FFmpeg
libavformat
rtpdec_h263.c
Go to the documentation of this file.
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/*
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* RTP H.263 Depacketizer, RFC 4629
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* Copyright (c) 2010 Martin Storsjo
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*
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* This file is part of FFmpeg.
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*
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* FFmpeg is free software; you can redistribute it and/or
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* modify it under the terms of the GNU Lesser General Public
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* License as published by the Free Software Foundation; either
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* version 2.1 of the License, or (at your option) any later version.
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*
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* FFmpeg is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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* Lesser General Public License for more details.
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*
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* You should have received a copy of the GNU Lesser General Public
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* License along with FFmpeg; if not, write to the Free Software
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* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
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*/
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#include "
avformat.h
"
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#include "
rtpdec_formats.h
"
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#include "
libavutil/attributes.h
"
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#include "
libavutil/intreadwrite.h
"
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int
ff_h263_handle_packet
(
AVFormatContext
*
ctx
,
PayloadContext
*
data
,
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AVStream
*st,
AVPacket
*
pkt
, uint32_t *timestamp,
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const
uint8_t *buf,
int
len
, uint16_t seq,
int
flags
)
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{
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uint8_t *ptr;
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uint16_t
header
;
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int
startcode, vrc,
picture_header
,
ret
;
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if
(
len
< 2) {
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av_log
(
ctx
,
AV_LOG_ERROR
,
"Too short H.263 RTP packet\n"
);
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return
AVERROR_INVALIDDATA
;
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}
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/* Decode the 16 bit H.263+ payload header, as described in section
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* 5.1 of RFC 4629. The fields of this header are:
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* - 5 reserved bits, should be ignored.
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* - One bit (P, startcode), indicating a picture start, picture segment
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* start or video sequence end. If set, two zero bytes should be
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* prepended to the payload.
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* - One bit (V, vrc), indicating the presence of an 8 bit Video
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* Redundancy Coding field after this 16 bit header.
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* - 6 bits (PLEN, picture_header), the length (in bytes) of an extra
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* picture header, following the VRC field.
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* - 3 bits (PEBIT), the number of bits to ignore of the last byte
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* of the extra picture header. (Not used at the moment.)
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*/
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header
=
AV_RB16
(buf);
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startcode = (
header
& 0x0400) >> 9;
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vrc =
header
& 0x0200;
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picture_header
= (
header
& 0x01f8) >> 3;
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buf += 2;
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len
-= 2;
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if
(vrc) {
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/* Skip VRC header if present, not used at the moment. */
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buf += 1;
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len
-= 1;
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}
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if
(
picture_header
) {
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/* Skip extra picture header if present, not used at the moment. */
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buf +=
picture_header
;
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len
-=
picture_header
;
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}
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if
(
len
< 0) {
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av_log
(
ctx
,
AV_LOG_ERROR
,
"Too short H.263 RTP packet\n"
);
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return
AVERROR_INVALIDDATA
;
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}
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if
((
ret
=
av_new_packet
(
pkt
,
len
+ startcode)) < 0) {
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av_log
(
ctx
,
AV_LOG_ERROR
,
"Out of memory\n"
);
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return
ret
;
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}
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pkt
->
stream_index
= st->
index
;
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ptr =
pkt
->
data
;
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if
(startcode) {
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*ptr++ = 0;
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*ptr++ = 0;
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}
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memcpy(ptr, buf,
len
);
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return
0;
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}
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const
RTPDynamicProtocolHandler
ff_h263_1998_dynamic_handler
= {
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.
enc_name
=
"H263-1998"
,
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.codec_type =
AVMEDIA_TYPE_VIDEO
,
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.codec_id =
AV_CODEC_ID_H263
,
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.need_parsing =
AVSTREAM_PARSE_FULL
,
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.parse_packet =
ff_h263_handle_packet
,
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};
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const
RTPDynamicProtocolHandler
ff_h263_2000_dynamic_handler
= {
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.
enc_name
=
"H263-2000"
,
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.codec_type =
AVMEDIA_TYPE_VIDEO
,
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.codec_id =
AV_CODEC_ID_H263
,
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.need_parsing =
AVSTREAM_PARSE_FULL
,
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.parse_packet =
ff_h263_handle_packet
,
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};
rtpdec_formats.h
AVPacket::data
uint8_t * data
Definition:
packet.h:374
data
const char data[16]
Definition:
mxf.c:146
picture_header
static int FUNC() picture_header(CodedBitstreamContext *ctx, RWContext *rw, MPEG2RawPictureHeader *current)
Definition:
cbs_mpeg2_syntax_template.c:210
RTPDynamicProtocolHandler::enc_name
const char * enc_name
Definition:
rtpdec.h:117
pkt
AVPacket * pkt
Definition:
movenc.c:59
AV_LOG_ERROR
#define AV_LOG_ERROR
Something went wrong and cannot losslessly be recovered.
Definition:
log.h:180
intreadwrite.h
av_new_packet
int av_new_packet(AVPacket *pkt, int size)
Allocate the payload of a packet and initialize its fields with default values.
Definition:
avpacket.c:97
ctx
AVFormatContext * ctx
Definition:
movenc.c:48
AVFormatContext
Format I/O context.
Definition:
avformat.h:1104
AV_CODEC_ID_H263
@ AV_CODEC_ID_H263
Definition:
codec_id.h:56
header
static const uint8_t header[24]
Definition:
sdr2.c:67
attributes.h
ff_h263_1998_dynamic_handler
const RTPDynamicProtocolHandler ff_h263_1998_dynamic_handler
Definition:
rtpdec_h263.c:92
len
int len
Definition:
vorbis_enc_data.h:426
ret
ret
Definition:
filter_design.txt:187
AVStream
Stream structure.
Definition:
avformat.h:838
avformat.h
AVStream::index
int index
stream index in AVFormatContext
Definition:
avformat.h:844
ff_h263_handle_packet
int ff_h263_handle_packet(AVFormatContext *ctx, PayloadContext *data, AVStream *st, AVPacket *pkt, uint32_t *timestamp, const uint8_t *buf, int len, uint16_t seq, int flags)
Definition:
rtpdec_h263.c:27
AVPacket::stream_index
int stream_index
Definition:
packet.h:376
AVMEDIA_TYPE_VIDEO
@ AVMEDIA_TYPE_VIDEO
Definition:
avutil.h:201
AVPacket
This structure stores compressed data.
Definition:
packet.h:351
AVSTREAM_PARSE_FULL
@ AVSTREAM_PARSE_FULL
full parsing and repack
Definition:
avformat.h:688
flags
#define flags(name, subs,...)
Definition:
cbs_av1.c:561
av_log
#define av_log(a,...)
Definition:
tableprint_vlc.h:27
AVERROR_INVALIDDATA
#define AVERROR_INVALIDDATA
Invalid data found when processing input.
Definition:
error.h:61
ff_h263_2000_dynamic_handler
const RTPDynamicProtocolHandler ff_h263_2000_dynamic_handler
Definition:
rtpdec_h263.c:100
PayloadContext
RTP/JPEG specific private data.
Definition:
rdt.c:83
RTPDynamicProtocolHandler
Definition:
rtpdec.h:116
AV_RB16
uint64_t_TMPL AV_WL64 unsigned int_TMPL AV_WL32 unsigned int_TMPL AV_WL24 unsigned int_TMPL AV_WL16 uint64_t_TMPL AV_WB64 unsigned int_TMPL AV_WB32 unsigned int_TMPL AV_WB24 unsigned int_TMPL AV_RB16
Definition:
bytestream.h:98
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