[Libav-user] Packet containing different content than expected when using DV container
ben at cardinalpeak.com
Wed Oct 22 17:42:28 CEST 2014
I had to recompile ffmpeg without threads support to solve a similar issue.
Can you try that?
On Oct 22, 2014 9:35 AM, "Info || Non-Lethal Applications" <
info at non-lethal-applications.com> wrote:
> Hi Bruce,
> thanks for your response!
> > It's sounds a bit like you're seeing multi-threaded decoding, in which
> each decode call gets back a frame that was previously passed in as a
> packet, and was decoded on another thread.
> > The returned frame should have an associated PTS, so it's not a problem.
> That’s the problem. The AVFrame's PTS is not set (well, it is set to
> The only thing I have left is the pkt_pts and pkt_dts which are both wrong.
> > Set the number of threads to 1 in your codec context and see if it
> Good idea! I tried that but it didn’t help.
> Any other ideas?
> >> On Oct 22, 2014, at 02:53, Info || Non-Lethal Applications <
> info at non-lethal-applications.com> wrote:
> >> I’m having problems with my own movie player I wrote using the FFmpeg
> >> The problem appears with a test DV clip created by Apple’s Compressor.
> It’s a generated clip, so I can upload it if it helps.
> >> Let me quickly outline what I’m doing:
> >> - I read video frames into a frame queue which is used as a source for
> >> - I read audio samples into a ring buffer which is used as a source for
> >> To not risk audio dropouts, I’m reading about 200 ms audio samples more
> than I would need to display the respective video frames.
> >> While reading audio samples, I’m storing all video packets that come
> along in a video packet queue.
> >> When the next video frame is requested, I’m searching the queue first
> and read from the file only when the queue is empty.
> >> This procedure worked fine for all other formats I’ve been working with
> so far (mostly MOV and MXF).
> >> I’ve been analyzing the issue for a couple of hours now and it seems to
> me that the packets that I put to the queue contain different content when
> I decode them later on.
> >> Actually, it seems that all packets in the queue decode to the frame
> that would be next in line when reading from the file.
> >> Is there anything I could do to prevent this from happening?
> >> As I said I would be happy to upload the file. It’s 2 minutes of DV
> PAL, about 430 MB in size. I could make it smaller.
> >> Thanks in advance!
> >> Best,
> >> Flo
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