static int latm_decode_frame(AVCodecContext *avctx, void *out, int *got_frame_ptr, AVPacket *avpkt) { struct LATMContext *latmctx = avctx->priv_data; int muxlength, err; GetBitContext gb; if ((err = init_get_bits8(&gb, avpkt->data, avpkt->size)) < 0) return err; // check for LOAS sync word if (get_bits(&gb, 11) != LOAS_SYNC_WORD) return AVERROR_INVALIDDATA; muxlength = get_bits(&gb, 13) + 3; // not enough data, the parser should have sorted this out if (muxlength > avpkt->size) return AVERROR_INVALIDDATA; if ((err = read_audio_mux_element(latmctx, &gb)) < 0) return err; if (!latmctx->initialized) { if (!avctx->extradata) { *got_frame_ptr = 0; return avpkt->size; } else { push_output_configuration(&latmctx->aac_ctx); if ((err = decode_audio_specific_config( &latmctx->aac_ctx, avctx, &latmctx->aac_ctx.oc[1].m4ac, avctx->extradata, avctx->extradata_size*8LL, 1)) < 0) { pop_output_configuration(&latmctx->aac_ctx); return err; } latmctx->initialized = 1; } } if (show_bits(&gb, 12) == 0xfff) { av_log(latmctx->aac_ctx.avctx, AV_LOG_ERROR, "ADTS header detected, probably as result of configuration " "misparsing\n"); return AVERROR_INVALIDDATA; } switch (latmctx->aac_ctx.oc[1].m4ac.object_type) { case AOT_ER_AAC_LC: case AOT_ER_AAC_LTP: case AOT_ER_AAC_LD: case AOT_ER_AAC_ELD: err = aac_decode_er_frame(avctx, out, got_frame_ptr, &gb); break; default: err = aac_decode_frame_int(avctx, out, got_frame_ptr, &gb, avpkt); } if (err < 0) return err; return muxlength; }
static int latm_decode_audio_specific_config(struct LATMContext *latmctx, GetBitContext *gb, int asclen) { AACContext *ac = &latmctx->aac_ctx; AVCodecContext *avctx = ac->avctx; MPEG4AudioConfig m4ac = { 0 }; int config_start_bit = get_bits_count(gb); int sync_extension = 0; int bits_consumed, esize; if (asclen) { sync_extension = 1; asclen = FFMIN(asclen, get_bits_left(gb)); } else asclen = get_bits_left(gb); if (config_start_bit % 8) { avpriv_request_sample(latmctx->aac_ctx.avctx, "Non-byte-aligned audio-specific config"); return AVERROR_PATCHWELCOME; } if (asclen <= 0) return AVERROR_INVALIDDATA; bits_consumed = decode_audio_specific_config(NULL, avctx, &m4ac, gb->buffer + (config_start_bit / 8), asclen, sync_extension); if (bits_consumed < 0) return AVERROR_INVALIDDATA; if (!latmctx->initialized || ac->oc[1].m4ac.sample_rate != m4ac.sample_rate || ac->oc[1].m4ac.chan_config != m4ac.chan_config) { if(latmctx->initialized) { av_log(avctx, AV_LOG_INFO, "audio config changed\n"); } else { av_log(avctx, AV_LOG_DEBUG, "initializing latmctx\n"); } latmctx->initialized = 0; esize = (bits_consumed+7) / 8; if (avctx->extradata_size < esize) { av_free(avctx->extradata); avctx->extradata = av_malloc(esize + AV_INPUT_BUFFER_PADDING_SIZE); if (!avctx->extradata) return AVERROR(ENOMEM); } avctx->extradata_size = esize; memcpy(avctx->extradata, gb->buffer + (config_start_bit/8), esize); memset(avctx->extradata+esize, 0, AV_INPUT_BUFFER_PADDING_SIZE); } skip_bits_long(gb, bits_consumed); return bits_consumed; }
static av_cold int aac_decode_init(AVCodecContext *avctx) { AACContext *ac = avctx->priv_data; ac->avctx = avctx; ac->m4ac.sample_rate = avctx->sample_rate; if (avctx->extradata_size > 0) { if (decode_audio_specific_config(ac, avctx->extradata, avctx->extradata_size)) return -1; } avctx->sample_fmt = SAMPLE_FMT_S16; AAC_INIT_VLC_STATIC( 0, 304); AAC_INIT_VLC_STATIC( 1, 270); AAC_INIT_VLC_STATIC( 2, 550); AAC_INIT_VLC_STATIC( 3, 300); AAC_INIT_VLC_STATIC( 4, 328); AAC_INIT_VLC_STATIC( 5, 294); AAC_INIT_VLC_STATIC( 6, 306); AAC_INIT_VLC_STATIC( 7, 268); AAC_INIT_VLC_STATIC( 8, 510); AAC_INIT_VLC_STATIC( 9, 366); AAC_INIT_VLC_STATIC(10, 462); ff_aac_sbr_init(); dsputil_init(&ac->dsp, avctx); ac->random_state = 0x1f2e3d4c; // -1024 - Compensate wrong IMDCT method. // 32768 - Required to scale values to the correct range for the bias method // for float to int16 conversion. if (ac->dsp.float_to_int16_interleave == ff_float_to_int16_interleave_c) { ac->add_bias = 385.0f; ac->sf_scale = 1. / (-1024. * 32768.); ac->sf_offset = 0; } else { ac->add_bias = 0.0f; ac->sf_scale = 1. / -1024.; ac->sf_offset = 60; } ff_aac_tableinit(); INIT_VLC_STATIC(&vlc_scalefactors,7,FF_ARRAY_ELEMS(ff_aac_scalefactor_code), ff_aac_scalefactor_bits, sizeof(ff_aac_scalefactor_bits[0]), sizeof(ff_aac_scalefactor_bits[0]), ff_aac_scalefactor_code, sizeof(ff_aac_scalefactor_code[0]), sizeof(ff_aac_scalefactor_code[0]), 352); ff_mdct_init(&ac->mdct, 11, 1, 1.0); ff_mdct_init(&ac->mdct_small, 8, 1, 1.0); // window initialization ff_kbd_window_init(ff_aac_kbd_long_1024, 4.0, 1024); ff_kbd_window_init(ff_aac_kbd_short_128, 6.0, 128); ff_init_ff_sine_windows(10); ff_init_ff_sine_windows( 7); cbrt_tableinit(); return 0; }