gstreamer/ext/jpeg/README

The Smoke Codec
---------------

This is a very simple compression algorithm I was toying with when doing a
Java based player. Decoding a JPEG in Java has acceptable speed so this codec
tries to exploit that feature. The algorithm first compares the last and the 
new image and finds all 16x16 blocks that have a squared difference bigger than
a configurable threshold. Then all these blocks are compressed into an NxM JPEG.
The quality of the JPEG is inversely proportional to the number of blocks, this
way, the picture quality degrades with heavy motion scenes but the bitrate stays
more or less constant.
Decoding decompresses the JPEG and then updates the old picture with the new
blocks.


TODO:
----
- make format extensible
- motion vectors
- do some real bitrate control
ext/jpeg/: Added a new simple jpeg based codec Original commit message from CVS: * ext/jpeg/Makefile.am: * ext/jpeg/README: * ext/jpeg/gstjpeg.c: (plugin_init): * ext/jpeg/gstsmokedec.c: (gst_smokedec_get_type), (gst_smokedec_base_init), (gst_smokedec_class_init), (gst_smokedec_init), (gst_smokedec_link), (gst_smokedec_chain): * ext/jpeg/gstsmokedec.h: * ext/jpeg/gstsmokeenc.c: (gst_smokeenc_get_type), (gst_smokeenc_base_init), (gst_smokeenc_class_init), (gst_smokeenc_init), (gst_smokeenc_getcaps), (gst_smokeenc_link), (gst_smokeenc_resync), (gst_smokeenc_chain), (gst_smokeenc_set_property), (gst_smokeenc_get_property): * ext/jpeg/gstsmokeenc.h: * ext/jpeg/smokecodec.c: (smokecodec_init_destination), (smokecodec_flush_destination), (smokecodec_term_destination), (smokecodec_init_source), (smokecodec_fill_input_buffer), (smokecodec_skip_input_data), (smokecodec_resync_to_restart), (smokecodec_term_source), (smokecodec_encode_new), (smokecodec_decode_new), (smokecodec_info_free), (smokecodec_set_quality), (smokecodec_get_quality), (smokecodec_set_threshold), (smokecodec_get_threshold), (smokecodec_set_bitrate), (smokecodec_get_bitrate), (find_best_size), (abs_diff), (put), (smokecodec_encode), (smokecodec_parse_header), (smokecodec_decode): * ext/jpeg/smokecodec.h: Added a new simple jpeg based codec 2004-06-08 11:47:35 +00:00			`The Smoke Codec`
			`---------------`

			`This is a very simple compression algorithm I was toying with when doing a`
			`Java based player. Decoding a JPEG in Java has acceptable speed so this codec`
			`tries to exploit that feature. The algorithm first compares the last and the`
			`new image and finds all 16x16 blocks that have a squared difference bigger than`
			`a configurable threshold. Then all these blocks are compressed into an NxM JPEG.`
			`The quality of the JPEG is inversely proportional to the number of blocks, this`
			`way, the picture quality degrades with heavy motion scenes but the bitrate stays`
			`more or less constant.`
			`Decoding decompresses the JPEG and then updates the old picture with the new`
			`blocks.`


			`TODO:`
			`----`
			`- make format extensible`
			`- motion vectors`
			`- do some real bitrate control`