[x264-devel] about single layer video coding and scalable video coding
Yufei Yuan
yfyuan at gmail.com
Fri Jun 19 21:24:36 CEST 2009
Excuse me, if that's only what you want, why don't you use JSVM
instead? You can find some good quality compressed material (if the
material length is of importance, otherwise, just use some reference
raw sequences that only have several hundred frames), decode it into
raw YUV sequence, and use JSVM to encode it into an SVC stream
whatever you like.
And you actually don't care about the encoding speed of JSVM, you are
going to encode once, get the trace, and use it for network simulation
many times without dealing with encoder again, if you are happy with
the encoding configurations.
Regards,
On Fri, Jun 19, 2009 at 1:45 PM, 武南龚<nangergong at gmail.com> wrote:
>
> thank you
>
> in fact, my purpose is simple
> I just want to encode a sequence into four or more layers
> and obtain sizes of each frame(or a layer segment)
> time duration of each frame
> and use such information for network simulation
> and then compute PSNR
> is there any good method?
>
>
> you said :
> Using the --b-pyramid option, it is also probably possible to generate
> a 3 layers stream, the first layer containning I/P frames, the second
> reference B frames and the third non-reference B frames.
> _______________________________________________
>
> can we treat I frame as the first layer
> P frame as the second one
> B frame as the third while the third non-refrence B(let's call it b) as the
> forth layer?
>
> besides, I didn't see any difference between single layer and such temporal
> SVC
> we just regard different frames as different layers
> I guess we can still treat these frames as in the same single layer?
>
>
>
>
> On Fri, Jun 19, 2009 at 9:24 AM, Loic Le Loarer <lll+vlc at m4x.org> wrote:
>>
>> Hi,
>>
>> On Thursday June 18 2009 at 12:30:26 PM +0200, 武南龚 wrote:
>> > thank you so much. I'm a little puzzled by the sentence below, can you
>> > give
>> > me some explanation.
>> >
>> > Yes, temporal scalability is just a single layer with non-reference
>> > frames at regular intervals.
>> > _______________________________________
>> >
>> > besides, x264 doesn't support SVC, can I treat the single layer coded
>> > video
>> > as a temporal scalable video coded one?
>>
>> Yes, you can do that if the coded stream has the correct properties. For
>> example, do be a correct temporal scalable video sequence with 2 layers,
>> the base layer at 15fps and the second at 30fps, it is enough to have
>> the following sequence of pictures in display order (using old MPEG2
>> style for references):
>>
>> I B P B P B P...
>>
>> The base layer contains only the I and P pictures, the second layer adds
>> the B pictures.
>>
>> Using x264, it is possible to generate such a sequence using the
>> following options (or similar):
>>
>> --bframes 1 --b-adapt 0 --ref 2
>>
>> Using the --b-pyramid option, it is also probably possible to generate
>> a 3 layers stream, the first layer containning I/P frames, the second
>> reference B frames and the third non-reference B frames.
>>
>> Once you have the generated the sequence using x264, you can turn it to
>> a real SVC sequence with temporal scalability by just adding the correct
>> SEI messages and may be changing some SPS or PPS parameters. I don't
>> know any tools whch can to this, but it isn't difficult to write this,
>> it could even be done directly in x264 and proposed for inclusion I
>> guess if there is interess in such a feature.
>>
>> Best regards.
>>
>> --
>> Loic
>>
>> Only a very small fraction of our DNA does anything; the rest is all
>> comments and ifdefs.
>>
>> > and is there any other tools similar to x264 that support SVC?
>> >
>> > thank you!
>> >
>> >
>> >
>> > 2009/6/18 Måns Rullgård <mans at mansr.com>
>> >
>> > > 武南龚 <nangergong at gmail.com> writes:
>> > >
>> > > > hi,all
>> > > >
>> > > > I'm using x.264 in linux now, I want to know which command line
>> > > argument
>> > > > decides whether the encoding is single layer video coding or
>> > > > scalable
>> > > video
>> > > > coding?
>> > > > and how to encode videos using different scalable video coding
>> > > > (temporal
>> > > > ,spatial and PSNR)?
>> > >
>> > > SVC is not supported in x264.
>> > >
>> > > > besides, is there any difference between single layer video coding
>> > > > and
>> > > > temporal scalable video coding? I thought they are the same
>> > >
>> > > Yes, temporal scalability is just a single layer with non-reference
>> > > frames at regular intervals.
>> > >
>> > > --
>> > > Måns Rullgård
>> > > mans at mansr.com
>> > > _______________________________________________
>> > > x264-devel mailing list
>> > > x264-devel at videolan.org
>> > > http://mailman.videolan.org/listinfo/x264-devel
>> > >
>> >
>> >
>> >
>> > --
>> > 此致
>> > 敬礼
>> >
>> > 龚武南
>> >
>> > GongWunan
>> >
>> > School of Electronic and Information Engineering
>> > Xi'an Jiaotong University,
>> > Xi'an 710049, People's Republic of China
>> > ^
>> > Computer and Communication Networks Engineering
>> > Politecnico di Torino,
>> > TORINO 10138,Italy
>> > Tel:+39-3881278481
>>
>> > _______________________________________________
>> > x264-devel mailing list
>> > x264-devel at videolan.org
>> > http://mailman.videolan.org/listinfo/x264-devel
>>
>> _______________________________________________
>> x264-devel mailing list
>> x264-devel at videolan.org
>> http://mailman.videolan.org/listinfo/x264-devel
>
>
>
> --
> 此致
> 敬礼
>
> 龚武南
>
> GongWunan
>
> School of Electronic and Information Engineering
> Xi'an Jiaotong University,
> Xi'an 710049, People's Republic of China
> ^
> Computer and Communication Networks Engineering
> Politecnico di Torino,
> TORINO 10138,Italy
> Tel:+39-3881278481
>
> _______________________________________________
> x264-devel mailing list
> x264-devel at videolan.org
> http://mailman.videolan.org/listinfo/x264-devel
>
>
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