Transmit absolute time

Pietro Bonfa' pietro_bonfa at
Wed Oct 28 05:19:24 PDT 2015

Dear Sebastian,

here's the standalone testcase.

However I am almost sure I'm doing a mistake.

A simple pipeline like this

appsrc name=mysrc ! videoconvert ! appsink name=mysink

works. If I introduce a "avenc_mpeg4 ! avdec_mpeg4" (or other similar
couples like x264enc ! decodebin ) it only works with I420 for the caps
in appsink.

To show this use ./test [colorspace] . If you specify a colorspace
different from I420 you will see "APPSINK meta: 7" just once. On the
other hand if you leave I420 colorspace "APPSINK meta: 7" is shown for
all received frames.


On 10/28/2015 08:30 AM, Sebastian Dröge wrote:
> On Di, 2015-10-27 at 18:27 +0100, Pietro Bonfa' wrote:
>> On 10/27/2015 05:14 PM, Sebastian Dröge wrote:
>>> You must be able to handle non-writable buffers, but just setting
>>> caps
>>> should not cause buffers to become unwritable.
>> Well, actually setting this caps in appsink:
>> "video/x-raw,format=(string)I420"
>> leaves the buffer writable (33 calls to meta_transform, all ok) while
>> most of the others (tried many, not all) don't (last 7 calls not
>> writable).
>> This tells me that videoconvert is keeping a reference. Removing
>> videconvert obviously solves my problem (but it is not an option).
> If you can create a standalone testcase for that, I can take a look.
> That doesn't sound right. videoconvert also shouldn't keep an
> additional reference around.
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> gstreamer-devel at

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