[FFmpeg-devel] Stream h264 with FEC

Steven Ellis mail_lists
Wed Feb 20 02:02:06 CET 2008


On Wed, February 20, 2008 06:54, Luca Abeni wrote:
> Hi,
>
> Fce.Valeins wrote:
> [...]
>>>>>> I have upload a sample file h264_rtp_stream_with_fec.raw in the ftp
>>>>>> server upload.mplayerhq.hu.
>>>>> Since I see the word "rtp" in it, I am interested in this sample...
>>>>> But I do not know how to access samples stored in upload.mplayerhq.hu
>>>>> (I tried to log on the ftp server and to do a "get
>>>> h264_rtp_stream_with_fec.raw",
>>>>> but it did not work). Is there a standard procedure to get such
>>>>> samples?
>>>> You can download it here
>>>> http://www.zshare.net/download/781125504afb51/
>
> Thanks, I downloaded it and had a look.
>
>
>> Thanks, I have download wireshark and for rtp it use rtpdump. What is
>> the best format for dump rtp with rtpdump ?
>> In the help of rtpdump I have the choice between
>>
>> format : hex|ascii|rtcp|short|payload|dump|header
>>
>> Usage: ./rtpdump [-F [hex|ascii|rtcp|short|payload|dump|header] [-t
>> minutes] [-o outputfile] [-f inputfile] [-x bytes] [multicast]/port >
>> file
>>
>> Tonight I will try the dump format of rtpdump tool
>
> After looking at the file, I do not think a network dump is needed: I
> checked the TS continuity counter, and there are no discontinuities
> corresponding to the video artefacts. So, I believe packet loss is
> not the issue.
>
> I think that the problem is not due to RTP, but to the fact that the
> video stream uses some H.264 feature that is not fully supported by
> libavcodec. I do not know the H.264 codec enough to help, sorry...

I've just taken a look at your sample with a clean SVN build of ffmpeg. It
appears you have the same artifact issues that I'm seeing with the test
DTT H.264 transmissions here in NZ. It would appear that the ffmpeg
implementation of PAFF + spatial direct isn't complete.

Steve





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