| Printable Version of Topic
Click here to view this topic in its original format |
| Unofficial VirtualDub Support Forums > Testing / Bug Reports > Lossles Jpeg Image Sequence Export |
| Posted by: Pancolart Feb 14 2011, 11:21 AM |
| If selecting Image sequence export and compression Jpeq with value 100 color dynamic is still impaired. I already wrote about the problem but we came to conclusion that for average user working with video it's OK. Well i found my solution by exporting png files and then convert to jpeg where required. Sadly top galleries allow only jpeg and i am stuck with double compression and time consuming conversions. Could you please make value 100 reserved for true lossless jpeg compression. I am sure many users would appreciate it. |
| Posted by: -SPM-Mad Feb 16 2011, 02:25 PM |
| I am sorry, but lossless jpeg compression is _not_ possible. JPG was designed represent image information in a different way that is not exactly 100% RGB, but needs alot less information for that. Same with most popular video codecs like mpeg1, 2, xvid h264 etc. The close you want to get to the actual RGB data, the redicules more data you need to save. The size difference between 90 and 100 ist alot bigger than between 50 and 60 for example. Yet most of these 'percentage' values are rather theoretical and depend on the libary/code used to generate the jpeg and how much data it stuffs into the imagefile. JPEG2000 and PNG are formats that allow saving the data in a way that allows 100% RGB reconstruction (i.e. lossless). JPGs cannot be lossless. Greetings Mad |