Alex Cohn <[email protected]> писал(а) в своём письме Wed, 25 Apr
2012 21:59:34 +0400:
On Apr 25, 2012 8:27 PM, "Григорий" <[email protected]> wrote:
Alex Cohn <[email protected]> писал(а) в своём письме Wed, 25
Apr
2012 17:54:44 +0400:
On Wed, Apr 25, 2012 at 16:45, Григорий <[email protected]> wrote:
Andrey Utkin <[email protected]> писал(а) в своём письме
Wed,
25 Apr 2012 17:29:09 +0400:
25 апреля 2012 г. 15:52 пользователь Григорий <[email protected]>
написал:
Hi all.
I've built libffmpeg for Android and am trying to decode H.264
stream
using
it. I'm receiving that stream via RTMP connection and passing all
video
packets (excluding first byte that contains flags related to RTMP)
to
the
avcodec_decode_video2 function. With H.263 it works perfectly, but
when I
try to use the same code (only with codec ID changed) for H.264,
every
call
to avcodec_decode_video2 returns -1 and nothing gets decoded.
Here is the output:
Do you know libavformat can read and demux RTMP stream by itself?
Seems like problem in your demuxer, because decoding the frames it
produces fail.
Yes I know, but I need more than simply receiving and playing, this
will be
a kind of VoIP service. My demuxer seems to work fine - I am able to
successfully decode audio using Speex and video using libavcodec when
it is
encoded into H.263. Only problem is with H.264.
Packing of h264 into a stream is not trivial. You may find some
curious information at
http://livertmpjavapublisher.blogspot.com/2011/06/h264-avcvideopacket.html
Alex
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Thank you for this link. I've made it to parse the decoder configuration
record, extract SPS, PPS and some other things. I've tried to pass PPS
and
SPS to avcodec_decode_video2 but it still returns -1, prints "no frame!"
and does not decode anything else. Prepending 0x00000001 before them or
making AVCDCR as described here
http://stackoverflow.com/questions/3493742/problem-to-decode-h264-video-over-rtp-with-ffmpeg-libavcodecgive
the same result.
H264 decoder expects SPS and PPS to arrive together with the first (IDR)
frame.
Удачи,
Alex
So I'm doing the following:
- Create a buffer
- Get a video RTMP packet from the queue
- Read 3 fields at the beginning of it - FLV flags (1 byte), AVC packet
type (1 byte), and CompositionTime (24-bit integer)
- If AVC packet type is 0, parse the rest of the packet as a decoder
configuration record. Build AVCDCR with PPS, SPS, AVCProfileIndication,
profile_compatibility and AVCLevelIndication and append it to the buffer.
- If AVC packet type is 1 and there is something in the buffer, append
packet (usually starts with 0x00000002) to the buffer, pass the buffer
contents to avcodec_decode_video2 and clear the buffer.
- If the buffer is empty, simply pass the packet to avcodec_decode_video2.
At the moment when I call avcodec_decode_video2 with buffer contents (that
consist of 2 AVCDCRs and one encoded frame), before lots of "no frame!" it
prints "Current profile doesn't provide more RBSP data in PPS, skipping".
I think I've made some progress but am still doing something wrong.
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