[vlc-commits] hxxx_nal: add generic AnnexB to AVC/HVC converter
Francois Cartegnie
git at videolan.org
Tue Dec 22 13:25:15 CET 2015
vlc | branch: master | Francois Cartegnie <fcvlcdev at free.fr> | Sun Dec 20 21:12:10 2015 +0100| [928acb9ece7b319aa4f0eb60fbd0ccae5d3ccfe7] | committer: Francois Cartegnie
hxxx_nal: add generic AnnexB to AVC/HVC converter
Converts any AnnexB prefix to any xVC prefix.
Adds zero copy optimizations for single NAL.
> http://git.videolan.org/gitweb.cgi/vlc.git/?a=commit;h=928acb9ece7b319aa4f0eb60fbd0ccae5d3ccfe7
---
modules/packetizer/h264_nal.c | 22 +++--
modules/packetizer/hxxx_nal.c | 182 +++++++++++++++++++++++++++++++++++++++++
modules/packetizer/hxxx_nal.h | 5 ++
3 files changed, 200 insertions(+), 9 deletions(-)
diff --git a/modules/packetizer/h264_nal.c b/modules/packetizer/h264_nal.c
index d771cf3..70808dc 100644
--- a/modules/packetizer/h264_nal.c
+++ b/modules/packetizer/h264_nal.c
@@ -166,30 +166,34 @@ static block_t *h264_increase_startcode_size( block_t *p_block,
size_t i_new_ofs;
/* Search all startcode of size 3 */
- while( i_buf > 0 )
+ unsigned i_bitflow = 0;
+ unsigned i_nalcount = 0;
+ while( i_buf-- )
{
- if( i_buf > 3 && memcmp( &p_buf[i_ofs], annexb_startcode3, 3 ) == 0 )
+ i_bitflow <<= 1;
+ if( *(p_buf++) != 0x01 )
{
- if( i_ofs == 0 || p_buf[i_ofs - 1] != 0 )
- i_grow++;
- i_buf -= 3;
- i_ofs += 3;
+ i_bitflow |= 1;
}
- else
+ else if( (i_bitflow & 0x06) == 0x06 ) /* two zero prefixed 1 */
{
- i_buf--;
- i_ofs++;
+ i_nalcount++;
+ if( !(i_bitflow & 0x08) ) /* max two zero prefixed 1 */
+ i_grow++;
}
}
if( i_grow == 0 )
return p_block;
+
+
/* Alloc a bigger buffer */
p_new = block_Alloc( p_block->i_buffer + i_grow );
if( !p_new )
return NULL;
i_buf = p_block->i_buffer - i_start_ofs;
+ p_buf = p_block->p_buffer;
p_new_buf = p_new->p_buffer;
i_new_ofs = i_ofs = i_start_ofs;
diff --git a/modules/packetizer/hxxx_nal.c b/modules/packetizer/hxxx_nal.c
new file mode 100644
index 0000000..dc49570
--- /dev/null
+++ b/modules/packetizer/hxxx_nal.c
@@ -0,0 +1,182 @@
+/*****************************************************************************
+ * Copyright © 2015 VideoLAN Authors
+ *
+ * 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.
+ *****************************************************************************/
+
+#include "hxxx_nal.h"
+
+#include <vlc_block.h>
+
+static bool block_WillRealloc( block_t *p_block, ssize_t i_prebody, size_t i_body )
+{
+ if( i_prebody <= 0 && i_body <= (size_t)(-i_prebody) )
+ return false;
+ else
+ return ( i_prebody + i_body <= p_block->i_size );
+}
+
+static inline void hxxx_WritePrefix( uint8_t i_nal_length_size, uint8_t *p_dest, uint32_t i_payload )
+{
+ if( i_nal_length_size == 4 )
+ SetDWBE( p_dest, i_payload );
+ else if( i_nal_length_size == 2 )
+ SetWBE( p_dest, i_payload );
+ else
+ *p_dest = i_payload;
+}
+
+static block_t *hxxx_AnnexB_to_xVC( block_t *p_block, uint8_t i_nal_length_size )
+{
+ unsigned i_nalcount = 0;
+ unsigned i_list = 16;
+ struct nalmoves_e
+ {
+ const uint8_t *p; /* start of prefixed nal */
+ uint8_t prefix; /* startcode length */
+ off_t move; /* move offset */
+ } *p_list = NULL;
+
+ if(!p_block->i_buffer || p_block->p_buffer[0])
+ goto error;
+
+ if(! (p_list = malloc( sizeof(*p_list) * i_list )) )
+ goto error;
+
+ /* Search all startcode of size 3 */
+ const uint8_t *p_buf = p_block->p_buffer;
+ const uint8_t *p_end = &p_block->p_buffer[p_block->i_buffer];
+ unsigned i_bitflow = 0;
+ off_t i_move = 0;
+ while( p_buf != p_end )
+ {
+ i_bitflow <<= 1;
+ if( !*p_buf )
+ {
+ i_bitflow |= 1;
+ }
+ else if( *p_buf == 0x01 && (i_bitflow & 0x06) == 0x06 ) /* >= two zero prefixed 1 */
+ {
+ if( i_bitflow & 0x08 ) /* three zero prefixed 1 */
+ {
+ p_list[i_nalcount].p = &p_buf[-3];
+ p_list[i_nalcount].prefix = 4;
+ }
+ else /* two zero prefixed 1 */
+ {
+ p_list[i_nalcount].p = &p_buf[-2];
+ p_list[i_nalcount].prefix = 3;
+ }
+ i_move += (off_t) i_nal_length_size - p_list[i_nalcount].prefix;
+ p_list[i_nalcount++].move = i_move;
+
+ /* Check and realloc our list */
+ if(i_nalcount == i_list)
+ {
+ i_list += 16;
+ struct nalmoves_e *p_new = malloc( sizeof(*p_new) * i_list );
+ if(unlikely(!p_new))
+ goto error;
+ p_list = p_new;
+ }
+ }
+ p_buf++;
+ }
+
+ if( !i_nalcount )
+ goto error;
+
+ /* Optimization for 1 NAL block only case */
+ if( i_nalcount == 1 && block_WillRealloc( p_block, p_list[0].move, p_block->i_buffer ) )
+ {
+ uint32_t i_payload = p_block->i_buffer - p_list[0].prefix;
+ block_t *p_newblock = block_Realloc( p_block, p_list[0].move, p_block->i_buffer );
+ if( unlikely(!p_newblock) )
+ goto error;
+ p_block = p_newblock;
+ hxxx_WritePrefix( i_nal_length_size, p_block->p_buffer , i_payload );
+ free( p_list );
+ return p_block;
+ }
+
+ block_t *p_release = NULL;
+ const uint8_t *p_source = NULL;
+ const uint8_t *p_sourceend = NULL;
+ uint8_t *p_dest = NULL;
+ const size_t i_dest = p_block->i_buffer + p_list[i_nalcount - 1].move;
+
+ if( p_list[i_nalcount - 1].move != 0 || i_nal_length_size != 4 ) /* We'll need to grow or shrink */
+ {
+ /* If we grow in size, try using realloc to avoid memcpy */
+ if( p_list[i_nalcount - 1].move > 0 && block_WillRealloc( p_block, 0, i_dest ) )
+ {
+ uint32_t i_sizebackup = p_block->i_buffer;
+ block_t *p_newblock = block_Realloc( p_block, 0, i_dest );
+ if( unlikely(!p_newblock) )
+ goto error;
+
+ p_block = p_newblock;
+ p_sourceend = &p_block->p_buffer[i_sizebackup];
+ p_source = p_dest = p_block->p_buffer;
+ }
+ else
+ {
+ block_t *p_newblock = block_Alloc( i_dest );
+ if( unlikely(!p_newblock) )
+ goto error;
+
+ p_release = p_block; /* Will be released after use */
+ p_source = p_release->p_buffer;
+ p_sourceend = &p_release->p_buffer[p_release->i_buffer];
+
+ p_block = p_newblock;
+ p_dest = p_newblock->p_buffer;
+ }
+ }
+ else
+ {
+ p_source = p_dest = p_block->p_buffer;
+ p_sourceend = &p_block->p_buffer[p_block->i_buffer];
+ }
+
+ if(!p_dest)
+ goto error;
+
+ /* Do reverse order moves, so we never overlap when growing only */
+ for( unsigned i=i_nalcount; i!=0; i-- )
+ {
+ const uint8_t *p_readstart = p_list[i - 1].p;
+ uint32_t i_payload = p_sourceend - p_readstart - p_list[i - 1].prefix;
+ off_t offset = p_list[i - 1].p - p_source + p_list[i - 1].prefix + p_list[i - 1].move;
+// printf(" move offset %ld, length = %ld prefix %ld move %ld\n", p_readstart - p_source, i_payload, p_list[i - 1].prefix, p_list[i-1].move);
+
+ /* move in same / copy between buffers */
+ memmove( &p_dest[ offset ], &p_list[i - 1].p[ p_list[i - 1].prefix ], i_payload );
+
+ hxxx_WritePrefix( i_nal_length_size, &p_dest[ offset - i_nal_length_size ] , i_payload );
+
+ p_sourceend = p_readstart;
+ }
+
+ if( p_release )
+ block_Release( p_release );
+ free( p_list );
+ return p_block;
+
+error:
+ free( p_list );
+ block_Release( p_block );
+ return NULL;
+}
diff --git a/modules/packetizer/hxxx_nal.h b/modules/packetizer/hxxx_nal.h
index 768c223..70d2eae 100644
--- a/modules/packetizer/hxxx_nal.h
+++ b/modules/packetizer/hxxx_nal.h
@@ -103,4 +103,9 @@ static inline uint8_t * hxxx_ep3b_to_rbsp(const uint8_t *p_src, size_t i_src, si
}
#endif
+/* Declarations */
+
+/* Takes any AnnexB NAL buffer and converts it to prefixed size (AVC/HEVC) */
+block_t *hxxx_AnnexB_to_xVC( block_t *p_block, uint8_t i_nal_length_size );
+
#endif // HXXX_NAL_H
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