1157262 - H.264 Decoding Error WebRTC using ffmpeg

Status: RESOLVED DUPLICATE of bug 1167544

(Core :: WebRTC: Audio/Video, defect)

Description

[ankur]

User Agent: Mozilla/5.0 (X11; Linux x86_64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/39.0.2171.95 Safari/537.36

Steps to reproduce:

Hi,
i am trying to decode H.264 video received from webrtc.
i am replying this SDP fragment back.

m=video 9 RTP/SAVPF 97
c=IN IP4 0.0.0.0
a=candidate:0 1 UDP 2128609535 192.168.0.138 53273 typ host
a=sendrecv
a=fmtp:97 profile-level-id=42801f;level-asymmetry-allowed=1
a=ice-pwd:a2e4fbd400cb908736603091775d47ec
a=ice-ufrag:a9ddd26d
a=rtcp-fb:97 nack
a=rtcp-fb:97 nack pli
a=rtcp-fb:97 ccm fir
a=rtcp-mux
a=rtpmap:97 H264/90000
a=setup:actpass

i successfully get the data.
but if i forward it any sip device. the device is unable to decode/partially decode the data.
if i try decoding it with ffmpeg. i get this error "non-existing PPS 1 referenced".
i have never seen this error come from any sip device.
firefox can successfully decode that i send to it from a sip entity.

Comment 1

[Randell Jesup [:jesup] (needinfo me)]

I'm sorry, this needs more info before any sort of comment or investigation can occur.  FF version, the full SDP, the other device(s) and versions, how you're piping this to FFMPEG (and version), debug logs (https://wiki.mozilla.org/Media/WebRTC/Logging), etc.

There is a known issue that for mode 0 FF is sending STAP-A packets, which are mode 1 (though almost all devices that support both will decode them anyways)

Comment 2

[ankur]

Hi,
I did not know that FF sends STAP-A packets for mode 0.
I will try and decode with this information in mind.
I will post an update after trying this out.

thanks and regards
Ankur

Comment 3

[Maire Reavy [:mreavy]]

Hi Ankur -- Do you have an update for us (ref: comment 2)?  Thanks.

Comment 4

[ankur]

Hi,
I did try and i see that firefox is sending NAL type 24(STAP-A). i can now successfully decode the video via FFmpeg.
But not all traditional hardware endpoints seem to be able to decode the Aggregate packet.

Regards

Comment 5

[Randell Jesup [:jesup] (needinfo me)]

Thanks!