Wireshark mailing list archives
Re: filter for jpeg can not use
From: chuck c <bubbasnmp () gmail com>
Date: Fri, 12 Jun 2020 22:02:57 -0500
The JPEG dissector ( https://code.wireshark.org/review/gitweb?p=wireshark.git;a=blob;f=epan/dissectors/packet-jpeg.c ) 1 /* packet-jpeg.c 2 * 3 * Routines for RFC 2435 JPEG dissection is following RFC 2435 (https://tools.ietf.org/html/rfc2435) which specifies width field: 3.1.5. Width: 8 bits This field encodes the width of the image in 8-pixel multiples (e.g., a width of 40 denotes an image 320 pixels wide). The maximum width is 2040 pixels. So the field in Wireshark is 8 bits with a max value of 255. 72 static header_field_info hfi_rtp_jpeg_main_hdr_width JPEG_HFI_INIT = { 73 "Width", 74 "jpeg.main_hdr.width", 75 FT_UINT8, BASE_DEC, NULL, 0, 76 NULL, HFILL On Fri, Jun 12, 2020 at 10:42 AM damker <damker () sina com> wrote:
Filter "jpeg.main_hdr.width == 640" can not use, it hints that "640 too big for this field, maxinum". This field encodes the width of the image in 8-pixel multiples (e.g., a width of 80 denotes an image 640 pixels wide). If I use "jpeg.main_hdr.width == 80", it means that the number of pixels is 80, and it didn't turn out to be what I wanted (I want that the number of pixels is 640) , it meight be a bug. ------------------------------ damker ___________________________________________________________________________ Sent via: Wireshark-users mailing list <wireshark-users () wireshark org> Archives: https://www.wireshark.org/lists/wireshark-users Unsubscribe: https://www.wireshark.org/mailman/options/wireshark-users mailto:wireshark-users-request () wireshark org ?subject=unsubscribe
___________________________________________________________________________ Sent via: Wireshark-users mailing list <wireshark-users () wireshark org> Archives: https://www.wireshark.org/lists/wireshark-users Unsubscribe: https://www.wireshark.org/mailman/options/wireshark-users mailto:wireshark-users-request () wireshark org?subject=unsubscribe
Current thread:
- New Journal: Journal of Cyber Forensics and Advanced Threat Investigations CyberSecurity UK (Jun 08)
- filter for jpeg can not use damker (Jun 12)
- Re: filter for jpeg can not use chuck c (Jun 13)
- Re: filter for jpeg can not use damker (Jun 14)
- Re: filter for jpeg can not use chuck c (Jun 15)
- Re: filter for jpeg can not use chuck c (Jun 13)
- filter for jpeg can not use damker (Jun 12)