[MPlayer-dev-eng] Re: h264+aac in lavf mp4

Erik Slagter erik at slagter.name
Sat Mar 25 12:17:23 CET 2006


On Sat, 2006-03-25 at 11:55 +0100, Nico Sabbi wrote:

> >BTW Did you check h264 + aac in mp4 using mencoder?
> it works if you use -oac faac -faacopts mpeg=4:raw ..., 

... otherwise the adts encapsulated stream is stored instead of the raw
aac ...

Should have known that :-(

> and I guess  using -oac lavc too.

Will try.

> May I ask the reason of this "passion" for mp4? No STB reads it,

Not true. The first DVD players supporting MP4 are available.

> no editor reads or writes it (except recent versions of avidemux),

Guess what I use ;-) BTW I apply avidemux to my remuxed (projectX)
ts'es, only for editing. The actual conversion I cannot do with
avidemux2 because it cannot write h264+aac in mp4.

> it's extremely bloated and complicated.

True, but the resulting stream overhead is actually very small. About
everything you'll even come up with can be included in it, either with
already specified semantics (good!) or private extensions.

Alternatives:

- matroska, seems to be bbd
- nut, maybe ready in ten years, only supported by open source tools
- mpeg ps, I don't know any player other than maybe mplayer that can
play h264 in mpeg ps
- mpeg ts, more or less acceptable but indeed much much overhead
- avi, actually I don't even want to start, it's so obsolete that even
microsoft abandoned it ages ago, there are no kludges in avi, it IS one
big kludge, and still the overhead is way bigger than mp4, even though
it doesn't even support PTS.

MP4's can encapsulate h264 and aac natively without kludges, it has
small overhead and seeks quick (much quicker and more accurate than ts).

Whether you'd want to try to achieve 100% iso mp4 compliance is another
discussion. I'd say yes, but I could imagine other people not agreeing.

> Even DVB

That's no suprise. TS is the best choice for DVB, for any codec.

> and Bluray refuse to use it and resort to mpegts (that sucks, too, but
> somewhat less).

This I don't understand, really. What are they thinking? We have plenty
of space, so let's waste it? Mpeg4 has complete standards for everything
you would need on a DVD, no need for any kludges (like on current
DVD's). One plain file would suffice.

As these sorts of decisions are generally taken on non-technical
grounds, I suppose it's again about money, which the BR firms don't want
to spent to Apple or something similar.

BTW I already noticed very little interest in mp4 muxing...
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