1
0
mirror of https://github.com/FFmpeg/FFmpeg.git synced 2024-12-02 03:06:28 +02:00
FFmpeg/libavformat/rtpdec_asf.c
Andreas Rheinhardt 7001ff74ba avformat/aviobuf: Add ffio_init_(read|write)_context()
Most users of ffio_init_context() simply want to wrap
a buffer into an AVIOContext; they do not provide
function pointers at all.

Therefore this commit adds shortcuts for these two common
operations. This also allows to accept const data when reading
(i.e. the const is now cast away at a central place in
ffio_init_read_context() instead of at several callers).
This also allows to constify the data in ff_text_init_buf().

Signed-off-by: Andreas Rheinhardt <andreas.rheinhardt@outlook.com>
2023-09-07 00:41:45 +02:00

316 lines
10 KiB
C

/*
* Microsoft RTP/ASF support.
* Copyright (c) 2008 Ronald S. Bultje
*
* 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
*/
/**
* @file
* @brief Microsoft RTP/ASF support
* @author Ronald S. Bultje <rbultje@ronald.bitfreak.net>
*/
#include "libavutil/base64.h"
#include "libavutil/avstring.h"
#include "libavutil/intreadwrite.h"
#include "rtpdec_formats.h"
#include "rtsp.h"
#include "asf.h"
#include "avio_internal.h"
#include "demux.h"
#include "internal.h"
/**
* From MSDN 2.2.1.4, we learn that ASF data packets over RTP should not
* contain any padding. Unfortunately, the header min/max_pktsize are not
* updated (thus making min_pktsize invalid). Here, we "fix" these faulty
* min_pktsize values in the ASF file header.
* @return 0 on success, <0 on failure (currently -1).
*/
static int rtp_asf_fix_header(uint8_t *buf, int len)
{
uint8_t *p = buf, *end = buf + len;
if (len < sizeof(ff_asf_guid) * 2 + 22 ||
memcmp(p, ff_asf_header, sizeof(ff_asf_guid))) {
return -1;
}
p += sizeof(ff_asf_guid) + 14;
do {
uint64_t chunksize = AV_RL64(p + sizeof(ff_asf_guid));
int skip = 6 * 8 + 3 * 4 + sizeof(ff_asf_guid) * 2;
if (memcmp(p, ff_asf_file_header, sizeof(ff_asf_guid))) {
if (chunksize > end - p)
return -1;
p += chunksize;
continue;
}
if (end - p < 8 + skip)
break;
/* skip most of the file header, to min_pktsize */
p += skip;
if (AV_RL32(p) == AV_RL32(p + 4)) {
/* and set that to zero */
AV_WL32(p, 0);
return 0;
}
break;
} while (end - p >= sizeof(ff_asf_guid) + 8);
return -1;
}
/**
* The following code is basically a buffered AVIOContext,
* with the added benefit of returning -EAGAIN (instead of 0)
* on packet boundaries, such that the ASF demuxer can return
* safely and resume business at the next packet.
*/
static int packetizer_read(void *opaque, uint8_t *buf, int buf_size)
{
return AVERROR(EAGAIN);
}
static void init_packetizer(FFIOContext *pb, uint8_t *buf, int len)
{
ffio_init_context(pb, buf, len, 0, NULL, packetizer_read, NULL, NULL);
/* this "fills" the buffer with its current content */
pb->pub.pos = len;
pb->pub.buf_end = buf + len;
}
int ff_wms_parse_sdp_a_line(AVFormatContext *s, const char *p)
{
int ret = 0;
if (av_strstart(p, "pgmpu:data:application/vnd.ms.wms-hdr.asfv1;base64,", &p)) {
FFIOContext pb;
RTSPState *rt = s->priv_data;
AVDictionary *opts = NULL;
int len = strlen(p) * 6 / 8;
char *buf = av_mallocz(len);
const AVInputFormat *iformat;
if (!buf)
return AVERROR(ENOMEM);
av_base64_decode(buf, p, len);
if (rtp_asf_fix_header(buf, len) < 0)
av_log(s, AV_LOG_ERROR,
"Failed to fix invalid RTSP-MS/ASF min_pktsize\n");
init_packetizer(&pb, buf, len);
if (rt->asf_ctx) {
avformat_close_input(&rt->asf_ctx);
}
if (!(iformat = av_find_input_format("asf")))
return AVERROR_DEMUXER_NOT_FOUND;
rt->asf_ctx = avformat_alloc_context();
if (!rt->asf_ctx) {
av_free(buf);
return AVERROR(ENOMEM);
}
rt->asf_ctx->pb = &pb.pub;
av_dict_set(&opts, "no_resync_search", "1", 0);
if ((ret = ff_copy_whiteblacklists(rt->asf_ctx, s)) < 0) {
av_dict_free(&opts);
return ret;
}
ret = avformat_open_input(&rt->asf_ctx, "", iformat, &opts);
av_dict_free(&opts);
if (ret < 0) {
av_free(pb.pub.buffer);
return ret;
}
av_dict_copy(&s->metadata, rt->asf_ctx->metadata, 0);
rt->asf_pb_pos = avio_tell(&pb.pub);
av_free(pb.pub.buffer);
rt->asf_ctx->pb = NULL;
}
return ret;
}
static int asfrtp_parse_sdp_line(AVFormatContext *s, int stream_index,
PayloadContext *asf, const char *line)
{
if (stream_index < 0)
return 0;
if (av_strstart(line, "stream:", &line)) {
RTSPState *rt = s->priv_data;
s->streams[stream_index]->id = strtol(line, NULL, 10);
if (rt->asf_ctx) {
int i;
for (i = 0; i < rt->asf_ctx->nb_streams; i++) {
if (s->streams[stream_index]->id == rt->asf_ctx->streams[i]->id) {
avcodec_parameters_copy(s->streams[stream_index]->codecpar,
rt->asf_ctx->streams[i]->codecpar);
ffstream(s->streams[stream_index])->need_parsing =
ffstream(rt->asf_ctx->streams[i])->need_parsing;
avpriv_set_pts_info(s->streams[stream_index], 32, 1, 1000);
}
}
}
}
return 0;
}
struct PayloadContext {
FFIOContext pb;
AVIOContext *pktbuf;
uint8_t *buf;
};
/**
* @return 0 when a packet was written into /p pkt, and no more data is left;
* 1 when a packet was written into /p pkt, and more packets might be left;
* <0 when not enough data was provided to return a full packet, or on error.
*/
static int asfrtp_parse_packet(AVFormatContext *s, PayloadContext *asf,
AVStream *st, AVPacket *pkt,
uint32_t *timestamp,
const uint8_t *buf, int len, uint16_t seq,
int flags)
{
FFIOContext *const pb0 = &asf->pb;
AVIOContext *const pb = &pb0->pub;
int res, mflags, len_off;
RTSPState *rt = s->priv_data;
if (!rt->asf_ctx)
return -1;
if (len > 0) {
int off, out_len = 0;
if (len < 4)
return -1;
av_freep(&asf->buf);
ffio_init_read_context(pb0, buf, len);
while (avio_tell(pb) + 4 < len) {
int start_off = avio_tell(pb);
mflags = avio_r8(pb);
len_off = avio_rb24(pb);
if (mflags & 0x20) /**< relative timestamp */
avio_skip(pb, 4);
if (mflags & 0x10) /**< has duration */
avio_skip(pb, 4);
if (mflags & 0x8) /**< has location ID */
avio_skip(pb, 4);
off = avio_tell(pb);
if (!(mflags & 0x40)) {
/**
* If 0x40 is not set, the len_off field specifies an offset
* of this packet's payload data in the complete (reassembled)
* ASF packet. This is used to spread one ASF packet over
* multiple RTP packets.
*/
if (asf->pktbuf && len_off != avio_tell(asf->pktbuf)) {
ffio_free_dyn_buf(&asf->pktbuf);
}
if (!len_off && !asf->pktbuf &&
(res = avio_open_dyn_buf(&asf->pktbuf)) < 0)
return res;
if (!asf->pktbuf)
return AVERROR(EIO);
avio_write(asf->pktbuf, buf + off, len - off);
avio_skip(pb, len - off);
if (!(flags & RTP_FLAG_MARKER))
return -1;
out_len = avio_close_dyn_buf(asf->pktbuf, &asf->buf);
asf->pktbuf = NULL;
} else {
/**
* If 0x40 is set, the len_off field specifies the length of
* the next ASF packet that can be read from this payload
* data alone. This is commonly the same as the payload size,
* but could be less in case of packet splitting (i.e.
* multiple ASF packets in one RTP packet).
*/
int cur_len = start_off + len_off - off;
int prev_len = out_len;
out_len += cur_len;
if (FFMIN(cur_len, len - off) < 0)
return -1;
if ((res = av_reallocp(&asf->buf, out_len)) < 0)
return res;
memcpy(asf->buf + prev_len, buf + off,
FFMIN(cur_len, len - off));
avio_skip(pb, cur_len);
}
}
init_packetizer(pb0, asf->buf, out_len);
pb->pos += rt->asf_pb_pos;
pb->eof_reached = 0;
rt->asf_ctx->pb = pb;
}
for (;;) {
int i;
res = ff_read_packet(rt->asf_ctx, pkt);
rt->asf_pb_pos = avio_tell(pb);
if (res != 0)
break;
for (i = 0; i < s->nb_streams; i++) {
if (s->streams[i]->id == rt->asf_ctx->streams[pkt->stream_index]->id) {
pkt->stream_index = i;
return 1; // FIXME: return 0 if last packet
}
}
av_packet_unref(pkt);
}
return res == 1 ? -1 : res;
}
static void asfrtp_close_context(PayloadContext *asf)
{
ffio_free_dyn_buf(&asf->pktbuf);
av_freep(&asf->buf);
}
#define RTP_ASF_HANDLER(n, s, t) \
const RTPDynamicProtocolHandler ff_ms_rtp_ ## n ## _handler = { \
.enc_name = s, \
.codec_type = t, \
.codec_id = AV_CODEC_ID_NONE, \
.priv_data_size = sizeof(PayloadContext), \
.parse_sdp_a_line = asfrtp_parse_sdp_line, \
.close = asfrtp_close_context, \
.parse_packet = asfrtp_parse_packet, \
}
RTP_ASF_HANDLER(asf_pfv, "x-asf-pf", AVMEDIA_TYPE_VIDEO);
RTP_ASF_HANDLER(asf_pfa, "x-asf-pf", AVMEDIA_TYPE_AUDIO);