/***************************************************************************** * mpegaudio.c: parse MPEG audio sync info and packetize the stream ***************************************************************************** * Copyright (C) 2001-2016 VLC authors and VideoLAN * $Id$ * * Authors: Laurent Aimar * Eric Petit * Christophe Massiot * Gildas Bazin * * This program is free software; you can redistribute it and/or modify it * under the terms of the GNU Lesser General Public License as published by * the Free Software Foundation; either version 2.1 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 Lesser General Public License for more details. * * You should have received a copy of the GNU Lesser General Public License * along with this program; if not, write to the Free Software Foundation, * Inc., 51 Franklin Street, Fifth Floor, Boston MA 02110-1301, USA. *****************************************************************************/ /***************************************************************************** * Preamble *****************************************************************************/ #ifdef HAVE_CONFIG_H # include "config.h" #endif #include #include #include #include #include #include #include #include "packetizer_helper.h" /***************************************************************************** * decoder_sys_t : decoder descriptor *****************************************************************************/ struct decoder_sys_t { /* * Input properties */ int i_state; block_bytestream_t bytestream; /* * Common properties */ date_t end_date; vlc_tick_t i_pts; int i_frame_size, i_free_frame_size; unsigned int i_channels_conf, i_chan_mode, i_channels; unsigned int i_rate, i_max_frame_size, i_frame_length; unsigned int i_layer, i_bit_rate; bool b_discontinuity; }; #define MAD_BUFFER_GUARD 8 #define MPGA_HEADER_SIZE 4 /**************************************************************************** * Local prototypes ****************************************************************************/ static int Open( vlc_object_t * ); static void Close( vlc_object_t * ); /***************************************************************************** * Module descriptor *****************************************************************************/ vlc_module_begin () set_category( CAT_INPUT ) set_subcategory( SUBCAT_INPUT_ACODEC ) set_description( N_("MPEG audio layer I/II/III packetizer") ) set_capability( "packetizer", 10 ) set_callbacks( Open, Close ) vlc_module_end () /***************************************************************************** * Flush: *****************************************************************************/ static void Flush( decoder_t *p_dec ) { decoder_sys_t *p_sys = p_dec->p_sys; date_Set( &p_sys->end_date, VLC_TICK_INVALID ); p_sys->i_state = STATE_NOSYNC; block_BytestreamEmpty( &p_sys->bytestream ); p_sys->b_discontinuity = true; } /***************************************************************************** * GetOutBuffer: *****************************************************************************/ static uint8_t *GetOutBuffer( decoder_t *p_dec, block_t **pp_out_buffer ) { decoder_sys_t *p_sys = p_dec->p_sys; if( p_dec->fmt_out.audio.i_rate != p_sys->i_rate || date_Get( &p_sys->end_date ) == VLC_TICK_INVALID ) { msg_Dbg( p_dec, "MPGA channels:%d samplerate:%d bitrate:%d", p_sys->i_channels, p_sys->i_rate, p_sys->i_bit_rate ); if( p_sys->end_date.i_divider_num == 0 ) date_Init( &p_sys->end_date, p_sys->i_rate, 1 ); else date_Change( &p_sys->end_date, p_sys->i_rate, 1 ); date_Set( &p_sys->end_date, p_sys->i_pts ); } p_dec->fmt_out.i_profile = p_sys->i_layer; p_dec->fmt_out.audio.i_rate = p_sys->i_rate; p_dec->fmt_out.audio.i_channels = p_sys->i_channels; p_dec->fmt_out.audio.i_frame_length = p_sys->i_frame_length; p_dec->fmt_out.audio.i_bytes_per_frame = p_sys->i_max_frame_size; p_dec->fmt_out.audio.i_physical_channels = p_sys->i_channels_conf; p_dec->fmt_out.audio.i_chan_mode = p_sys->i_chan_mode; p_dec->fmt_out.i_bitrate = p_sys->i_bit_rate * 1000; block_t *p_block = block_Alloc( p_sys->i_frame_size ); if( p_block == NULL ) return NULL; p_block->i_pts = p_block->i_dts = date_Get( &p_sys->end_date ); p_block->i_length = date_Increment( &p_sys->end_date, p_sys->i_frame_length ) - p_block->i_pts; *pp_out_buffer = p_block; return p_block->p_buffer; } /***************************************************************************** * SyncInfo: parse MPEG audio sync info *****************************************************************************/ static int SyncInfo( uint32_t i_header, unsigned int * pi_channels, unsigned int * pi_channels_conf, unsigned int * pi_chan_mode, unsigned int * pi_sample_rate, unsigned int * pi_bit_rate, unsigned int * pi_frame_length, unsigned int * pi_max_frame_size, unsigned int * pi_layer) { static const int ppi_bitrate[2][3][16] = { { /* v1 l1 */ { 0, 32, 64, 96, 128, 160, 192, 224, 256, 288, 320, 352, 384, 416, 448, 0}, /* v1 l2 */ { 0, 32, 48, 56, 64, 80, 96, 112, 128, 160, 192, 224, 256, 320, 384, 0}, /* v1 l3 */ { 0, 32, 40, 48, 56, 64, 80, 96, 112, 128, 160, 192, 224, 256, 320, 0} }, { /* v2 l1 */ { 0, 32, 48, 56, 64, 80, 96, 112, 128, 144, 160, 176, 192, 224, 256, 0}, /* v2 l2 */ { 0, 8, 16, 24, 32, 40, 48, 56, 64, 80, 96, 112, 128, 144, 160, 0}, /* v2 l3 */ { 0, 8, 16, 24, 32, 40, 48, 56, 64, 80, 96, 112, 128, 144, 160, 0} } }; static const int ppi_samplerate[2][4] = /* version 1 then 2 */ { { 44100, 48000, 32000, 0 }, { 22050, 24000, 16000, 0 } }; int i_version, i_mode, i_emphasis; bool b_padding, b_mpeg_2_5; int i_frame_size = 0; int i_bitrate_index, i_samplerate_index; int i_max_bit_rate; b_mpeg_2_5 = 1 - ((i_header & 0x100000) >> 20); i_version = 1 - ((i_header & 0x80000) >> 19); *pi_layer = 4 - ((i_header & 0x60000) >> 17); //bool b_crc = !((i_header >> 16) & 0x01); i_bitrate_index = (i_header & 0xf000) >> 12; i_samplerate_index = (i_header & 0xc00) >> 10; b_padding = (i_header & 0x200) >> 9; /* Extension */ i_mode = (i_header & 0xc0) >> 6; /* Modeext, copyright & original */ i_emphasis = i_header & 0x3; *pi_chan_mode = 0; if( *pi_layer != 4 && i_bitrate_index < 0x0f && i_samplerate_index != 0x03 && i_emphasis != 0x02 ) { switch ( i_mode ) { case 2: /* dual-mono */ *pi_chan_mode = AOUT_CHANMODE_DUALMONO; /* fall through */ case 0: /* stereo */ case 1: /* joint stereo */ *pi_channels = 2; *pi_channels_conf = AOUT_CHAN_LEFT | AOUT_CHAN_RIGHT; break; case 3: /* mono */ *pi_channels = 1; *pi_channels_conf = AOUT_CHAN_CENTER; break; } *pi_bit_rate = ppi_bitrate[i_version][*pi_layer-1][i_bitrate_index]; i_max_bit_rate = ppi_bitrate[i_version][*pi_layer-1][14]; *pi_sample_rate = ppi_samplerate[i_version][i_samplerate_index]; if ( b_mpeg_2_5 ) { *pi_sample_rate >>= 1; } switch( *pi_layer ) { case 1: i_frame_size = ( 12000 * *pi_bit_rate / *pi_sample_rate + b_padding ) * 4; *pi_max_frame_size = ( 12000 * i_max_bit_rate / *pi_sample_rate + 1 ) * 4; *pi_frame_length = 384; break; case 2: i_frame_size = 144000 * *pi_bit_rate / *pi_sample_rate + b_padding; *pi_max_frame_size = 144000 * i_max_bit_rate / *pi_sample_rate + 1; *pi_frame_length = 1152; break; case 3: i_frame_size = ( i_version ? 72000 : 144000 ) * *pi_bit_rate / *pi_sample_rate + b_padding; *pi_max_frame_size = ( i_version ? 72000 : 144000 ) * i_max_bit_rate / *pi_sample_rate + 1; *pi_frame_length = i_version ? 576 : 1152; break; default: break; } /* Free bitrate mode can support higher bitrates */ if( !*pi_bit_rate ) *pi_max_frame_size *= 2; } else { return -1; } return i_frame_size; } /**************************************************************************** * DecodeBlock: the whole thing **************************************************************************** * This function is called just after the thread is launched. ****************************************************************************/ static block_t *DecodeBlock( decoder_t *p_dec, block_t **pp_block ) { decoder_sys_t *p_sys = p_dec->p_sys; uint8_t p_header[MAD_BUFFER_GUARD]; uint32_t i_header; uint8_t *p_buf; block_t *p_out_buffer; block_t *p_block = pp_block ? *pp_block : NULL; if (p_block) { if( p_block->i_flags & (BLOCK_FLAG_DISCONTINUITY|BLOCK_FLAG_CORRUPTED) ) { /* First always drain complete blocks before discontinuity */ block_t *p_drain = DecodeBlock( p_dec, NULL ); if( p_drain ) return p_drain; Flush( p_dec ); if( p_block->i_flags & BLOCK_FLAG_CORRUPTED ) { block_Release( p_block ); return NULL; } } if( !date_Get( &p_sys->end_date ) && p_block->i_pts <= VLC_TICK_INVALID ) { /* We've just started the stream, wait for the first PTS. */ msg_Dbg( p_dec, "waiting for PTS" ); block_Release( p_block ); return NULL; } block_BytestreamPush( &p_sys->bytestream, p_block ); } while( 1 ) { switch( p_sys->i_state ) { case STATE_NOSYNC: while( block_PeekBytes( &p_sys->bytestream, p_header, 2 ) == VLC_SUCCESS ) { /* Look for sync word - should be 0xffe */ if( p_header[0] == 0xff && (p_header[1] & 0xe0) == 0xe0 ) { p_sys->i_state = STATE_SYNC; break; } block_SkipByte( &p_sys->bytestream ); } if( p_sys->i_state != STATE_SYNC ) { block_BytestreamFlush( &p_sys->bytestream ); /* Need more data */ return NULL; } /* fallthrough */ case STATE_SYNC: /* New frame, set the Presentation Time Stamp */ p_sys->i_pts = p_sys->bytestream.p_block->i_pts; if( p_sys->i_pts > VLC_TICK_INVALID && p_sys->i_pts != date_Get( &p_sys->end_date ) ) { if( p_dec->fmt_in.i_original_fourcc == VLC_FOURCC( 'D','V','R',' ') ) { if( date_Get( &p_sys->end_date ) == VLC_TICK_INVALID ) date_Set( &p_sys->end_date, p_sys->i_pts ); } else if ( p_sys->i_pts != date_Get( &p_sys->end_date ) ) { date_Set( &p_sys->end_date, p_sys->i_pts ); } } p_sys->i_state = STATE_HEADER; /* fallthrough */ case STATE_HEADER: /* Get MPGA frame header (MPGA_HEADER_SIZE bytes) */ if( block_PeekBytes( &p_sys->bytestream, p_header, MPGA_HEADER_SIZE ) != VLC_SUCCESS ) { /* Need more data */ return NULL; } /* Build frame header */ i_header = GetDWBE(p_header); /* Check if frame is valid and get frame info */ p_sys->i_frame_size = SyncInfo( i_header, &p_sys->i_channels, &p_sys->i_channels_conf, &p_sys->i_chan_mode, &p_sys->i_rate, &p_sys->i_bit_rate, &p_sys->i_frame_length, &p_sys->i_max_frame_size, &p_sys->i_layer ); if( p_sys->i_frame_size == -1 ) { msg_Dbg( p_dec, "emulated startcode" ); block_SkipByte( &p_sys->bytestream ); p_sys->i_state = STATE_NOSYNC; break; } if( p_sys->i_bit_rate == 0 ) { /* Free bitrate, but 99% emulated startcode :( */ if( p_dec->p_sys->i_free_frame_size == MPGA_HEADER_SIZE ) { msg_Dbg( p_dec, "free bitrate mode"); } /* The -1 below is to account for the frame padding */ p_sys->i_frame_size = p_sys->i_free_frame_size - 1; } p_sys->i_state = STATE_NEXT_SYNC; /* fallthrough */ case STATE_NEXT_SYNC: /* Check if next expected frame contains the sync word */ if( block_PeekOffsetBytes( &p_sys->bytestream, p_sys->i_frame_size, p_header, MAD_BUFFER_GUARD ) != VLC_SUCCESS ) { if( p_block == NULL ) /* drain */ { p_sys->i_state = STATE_SEND_DATA; break; } /* Need more data */ return NULL; } if( p_header[0] == 0xff && (p_header[1] & 0xe0) == 0xe0 ) { /* Startcode is fine, let's try the header as an extra check */ int i_next_frame_size; unsigned int i_next_channels, i_next_stereo_mode, i_next_channels_conf; unsigned int i_next_rate, i_next_bit_rate; unsigned int i_next_frame_length, i_next_max_frame_size; unsigned int i_next_layer; /* Build frame header */ i_header = GetDWBE(p_header); i_next_frame_size = SyncInfo( i_header, &i_next_channels, &i_next_channels_conf, &i_next_stereo_mode, &i_next_rate, &i_next_bit_rate, &i_next_frame_length, &i_next_max_frame_size, &i_next_layer ); /* Free bitrate only */ if( p_sys->i_bit_rate == 0 && i_next_frame_size == -1 ) { if( (unsigned int)p_sys->i_frame_size > p_sys->i_max_frame_size ) { msg_Dbg( p_dec, "frame too big %d > %d " "(emulated startcode ?)", p_sys->i_frame_size, p_sys->i_max_frame_size ); block_SkipByte( &p_sys->bytestream ); p_sys->i_state = STATE_NOSYNC; p_sys->i_free_frame_size = MPGA_HEADER_SIZE; break; } p_sys->i_frame_size++; break; } if( i_next_frame_size == -1 ) { msg_Dbg( p_dec, "emulated startcode on next frame" ); block_SkipByte( &p_sys->bytestream ); p_sys->i_state = STATE_NOSYNC; break; } /* Check info is in sync with previous one */ if( i_next_channels_conf != p_sys->i_channels_conf || i_next_stereo_mode != p_sys->i_chan_mode || i_next_rate != p_sys->i_rate || i_next_layer != p_sys->i_layer || i_next_frame_length != p_sys->i_frame_length ) { /* Free bitrate only */ if( p_sys->i_bit_rate == 0 ) { p_sys->i_frame_size++; break; } msg_Dbg( p_dec, "parameters changed unexpectedly " "(emulated startcode ?)" ); block_SkipByte( &p_sys->bytestream ); p_sys->i_state = STATE_NOSYNC; break; } /* Free bitrate only */ if( p_sys->i_bit_rate == 0 ) { if( i_next_bit_rate != 0 ) { p_sys->i_frame_size++; break; } } } else { /* Free bitrate only */ if( p_sys->i_bit_rate == 0 ) { if( (unsigned int)p_sys->i_frame_size > p_sys->i_max_frame_size ) { msg_Dbg( p_dec, "frame too big %d > %d " "(emulated startcode ?)", p_sys->i_frame_size, p_sys->i_max_frame_size ); block_SkipByte( &p_sys->bytestream ); p_sys->i_state = STATE_NOSYNC; p_sys->i_free_frame_size = MPGA_HEADER_SIZE; break; } p_sys->i_frame_size++; break; } msg_Dbg( p_dec, "emulated startcode " "(no startcode on following frame)" ); p_sys->i_state = STATE_NOSYNC; block_SkipByte( &p_sys->bytestream ); break; } p_sys->i_state = STATE_GET_DATA; break; case STATE_GET_DATA: /* Make sure we have enough data. * (Not useful if we went through NEXT_SYNC) */ if( block_WaitBytes( &p_sys->bytestream, p_sys->i_frame_size ) != VLC_SUCCESS ) { /* Need more data */ return NULL; } p_sys->i_state = STATE_SEND_DATA; /* fallthrough */ case STATE_SEND_DATA: if( !(p_buf = GetOutBuffer( p_dec, &p_out_buffer )) ) { return NULL; } /* Free bitrate only */ if( p_sys->i_bit_rate == 0 ) { p_sys->i_free_frame_size = p_sys->i_frame_size; } /* Copy the whole frame into the buffer. */ if (block_GetBytes( &p_sys->bytestream, p_buf, __MIN( (unsigned)p_sys->i_frame_size, p_out_buffer->i_buffer ) )) { block_Release(p_out_buffer); return NULL; } p_sys->i_state = STATE_NOSYNC; /* Make sure we don't reuse the same pts twice */ if( p_sys->i_pts == p_sys->bytestream.p_block->i_pts ) p_sys->i_pts = p_sys->bytestream.p_block->i_pts = VLC_TICK_INVALID; if( p_sys->b_discontinuity ) { p_out_buffer->i_flags |= BLOCK_FLAG_DISCONTINUITY; p_sys->b_discontinuity = false; } /* So p_block doesn't get re-added several times */ p_block = block_BytestreamPop( &p_sys->bytestream ); if (pp_block) *pp_block = p_block; else if (p_block) block_Release(p_block); return p_out_buffer; } } return NULL; } /***************************************************************************** * Close: clean up the decoder *****************************************************************************/ static void Close( vlc_object_t *p_this ) { decoder_t *p_dec = (decoder_t *)p_this; decoder_sys_t *p_sys = p_dec->p_sys; block_BytestreamRelease( &p_sys->bytestream ); free( p_sys ); } /***************************************************************************** * Open: probe the decoder and return score *****************************************************************************/ static int Open( vlc_object_t *p_this ) { decoder_t *p_dec = (decoder_t*)p_this; decoder_sys_t *p_sys; if( p_dec->fmt_in.i_cat != AUDIO_ES ) return VLC_EGENERIC; if(( p_dec->fmt_in.i_codec != VLC_CODEC_MPGA ) && ( p_dec->fmt_in.i_codec != VLC_CODEC_MP3 ) ) { return VLC_EGENERIC; } /* Allocate the memory needed to store the decoder's structure */ if( ( p_dec->p_sys = p_sys = (decoder_sys_t *)malloc(sizeof(decoder_sys_t)) ) == NULL ) return VLC_ENOMEM; /* Misc init */ p_sys->i_state = STATE_NOSYNC; date_Init( &p_sys->end_date, 1, 1 ); date_Set( &p_sys->end_date, VLC_TICK_INVALID ); block_BytestreamInit( &p_sys->bytestream ); p_sys->i_pts = VLC_TICK_INVALID; p_sys->b_discontinuity = false; p_sys->i_frame_size = 0; p_sys->i_channels_conf = p_sys->i_chan_mode = p_sys->i_channels = p_sys->i_rate = p_sys->i_max_frame_size = p_sys->i_frame_length = p_sys->i_layer = p_sys->i_bit_rate = 0; /* Set output properties */ p_dec->fmt_out.i_codec = VLC_CODEC_MPGA; p_dec->fmt_out.audio.i_rate = 0; /* So end_date gets initialized */ /* Set callback */ p_dec->pf_packetize = DecodeBlock; p_dec->pf_flush = Flush; /* Start with the minimum size for a free bitrate frame */ p_sys->i_free_frame_size = MPGA_HEADER_SIZE; return VLC_SUCCESS; }