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FFmpeg/libavformat/rtpdec_h263.c
Michael Niedermayer 4a519b6e03 Merge remote-tracking branch 'qatar/master'
* qatar/master:
  mov: Use defines for sample flags in fragments
  mov: Use defines for trun flags
  mov: Use defines for tfhd flags
  proresenc: force bitrate not to exceed given limit
  vc1parse: call vc1_init_common().
  wma: don't return 0 on invalid packets.
  asf: prevent packet_size_left from going negative if hdrlen > pktlen.
  mjpegb: don't return 0 at the end of frame decoding.
  rtpdec: Identify incorrectly signalled H263
  vp8dsp: split long line.
  aiff: don't skip block_align==0 check on COMM-after-SSND files.
  dpcm: ignore extra unpaired bytes in stereo streams.
  mp3on4: require a minimum framesize.
  mpc7: assign an error level + context to av_log() msg.
  huffyuv: error out on bit overrun.
  dct-test: Add the missing ff_ prefix to the altivec functions
  dct-test: Remove a stray declaration of a nonexistent function
  movenc: Write the unknown duration as 64 bit fields in ismv
  movenc: Write track durations with all bits set if duration is unknown

Conflicts:
	libavcodec/dct-test.c
	libavcodec/wmadec.c

Merged-by: Michael Niedermayer <michaelni@gmx.at>
2012-02-19 01:47:10 +01:00

104 lines
3.4 KiB
C

/*
* RTP H.263 Depacketizer, RFC 4629
* Copyright (c) 2010 Martin Storsjo
*
* This file is part of FFmpeg.
*
* 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 "avformat.h"
#include "rtpdec_formats.h"
#include "libavutil/intreadwrite.h"
int ff_h263_handle_packet(AVFormatContext *ctx, PayloadContext *data,
AVStream *st, AVPacket *pkt, uint32_t *timestamp,
const uint8_t *buf, int len, int flags)
{
uint8_t *ptr;
uint16_t header;
int startcode, vrc, picture_header;
if (len < 2) {
av_log(ctx, AV_LOG_ERROR, "Too short H.263 RTP packet\n");
return AVERROR_INVALIDDATA;
}
/* Decode the 16 bit H.263+ payload header, as described in section
* 5.1 of RFC 4629. The fields of this header are:
* - 5 reserved bits, should be ignored.
* - One bit (P, startcode), indicating a picture start, picture segment
* start or video sequence end. If set, two zero bytes should be
* prepended to the payload.
* - One bit (V, vrc), indicating the presence of an 8 bit Video
* Redundancy Coding field after this 16 bit header.
* - 6 bits (PLEN, picture_header), the length (in bytes) of an extra
* picture header, following the VRC field.
* - 3 bits (PEBIT), the number of bits to ignore of the last byte
* of the extra picture header. (Not used at the moment.)
*/
header = AV_RB16(buf);
startcode = (header & 0x0400) >> 9;
vrc = header & 0x0200;
picture_header = (header & 0x01f8) >> 3;
buf += 2;
len -= 2;
if (vrc) {
/* Skip VRC header if present, not used at the moment. */
buf += 1;
len -= 1;
}
if (picture_header) {
/* Skip extra picture header if present, not used at the moment. */
buf += picture_header;
len -= picture_header;
}
if (len < 0) {
av_log(ctx, AV_LOG_ERROR, "Too short H.263 RTP packet\n");
return AVERROR_INVALIDDATA;
}
if (av_new_packet(pkt, len + startcode)) {
av_log(ctx, AV_LOG_ERROR, "Out of memory\n");
return AVERROR(ENOMEM);
}
pkt->stream_index = st->index;
ptr = pkt->data;
if (startcode) {
*ptr++ = 0;
*ptr++ = 0;
}
memcpy(ptr, buf, len);
return 0;
}
RTPDynamicProtocolHandler ff_h263_1998_dynamic_handler = {
.enc_name = "H263-1998",
.codec_type = AVMEDIA_TYPE_VIDEO,
.codec_id = CODEC_ID_H263,
.parse_packet = ff_h263_handle_packet,
};
RTPDynamicProtocolHandler ff_h263_2000_dynamic_handler = {
.enc_name = "H263-2000",
.codec_type = AVMEDIA_TYPE_VIDEO,
.codec_id = CODEC_ID_H263,
.parse_packet = ff_h263_handle_packet,
};