[vlc-devel] commit: Fix AAC muxing into TS ( Rafaël Carré )

[git version control]

vlc | branch: master | Rafaël Carré <funman at videolan.org> | Fri Mar 14 10:07:40 2008 +0100| [805a9ad61bb628aee2ca936d048a86f16503bc56]

Fix AAC muxing into TS

Add ADTS headers on top of the raw AAC frames
Use the ADTS stream type (0x0f) since LOAS isn't implemented
    This was wrong since we were streaming raw, not LOAS/LATM

> http://git.videolan.org/gitweb.cgi/vlc.git/?a=commit;h=805a9ad61bb628aee2ca936d048a86f16503bc56
---

 modules/mux/mpeg/ts.c |   66 +++++++++++++++++++++++++++++++++++++++++++++++-
 1 files changed, 64 insertions(+), 2 deletions(-)

diff --git a/modules/mux/mpeg/ts.c b/modules/mux/mpeg/ts.c
index 7849021..ad4b263 100644
--- a/modules/mux/mpeg/ts.c
+++ b/modules/mux/mpeg/ts.c
@@ -459,6 +459,7 @@ static int DelStream( sout_mux_t *, sout_input_t * );
 static int Mux      ( sout_mux_t * );
 
 static block_t *FixPES( sout_mux_t *p_mux, block_fifo_t *p_fifo );
+static block_t *Add_ADTS( block_t *, es_format_t * );
 static void TSSchedule  ( sout_mux_t *p_mux, sout_buffer_chain_t *p_chain_ts,
                           mtime_t i_pcr_length, mtime_t i_pcr_dts );
 static void TSDate      ( sout_mux_t *p_mux, sout_buffer_chain_t *p_chain_ts,
@@ -972,7 +973,10 @@ static int AddStream( sout_mux_t *p_mux, sout_input_t *p_input )
                     p_stream->i_stream_id = 0xbd;
                     break;
                 case VLC_FOURCC( 'm', 'p','4', 'a' ):
-                    p_stream->i_stream_type = 0x11;
+                    /* XXX: make that configurable in some way when LOAS
+                     * is implemented for AAC in TS */
+                    //p_stream->i_stream_type = 0x11; /* LOAS/LATM */
+                    p_stream->i_stream_type = 0x0f; /* ADTS */
                     p_stream->i_stream_id = 0xfa;
                     p_sys->i_mpeg4_streams++;
                     p_stream->i_es_id = p_stream->i_pid;
@@ -1395,7 +1399,13 @@ static int Mux( sout_mux_t *p_mux )
                     if( p_stream == p_pcr_stream || p_sys->b_data_alignment
                          || p_input->p_fmt->i_codec !=
                              VLC_FOURCC('m', 'p', 'g', 'a') )
+                    {
                         p_data = block_FifoGet( p_input->p_fifo );
+
+                        if( p_input->p_fmt->i_codec ==
+                                VLC_FOURCC('m', 'p', '4', 'a' ) )
+                            p_data = Add_ADTS( p_data, p_input->p_fmt );
+                    }
                     else
                         p_data = FixPES( p_mux, p_input->p_fifo );
 
@@ -1655,7 +1665,7 @@ static int Mux( sout_mux_t *p_mux )
 static block_t *FixPES( sout_mux_t *p_mux, block_fifo_t *p_fifo )
 {
     block_t *p_data;
-    int i_size;
+    size_t i_size;
 
     p_data = block_FifoShow( p_fifo );
     i_size = p_data->i_buffer;
@@ -1714,6 +1724,58 @@ static block_t *FixPES( sout_mux_t *p_mux, block_fifo_t *p_fifo )
     }
 }
 
+static block_t *Add_ADTS( block_t *p_data, es_format_t *p_fmt )
+{
+    uint8_t *p_extra = p_fmt->p_extra;
+
+    if( !p_data || p_fmt->i_extra < 2 || !p_extra )
+        return p_data; /* no data to construct the headers */
+
+    int i_index = ( (p_extra[0] << 1) | (p_extra[1] >> 7) ) & 0x0f;
+    int i_profile = (p_extra[0] >> 3) - 1; /* i_profile < 4 */
+
+    if( i_index == 0x0f && p_fmt->i_extra < 5 )
+        return p_data; /* not enough data */
+
+    int i_channels = (p_extra[i_index == 0x0f ? 4 : 1] >> 3) & 0x0f;
+
+#define ADTS_HEADER_SIZE 7 /* CRC needs 2 more bytes */
+
+
+    /* keep a copy in case block_Realloc() fails */
+    block_t *p_bak_block = block_Duplicate( p_data );
+    if( !p_bak_block ) /* OOM, block_Realloc() is likely to lose our block */
+        return p_data; /* the frame isn't correct but that's the best we have */
+
+    block_t *p_new_block = block_Realloc( p_data, ADTS_HEADER_SIZE,
+                                            p_data->i_buffer );
+    if( !p_new_block )
+        return p_bak_block; /* OOM, send the (incorrect) original frame */
+
+    block_Release( p_bak_block ); /* we don't need the copy anymore */
+
+
+    uint8_t *p_buffer = p_new_block->p_buffer;
+
+    /* fixed header */
+    p_buffer[0] = 0xff;
+    p_buffer[1] = 0xf1; /* 0xf0 | 0x00 | 0x00 | 0x01 */
+    p_buffer[2] = (i_profile << 6) | ((i_index & 0x0f) << 2) | ((i_channels >> 2) & 0x01) ;
+    p_buffer[3] = (i_channels << 6) | ((p_data->i_buffer >> 11) & 0x03);
+
+    /* variable header (starts at last 2 bits of 4th byte) */
+
+    int i_fullness = 0x7ff; /* 0x7ff means VBR */
+    /* XXX: We should check if it's CBR or VBR, but no known implementation
+     * do that, and it's a pain to calculate this field */
+
+    p_buffer[4] = p_data->i_buffer >> 3;
+    p_buffer[5] = ((p_data->i_buffer & 0x07) << 5) | ((i_fullness >> 6) & 0x1f);
+    p_buffer[6] = ((i_fullness & 0x3f) << 2) /* | 0xfc */;
+
+    return p_new_block;
+}
+
 static void TSSchedule( sout_mux_t *p_mux, sout_buffer_chain_t *p_chain_ts,
                         mtime_t i_pcr_length, mtime_t i_pcr_dts )
 {