PCM files not playing

[DeusExMachina]

Was hoping the latest update would address this, but unfortunately, these files still do not play. I am getting conflicting information about whether VLC can handle PCM, but either way, would like to be able to playback these tracks.
I'd upload a sample if I was able.
Any clue what the issue is?

[Lotesdelere]

Please open Tools -> Messages (set Verbosity to 2) before you start the playback and then paste the full resulting log here or on Pastebin.com if it's too long.

Also upload a short sample of a problematic file to either http://streams.videolan.org/upload/ or to EmbedUpload.com, the latter will upload the file for you to several other hosts and then post the link to the file here.

[DeusExMachina]

Will do. FYI, it is not a single problematic file, but every PCM file generated by an app I am using.
The file is uploaded to streams.videolan.org.
Here is the log:

main error: demux doesn't like DEMUX_GET_TIME
.
.
.
... Repeated 569 times
.
.
.
main error: demux doesn't like DEMUX_GET_TIME
main debug: EOF reached
main debug: Stream buffering done (0 ms in 0 ms)
main debug: Decoder buffering done in 8 ms
main debug: finished input
main debug: removing module "cdg"
main debug: killing decoder fourcc `CDG ', 0 PES in FIFO
main debug: removing module "mpeg_audio"
main debug: killing decoder fourcc `mpga', 0 PES in FIFO
main debug: removing module "avcodec"
avcodec debug: ffmpeg codec (MPEG-1/2 Video) stopped
main debug: killing decoder fourcc `mpgv', 0 PES in FIFO
main debug: removing module "packetizer_mpegvideo"
main debug: removing module "avcodec"
avcodec debug: ffmpeg codec (MPEG-1/2 Video) stopped
main debug: killing decoder fourcc `mpgv', 0 PES in FIFO
main debug: removing module "packetizer_mpegvideo"
main debug: removing module "avcodec"
avcodec debug: ffmpeg codec (MPEG-1/2 Video) stopped
main debug: killing decoder fourcc `mpgv', 0 PES in FIFO
main debug: removing module "packetizer_mpegvideo"
main debug: removing module "avcodec"
avcodec debug: ffmpeg codec (MPEG-1/2 Video) stopped
main debug: killing decoder fourcc `mpgv', 0 PES in FIFO
main debug: removing module "packetizer_mpegvideo"
macosx debug: releasing sleep blocker (300)
main debug: removing module "avcodec"
avcodec debug: ffmpeg codec (MPEG-1/2 Video) stopped
main debug: killing decoder fourcc `mpgv', 0 PES in FIFO
main debug: removing module "packetizer_mpegvideo"
main debug: removing module "avcodec"
avcodec debug: ffmpeg codec (MPEG-1/2 Video) stopped
main debug: killing decoder fourcc `mpgv', 0 PES in FIFO
main debug: removing module "packetizer_mpegvideo"
main debug: removing module "avcodec"
avcodec debug: ffmpeg codec (MPEG-1/2 Video) stopped
main debug: killing decoder fourcc `mpgv', 0 PES in FIFO
main debug: removing module "packetizer_mpegvideo"
main debug: removing module "avcodec"
avcodec debug: ffmpeg codec (MPEG-1/2 Video) stopped
main debug: killing decoder fourcc `mpgv', 0 PES in FIFO
main debug: removing module "packetizer_mpegvideo"
main debug: removing module "avcodec"
avcodec debug: ffmpeg codec (MPEG-1/2 Video) stopped
main debug: killing decoder fourcc `mpgv', 0 PES in FIFO
main debug: removing module "packetizer_mpegvideo"
main debug: removing module "avcodec"
avcodec debug: ffmpeg codec (MPEG-1/2 Video) stopped
main debug: killing decoder fourcc `mpgv', 0 PES in FIFO
main debug: removing module "packetizer_mpegvideo"
main debug: removing module "avcodec"
avcodec debug: ffmpeg codec (MPEG-1/2 Video) stopped
main debug: killing decoder fourcc `mpgv', 0 PES in FIFO
main debug: removing module "packetizer_mpegvideo"
main debug: removing module "avcodec"
avcodec debug: ffmpeg codec (MPEG-1/2 Video) stopped
main debug: killing decoder fourcc `mpgv', 0 PES in FIFO
main debug: removing module "packetizer_mpegvideo"
main debug: removing module "ps"
main debug: removing module "stream_filter_record"
main debug: removing module "filesystem"
main debug: removing module "demux_cdg"
main debug: removing module "stream_filter_record"
main debug: removing module "filesystem"
main debug: Program doesn't contain anymore ES
main debug: dead input
main debug: changing item without a request (current 0/1)
main debug: nothing to play

[DeusExMachina]

Oh, FTR, this file can be imported just fine into Audacity, and plays fine in the app that creates it.

[Jean-Baptiste Kempf]

This file claims it has video in it...

[DeusExMachina]

It shouldn't contain video. the PCM file generated by the app is a headless audio datastream, 44k 16bit stereo little endian, that is all. No other data But as additional information, the file is created from an MP3+G pair from a karaoke application. Basically, the app unzips the MP3 and CDG that are zipped together, converts the MP3 to PCM (to allow proper time code syncing to the CDG, and then plays back the PCM in conjunction with the CDG file.
A word on what my intent is with these files:
My hope is to write a small script that follow what the main app is doing, in terms of what karaoke CDG track it is currently playing, and have VLC mirror it. So if the main app is playing a given track, VLC will also play that track at the same time, as a back up failsafe. But while VLC can handle the CDG, it balks at the PCM file the app is generating in its cache folder. Alternately I could have my script re-unzip the zipped pair to a separate location and read that, but that will lead to the two being that much farther out of sync, take extra resources, and just not be anywhere near as elegant a solution.

[davecotter]

Jean-

are you sure it's not the app sniffing the PCM file and "seeing" video data where there is none? or: what do you mean when you say "This file claims it has video in it..." ?

[Lotesdelere]

As requested, please upload a sample file.

[DeusExMachina]

I did yesterday. Pretty sure from context that Jean has already looked at it.
BTW, Dave is the app dev mentioned above.

[Jean-Baptiste Kempf]

I don't see what PCM format is that supposed to be...
Does not open anywhere and starts with a lot of 0...

[DeusExMachina]

Jean:
It starts with zeros because it has a leading ten seconds of silence. Also, as I have said, the file plays fine in audacity, so pretty sure it is a valid PCM file.

[Jean-Baptiste Kempf]

I disagree that this is a playable file, automatically. If you want raw audio, put it in .wav.

[DeusExMachina]

Well, since I can play it, in both the original app, as well as by importing as signed 16-bit little endian PCM into Audacity, it is, by definition, playable.
In addition, I have made sample files by exporting other audio as RAW, using a different app, and these will also not play in VLC, but will play fine in Audacity, and other apps that can handle PCM files.
So it seems pretty clear that these files are playable, but that VLC won't play them.
Saving as WAV is not an option. Nor, to be honest, does that make any sense in terms of playing PCM files. WAV files are not PCM files, they are files that have PCM data inside them. So is the true answer I am getting here that, despite what is claimed regarding the raw codec, VLC can not play PCM audio files (as opposed to WAV/AIFF files with PCM audio)? That seems to be the consensus, both from other threads in these fora complaining of failure to play PCM audio, as well as reading between the lines here.
Would I perhaps have more luck resorting to the command line, feeding it the specific parameters of the file in question (16-bit, signed, little endian)?

Update:
I have downloaded and checked this assertion on yet another audio player, this time BZR Player, a Windows App run via WINE, and it too plays the file, albeit only after the file extension is changed from .pcm to .raw. So that is four apps that play the raw audio file in one form or another. VLC can not play the same file, no matter what I name the file. So far, not matter what the source of the original file, I have yet to find a single example of a headerless PCM raw audio file that VLC can actually play, regardless of the claims vís-a-vís VLC and the araw codec to the contrary.

[Jean-Baptiste Kempf]

Audacity is an audio editor. Media players are different: no headers means no format autodetection.

[DeusExMachina]

BZR Player is an audio player. It plays the files just fine.
But it seems that you are saying that VLC can not in any way play PCM files, which by definition do not have headers.
That is kinda frustrating, especially in light of the fact that the VLC wiki claims it can play PCM_ fourcc files. If VLC can not do this, this claim is clearly incorrect, as PCM files (as opposed to WAV/AIFF files with PCM data) by definition have no header.

[DeusExMachina]

Well, taking my own advice, I headed over to CLI land and used:

$ /Applications/VLC.app/Contents/MacOS/VLC -I rc --demux=rawaud --rawaud-channels=2 --rawaud-samplerate=44000 /Path/To/MyFile.pcm

Success. So it turns out VLC can play the file, if you hard code the file data. Good. Now to see if I can figure out how to get VLC to see and play the CDG in conjunction with the pcm file. Gonna be a long night.

Update:
Not so long after all. I now have the two playing in sync, as long as you don't trigger the long standing graphics bug if you scrub or click in the scrub bar.

[DeusExMachina]

Anyway, the take home message here, to avoid similar misinformation on this topic, is that, yes, the file IS an audio file, DOES contain raw audio data, does NOT contain any video data, regardless of what a superficial analysis of the messages in the Message window imply, yet, nonetheless, VLC, as accessed through the standard UI, can not play it.

Perhaps a set of default values specified in the preferences, such as 44k, stereo, little-endian would allow these files to be played without having to resort to CLI hacks. (I suspect these values are pretty standard, or there is a way to deduce them heuristically from the bitstream, as several audio players played the file with no parametric input whatsoever.)

[Jean-Baptiste Kempf]

Sorry, but no.

[DeusExMachina]

No? To which part, the first or the second? To the first part, that would just be plain incorrect. Again, it IS a playable audio file with NO video.
To the second part, well, that mirrors the basic response to others who have posted in these fora about the same general issue. If nothing is going to be done to allow VLC to play perfectly playable (despite claims to the contrary) files, especially a file format that VLC claims to play, via the UI, then VLC really should not be claiming it can play them.
Clearly, at least via the UI, VLC can not play pcm files, the fact that it can play pcm format audio notwithstanding. Again, WAV and AIF are NOT pcm files, so the fact that VLC can play them has no bearing on whether it can play pcm files.
Having read through the responses in the various threads posted by people seeking help or information on similar issues here I guess I should not find the present response surprising.

[Jean-Baptiste Kempf]

No? To which part, the first or the second? To the first part, that would just be plain incorrect. Again, it IS a playable audio file with NO video.
To the second part, well, that mirrors the basic response to others who have posted in these fora about the same general issue. If nothing is going to be done to allow VLC to play perfectly playable (despite claims to the contrary) files, especially a file format that VLC claims to play, via the UI, then VLC really should not be claiming it can play them.
Clearly, at least via the UI, VLC can not play pcm files, the fact that it can play pcm format audio notwithstanding. Again, WAV and AIF are NOT pcm files, so the fact that VLC can play them has no bearing on whether it can play pcm files.
Having read through the responses in the various threads posted by people seeking help or information on similar issues here I guess I should not find the present response surprising.

You still refuse to understand that this format is against any autodetection. Use manual araw module and raw demuxer.
If you are not pleased, I will wait your contributions.

But so far, I think expecting raw audio files to just work is broken.

[DeusExMachina]

I am not refusing to understand. I understand just fine, including the fact that these files are, contrary to the comments above, playable audio files, and do not contain video, regardless of the output in the Messages window. In addition, I understand that without having the parameters passed to it, namely the sample rate, number of channels, and endian-ness, VLC can not guarantee playback with 100% precision. But just like the UI allows such things as playback volume and output size to be specified in the UI for tracks it can play, so too could these parameters be specified to allow playback. Otherwise, again, you are left with a GUI app that claims to play pcm files when in fact it can not. Several suggestions have been made in these fora when this issue has come up,to allow at least rudimentary playback, such as using default parameters and then letting the user modify these if the playback is not satisfactory. These suggestions were rejected. But the fact that passing VLC via the command line only 3 parameters allowed the file to play indicates that it is the UI that is lacking here, not a deficit in the file format.
However, I suspect most people would feel that a file that plays back too fast or too slow (as would happen if the default value for sample rate was wrong) would be preferable to a track that VLC simply will not play at all, and which, in fact, gives the UI interface fits. A few simple tweaks to UI controls could the have the file playing back accurately.
Again, I should point out that other player apps, such as the Windows-based BZRPlayer, managed to play the pcm file just fine, as is, without any parameters being given, so it is either doing exactly this, using default values for these parameters, or else the player is able to deduce these values. Either way, getting some audio out the file it surely preferable to the interface choking on the file for a half minute or so, and then freezing.

[Jean-Baptiste Kempf]

I am not refusing to understand. I understand just fine, including the fact that these files are, contrary to the comments above, playable audio files, and do not contain video, regardless of the output in the Messages window.

The issue is not playable or not, the issue is if it should be automatically playable or not. Those play absolutely fine in VLC if you set the right parameters.

[DeusExMachina]

In that case, hey, why bother to have a GUI at all? Any file VLC can play simply by double clicking could also play via the command line. Without the UI, they too would play absolutely fine. Any argument that can be made for making MPEGs play in the UI can just as easily be made for PCM files.
Or to address the matter more directly, in order that people who have no familiarity with complicated command structures, who may even be intimidated or turned off by them, can still use the application to play files.
For a player application that aims to be universal as one of its stated goals, after all, the issue is not whether "it should be automatically playable", it is why it should not be.

[Jean-Baptiste Kempf]

In that case, hey, why bother to have a GUI at all? Any file VLC can play simply by double clicking could also play via the command line. Without the UI, they too would play absolutely fine. Any argument that can be made for making MPEGs play in the UI can just as easily be made for PCM files.

Of course not. There is nothing in this file that tells you it is a PCM file. Absolutely nothing, no header, no magic number.
Therefore, it is not automatically playable by VLC. User will have to fill the info themselves and the file plays.

If you do not like it, and have a better solution, please share a patch. Else, please stop your rant.

[DeusExMachina]

Sigh. Why is it that anyone who disagrees with the statements of the powers that be here on the fora are ranting? I am not ranting. I am merely pointing out obvious illogical inconsistencies in your statements, that underly a foundational philosophy that hampers the usefulness of the application.
For instance it is a clear error that "there is nothing in this file that tells you it is a PCM file. Absolutely nothing, no header, no magic number." This statement is totally incorrect, and without merit. There most certainly is something in the file that tells anyone who looks at it that it is a PCM file, without ever having to open the file in any sort of editor, namely, the file name. When a file is named AudioFile.PCM, I suspect that well over 90% of the time, it can be assumed that it is a PCM file. It is certainly 100% of the time that this assumption is justified. How is it that you think that the other players I have opened the file in and played it with no problem manage to figure it out?!? Surely this would not be the only application that has ever used the file extension to tell it information about the file type. (That is, after all the entire POINT of the file extension in the first place.)
The "better solution" here is obvious. If a file has a fourCC or three place file extension of ".pcm " or "pcm", assume it is pcm, and play it as such, with default parameters 44k (CD) stereo (most common) little-endian (Intel). These are very reasonable assumptions, and even if they are wrong, will result in SOME sort of meaningful playback that will allow further tweaking via an editable set of parametric fields in the Media Info dialogue box. For instance, if the file sounds like it is playing back at too high a pitch, increase sample rate parameter.