Which container for H.264 video and LPCM (or lossless) audio?

[fellowweb]

Hi everyone,

I hope that I took the right sub-forum. I wouldn't refer to my question as an "advanced" one but it is about captured (not downloaded) video/audio. If necessary I would be thankful if an admin could move it to the respective category.

I intend to archive my father's concert Laserdiscs (classical music only) using composite PAL video and uncompressed stereo-only LPCM audio via SPIDF as discussed in this post. Now that I get more and more comfortable with the capturing part, I ask myself which container format I should use.

As video quality is of minor importance the H.264 codec should perfectly suit my needs and will allow for a nice compression. However, with respect to my father being probably more towards the audiophile end of the spectrum, audio quality matters much more. This is why I intend to capture (and keep) the uncompressed stereo LPCM directly via SPDIF.

Eventually, the container files should be played on TV (SD only, no HD yet) and a high-end hifi via a media player device comparable to the WD TV by Western Digital.

On Wikipedia's comparison of container formats I found that Matroska (MKV) and Enhanced VOB (EVO) could most probably support the combination of H.264 and LPCM.

So, my questions are:

1. Is Enhanced VOB something interesting for end user playback (as we would use it)?
   
2. For Matroska, Wikipedia's comparison states that "virtually anything" referring to video and audio codecs is supported. It does not list LPCM explicitly and I couldn't find further information via Google. Do you know whether it supports LPCM?
   
3. If Matroska didn't support LPCM, wouldn't FLAC (as stated by Wikipedia) be a great alternative for my purpose?
   
4. For DivX, Wikipedia's comparison states that it supports PCM (LPCM is not mentioned. Would this be a viable option for me?
   
5. For some other containers, Wikipedia states that LPCM is supported "only in private streams". What does this mean?

If possible, I would probably prefer Matroska since it is simply a container format I am comfortable with. As it is an open free standard, it sounds pretty future proof.

[creamyhorror]

If you want lossless, FLAC is all you need. Audiophiles regularly use it to store their CDs on their media servers. It's perfectly lossless like LPCM, just a lot smaller.

Matroska is the way to go if you're using H.264 for video. I'm not sure if MP4 (the other modern alternative) accepts FLAC. Both are playable on the WDTV and other modern standalone players. The WD TV in particular has recently gained support for FLAC streams in MKV, so it'll be able to play back the files.

edit: BTW, if video were a concern, you should still use H.264, because it's a more efficient codec that will preserve more quality for any given bitrate.

[BetaBoy]

We have added Apple Lossless to Matroska and will officially announce support for it later this week and/or before Cocktails is announced.

[jagabo]

I would just leave the audio LPCM.

Divx7 h.264 saves as .MKV. Divx 7 ASP, and Divx 6 and below, is usually in .AVI (.DIVX is a minor extension to .AVI) which supports LPCM but h.264 doesn't work well in .AVI.

I believe LPCM is the same as PCM as far as Windows uncompressed audio is concerned.

[creamyhorror]

I would just leave the audio LPCM.

Hmm, why? Compatibility?

[jagabo]

I would just leave the audio LPCM.

Hmm, why? Compatibility?

Yes, compatability. And 2 channel, 16 bit, 44.1 or 48 KHz LPCM isn't all that big when you can buy a 1 TB hard drive for well under US$100.

[creamyhorror]

Fair enough. But it's always nice to save space where you can, if you know the codec is compatible with your player anyway.

[fellowweb]

Hi everyone, thank you very much for your comprehensive discussion!

Everything seems to be clear. I will most probably go with FLAC. Apple Lossless is an interesting option. However, as FLAC is free, I would probably prefer it over Apple Lossless.

@jagabo: Are you sure that LPCM/PCM is supported by Matroska containers?

On matroska.org I could only find the following information and I am not sure whether this is what I am looking for:

CODEC ID | NAME | Description

A_PCM/INT/BIG | PCM Integer Big Endian | The private data is void. The bitdepth has to be read and set from KaxAudioBitDepth element | Corresponding ACM wFormatTag : ???

A_PCM/INT/LIT | PCM Integer Little Endian | The private data is void. The bitdepth has to be read and set from KaxAudioBitDepth element |Corresponding ACM wFormatTag : 0x0001

A_PCM/FLOAT/IEEE | Floating Point, IEEE compatible | The private data is void. The bitdepth has to be read and set from KaxAudioBitDepth element (32 bit in most cases). The float are stored in little endian order (most common float format). | Corresponding ACM wFormatTag : 0x0003

[jagabo]

MKV definitely supports PCM: pcmtest.mkv

[t0nee1]

We have added Apple Lossless to Matroska and will officially announce support for it later this week and/or before Cocktails is announced.

Interesting, thanks for the heads up!.. 8)

I would have to agree with creamyhorror, it's hardly chump-space when flac compression is ~65% of original wav, it will save you hundreds of GB's, if you have large collection of audio file(s)..That said @ OP, you can use Itunes to convert wav to ALAC (Apple Lossless)...

[jagabo]

I would have to agree with creamyhorror, it's hardly chump-space when flac compression is ~65% of original wav

It's close to chump space when you consider there will be video along with audio. What happens five years from now when it's time to replace a dead WDTV? Will the players then be able to play flac? What about 10 or 20 years from now? Sure, you can decompress back to uncompressed PCM but why put yourself in that position when the benefits now are minor.

[t0nee1]

jagabo wrote:
Will the players then be able to play flac?

Yes, of course, and I see you made sure you answered as well...B/C in 10 -20 years if you want wav you can de-compress/decode the flacs back to it's original state..I'm not quite sure on flac going away anytime soon, however..It's becoming more and more popular/compatible/very tag-gable, etc..Some just don't like their audio compressed, even if it is LOSSLESS..
That said, I was only offering an opinion and an alternative to the OP, and simply agreeing on the space issue..

Cheers!.. 8)

[creamyhorror]

What happens five years from now when it's time to replace a dead WDTV? Will the players then be able to play flac?

Of course they will. FLAC is getting very popular and mostly anything that plays MKVs plays FLAC. There's no way FLAC will disappear when it's the only free lossless codec around.

If you're using MKV as a container, there's simply no reason to use LPCM - unless your player for some reason doesn't support FLAC in MKV.

[El Heggunte]

We have added Apple Lossless to Matroska and will officially announce support for it later this week and/or before Cocktails is announced.

At last!

That said @ OP, you can use Itunes to convert wav to ALAC (Apple Lossless)...

ffmpeg -i input.wav -acodec alac output.m4a

creamyhorror wrote:

There's no way FLAC will disappear when it's the only free lossless codec around.

What about TTA, WavPack, and APE

[creamyhorror]

What about TTA, WavPack, and APE

Oops I was thinking about this line:

It is the first truly open and free lossless audio format.

I don't know how I forgot about APE and the others.

[t0nee1]

t0nee1 wrote:

That said @ OP, you can use Itunes to convert wav to ALAC (Apple Lossless)...

El Heggunte wrote:

ffmpeg -i input.wav -acodec alac output.m4a

Indeed!....However, using GUI/apps/tools such as iTunes or dBpoweramp make your toes wiggle and the converted audio file(s) are more danceable..

[creamyhorror]

Indeed!....However, using GUI/apps/tools such as iTunes or dBpoweramp make your toes wiggle and the converted audio file(s) are more danceable..

much like your $7k power cables make music more danceable :P

[fellowweb]

Again a sincere thank you to all of you!

It will probably still take some time before I can start the LD archiving. However, I will then add my experiences in an additional post here.