Hi,
I have problems while decoding the first frame of a stream, which is streamed from DSS to VLC (0.7.2). I always get following messages (only for the first frame):
bad picture start code
header damaged
...
first frame is no key frame
after getting the next key frame, the stream is OK. I have everything correctly installed - ffmpeg, livedotcom, DSS and vlc
The stream is a .3gp rel4 (h263 video, no audio) compatible.
I have the same problem with win32 and linux version of vlc and different streams, with mplayer there is no problem.
regards
Petr K.
Problems with first frame, when streaming from Darwin Stream
-
Petr Kadlec
- New Cone
- Posts: 6
- Joined: 14 Oct 2004 10:26
The way most CODECs work is to send a key frame (a complete picture, best compression possible), followed by a bunch of delta frames (only sending pieces of the whole picture, areas with changes).
You need a key frame to get that overall picture -- the delta frames only give bits and pieces.
VLC does its best to play everything, meaning it'll start popping up the delta frames as they come in, not waiting for a first key frame. Depending on your source video, you might see several seconds of "speckling", little bits of the picture filling in, until the first key frame, when the whole image appears.
VLC, however, warns you that it's not starting from a complete key frame -- that's the message you're seeing.
Other players just drop video packets on the floor (ignore them entirely) until they see the first key frame.
Personal choice -- I'd rather watch the couple of seconds of partial pictures than stare at the application box for a few more seconds (before seeing anything)
You need a key frame to get that overall picture -- the delta frames only give bits and pieces.
VLC does its best to play everything, meaning it'll start popping up the delta frames as they come in, not waiting for a first key frame. Depending on your source video, you might see several seconds of "speckling", little bits of the picture filling in, until the first key frame, when the whole image appears.
VLC, however, warns you that it's not starting from a complete key frame -- that's the message you're seeing.
Other players just drop video packets on the floor (ignore them entirely) until they see the first key frame.
Personal choice -- I'd rather watch the couple of seconds of partial pictures than stare at the application box for a few more seconds (before seeing anything)
-
Petr Kadlec
- New Cone
- Posts: 6
- Joined: 14 Oct 2004 10:26
Problems with first frame, when streaming from Darwin Stream
markfm: thank you for your advice, but you understood me wrong, the video stream is OK, the first frame of the stream is an I-frame.
But vlc cannot decode the first frame, i took a look in the source code and I saw, that this frame has 1371 bytes (rtp payload for h263 + raw h263 data), this data arrive OK and are written to the FIFO, but vlc decodes only the first 7 bytes of the stream as the first frame and then as it is trying to decode the next frame it starts reading offset by the previous read 7 bytes- this results in the 'header damaged' warning
the decoding of the real second frame (P-frame) and all following frames, is OK
- Petr K.
But vlc cannot decode the first frame, i took a look in the source code and I saw, that this frame has 1371 bytes (rtp payload for h263 + raw h263 data), this data arrive OK and are written to the FIFO, but vlc decodes only the first 7 bytes of the stream as the first frame and then as it is trying to decode the next frame it starts reading offset by the previous read 7 bytes- this results in the 'header damaged' warning
the decoding of the real second frame (P-frame) and all following frames, is OK
- Petr K.
Return to “VLC stream-output (sout)”
Who is online
Users browsing this forum: No registered users and 23 guests