[FFmpeg-devel] Request for comment: Tutorial

Stephen Dranger dranger
Tue May 22 10:21:01 CEST 2007


> Message: 1
> Date: Tue, 22 May 2007 15:16:36 +1000
> From: "mark cox" <markcox at email.com>
> Subject: Re: [FFmpeg-devel] Request for comment: Tutorial
> To: "FFmpeg development discussions and patches"
>         <ffmpeg-devel at mplayerhq.hu>
> Message-ID:
>         <e2c9b5730705212216v3440f5a1q67bbb70d28457d79 at mail.gmail.com>
> Content-Type: text/plain; charset=ISO-8859-1; format=flowed
>
> On 5/22/07, Stephen Dranger <dranger at gmail.com> wrote:
> >
> > I have written a rather lengthy ffmpeg tutorial that starts by going
> > over Martin Bohme's old tutorial, then proceeding to recreate
> > ffplay.c, teaching about how ffmpeg, SDL, and video in general works.
> >
> > Here's the link:
> > http://dranger.com/ffmpeg/ffmpeg.html
>
>
>
> >From http://dranger.com/ffmpeg/tutorial01.html
> "Packets are pieces of data that can contain complete frames..."
>
> Packets do not always contain complete frames. Frames can be spread across
> packets.
> mark
>
I thought so too until I read this in the doxygen docs:
"For video, the packet contains exactly one frame. For audio, it
contains an integer number of frames if each frame has a known fixed
size (e.g. PCM or ADPCM data). If the audio frames have a variable
size (e.g. MPEG audio), then it contains one frame."

I figured it was the case that sometimes video or audio packets could
not be decompressed because the information they need is in a packet
somewheres else (like B frames).

--Stephen




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