ref: 22a3ded7fe5bd548a17297d27ff0f1d8e4faee4b
dir: /frontend/mp4atom.c/
/****************************************************************************
MP4 output module
Copyright (C) 2017 Krzysztof Nikiel
This program is free software: you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation, either version 3 of the License, or
(at your option) any later version.
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program. If not, see <http://www.gnu.org/licenses/>.
****************************************************************************/
#include <stdlib.h>
#include <stdio.h>
#include <stdint.h>
#ifndef WORDS_BIGENDIAN
//#include <byteswap.h>
#endif
#include <string.h>
#include <sys/time.h>
enum ATOM_TYPE
{
ATOM_STOP = 0 /* end of atoms */ ,
ATOM_NAME /* plain atom */ ,
ATOM_DESCENT, /* starts group of children */
ATOM_ASCENT, /* ends group */
ATOM_DATA,
};
typedef struct
{
uint16_t opcode;
void *data;
} creator_t;
#include "mp4atom.h"
mp4config_t mp4config = { 0 };
static FILE *g_fout = NULL;
static inline uint32_t bswap32(uint32_t u32)
{
#ifndef WORDS_BIGENDIAN
//return __bswap_32(u32);
return __builtin_bswap32(u32);
#endif
}
static inline uint16_t bswap16(uint16_t u16)
{
#ifndef WORDS_BIGENDIAN
//return __bswap_16(u16);
return __builtin_bswap16(u16);
#endif
}
static int dataout(const void *data, int size)
{
if (fwrite(data, 1, size, g_fout) != size)
{
perror("mp4out");
return -1;
}
return size;
}
static int stringout(const char *txt)
{
return dataout(txt, strlen(txt));
}
static int u32out(uint32_t u32)
{
u32 = bswap32(u32);
return dataout(&u32, 4);
}
static int u16out(uint16_t u16)
{
u16 = bswap16(u16);
return dataout(&u16, 2);
}
static int u8out(uint8_t u8)
{
if (fwrite(&u8, 1, 1, g_fout) != 1)
{
perror("mp4 out");
return 0;
}
return 1;
}
static int ftypout(void)
{
int size = 0;
size += stringout("isom");
size += u32out(0);
size += stringout("M4A ");
size += stringout("mp42");
size += stringout("mp41");
return size;
}
enum
{ SECSINDAY = 24 * 60 * 60 };
uint32_t mp4time(void)
{
int y;
struct timeval t;
gettimeofday(&t, NULL);
// add some time from the start of 1904 to the start of 1970
for (y = 1904; y < 1970; y++)
{
t.tv_sec += 365 * SECSINDAY;
if (!(y & 3))
t.tv_sec += SECSINDAY;
}
return t.tv_sec;
}
static int mvhdout(void)
{
int size = 0;
int cnt;
// version
size += u8out(0);
// flags
size += u8out(0);
size += u16out(0);
// Creation time
size += u32out(mp4time());
// Modification time
size += u32out(mp4time());
// Time scale (samplerate)
size += u32out(mp4config.samplerate);
// Duration
size += u32out(mp4config.samples);
// rate
size += u32out(0x00010000);
// volume
size += u16out(0x0100);
// reserved
size += u16out(0);
size += u32out(0);
size += u32out(0);
// matrix
size += u32out(0x00010000);
size += u32out(0);
size += u32out(0);
size += u32out(0);
size += u32out(0x00010000);
size += u32out(0);
size += u32out(0);
size += u32out(0);
size += u32out(0x40000000);
for (cnt = 0; cnt < 6; cnt++)
size += u32out(0);
// Next track ID
size += u32out(2);
return size;
};
static int tkhdout(void)
{
int size = 0;
// version
size += u8out(0);
// flags
// bits 8-23
size += u16out(0);
// bits 0-7
size += u8out(1 /*track enabled */ );
// Creation time
size += u32out(mp4time());
// Modification time
size += u32out(mp4time());
// Track ID
size += u32out(1);
// Reserved
size += u32out(0);
// Duration
size += u32out(mp4config.samples);
// Reserved
size += u32out(0);
size += u32out(0);
// Layer
size += u16out(0);
// Alternate group
size += u16out(0);
// Volume
size += u16out(0x0100);
// Reserved
size += u16out(0);
// matrix
size += u32out(0x00010000);
size += u32out(0);
size += u32out(0);
size += u32out(0);
size += u32out(0x00010000);
size += u32out(0);
size += u32out(0);
size += u32out(0);
size += u32out(0x40000000);
// Track width
size += u32out(0);
// Track height
size += u32out(0);
return size;
};
static int mdhdout(void)
{
int size = 0;
// version/flags
size += u32out(0);
// Creation time
size += u32out(mp4time());
// Modification time
size += u32out(mp4time());
// Time scale
size += u32out(mp4config.samplerate);
// Duration
size += u32out(mp4config.samples);
// Language
size += u16out(0 /*0=English */ );
// pre_defined
size += u16out(0);
return size;
};
static int hdlr1out(void)
{
int size = 0;
// version/flags
size += u32out(0);
// pre_defined
size += u32out(0);
// Component subtype
size += stringout("soun");
// reserved
size += u32out(0);
size += u32out(0);
size += u32out(0);
// name
// null terminate
size += u8out(0);
return size;
};
static int smhdout(void)
{
int size = 0;
// version/flags
size += u32out(0);
// Balance
size += u16out(0 /*center */ );
// Reserved
size += u16out(0);
return size;
};
static int drefout(void)
{
int size = 0;
// version/flags
size += u32out(0);
// Number of entries
size += u32out(1 /*url reference */ );
return size;
};
static int urlout(void)
{
int size = 0;
size += u32out(1);
return size;
};
static int stsdout(void)
{
int size = 0;
// version/flags
size += u32out(0);
// Number of entries(one 'mp4a')
size += u32out(1);
return size;
};
static int mp4aout(void)
{
int size = 0;
// Reserved (6 bytes)
size += u32out(0);
size += u16out(0);
// Data reference index
size += u16out(1);
// Version
size += u16out(0);
// Revision level
size += u16out(0);
// Vendor
size += u32out(0);
// Number of channels
size += u16out(mp4config.channels);
// Sample size (bits)
size += u16out(mp4config.bits);
// Compression ID
size += u16out(0);
// Packet size
size += u16out(0);
// Sample rate (16.16)
// rate integer part
size += u16out(mp4config.samplerate);
// rate reminder part
size += u16out(0);
return size;
}
static int esdsout(void)
{
int size = 0;
// descriptor definitions:
// systems/mp4_file_format/libisomediafile/src/MP4Descriptors.h
// systems/mp4_file_format/libisomediafile/src/MP4Descriptors.c
//
// descriptor tree:
// MP4ES_Descriptor
// MP4DecoderConfigDescriptor
// MP4DecSpecificInfoDescriptor
// MP4SLConfigDescriptor
struct
{
int es;
int dc; // DecoderConfig
int dsi; // DecSpecificInfo
int sl; // SLConfig
} dsize;
enum
{ TAG_ES = 3, TAG_DC = 4, TAG_DSI = 5, TAG_SLC = 6 };
// calc sizes
#define DESCSIZE(x) (x + 2/*.tag+.size*/)
dsize.sl = 1;
dsize.dsi = mp4config.asc.size;
dsize.dc = 13 + DESCSIZE(dsize.dsi);
dsize.es = 3 + DESCSIZE(dsize.dc) + DESCSIZE(dsize.sl);
// output esds atom data
// version/flags ?
size += u32out(0);
// mp4es
size += u8out(TAG_ES);
size += u8out(dsize.es);
// ESID
size += u16out(0);
// flags(url(bit 6); ocr(5); streamPriority (0-4)):
size += u8out(0);
size += u8out(TAG_DC);
size += u8out(dsize.dc);
size += u8out(0x40 /*MPEG-4 audio */ );
// DC flags: upstream(bit 1); streamType(2-7)
// this field is typically 0x15 but I think it
// could store "Object Type ID", why not
size += u8out(2 /*AAC LC*/ << 2);
// buffer size (24 bits)
size += u16out(mp4config.buffersize >> 8);
size += u8out(mp4config.buffersize && 0xff);
// bitrate
size += u32out(mp4config.bitratemax);
size += u32out(mp4config.bitrateavg);
size += u8out(TAG_DSI);
size += u8out(dsize.dsi);
// AudioSpecificConfig
size += dataout(mp4config.asc.data, mp4config.asc.size);
size += u8out(TAG_SLC);
size += u8out(dsize.sl);
// "predefined" (no idea)
size += u8out(2);
return size;
}
static int sttsout(void)
{
int size = 0;
// version/flags
size += u32out(0);
// Number of entries
size += u32out(1);
// only one entry
// Sample count (number of frames)
size += u32out(mp4config.frame.ents);
// Sample duration (samples per frame)
size += u32out(mp4config.framesamples);
return size;
}
static int stszout(void)
{
int size = 0;
int cnt;
// version/flags
size += u32out(0);
// Sample size
size += u32out(0 /*i.e. variable size */ );
// Number of entries
if (!mp4config.frame.ents)
return size;
if (!mp4config.frame.data)
return size;
size += u32out(mp4config.frame.ents);
for (cnt = 0; cnt < mp4config.frame.ents; cnt++)
size += u32out(mp4config.frame.data[cnt]);
return size;
}
static int stscout(void)
{
int size = 0;
// version/flags
size += u32out(0);
// Number of entries
size += u32out(2);
// 1st entry
// first chunk
size += u32out(1);
// frames per chunks (256 for simplicity)
size += u32out(0x100);
// sample id
size += u32out(1);
// 2nd entry
// last chunk
size += u32out((mp4config.frame.ents >> 8) + 1);
// frames in last chunk
size += u32out(mp4config.frame.ents & 0xff);
// sample id
size += u32out(1);
return size;
}
static int stcoout(void)
{
int size = 0;
int chunks = (mp4config.frame.ents >> 8) + 1;
int cnt;
uint32_t ofs = mp4config.mdatofs;
// version/flags
size += u32out(0);
// Number of entries
size += u32out(chunks);
// Chunk offset table
if (!mp4config.frame.ents)
return size;
if (!mp4config.frame.data)
return size;
for (cnt = 0; cnt < mp4config.frame.ents; cnt++)
{
if (!(cnt & 0xff))
size += u32out(ofs);
ofs += mp4config.frame.data[cnt];
}
return size;
}
static int tagtxt(char *tagname, const char *tagtxt)
{
int txtsize = strlen(tagtxt);
int size = 0;
int datasize = txtsize + 16;
size += u32out(datasize + 8);
size += dataout(tagname, 4);
size += u32out(datasize);
size += dataout("data", 4);
size += u32out(1); // data type text
size += u32out(0);
size += dataout(tagtxt, txtsize);
return size;
}
static int tagu32(char *tagname, int n /*number of stored fields*/)
{
int numsize = n * 4;
int size = 0;
int datasize = numsize + 16;
size += u32out(datasize + 8);
size += dataout(tagname, 4);
size += u32out(datasize);
size += dataout("data", 4);
size += u32out(0); // data type uint32
size += u32out(0);
return size;
}
static int metaout(void)
{
int size = 0;
// version/flags
size += u32out(0);
return size;
}
static int hdlr2out(void)
{
int size = 0;
// version/flags
size += u32out(0);
// Predefined
size += u32out(0);
// Handler type
size += stringout("mdir");
size += stringout("appl");
// Reserved
size += u32out(0);
size += u32out(0);
// null terminator
size += u8out(0);
return size;
};
static int ilstout(void)
{
int size = 0;
size += tagtxt("\xa9" "too", mp4config.tag.encoder);
if (mp4config.tag.artist)
size += tagtxt("\xa9" "ART", mp4config.tag.artist);
if (mp4config.tag.composer)
size += tagtxt("\xa9" "wrt", mp4config.tag.composer);
if (mp4config.tag.title)
size += tagtxt("\xa9" "nam", mp4config.tag.title);
if (mp4config.tag.genre)
size += tagtxt("gnre", mp4config.tag.genre);
if (mp4config.tag.album)
size += tagtxt("\xa9" "alb", mp4config.tag.album);
if (mp4config.tag.compilation)
{
size += tagu32("cpil", 1);
size += u32out(mp4config.tag.compilation);
}
if (mp4config.tag.trackno)
{
size += tagu32("trkn", 1);
size += u32out(mp4config.tag.trackno);
}
if (mp4config.tag.discno)
{
size += tagu32("disk", 1);
size += u32out(mp4config.tag.discno);
}
if (mp4config.tag.year)
size += tagtxt("\xa9" "day", mp4config.tag.year);
#if 0
if (mp4config.tag.cover)
size += tagtxt("\xa9" "covr", mp4config.tag.cover);
#endif
if (mp4config.tag.comment)
size += tagtxt("\xa9" "cmt", mp4config.tag.comment);
return size;
};
static creator_t g_head[] = {
{ATOM_NAME, "ftyp"},
{ATOM_DATA, ftypout},
{ATOM_NAME, "free"},
{ATOM_NAME, "mdat"},
{0}
};
static creator_t g_tail[] = {
{ATOM_NAME, "moov"},
{ATOM_DESCENT},
{ATOM_NAME, "mvhd"},
{ATOM_DATA, mvhdout},
{ATOM_NAME, "trak"},
{ATOM_DESCENT},
{ATOM_NAME, "tkhd"},
{ATOM_DATA, tkhdout},
{ATOM_NAME, "mdia"},
{ATOM_DESCENT},
{ATOM_NAME, "mdhd"},
{ATOM_DATA, mdhdout},
{ATOM_NAME, "hdlr"},
{ATOM_DATA, hdlr1out},
{ATOM_NAME, "minf"},
{ATOM_DESCENT},
{ATOM_NAME, "smhd"},
{ATOM_DATA, smhdout},
{ATOM_NAME, "dinf"},
{ATOM_DESCENT},
{ATOM_NAME, "dref"},
{ATOM_DATA, drefout},
{ATOM_DESCENT},
{ATOM_NAME, "url "},
{ATOM_DATA, urlout},
{ATOM_ASCENT},
{ATOM_ASCENT},
{ATOM_NAME, "stbl"},
{ATOM_DESCENT},
{ATOM_NAME, "stsd"},
{ATOM_DATA, stsdout},
{ATOM_DESCENT},
{ATOM_NAME, "mp4a"},
{ATOM_DATA, mp4aout},
{ATOM_DESCENT},
{ATOM_NAME, "esds"},
{ATOM_DATA, esdsout},
{ATOM_ASCENT},
{ATOM_ASCENT},
{ATOM_NAME, "stts"},
{ATOM_DATA, sttsout},
{ATOM_NAME, "stsc"},
{ATOM_DATA, stscout},
{ATOM_NAME, "stsz"},
{ATOM_DATA, stszout},
{ATOM_NAME, "stco"},
{ATOM_DATA, stcoout},
{ATOM_ASCENT},
{ATOM_ASCENT},
{ATOM_ASCENT},
{ATOM_ASCENT},
{ATOM_NAME, "udta"},
{ATOM_DESCENT},
{ATOM_NAME, "meta"},
{ATOM_DATA, metaout},
{ATOM_DESCENT},
{ATOM_NAME, "hdlr"},
{ATOM_DATA, hdlr2out},
{ATOM_NAME, "ilst"},
{ATOM_DATA, ilstout},
{0}
};
static creator_t *g_atom = 0;
static int create(void)
{
long apos = ftell(g_fout);;
int size;
size = u32out(8);
size += dataout(g_atom->data, 4);
g_atom++;
if (g_atom->opcode == ATOM_DATA)
{
size += ((int (*)(void)) g_atom->data) ();
g_atom++;
}
if (g_atom->opcode == ATOM_DESCENT)
{
g_atom++;
while (g_atom->opcode != ATOM_STOP)
{
if (g_atom->opcode == ATOM_ASCENT)
{
g_atom++;
break;
}
size += create();
}
}
fseek(g_fout, apos, SEEK_SET);
u32out(size);
fseek(g_fout, apos + size, SEEK_SET);
return size;
}
enum {BUFSTEP = 0x4000};
int mp4atom_frame(uint8_t * buf, int size, int samples)
{
if (mp4config.framesamples <= samples)
{
int bitrate = 8.0 * size * mp4config.samplerate / samples;
if (mp4config.bitratemax < bitrate)
mp4config.bitratemax = bitrate;
mp4config.framesamples = samples;
}
if (mp4config.buffersize < size)
mp4config.buffersize = size;
mp4config.samples += samples;
mp4config.mdatsize += dataout(buf, size);
if (((mp4config.frame.ents + 1) * sizeof(*(mp4config.frame.data)))
> mp4config.frame.bufsize)
{
mp4config.frame.bufsize += BUFSTEP;
mp4config.frame.data = realloc(mp4config.frame.data,
mp4config.frame.bufsize);
}
mp4config.frame.data[mp4config.frame.ents++] = size;
return 0;
}
int mp4atom_close(void)
{
if (g_fout)
{
fseek(g_fout, mp4config.mdatofs - 8, SEEK_SET);
u32out(mp4config.mdatsize + 8);
fclose(g_fout);
g_fout = 0;
}
if (mp4config.frame.data)
{
free(mp4config.frame.data);
mp4config.frame.data = 0;
}
return 0;
}
int mp4atom_open(char *name)
{
mp4atom_close();
g_fout = fopen(name, "wb");
if (!g_fout)
return 1;
mp4config.mdatsize = 0;
mp4config.frame.bufsize = BUFSTEP;
mp4config.frame.data = malloc(mp4config.frame.bufsize);
return 0;
}
int mp4atom_head(void)
{
g_atom = g_head;
while (g_atom->opcode != ATOM_STOP)
create();
mp4config.mdatofs = ftell(g_fout);
return 0;
}
int mp4atom_tail(void)
{
mp4config.bitrateavg = 8.0 * mp4config.mdatsize
* mp4config.samplerate / mp4config.samples;
g_atom = g_tail;
while (g_atom->opcode != ATOM_STOP)
create();
return 0;
}