Hi Joe, On Tue, 2002-01-22 at 09:41, joe briggs wrote: > Please forgive the broad mailing. I am using a modified ffmpeg (I pulled in > motion detection stuff from the motion project, and insert text into the > image before compression) to read 30 fps from a v4l device (bt878) and render > to MPEG. The chip is initialized in yuv420p format, which is what the mpeg > encoder wants to see so the real-time encoding process can keep up with the > frame rate (i.e., no conversions). However, I need to periodically (once or > twice per second) create a snapshot and save it as a commonly recognizable > compressed file format such as jpeg. I am trying hard to avoid the rather > expensive yuv->rgb conversions. Can anyone recommend a compressed output > file format (such as jpeg) that most browsers can recognize & decode, and if > it is possible to create it from a yuv420p image (without the compressor > converting to rgb first)? Thanks! You can create JPEG from YUV. If you create JPEG from RGB, it will convert to YUV internally ;-). You can basically use code from gstreamer's jpegenc (http://www.sf.net/projects/gstreamer -> CVS -> Browse CVS Repository -> gst-plugins/ -> ext/ -> jpeg/ -> gstjpegenc.c) or mjpegtools' JPEG handling library (http://www.sf.net/projects/mjpeg -> CVS -> Browse CVS Repository -> mjpeg_play/ -> lavtools/ -> jpegutils.c). The second is probably a bit easier. Just either copypaste the function or link to "`mjpegtools-config --cflags --libs` -llavjpeg" and call encode_jpeg_raw(). encode_jpeg_raw() takes planar yuv-420 (YUV420P) as input and outputs a JPEG buffer. Ronald -- - .-. - /V\ | Ronald Bultje <rbultje@xxxxxxxxxxxxxxxxxxx> - // \\ | Running: Linux 2.4.17-XFS and OpenBSD 3.0 - /( )\ | http://ronald.bitfreak.net/ - ^^-^^
