docs/random/ensonic/embedded.txt - mtk-gstreamer - Git at Google

 $Id$

 = embedded =

 == index handling ==
 For avidemux I currently have a big patch doing memory optimized index handling.
 It basically thins out the index to save memory. Right now it only keeps index
 entries marked with the avi keyframe flag.

 In gstreamer core we have some indexing objects. They are curently used nowhere.
 The idea is to use them and to make the index strategy plugable or configurable
 at run time.

 The challenge is then to rewrite muxers and demuxers to use them instead of the
 built in index logic.

 This way the different requirements of desktop and embedded platforms could be
 encapsulated in the indexer strategy.

 == ranking ==
 Autopluggers like playbin and decodebin use the element caps plus static ranks
 to create piplines.
 The rank of an elemnt right now refers to the quality/maturity of the element.
 Elements with higher rank should be functionally more complete. If we have
 multiple elements that are feature complete there is a draw.

 There are more decission criteria thinkable:
 * target processor (CPU,DSP,GPU)
 * ressource usage (CPU, memory)
 * license (proprietary, open source)
 * quality (in terms of the audio/image quality)

 One problem of taking criteria like quality and performance into account when
 autoplugging, is that elements might have objects-properties that influence
 them.

 Beside adding more ranking criteria, we might consider adding an overridable
 mechanism for picking elements (basically registry filters that not decide on
 the base of ranks). Applications might choose the filter mechanism based on the
 use-case (which gstreamer not know right now).

 == g_malloc vs. g_try_malloc ==
 g_malloc/g_new should not be used when allocating space of a size that is
 derived from a value found in the file. Instead one should use g_try_malloc or
 g_try_new and check the return value.

 $ find . -name "*.c" -exec grep "g_malloc" {} \; | wc -l
 190
 $ find . -name "*.c" -exec grep "g_try_malloc" {} \; | wc -l
 0
 $ find . -name "*.c" -exec grep "g_new" {} \; | wc -l
 398
 $ find . -name "*.c" -exec grep "g_try_new" {} \; | wc -l
 3

 This is not strickly related to embedded, but its easier to crash gstreamer on
 embedded this way.
	$Id$

	= embedded =

	== index handling ==
	For avidemux I currently have a big patch doing memory optimized index handling.
	It basically thins out the index to save memory. Right now it only keeps index
	entries marked with the avi keyframe flag.

	In gstreamer core we have some indexing objects. They are curently used nowhere.
	The idea is to use them and to make the index strategy plugable or configurable
	at run time.

	The challenge is then to rewrite muxers and demuxers to use them instead of the
	built in index logic.

	This way the different requirements of desktop and embedded platforms could be
	encapsulated in the indexer strategy.

	== ranking ==
	Autopluggers like playbin and decodebin use the element caps plus static ranks
	to create piplines.
	The rank of an elemnt right now refers to the quality/maturity of the element.
	Elements with higher rank should be functionally more complete. If we have
	multiple elements that are feature complete there is a draw.

	There are more decission criteria thinkable:
	* target processor (CPU,DSP,GPU)
	* ressource usage (CPU, memory)
	* license (proprietary, open source)
	* quality (in terms of the audio/image quality)

	One problem of taking criteria like quality and performance into account when
	autoplugging, is that elements might have objects-properties that influence
	them.

	Beside adding more ranking criteria, we might consider adding an overridable
	mechanism for picking elements (basically registry filters that not decide on
	the base of ranks). Applications might choose the filter mechanism based on the
	use-case (which gstreamer not know right now).

	== g_malloc vs. g_try_malloc ==
	g_malloc/g_new should not be used when allocating space of a size that is
	derived from a value found in the file. Instead one should use g_try_malloc or
	g_try_new and check the return value.

	$ find . -name "*.c" -exec grep "g_malloc" {} \; \| wc -l
	190
	$ find . -name "*.c" -exec grep "g_try_malloc" {} \; \| wc -l
	0
	$ find . -name "*.c" -exec grep "g_new" {} \; \| wc -l
	398
	$ find . -name "*.c" -exec grep "g_try_new" {} \; \| wc -l
	3

	This is not strickly related to embedded, but its easier to crash gstreamer on
	embedded this way.