the source and copy to ASF the resultant file could be played in VLC and showed up as a MP4S but could not be played in MPC. Trying the copy transcode IE The source audio (MPGa) is copied and the transcode is XviD to DivX did again work in both players but had the same end result IE it was recognized as a MP43 instead of a DivX file. Now I realize that the ASF container is not very common for these formats.

The end results are very confusing and not what one would expect by using the transcode functions of VLC. It also can be noted that none of these problems seem to exist when using various MPEG forms as a source, Except for OGM and using DivX3 in a ASF container will still show up as a MP43.

After trying this for hours and not finding a real answer for Windows Direct Show. As almost nothing here was truly compatible or at very least had some kind of problem. I decided to move to the Mac world using QuickTime as the reference. So using DivX or XviD as the source I must always transcode everything into a MP4 or MOV container using H.264 or MP4v with MP4a (AAC) audio. Now it has been noted on this forum that multi channel ACC has a ticket however considering the source is MPGa and the transcode is two channels no problems should be encountered in this regard.

The first attempt was with a DivX source to mp4v and mp4a in a mp4 container. Both VLC and QT would play audio only. Using XviD as the source VLC and QT would play the file normally both audio and video. The same was true for the MOV container.

The second attempt was with a DivX source to h.264 and mp4a in a mp4 container. Both VLC and QT would play the file normally for both audio and video. The same was true for XviD and for the MOV container.

I have not had a problem with any forms of MPEG into these standard QT formats. So this suggests that Mac people are having less problems with transcodes than PC people are.

Now as I continued having problems with VLC 0.8.5 Test 3 crashing an earlier 0.8.5 version was used for most of the tests but spotting 0.8.4a the same problem areas also existed.

If you can't create successful transcodes how are we expected to stream data successfully and be able to use other players for the client or in many cases even VLC for the client.

Now I have also read within these Threads of people having problems with raw video such as many SD TV cards or cams put out, not being able to stream or make successful transcodes using any compatible QT form. So while I haven't tried ASF to a QT form, this suggests that it doesn't work either. But near as I can tell raw video and audio does kinda sorta work with ASF. Now perhaps this last statement is a little over the top as I have not spent any time to prove this. But the test results do speak for themselves.

Does anyone else see a problem with all of this???

It seems that the developers are shrugging it off rather than making an attempt to fix these items, in that I haven't been able to find any trouble reports on these issues. Or perhaps it is believed that Mac and Linux users take a front seat and Windows users are moved to the back of the buss.

[Guest]

Have you looked at this? http://www.videolan.org/streaming/features.html

[Guest]

Been there done that! In case you didn't notice, most of the references were gained from that page for things that are supposed to work that don't.

[DJ]

Transcoding a DivX or XviD with MPEG audio (not mp3) in an AVI format into an MP2v with MPG2a in a MPEG-TS or PS format Test 3 crashes VLC after stopping or finishing the transcode. Have also tried MPGa.

Doing this in earlier versions of VLC did not crash the player. The end result is a .ts or .mpeg file that plays audio only and the same is true for another player like MPC. So it seems fairly obvious that the pins for the MP2v video filter in transcoding are not connecting. But why? Both of these are standard forms.

1. Download and install this: http://downloads.videolan.org/pub/video ... 8.5-test4/
as it should resolve the crashing problem.

2. I'm not quite sure when this was added (early 0.8.5 I think), but you must know the frame rate for the source video and include it in the transcode. It takes this form: fps=<frame rate> or as a command line option: --sout-transcode-fps <float> Video frame-rate. This should resolve the issue for transcoding DivX, XviD or MP4v into a MP2v format for a MPEG-TS or PS container.

3. I am aware of an issue with these source formats being transcoded into MP2v in MPEG-TS as a compatibility problem, where when played on another player the video will randomly freeze and then play again and or the file shows incorrect time information. VLC's Messages shows a constant flow of backward PTS. But the file does play normally within VLC, but may not stream without showing the random freeze problem. This problem does NOT show up with any of these source formats either copied or transcoded and muxed in the MPEG-PS container. It also doesn't show up when copied (not transcoded) into the MPEG-TS container but of coarse there is no compatibility for these Non Standard forms.

I will get back to you on some of the rest of your issues as the information becomes available.

Hope this helps you!

[Guest]

I have tried the newer version and it does appear more stable than Test 3. I also have tried tried transcoding and does appear to work as indicated. Kinda clumsy though. I would expect this is not good news for users of the dbox or similar.

I'm looking forward to more answers in this regard.
Thanks!

[DJ]

I'm moving this up, because there seems to be lots of transcode, and dbox questions. In the hope that others will see it.