Today, I finally gave the JPEG / JFIF baseline encoder part. Tired ~~~~~~~~~~~~~ Test it, encode 250 frames 320x240 BMP, including read and storage. Sampling format 4: 1: 1, quality factor = 50, time consuming 5s. The original encoding program is 14s. This is to encode 25 frames per second, time consuming about 0.5s. Now worrying is a few things: 1 decoder HUFFMAN decoding The speed is not fast enough. 2 Although the encoding needs 0.5s, add other time, UDP transmission, sampling, playback ... both ends with PC, time is afraid, is still not enough. I estimate that the code current buffer operation at the bottom of the encoder. The call function is too much, too time. 2005.3.21
These days have been adjusted on the encoder architecture and interface. Now this is more satisfied. Ha ha ~~~~~ Although the speed is still the same. Discover:% 20 is used in pure I / O% more than 60 times In FDCT and quantifying less than% 10, the remaining time is used for other calculations, initialization, etc. in the stream, initialization, etc. Try to change the integer AAN as DCT, the effect is not very obvious. Or floating point Let's have high precision. 2005.3.24
Today, I finally got the decoder. Detailed annotations have been added to each module. At this stage, I will write the 15 when doing the itinerary decoding 16, and the result is the lower half after decoding. The phenomenon of partial color. I checked N for a long time, I finally got it. Ha ha ~~~~~~~~ Sure enough, Huffman decoding is slow .25 320 x 240 Real color BMP4: 1: 1 Sampling format 50 quality factor compression time is about 0.49 second decompression time is about 0.53 seconds. 2005.3.25
I haven't written a diary for a few days. I didn't make progress. I would like to write a video collection section in DEV-C . But I found that there is libvfw32.a but there is no vfw.h, halo, I don't know what to do. Next to learn SDK , Winsock, ... a lot of things. 2005.3.29
I have learned some UDP broadcasts and multicast. I wrote two programs. Continuously send 1K broadcast package to the network. Almost hacking the online game in the dormitory. 55555 ......... Not fun. 2005.3.31
It is another month, so fast. I wrote a simple packet sniffer today. Fun, huh, huh ~~~~~ To prepare the variety of colors, I have to talk about it next week. It's so tired, sleep. ..2005.4.1
These two days learning networks, do a few tools: IP Packet Sniffert CP / UDP ScanerMac DetectorHost Detector does still look at the information and books, the writing program is just auxiliary learning, it is used to deepen understanding. Not all.2005.4.3
Multi-thread TCP SYN scan. Positive port, if you receive a SYN package, then it will return a SYN | ACK (0x12) package, if a closed port receives the SYN package, you will return a PSH | RST | SYN (0x14) package, and the SYN serial number is 0. If the remote host does not exist, then no packets are returned. Just starting to use the non-blocking Connect and immediately do SYN Scner, but use Sniffer to see that it has been completed. : A ---- SYN ----> BA <- SYN | ACK - BA ---- ACK ----> B and TCP three handshake, use Sniffer to see unclear, there is a possible data package to send Many times. Halo ... I have to build IP bags yourself, watching others' articles, or in the place of Check_sum, it is wrong. 2005.4.4
Tired is a word. These two days of summary color space (color space) related content, wrote a note. I finally got it .2005.4.7
Take a graduation next week ~~~~~ So fast ... Monday to the opening report. To learn VC, chip ... is also a bunch, 555552005.4.8
