* Christophe Massiot <massiot@via.ecp.fr>
* Gildas Bazin <gbazin@videolan.org>
* Lauren Aimar <fenrir _AT_ videolan _DOT_ org >
+ * Steinar H. Gunderson <steinar+vlc@gunderson.no>
*
* 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
static int OpenPacketizer( vlc_object_t * );
static void CloseCommon ( vlc_object_t * );
+#ifdef ENABLE_SOUT
+static int OpenEncoder ( vlc_object_t * );
+static void CloseEncoder ( vlc_object_t * );
+static block_t *EncodeFrames( encoder_t *, aout_buffer_t * );
+#endif
+
vlc_module_begin ()
set_category( CAT_INPUT )
set_capability( "packetizer", 100 )
set_callbacks( OpenPacketizer, CloseCommon )
+#ifdef ENABLE_SOUT
+ add_submodule ()
+ set_description( N_("Linear PCM audio encoder") )
+ set_capability( "encoder", 100 )
+ set_callbacks( OpenEncoder, CloseEncoder )
+ add_shortcut( "lpcm" )
+#endif
+
vlc_module_end ()
int i_type;
};
+#ifdef ENABLE_SOUT
+struct encoder_sys_t
+{
+ int i_channels;
+ int i_rate;
+
+ int i_frame_samples;
+ uint8_t *p_buffer;
+ int i_buffer_used;
+ int i_frame_num;
+};
+#endif
+
/*
* LPCM DVD header :
- * - frame number (8 bits)
- * - unknown (16 bits) == 0x0003 ?
- * - unknown (4 bits)
- * - current frame (4 bits)
- * - unknown (2 bits)
- * - frequency (2 bits) 0 == 48 kHz, 1 == 32 kHz, 2 == ?, 3 == ?
- * - unknown (1 bit)
+ * - number of frames in this packet (8 bits)
+ * - first access unit (16 bits) == 0x0003 ?
+ * - emphasis (1 bit)
+ * - mute (1 bit)
+ * - reserved (1 bit)
+ * - current frame (5 bits)
+ * - quantisation (2 bits) 0 == 16bps, 1 == 20bps, 2 == 24bps, 3 == illegal
+ * - frequency (2 bits) 0 == 48 kHz, 1 == 96 kHz, 2 == 44.1 kHz, 3 == 32 kHz
+ * - reserved (1 bit)
* - number of channels - 1 (3 bits) 1 == 2 channels
- * - start code (8 bits) == 0x80
+ * - dynamic range (8 bits) 0x80 == neutral
*
* LPCM DVD-A header (http://dvd-audio.sourceforge.net/spec/aob.shtml)
* - continuity counter (8 bits, clipped to 0x00-0x1f)
free( p_dec->p_sys );
}
+#ifdef ENABLE_SOUT
+/*****************************************************************************
+ * OpenEncoder: lpcm encoder construction
+ *****************************************************************************/
+static int OpenEncoder( vlc_object_t *p_this )
+{
+ encoder_t *p_enc = (encoder_t *)p_this;
+ encoder_sys_t *p_sys;
+
+ /* We only support DVD LPCM yet. */
+ if( p_enc->fmt_out.i_codec != VLC_CODEC_DVD_LPCM )
+ return VLC_EGENERIC;
+
+ if( p_enc->fmt_in.audio.i_rate != 48000 &&
+ p_enc->fmt_in.audio.i_rate != 96000 &&
+ p_enc->fmt_in.audio.i_rate != 44100 &&
+ p_enc->fmt_in.audio.i_rate != 32000 )
+ {
+ msg_Err( p_enc, "DVD LPCM supports only sample rates of 48, 96, 44.1 or 32 kHz" );
+ return VLC_EGENERIC;
+ }
+
+ if( p_enc->fmt_in.audio.i_channels > 8 )
+ {
+ msg_Err( p_enc, "DVD LPCM supports a maximum of eight channels" );
+ return VLC_EGENERIC;
+ }
+
+ /* Allocate the memory needed to store the encoder's structure */
+ if( ( p_enc->p_sys = p_sys =
+ (encoder_sys_t *)malloc(sizeof(encoder_sys_t)) ) == NULL )
+ return VLC_ENOMEM;
+
+ /* In DVD LCPM, a frame is always 150 PTS ticks. */
+ p_sys->i_frame_samples = p_enc->fmt_in.audio.i_rate * 150 / 90000;
+ p_sys->p_buffer = (uint8_t *)malloc(
+ p_sys->i_frame_samples *
+ p_enc->fmt_in.audio.i_channels *
+ p_enc->fmt_in.audio.i_bitspersample);
+ p_sys->i_buffer_used = 0;
+ p_sys->i_frame_num = 0;
+
+ p_sys->i_channels = p_enc->fmt_in.audio.i_channels;
+ p_sys->i_rate = p_enc->fmt_in.audio.i_rate;
+
+ p_enc->pf_encode_audio = EncodeFrames;
+ p_enc->fmt_in.i_codec = p_enc->fmt_out.i_codec;
+
+ p_enc->fmt_in.audio.i_bitspersample = 16;
+ p_enc->fmt_in.i_codec = VLC_CODEC_S16B;
+
+ p_enc->fmt_out.i_bitrate =
+ p_enc->fmt_in.audio.i_channels *
+ p_enc->fmt_in.audio.i_rate *
+ p_enc->fmt_in.audio.i_bitspersample *
+ (p_sys->i_frame_samples + LPCM_VOB_HEADER_LEN) /
+ p_sys->i_frame_samples;
+
+ return VLC_SUCCESS;
+}
+
+/*****************************************************************************
+ * CloseEncoder: lpcm encoder destruction
+ *****************************************************************************/
+static void CloseEncoder ( vlc_object_t *p_this )
+{
+ VLC_UNUSED(p_this);
+}
+
+/*****************************************************************************
+ * EncodeFrames: encode zero or more LCPM audio packets
+ *****************************************************************************/
+static block_t *EncodeFrames( encoder_t *p_enc, aout_buffer_t *p_aout_buf )
+{
+ encoder_sys_t *p_sys = p_enc->p_sys;
+ block_t *p_first_block = NULL, *p_last_block = NULL;
+
+ if( !p_aout_buf || !p_aout_buf->i_buffer ) return NULL;
+
+ const int i_num_frames = ( p_sys->i_buffer_used + p_aout_buf->i_nb_samples ) /
+ p_sys->i_frame_samples;
+ const int i_leftover_samples = ( p_sys->i_buffer_used + p_aout_buf->i_nb_samples ) %
+ p_sys->i_frame_samples;
+ const int i_frame_size = p_sys->i_frame_samples * p_sys->i_channels * 2 + LPCM_VOB_HEADER_LEN;
+ const int i_start_offset = -p_sys->i_buffer_used;
+
+ uint8_t i_freq_code = 0;
+
+ switch( p_sys->i_rate ) {
+ case 48000:
+ i_freq_code = 0;
+ break;
+ case 96000:
+ i_freq_code = 1;
+ break;
+ case 44100:
+ i_freq_code = 2;
+ break;
+ case 32000:
+ i_freq_code = 3;
+ break;
+ default:
+ assert(0);
+ }
+
+ int i_bytes_consumed = 0;
+
+ for ( int i = 0; i < i_num_frames; ++i )
+ {
+ block_t *p_block = block_New( p_enc, i_frame_size );
+ if( !p_block )
+ return NULL;
+
+ uint8_t *frame = (uint8_t *)p_block->p_buffer;
+ frame[0] = 1; /* one frame in packet */
+ frame[1] = 0;
+ frame[2] = 0; /* no first access unit */
+ frame[3] = (p_sys->i_frame_num + i) & 0x1f; /* no emphasis, no mute */
+ frame[4] = (i_freq_code << 4) | (p_sys->i_channels - 1);
+ frame[5] = 0x80; /* neutral dynamic range */
+
+ const int i_consume_samples = p_sys->i_frame_samples - p_sys->i_buffer_used;
+ const int i_kept_bytes = p_sys->i_buffer_used * p_sys->i_channels * 2;
+ const int i_consume_bytes = i_consume_samples * p_sys->i_channels * 2;
+
+ memcpy( frame + 6, p_sys->p_buffer, i_kept_bytes );
+ memcpy( frame + 6 + i_kept_bytes, p_aout_buf->p_buffer + i_bytes_consumed, i_consume_bytes );
+
+ p_sys->i_frame_num++;
+ p_sys->i_buffer_used = 0;
+ i_bytes_consumed += i_consume_bytes;
+
+ p_block->i_dts = p_block->i_pts = p_aout_buf->i_pts +
+ (i * p_sys->i_frame_samples + i_start_offset) * CLOCK_FREQ / p_sys->i_rate;
+ p_block->i_length = p_sys->i_frame_samples * CLOCK_FREQ / p_sys->i_rate;
+
+ if( !p_first_block )
+ p_first_block = p_last_block = p_block;
+ else
+ p_last_block = p_last_block->p_next = p_block;
+ }
+
+ memcpy( p_sys->p_buffer,
+ p_aout_buf->p_buffer + i_bytes_consumed,
+ i_leftover_samples * p_sys->i_channels * 2 );
+ p_sys->i_buffer_used = i_leftover_samples;
+
+ return p_first_block;
+}
+#endif
+
/*****************************************************************************
*
*****************************************************************************/
projects / vlc / commitdiff