Re: [fpc-pascal] where to find materials about MP3 file format
Lets try to gues how MP3directcut work. The right is, that I can remove and move block of MP3 files when it is loaded. For example, I can copy part of MP3 audio data to clipboard and paste it to other part of loaded other MP3 file. And there is no long time while working by this way. So MR Pesh must use some very smart approach. When I choose save all function, data are stored to other file. Other temporary file is being created. Yes, volume function is being used also if user choose it. May be, that somebody have invented several complex mathematical formulas which can remove data of MP3 files without decompress it. Sure, some ststrange sound can happen, if user cut some part of active sound, but it is also possible when using audio editors which open MP3 file and decompress it. I must start from The most simple steps. How to detect key presses while using Android unit And PPCJVM ANdroid JVM target mode. To know, if user have pressed left arrow, right arrow on his external bluetooth keyboard. Next event will be based on GUI element presses detection by using onwievclick procedure. So condition blocks will assign two various events. From Bluetooth keyboard or other keyboard. The disadvantage of my desire is The fact, that I must always unhyde keyboard so other commands will detect keyboard presses, so keyboard will interfere with app GUI on The screen. But there is no other way. ___ fpc-pascal maillist - fpc-pascal@lists.freepascal.org https://lists.freepascal.org/cgi-bin/mailman/listinfo/fpc-pascal
Re: [fpc-pascal] where to find materials about MP3 file format
El 15/08/2019 a las 11:04, George Bakhtadze escribió: mp3 is a loosy audio format. It means that some part of information is lost while encoding. So doing a decoding/encoding cycle just to remove some piece of file is a bad idea. I'd try to find a way to remove piece of audio data without decompressing the file similar to lossless operations on JPEG files. Hello, As JPEG only have limited operations without decompressing (limited rotation and limited cropping), mp3 also have limited operations without decompressing, in this case only frame volume change. -- ___ fpc-pascal maillist - fpc-pascal@lists.freepascal.org https://lists.freepascal.org/cgi-bin/mailman/listinfo/fpc-pascal
Re: [fpc-pascal] where to find materials about MP3 file format
Hello, 14.08.2019, 23:24, "Mgr. Janusz Chmiel" : > But how to achieve The complex algorithm for recreating MP3 file. It> will not be easy walk across The park. I will also have to use effective> approach to prevent memory allocation problems. mp3 is a loosy audio format. It means that some part of information is lost while encoding.So doing a decoding/encoding cycle just to remove some piece of file is a bad idea.I'd try to find a way to remove piece of audio data without decompressing the file similar to lossless operations on JPEG files. ---Best regards, George ___ fpc-pascal maillist - fpc-pascal@lists.freepascal.org https://lists.freepascal.org/cgi-bin/mailman/listinfo/fpc-pascal
Re: [fpc-pascal] where to find materials about MP3 file format
El 14/08/2019 a las 22:23, Mgr. Janusz Chmiel escribió: I have A very big and non easy dream. Making similar MP3 editor like MP3 direct cut for Windows is. But sure! [...] operations to assign beginning of block and its end. And mainly, I want to use remove block command, which will hae immediate effect. So MP3 [...] Who of us would have some tip how to find MP3 file format technical specifications? Hello, There are several documents about the MP3 format, but you only need for sure ID3V1, ID3V2 and MP3 frame format. You need ID3V1 and ID3V2 in order to skip this information (if you will not use it, as it is metadata only) and the MP3 frame format if you want to fast scan MP3 time duration and scan for stream errors. https://www.mp3-tech.org/programmer/frame_header.html All other operations should be done with decompressed audio and in this situation nothing is different from MP3, WAV, AAC, OGG, etc. There are only a few operations that you can apply to a MP3 stream without decompressing it, mainly volume change, as you can not, in example, remove a block directly from the MP3 stream even if the block is an MP3 frame because each frame is dependent of previous frames and if you remove one an audible "bleep" can happen (high chance). So you only need something to decompress MP3 (and maybe other formats). -- ___ fpc-pascal maillist - fpc-pascal@lists.freepascal.org https://lists.freepascal.org/cgi-bin/mailman/listinfo/fpc-pascal
