mad-dev

mad-dev@lists.mars.org

682 discussions

repetative decoding of last frame why
by prafulla chandra 24 Dec '05

24 Dec '05

Hi all, finally i am almost succeded in the mp3 decoding with buffering concept except in the decoding of last buffer .for last buffer i am dynamically creating memory and appending MAD_BUFFER_GAURD. what i am getting 2-12 more no. of frames extra compared to the memory mapping approch in the minimad.cwhy is this so ?? can any one tell where the problem is ?? below i am providing our modified input callback function. thanks in advance. prafulla chandra. FILE *fptr; FILE *pfOutput; int function(int length); void moving_fb_decodeengine(int move_length,int destination); static char memory[4096]; static char buffer_frame[4096]; static int instant_memory_size = 4096; static unsigned long framesdecoded; static int remainmemory_length; static unsigned long offset ; static int flag ; static int count; static enum mad_flow input(void *data, struct mad_stream *stream) { struct buffer *buffer = data ; int ltb_shifted,i; unsigned char temp; unsigned char *finalbuffer; int end; int destination; if(!buffer->length) { printf("total number of frames decoded %ld are ",framesdecoded); return MAD_FLOW_STOP; } if(flag==0) { end=function(instant_memory_size); if(!end) { destination=1; } else destination=0; moving_fb_decodeengine(instant_memory_size,destination); } else { ltb_shifted =stream->next_frame-buffer->start; remainmemory_length=instant_memory_size-ltb_shifted; for(i=0;i<instant_memory_size;i++) { if(i==remainmemory_length) { end = function(ltb_shifted); if(!end) { destination=1; } else destination=0; moving_fb_decodeengine(ltb_shifted,destination); break ; } temp=memory[i+ltb_shifted]; memory[i]=temp; } } if(!end) { finalbuffer=malloc(count+MAD_BUFFER_GUARD); if(finalbuffer==0) { return MAD_FLOW_BREAK; } memcpy(finalbuffer,memory,count); memset(finalbuffer+count,0,MAD_BUFFER_GUARD); buffer->start=finalbuffer; buffer->length=count+MAD_BUFFER_GUARD; mad_stream_buffer(stream, buffer->start, buffer->length); } else { buffer->length=instant_memory_size; mad_stream_buffer(stream, buffer->start, buffer->length); } if(!end) { buffer->length=0; } flag =1; return MAD_FLOW_CONTINUE; } void moving_fb_decodeengine( int move_length,int destination) { unsigned char temp; int j,l; if(flag!=0) { for(j =0;j<4096;j++) { temp=buffer_frame[j]; memory[remainmemory_length+j]=temp; if(destination) { if(j==count) count=remainmemory_length+j; } } } else { for(l=0;l<instant_memory_size;l++) { temp=buffer_frame[l]; memory[l]=temp; if(destination) { if(l==count) count=l; } } } } int function(int movement_length) { unsigned int controlvar_length_funct=0,i; int cVar1_funct,count1=0; fptr = fopen("BawreNain_1950-Rajkumari-MereRutheHuyeChanda-KidarSharma_Roshan.mp3","rb"); fseek(fptr,offset,SEEK_SET); for(i=0;i<movement_length;i++) { cVar1_funct=fgetc(fptr); if(cVar1_funct==EOF) { count=count1; fclose(fptr); return(0); } else { count1++; buffer_frame[i]=cVar1_funct; offset++; } } fclose(fptr); return(1); }

1 0

decoding errors
by prafulla chandra 20 Dec '05

20 Dec '05

Hi all , we compiled MAD decoder using the High level api giving some chunks of data every time instead of whole file in the input callback.but while compiling most of the times we are getting errors as decoding error 0x0101 (lost synchronization) at byte offset 522 decoding error 0x0103 (forbidden bitrate value) at byte offset 537 decoding error 0x0103 (forbidden bitrate value) at byte offset 538 decoding error 0x0103 (forbidden bitrate value) at byte offset 539 decoding error 0x0103 (forbidden bitrate value) at byte offset 540 decoding error 0x0103 (forbidden bitrate value) at byte offset 541 . .................... .... ..........this continues and after some time we are getting decoding error 0x0235 (bad main_data_begin pointer) at byte offset 1024 decoding error 0x0101 (lost synchronization) at byte offset 522 decoding error 0x0101 (lost synchronization) at byte offset 897 decoding error 0x0235 (bad main_data_begin pointer) at byte offset 1039 decoding error 0x0101 (lost synchronization) at byte offset 522 decoding error 0x0101 (lost synchronization) at byte offset 699 decoding error 0x0103 (forbidden bitrate value) at byte offset 714 decoding error 0x0103 (forbidden bitrate value) at byte offset 715 decoding error 0x0104 (reserved sample frequency value) at byte offset 716 decoding error 0x0102 (reserved header layer value) at byte offset 874 decoding error 0x0103 (forbidden bitrate value) at byte offset 876 .. ........... ............. why these errors are coming ........will these errors have any impact on the final output pcm file size?? means any data lost?? bcz i am getting 50MB as output pcm file size rather than 55MB(using other softwares like COOL EDIT). can someone points out where the problem is? Please kindly indicates me some clues to fix the problem. Thanks in advance prafulla chandra.

1 0

buffering using the high level api
by prafulla chandra 17 Dec '05

17 Dec '05

Hi all, as I told earlier I am doing mp3 streaming using high level api of MAD decoder for buffering I am using the "*streamnextframe*" which is in the * frame.c* file and for the beginning frame address I am using "*framebegin " *which is in the *stream.c . *By using these two variables I am filling the buffer in the *input callback*.with this concept I am able to decode the song .with some errors messages are comming as bad data pointer ,forbidden bitrate value etc.........and while playing in the winamp some little noise and some of the song words are some what changed(Pronunciation is different but perceptually identifiable )at every 20 sec or 30 sec ( this time duration is varying some times) .whether my concept of filling the buffer with those variables are correct or not .next problem is I am converting the output file into WAV file using the software and at the same time I am giving the same input file to the other soft wares which will convert directly from MP3 to WAV . then what I feel was the file size I am getting is less compared to the other one (software decoded). why is it so .where is the problem . I am some what suspicious above concept. whether that is correct or not .if it is not what i have to do and how I have to make links with the decode engine in such a way that i can able to play the song with buffering concept. thanks in advance regards, prafulla chandra

1 0

how to implement input buffer to execute mad
by prafulla chandra 03 Dec '05

03 Dec '05

Hi all, i am working on mad code to decode the mp3 .my requirement is instead of giving the whole file as input to the mad decoder i have to give the input of 8k every time . what i understand from the code is it will ask for input when ever there is insufficient data to decode the frame that time it will refer input buffer using the input callback. i am extracting frame by frame by using the same sync search algorithm.now these extracted frame i am keeping in the 8k buffer at the initial time .when ever it asks for data i am loading the next frame into the buffer by deleating the first frame in the buffer and moving the remaining data to that possition and appending the new frame at the last . now my doubt is how many frames i have to keep in the input buffer and how i have to link this code in the original mad code means, how my code has to communicate with the mad code ,where i have to do the changes to achieve the same.and in how many approches this can be achieved .because this is my idea only i dont know how to do manupulations and where to do in the code whether my approch is correct or not ,if not please tell how i have to approch for this problem . regards, prafulla chandra.

1 0

Lost synchronization errors
by a19617＠ualg.pt 30 Nov '05

30 Nov '05

hi, I've tryed that program, audacity, and so far the errors dont't affect the decoded sound. but i'm going to try your implementation. thanks... Sonia G. ;)

1 0

Decodding error
by a19617＠ualg.pt 30 Nov '05

30 Nov '05

hi there... :) I've using libmad, and I want to decode a mp3 file, but I get the following decoding errors. this example is for a very small mp3. decoding error 0x0101 (lost synchronization) at byte offset 0 decoding error 0x0102 (reserved header layer value) at byte offset 67 decoding error 0x0101 (lost synchronization) at byte offset 85 decoding error 0x0101 (lost synchronization) at byte offset 104 but most of the times I get the following, this example is for another mp3 file, decoding error 0x0101 (lost synchronization) at byte offset 0 decoding error 0x0101 (lost synchronization) at byte offset 6034865 it seems that I get errors at the begin and at the end of the offsets. Should I worry with this ? I does it happen? If someone could help me.. ;) thanks... Sónia Gonçalves

2 1

Lost synchronization errors
by Tiemen Schut 30 Nov '05

30 Nov '05

Hi, We're trying to let minimad play a buffered mp3 on an embedded arm processor. We're using an 8KB buffer (array of chars), which we are filling in the input callback function. As read somewhere else in the newsgroups you have to start every "new" buffer with stream->next_frame till stream->bufend to prevent a lot of sync errors. We've tried this, but without luck so far. Maybe someone here sees a glitch. (code is at end of message). On top of that we got a lot of various decoding errors ALWAYS in the last half of our buffer. Even if we increase/decrease the size of the buffer, there are always a lot of errors in the last half of the buffer. We solved this simply by making stream->length as long as half of the buffer, but it's quite a waste of precious cycles to fill the entire buffer everytime when you decode only half of it :s Hoping for some suggestions, Tiemen Schut This is the code for the input callback function: static enum mad_flow input(void *data, struct mad_stream *stream) { struct buffer *buffer = data; int byte; buffer->length = 0; // make sure the last frame is included in new buffer int pos = 0; if (stream->next_frame != 0 && stream->next_frame != stream->bufend) { while (stream->next_frame + pos != stream->bufend) { todecode[pos] = *(stream->next_frame + pos); pos++; } todecode[pos] = *stream->bufend; } getnextcluster (&bestand, f); byte = cluster2byte (bestand.curcluster, f); readblock(byte, 4096, &todecode[pos]); bestand.curcluster = bestand.nextcluster; getnextcluster (&bestand, f); byte = cluster2byte (bestand.curcluster, f); readblock(byte, 4096, &todecode[pos + 4096]); bestand.curcluster = bestand.nextcluster; buffer->length = BUFFERSIZE / 2; buffer->start = &todecode[0]; mad_stream_buffer(stream, buffer->start, buffer->length); return MAD_FLOW_CONTINUE; } We're reading data from a SD-card, hence the cluster-stuff...

2 1

Re: mad-dev Digest, Vol 6, Issue 8
by a19617＠ualg.pt 30 Nov '05

30 Nov '05

Hi.. I?ve tried that program that you said, and my pcm file is totally corrupted.. Whish is not good at wall. To get it I use the libmad and follow the steps: ################################# make make install make minimad ./minimad <music.mp3>test.pcm ################################### I compile that in Linux, gentoo. I'm doing anything wrong? I'm very concern about it. Quoting mad-dev-request(a)lists.mars.org: > Send mad-dev mailing list submissions to > mad-dev(a)lists.mars.org > > To subscribe or unsubscribe via the World Wide Web, visit > http://www.mars.org/bin/mailman/listinfo/mad-dev > or, via email, send a message with subject or body 'help' to > mad-dev-request(a)lists.mars.org > > You can reach the person managing the list at > mad-dev-owner(a)lists.mars.org > > When replying, please edit your Subject line so it is more specific > than "Re: Contents of mad-dev digest..." > > > Today's Topics: > > 1. Decodding error (a19617(a)ualg.pt) > 2. Decoding error (H?vard Engebretsen) > 3. RE: Decodding error (Bruno Gauthier) > > > ---------------------------------------------------------------------- > > Message: 1 > Date: Sun, 27 Nov 2005 21:38:48 +0000 > From: a19617(a)ualg.pt > Subject: [mad-dev] Decodding error > To: mad-dev(a)lists.mars.org > Message-ID: <20051127213848.qvrwkf0t68skog4g(a)wmail.ualg.pt> > Content-Type: text/plain; charset=ISO-8859-1 > > hi there... :) > I've using libmad, and I want to decode a mp3 file, but I get the following > decoding errors. > > this example is for a very small mp3. > > decoding error 0x0101 (lost synchronization) at byte offset 0 > decoding error 0x0102 (reserved header layer value) at byte offset 67 > decoding error 0x0101 (lost synchronization) at byte offset 85 > decoding error 0x0101 (lost synchronization) at byte offset 104 > > but most of the times I get the following, this example is for > another mp3 file, > > decoding error 0x0101 (lost synchronization) at byte offset 0 > decoding error 0x0101 (lost synchronization) at byte offset 6034865 > > it seems that I get errors at the begin and at the end of the offsets. > > Should I worry with this ? > I does it happen? > If someone could help me.. ;) > > > thanks... > > Sónia Gonçalves > > > > > > ------------------------------ > > Message: 2 > Date: Mon, 28 Nov 2005 00:33:24 +0100 > From: H?vard Engebretsen <havardsp(a)stud.ntnu.no> > Subject: [mad-dev] Decoding error > To: <mad-dev(a)lists.mars.org> > Message-ID: <20051127233319.D925F66CA2(a)royk.itea.ntnu.no> > Content-Type: text/plain; charset="iso-8859-1" > > Hi, > > > > I dont know if this helps, but Im getting the same errors as you do when I > decode small mp3 files who is just a part of a song. My experience is that > these errors does not effect the decoded file. Have you tried to play the > decoded .pcm file? I do so with Audacity (http://audacity.sourceforge.net/, > I import .pcm file as raw audio data in the project menu) and I cant say > there is anything wrong with the decoded file, at least from just listening > to it. > > > > Regards, > > H. > >

2 1

RE: [mad-dev] Decodding error
by Bruno Gauthier 28 Nov '05

28 Nov '05

Hi there, I had the same problem. The way I fixed it was to feed the MAD decoder with 1 second audio chucks that starting with the ADTS (Audio Data Transport Stream) sync word (0xFFFC). I'm not a MPEG1 specialist but, if I remember well, every second, over the 37 audio chunks, an ADTS header is injected. That header is always starting with the sync word: 0xFFFC. Therefore, if you provide the MAD decoder with 1 second audio chunk (starting with the ADTS header) you should avoid the lost of synchronization problem. Regards Bruno -----Message d'origine----- De : mad-dev-bounces(a)lists.mars.org [mailto:mad-dev-bounces@lists.mars.org] De la part de a19617(a)ualg.pt Envoyé : 27 novembre 2005 16:39 À : mad-dev(a)lists.mars.org Objet : [mad-dev] Decodding error hi there... :) I've using libmad, and I want to decode a mp3 file, but I get the following decoding errors. this example is for a very small mp3. decoding error 0x0101 (lost synchronization) at byte offset 0 decoding error 0x0102 (reserved header layer value) at byte offset 67 decoding error 0x0101 (lost synchronization) at byte offset 85 decoding error 0x0101 (lost synchronization) at byte offset 104 but most of the times I get the following, this example is for another mp3 file, decoding error 0x0101 (lost synchronization) at byte offset 0 decoding error 0x0101 (lost synchronization) at byte offset 6034865 it seems that I get errors at the begin and at the end of the offsets. Should I worry with this ? I does it happen? If someone could help me.. ;) thanks... Sónia Gonçalves

1 0

Decoding error
by Håvard Engebretsen 27 Nov '05

27 Nov '05

Hi, I dont know if this helps, but Im getting the same errors as you do when I decode small mp3 files who is just a part of a song. My experience is that these errors does not effect the decoded file. Have you tried to play the decoded .pcm file? I do so with Audacity (http://audacity.sourceforge.net/, I import .pcm file as raw audio data in the project menu) and I cant say there is anything wrong with the decoded file, at least from just listening to it. Regards, H.

1 0

← Newer
1
...
11
12
13
14
15
16
17
...
69
Older →

Jump to page:

2024

2023

2022

2021

2020

2019

2018

2017

2016

2015

2014

2013

2012

2011

2010

2009

2008

2007

2006

2005

2004

2003

2002

2001

2000

mad-dev