GNOME Bugzilla – Bug 619522
basetransform fix for upstream caps-renegotiation
Last modified: 2010-07-28 10:23:54 UTC
If initially pass-through caps are negotiated between a transform element's sink and src pads, but then the downstream element returns different caps on a buffer from pad_alloc(), basetransform gets stuck with proxy_alloc=TRUE even though the upstream peer doesn't accept the caps, causing gst_pad_peer_accept_caps() to be called on each buffer in _buffer_alloc(): if (!gst_caps_is_equal (newcaps, caps)) { GST_DEBUG_OBJECT (trans, "caps are new"); /* we have new caps, see if we can proxy downstream */ >> if (gst_pad_peer_accept_caps (pad, newcaps)) { /* peer accepts the caps, return a buffer in this format */ GST_DEBUG_OBJECT (trans, "peer accepted new caps"); which is taking ~40ms/frame. This patch does two things. (1) if the buffer returned from pad_alloc() has new caps, trigger the decision whether to proxy the buffer-alloc to be revisited, and (2) disable proxy if peer does not accept new caps. (The first part may not be strictly needed, but seemed like a good idea.) Note that this issue would not arise except in case of downstream elements who have on their template-caps, some that would be suitable for pass-through, but at runtime pick more restrictive caps (for ex, after querying a driver for what formats it actually supports).
Created attachment 161870 [details] [review] basetransform fix for upstream caps-renegotiation
commit 29289ee79e1b49b6dcbb314bee8c760395e5c8e9 Author: Rob Clark <rob@ti.com> Date: Sat May 22 16:33:11 2010 -0500 basetransform fix for upstream caps-renegotiation If initially pass-through caps are negotiated between a transform element's sink and src pads, but then the downstream element returns different caps on a buffer from pad_alloc(), basetransform gets stuck with proxy_alloc=TRUE even though the upstream peer doesn't accept the caps, causing gst_pad_peer_accept_caps() to be called on each buffer in _buffer_alloc(): if (!gst_caps_is_equal (newcaps, caps)) { GST_DEBUG_OBJECT (trans, "caps are new"); /* we have new caps, see if we can proxy downstream */ >> if (gst_pad_peer_accept_caps (pad, newcaps)) { /* peer accepts the caps, return a buffer in this format */ GST_DEBUG_OBJECT (trans, "peer accepted new caps"); which is taking ~40ms/frame. This patch does two things. (1) if the buffer returned from pad_alloc() has new caps, trigger the decision whether to proxy the buffer-alloc to be revisited, and (2) disable proxy if peer does not accept new caps. (The first part may not be strictly needed, but seemed like a good idea.) Note that this issue would not arise except in case of downstream elements who have on their template-caps, some that would be suitable for pass-through, but at runtime pick more restrictive caps (for ex, after querying a driver for what formats it actually supports).