aacdec.c

   1 /*
   2  * Copyright (C) 2006-2008 Andre Noll <maan@systemlinux.org>
   3  *
   4  * Licensed under the GPL v2. For licencing details see COPYING.
   5  */
   6 /*
   7  * based in parts on libfaad, Copyright (C) 2003-2005 M. Bakker,
   8  * Ahead Software AG
   9  */
  10
  11 /** \file aacdec.c paraslash's aac (m4a) decoder */
  12
  13 #include "para.h"
  14
  15 #include "list.h"
  16 #include "sched.h"
  17 #include "filter.h"
  18 #include "error.h"
  19 #include "string.h"
  20 #include "aac.h"
  21
  22 /** the output buffer size */
  23 #define AAC_OUTBUF_SIZE (32 * 1024)
  24
  25 /** give up decoding after that many errors */
  26 #define MAX_ERRORS 20
  27
  28 /**
  29  * data specific to the aacdec filter
  30  *
  31  * \sa filter, filter_node
  32  */
  33 struct private_aacdec_data {
  34         /** the return value of aac_open */
  35         NeAACDecHandle handle;
  36         /** info about the currently decoded frame */
  37         NeAACDecFrameInfo frame_info;
  38         /** whether this instance of the aac decoder is already initialized */
  39         int initialized;
  40         /**
  41          * return value of aac_find_esds(). Used to call the right aacdec
  42          * init function
  43          */
  44         unsigned long decoder_length;
  45         /** number of times the decoder returned an error */
  46         unsigned error_count;
  47         /** number of bytes already consumed from the imput stream */
  48         size_t consumed_total;
  49         /** return value of aac_find_entry_point */
  50         size_t entry;
  51 };
  52
  53 static ssize_t aacdec(char *input_buffer, size_t len, struct filter_node *fn)
  54 {
  55         struct private_aacdec_data *padd = fn->private_data;
  56         struct filter_chain *fc = fn->fc;
  57         int i, ret;
  58         unsigned char *p, *outbuffer;
  59         unsigned char *inbuf = (unsigned char*)input_buffer;
  60         size_t skip, consumed = 0;
  61
  62         if (fn->loaded > fn->bufsize * 3 / 5)
  63                 return 0;
  64         if (len < 2048 && !*fc->input_error)
  65                 return 0;
  66
  67         if (!padd->initialized) {
  68                 unsigned long rate = 0;
  69                 unsigned char channels = 0;
  70                 ret = aac_find_esds(inbuf, len, &skip, &padd->decoder_length);
  71                 if (ret < 0) {
  72                         PARA_INFO_LOG("%s\n", para_strerror(-ret));
  73                         ret = NeAACDecInit(padd->handle, inbuf,
  74                                 len, &rate, &channels);
  75                         PARA_INFO_LOG("decoder init: %d\n", ret);
  76                         if (ret < 0) {
  77                                 ret = -E_AACDEC_INIT;
  78                                 goto out;
  79                         }
  80                         consumed = ret;
  81                 } else {
  82                         PARA_INFO_LOG("decoder len: %lu\n",
  83                                 padd->decoder_length);
  84                         consumed += skip;
  85                         p = inbuf + consumed;
  86                         ret = -E_AACDEC_INIT;
  87                         if (NeAACDecInit2(padd->handle, p,
  88                                         padd->decoder_length, &rate,
  89                                         &channels) < 0)
  90                                 goto out;
  91                 }
  92                 fc->samplerate = rate;
  93                 fc->channels = channels;
  94                 PARA_INFO_LOG("rate: %u, channels: %d\n",
  95                         fc->samplerate, fc->channels);
  96                 padd->initialized = 1;
  97         }
  98         if (padd->decoder_length > 0) {
  99                 consumed = 0;
 100                 if (!padd->entry) {
 101                         ret = aac_find_entry_point(inbuf + consumed,
 102                                 len - consumed, &skip);
 103                         if (ret < 0) {
 104                                 ret = len;
 105                                 goto out;
 106                         }
 107                         consumed += skip;
 108                         padd->entry = ret;
 109                         PARA_INFO_LOG("entry: %zu\n", padd->entry);
 110                 }
 111                 ret = len;
 112                 if (padd->consumed_total + len < padd->entry)
 113                         goto out;
 114                 if (padd->consumed_total < padd->entry)
 115                         consumed = padd->entry - padd->consumed_total;
 116         }
 117         for (; consumed < len; consumed++)
 118                 if ((inbuf[consumed] & 0xfe) == 0x20)
 119                         break;
 120         if (consumed >= len)
 121                 goto success;
 122         p = inbuf + consumed;
 123         outbuffer = NeAACDecDecode(padd->handle, &padd->frame_info, p,
 124                 len - consumed);
 125         if (padd->frame_info.error) {
 126                 ret = -E_AAC_DECODE;
 127                 if (padd->error_count++ > MAX_ERRORS)
 128                         goto out;
 129                 PARA_ERROR_LOG("frame_error: %d, consumed: %zu + %zd + %lu\n",
 130                         padd->frame_info.error, padd->consumed_total,
 131                         consumed, padd->frame_info.bytesconsumed);
 132                 PARA_ERROR_LOG("%s\n", NeAACDecGetErrorMessage(
 133                         padd->frame_info.error));
 134                 consumed++; /* catch 21 */
 135                 goto success;
 136         }
 137         padd->error_count = 0;
 138         consumed += padd->frame_info.bytesconsumed;
 139         ret = consumed;
 140         if (!padd->frame_info.samples)
 141                 goto out;
 142         ret = -E_AAC_OVERRUN;
 143         if (padd->frame_info.samples * 2 + fn->loaded > fn->bufsize)
 144                 goto out;
 145         for (i = 0; i < padd->frame_info.samples; i++) {
 146                 short *s = (short *)outbuffer;
 147                 write_int16_host_endian(fn->buf + fn->loaded, s[i]);
 148                 fn->loaded += 2;
 149         }
 150 success:
 151         ret = consumed;
 152 out:
 153         if (ret > 0)
 154                 padd->consumed_total += ret;
 155         return ret;
 156 }
 157
 158 static void aacdec_open(struct filter_node *fn)
 159 {
 160         fn->private_data = para_calloc(sizeof(struct private_aacdec_data));
 161         struct private_aacdec_data *padd = fn->private_data;
 162
 163         fn->bufsize = AAC_OUTBUF_SIZE;
 164         fn->buf = para_calloc(fn->bufsize);
 165         padd->handle = aac_open();
 166 }
 167
 168 static void aacdec_close(struct filter_node *fn)
 169 {
 170         struct private_aacdec_data *padd = fn->private_data;
 171
 172         NeAACDecClose(padd->handle);
 173         free(fn->buf);
 174         fn->buf = NULL;
 175         free(padd);
 176         fn->private_data = NULL;
 177 }
 178
 179 /**
 180  * the init function of the aacdec filter
 181  *
 182  * \param f pointer to the filter struct to initialize
 183  *
 184  * \sa filter::init
 185  */
 186 void aacdec_init(struct filter *f)
 187 {
 188         f->open = aacdec_open;
 189         f->convert = aacdec;
 190         f->close = aacdec_close;
 191 }