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author | Panagiotis Issaris <takis.issaris@uhasselt.be> | 2006-12-11 01:00:50 +0000 |
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committer | Panagiotis Issaris <takis.issaris@uhasselt.be> | 2006-12-11 01:00:50 +0000 |
commit | e39e60a37ea11900204aa1170b78a61fb4faf576 (patch) | |
tree | ca1240a6d5a701d211d05c0688219cad944bd789 /libavcodec/h264enc.c | |
parent | 15f14fc7c20914f388f85163ed3a27f80ff27301 (diff) | |
download | ffmpeg-streaming-e39e60a37ea11900204aa1170b78a61fb4faf576.zip ffmpeg-streaming-e39e60a37ea11900204aa1170b78a61fb4faf576.tar.gz |
Adding function which enables writing H.264 NAL units.
Originally committed as revision 7273 to svn://svn.ffmpeg.org/ffmpeg/trunk
Diffstat (limited to 'libavcodec/h264enc.c')
-rw-r--r-- | libavcodec/h264enc.c | 107 |
1 files changed, 107 insertions, 0 deletions
diff --git a/libavcodec/h264enc.c b/libavcodec/h264enc.c new file mode 100644 index 0000000..15e1823 --- /dev/null +++ b/libavcodec/h264enc.c @@ -0,0 +1,107 @@ +/* + * H.264 encoder + * + * FFmpeg 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. + * + * FFmpeg 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 FFmpeg; if not, write to the Free Software + * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA + */ + + +#include "common.h" +#include "bitstream.h" +#include "mpegvideo.h" +#include "h264data.h" + +/** + * Write out the provided data into a NAL unit. + * @param nal_ref_idc NAL reference IDC + * @param nal_unit_type NAL unit payload type + * @param dest the target buffer, dst+1 == src is allowed as a special case + * @param destsize the length of the dst array + * @param b2 the data which should be escaped + * @returns pointer to current position in the output buffer or NULL if an error occured + */ +static uint8_t *h264_write_nal_unit(int nal_ref_idc, int nal_unit_type, uint8_t *dest, int *destsize, + PutBitContext *b2) +{ + PutBitContext b; + int i, destpos, rbsplen, escape_count; + uint8_t *rbsp; + + if (nal_unit_type != NAL_END_STREAM) + put_bits(b2,1,1); // rbsp_stop_bit + + // Align b2 on a byte boundary + align_put_bits(b2); + rbsplen = put_bits_count(b2)/8; + flush_put_bits(b2); + rbsp = b2->buf; + + init_put_bits(&b,dest,*destsize); + + put_bits(&b,16,0); + put_bits(&b,16,0x01); + + put_bits(&b,1,0); // forbidden zero bit + put_bits(&b,2,nal_ref_idc); // nal_ref_idc + put_bits(&b,5,nal_unit_type); // nal_unit_type + + flush_put_bits(&b); + + destpos = 5; + escape_count= 0; + + for (i=0; i<rbsplen; i+=2) + { + if (rbsp[i]) continue; + if (i>0 && rbsp[i-1]==0) + i--; + if (i+2<rbsplen && rbsp[i+1]==0 && rbsp[i+2]<=3) + { + escape_count++; + i+=2; + } + } + + if(escape_count==0) + { + if(dest+destpos != rbsp) + { + memcpy(dest+destpos, rbsp, rbsplen); + *destsize -= (rbsplen+destpos); + } + return dest+rbsplen+destpos; + } + + if(rbsplen + escape_count + 1> *destsize) + { + av_log(NULL, AV_LOG_ERROR, "Destination buffer too small!\n"); + return NULL; + } + + // this should be damn rare (hopefully) + for (i = 0 ; i < rbsplen ; i++) + { + if (i + 2 < rbsplen && (rbsp[i] == 0 && rbsp[i+1] == 0 && rbsp[i+2] < 4)) + { + dest[destpos++] = rbsp[i++]; + dest[destpos++] = rbsp[i]; + dest[destpos++] = 0x03; // emulation prevention byte + } + else + dest[destpos++] = rbsp[i]; + } + *destsize -= destpos; + return dest+destpos; +} + |