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PCM audio in MP4, is it possible
nickske
post Apr 12 2004, 15:47
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Hi,

I'm experimenting with MP4 files. I can already include video into my MP4 file, but now I also want to include audio. I know that MP4 supports AAC audio.
My question is: is it also possible to store raw audio, say PCM audio 16 bit into the MP4 file?
The goal is to create a MP4 file that contains PCM audio and that can be played with a normal player.

Thanks
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ChristianHJW
post Apr 13 2004, 14:03
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Sure, from a technical point of view, MP4 can hold PCM audio, no doubt. The MP4 Pro's here may answer if the MP4 spec creators have included this in the specs or not, i honestly dont know ....


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bond
post Apr 14 2004, 23:14
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threoretically its possible to place any stream in mp4, but practically the specs afaik dont define how to place pcm (or lossless audio) in mp4

specified are for example aac, mp3, mp2


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nickske
post Apr 16 2004, 11:37
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Thanks for the responses!

I know that you can indeed include any stream you want in an MP4 file (in theory).
The problem is indeed that MP4 doesn't have and ObjectType and streamType to deal with PCM audio.

Greetz,

nickske
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ChristianHJW
post Apr 19 2004, 10:28
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MP4 files will have a great future for content distribution, and therefore its creators will aim at the highest possible compatibility and playability. I dont understand why PCM was not included as an option, because basically any device on the market should be able to support it with very little extra programming effort, but i fully understand that MP4 will be restricted to only a number of specific audio and video codecs, bearing in mind what was said above.

I dont know what your plans are and what you need these files for, but to combine MPEG4 video with PCM audio even good old AVI should do fine ?


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iss
post May 25 2004, 09:31
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Hi Guys,
I have to correct some assumptions here: There IS an AudioObjectType and StreamType for PCM.
streamType (audio) and aot=0! The problem is, that the audio specific config for aot 0 is not completely defined. What you can define is aot, nofChannels, samplingFreq.
The problem is, that there is no way to define the type of pcm audio you are using. e.g.:
16bit / 24bit / float, etc. but i am still investigating and will post if I found someth.

Greetings,

iss blink.gif
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iss
post May 25 2004, 09:40
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hi, me again,
raw pcm must be in 16 bit signed integer format in the range from -32768 to 32767

Greetings,

iss biggrin.gif biggrin.gif
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