1092 MPEG 1/2 Audio Layer I Audio This is an outline record only, and requires further details, research or authentication to provide information that will enable users to further understand the format and to assess digital preservation risks associated with it if appropriate. If you are able to help by supplying any additional information concerning this entry, please return to the main PRONOM page and select ‘Add an Entry’. Text 165 Georgia Tech Research Institute / Georgia Tech Research Institute 21 Apr 2011 Submitted by Georgia Tech Research Institute 21 Apr 2011 audio/mpeg MIME fmt/347 PUID mp1 File extension 491 MPEG 1 Audio Layer I (protected) You have to check for two or more frames in a row to be sure you are dealing with an mpeg file. Frame header: MPEG-1, layer I, protected (FFF6h); Bitrate index Sampling Frequency, padding bit (1 byte), Minimum value 10h, maximum value Ebh; Minimum length of frame-3 to maximum length of frame -3; next frame header (FFF6h) repeat 1 Absolute from BOF 0 FFF6[10:EB]{29-769}FFF6[10:EB]{29-769}FFF6[10:EB]{29-769}FFF6[10:EB]{29-769} 492 MPEG 1 Audio Layer I (unprotected) You have to check for two or more frames in a row to be sure you are dealing with an mpeg file. Frame header: MPEG-1, layer I, unprotected (FFF7h); Bitrate index Sampling Frequency, padding bit (1 byte), Minimum value 10h, maximum value EBh; Minimum length of frame-3 to maximum length of frame -3; next frame header (FFF7h) repeat 1 Absolute from BOF 0 FFF7[10:EB]{29-769}FFF7[10:EB]{29-769}FFF7[10:EB]{29-769}FFF7[10:EB]{29-769} 493 MPEG 2 Audio Layer I (protected) You have to check for two or more frames in a row to be sure you are dealing with an mpeg file. Frame header: MPEG-2, layer I, protected (FFFEh); Bitrate index Sampling Frequency, padding bit (1 byte), Minimum value 10h, maximum value Ebh; Minimum length of frame-3 to maximum length of frame -3; next frame header (FFFEh) repeat 1 Absolute from BOF 0 FFFE[10:EB]{29-769}FFFE[10:EB]{29-769}FFFE[10:EB]{29-769}FFFE[10:EB]{29-769} 494 MPEG 2 Audio Layer I (unprotected) You have to check for two or more frames in a row to be sure you are dealing with an mpeg file. Frame header: MPEG-2, layer I, unprotected (FFFFh); Bitrate index Sampling Frequency, padding bit (1 byte), Minimum value 10h, maximum value EBh; Minimum length of frame-3 to maximum length of frame -3; next frame header (FFFFh) repeat 1 Absolute from BOF 0 FFFF[10:EB]{29-769}FFFF[10:EB]{29-769}FFFF[10:EB]{29-769}FFFF[10:EB]{29-769} Is subtype of 923 MPEG Audio Stream Layer II