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ffmpeg/libavformat/prompeg.c
David Holroyd ffc1208266 lavf/prompeg: prompeg_write() must report data all was written 
Previously, prompeg_write() would only report to caller that bytes we
written when a FEC packet was actually created.  Not all RTP packets are
expected to generate a FEC packet however, so this behavior was causing
avio to retry writing the RTP packet, eventually forcing the FEC state
machine to send a FEC packet erroneously (and so breaking out of the
retry loop).

This was resulting in incorrect FEC data being generated, and far too
many FEC packets to be sent (~100% FEC overhead).

fix #7863

Signed-off-by: David Holroyd <david.holroyd@m2amedia.tv>
2020-06-14 12:27:49 +08:00

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/*
* Pro-MPEG Code of Practice #3 Release 2 FEC
* Copyright (c) 2016 Mobibase, France (http://www.mobibase.com)
*
* 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
* Pro-MPEG Code of Practice #3 Release 2 FEC protocol
* @author Vlad Tarca <vlad.tarca@gmail.com>
*/
/*
* Reminder:
[RFC 2733] FEC Packet Structure
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| RTP Header |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| FEC Header |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| FEC Payload |
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
[RFC 3550] RTP header
0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|V=2|P|X| CC |M| PT | sequence number |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| timestamp |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| synchronization source (SSRC) identifier |
+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+
| contributing source (CSRC) identifiers |
| .... |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
[RFC 3550] RTP header extension (after CSRC)
0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| defined by profile | length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| header extension |
| .... |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
[Pro-MPEG COP3] FEC Header
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| SNBase low bits | length recovery |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|E| PT recovery | mask |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| TS recovery |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|X|D|type |index| offset | NA |SNBase ext bits|
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
*/
#include "libavutil/avstring.h"
#include "libavutil/intreadwrite.h"
#include "libavutil/opt.h"
#include "libavutil/parseutils.h"
#include "libavutil/random_seed.h"
#include "avformat.h"
#include "config.h"
#include "url.h"
#define PROMPEG_RTP_PT 0x60
#define PROMPEG_FEC_COL 0x0
#define PROMPEG_FEC_ROW 0x1
typedef struct PrompegFec {
uint16_t sn;
uint32_t ts;
uint8_t *bitstring;
} PrompegFec;
typedef struct PrompegContext {
const AVClass *class;
URLContext *fec_col_hd, *fec_row_hd;
PrompegFec **fec_arr, **fec_col_tmp, **fec_col, *fec_row;
int ttl;
uint8_t l, d;
uint8_t *rtp_buf;
uint16_t rtp_col_sn, rtp_row_sn;
uint16_t length_recovery;
int packet_size;
int packet_idx, packet_idx_max;
int fec_arr_len;
int bitstring_size;
int rtp_buf_size;
int init;
int first;
} PrompegContext;
#define OFFSET(x) offsetof(PrompegContext, x)
#define E AV_OPT_FLAG_ENCODING_PARAM
static const AVOption options[] = {
{ "ttl", "Time to live (in milliseconds, multicast only)", OFFSET(ttl), AV_OPT_TYPE_INT, { .i64 = -1 }, -1, INT_MAX, .flags = E },
{ "l", "FEC L", OFFSET(l), AV_OPT_TYPE_INT, { .i64 = 5 }, 4, 20, .flags = E },
{ "d", "FEC D", OFFSET(d), AV_OPT_TYPE_INT, { .i64 = 5 }, 4, 20, .flags = E },
{ NULL }
};
static const AVClass prompeg_class = {
.class_name = "prompeg",
.item_name = av_default_item_name,
.option = options,
.version = LIBAVUTIL_VERSION_INT,
};
static void xor_fast(const uint8_t *in1, const uint8_t *in2, uint8_t *out, int size) {
int i, n, s;
#if HAVE_FAST_64BIT
uint64_t v1, v2;
n = size / sizeof (uint64_t);
s = n * sizeof (uint64_t);
for (i = 0; i < n; i++) {
v1 = AV_RN64A(in1);
v2 = AV_RN64A(in2);
AV_WN64A(out, v1 ^ v2);
in1 += 8;
in2 += 8;
out += 8;
}
#else
uint32_t v1, v2;
n = size / sizeof (uint32_t);
s = n * sizeof (uint32_t);
for (i = 0; i < n; i++) {
v1 = AV_RN32A(in1);
v2 = AV_RN32A(in2);
AV_WN32A(out, v1 ^ v2);
in1 += 4;
in2 += 4;
out += 4;
}
#endif
n = size - s;
for (i = 0; i < n; i++) {
out[i] = in1[i] ^ in2[i];
}
}
static int prompeg_create_bitstring(URLContext *h, const uint8_t *buf, int size,
uint8_t **bitstring) {
PrompegContext *s = h->priv_data;
uint8_t *b;
if (size < 12 || (buf[0] & 0xc0) != 0x80 || (buf[1] & 0x7f) != 0x21) {
av_log(h, AV_LOG_ERROR, "Unsupported stream format (expected MPEG-TS over RTP)\n");
return AVERROR(EINVAL);
}
if (size != s->packet_size) {
av_log(h, AV_LOG_ERROR, "The RTP packet size must be constant (set pkt_size)\n");
return AVERROR(EINVAL);
}
*bitstring = av_malloc(s->bitstring_size);
if (!*bitstring) {
av_log(h, AV_LOG_ERROR, "Failed to allocate the bitstring buffer\n");
return AVERROR(ENOMEM);
}
b = *bitstring;
// P, X, CC
b[0] = buf[0] & 0x3f;
// M, PT
b[1] = buf[1];
// Timestamp
b[2] = buf[4];
b[3] = buf[5];
b[4] = buf[6];
b[5] = buf[7];
/*
* length_recovery: the unsigned network-ordered sum of lengths of CSRC,
* padding, extension and media payload
*/
AV_WB16(b + 6, s->length_recovery);
// Payload
memcpy(b + 8, buf + 12, s->length_recovery);
return 0;
}
static int prompeg_write_fec(URLContext *h, PrompegFec *fec, uint8_t type) {
PrompegContext *s = h->priv_data;
URLContext *hd;
uint8_t *buf = s->rtp_buf; // zero-filled
uint8_t *b = fec->bitstring;
uint16_t sn;
int ret;
sn = type == PROMPEG_FEC_COL ? ++s->rtp_col_sn : ++s->rtp_row_sn;
// V, P, X, CC
buf[0] = 0x80 | (b[0] & 0x3f);
// M, PT
buf[1] = (b[1] & 0x80) | PROMPEG_RTP_PT;
// SN
AV_WB16(buf + 2, sn);
// TS
AV_WB32(buf + 4, fec->ts);
// CSRC=0
//AV_WB32(buf + 8, 0);
// SNBase low bits
AV_WB16(buf + 12, fec->sn);
// Length recovery
buf[14] = b[6];
buf[15] = b[7];
// E=1, PT recovery
buf[16] = 0x80 | b[1];
// Mask=0
//buf[17] = 0x0;
//buf[18] = 0x0;
//buf[19] = 0x0;
// TS recovery
buf[20] = b[2];
buf[21] = b[3];
buf[22] = b[4];
buf[23] = b[5];
// X=0, D, type=0, index=0
buf[24] = type == PROMPEG_FEC_COL ? 0x0 : 0x40;
// offset
buf[25] = type == PROMPEG_FEC_COL ? s->l : 0x1;
// NA
buf[26] = type == PROMPEG_FEC_COL ? s->d : s->l;
// SNBase ext bits=0
//buf[27] = 0x0;
// Payload
memcpy(buf + 28, b + 8, s->length_recovery);
hd = type == PROMPEG_FEC_COL ? s->fec_col_hd : s->fec_row_hd;
ret = ffurl_write(hd, buf, s->rtp_buf_size);
return ret;
}
static int prompeg_open(URLContext *h, const char *uri, int flags) {
PrompegContext *s = h->priv_data;
AVDictionary *udp_opts = NULL;
int rtp_port;
char hostname[256];
char buf[1024];
s->fec_col_hd = NULL;
s->fec_row_hd = NULL;
if (s->l * s->d > 100) {
av_log(h, AV_LOG_ERROR, "L * D must be <= 100\n");
return AVERROR(EINVAL);
}
av_url_split(NULL, 0, NULL, 0, hostname, sizeof (hostname), &rtp_port,
NULL, 0, uri);
if (rtp_port < 1 || rtp_port > UINT16_MAX - 4) {
av_log(h, AV_LOG_ERROR, "Invalid RTP base port %d\n", rtp_port);
return AVERROR(EINVAL);
}
if (s->ttl > 0) {
av_dict_set_int(&udp_opts, "ttl", s->ttl, 0);
}
ff_url_join(buf, sizeof (buf), "udp", NULL, hostname, rtp_port + 2, NULL);
if (ffurl_open_whitelist(&s->fec_col_hd, buf, flags, &h->interrupt_callback,
&udp_opts, h->protocol_whitelist, h->protocol_blacklist, h) < 0)
goto fail;
ff_url_join(buf, sizeof (buf), "udp", NULL, hostname, rtp_port + 4, NULL);
if (ffurl_open_whitelist(&s->fec_row_hd, buf, flags, &h->interrupt_callback,
&udp_opts, h->protocol_whitelist, h->protocol_blacklist, h) < 0)
goto fail;
h->max_packet_size = s->fec_col_hd->max_packet_size;
s->init = 1;
av_dict_free(&udp_opts);
av_log(h, AV_LOG_INFO, "ProMPEG CoP#3-R2 FEC L=%d D=%d\n", s->l, s->d);
return 0;
fail:
ffurl_closep(&s->fec_col_hd);
ffurl_closep(&s->fec_row_hd);
av_dict_free(&udp_opts);
return AVERROR(EIO);
}
static int prompeg_init(URLContext *h, const uint8_t *buf, int size) {
PrompegContext *s = h->priv_data;
uint32_t seed;
int i;
s->fec_arr = NULL;
s->rtp_buf = NULL;
if (size < 12 || size > UINT16_MAX + 12) {
av_log(h, AV_LOG_ERROR, "Invalid RTP packet size\n");
return AVERROR_INVALIDDATA;
}
s->packet_idx = 0;
s->packet_idx_max = s->l * s->d;
s->packet_size = size;
s->length_recovery = size - 12;
s->rtp_buf_size = 28 + s->length_recovery; // 12 + 16: RTP + FEC headers
s->bitstring_size = 8 + s->length_recovery; // 8: P, X, CC, M, PT, SN, TS
s->fec_arr_len = 1 + 2 * s->l; // row + column tmp + column out
if (h->flags & AVFMT_FLAG_BITEXACT) {
s->rtp_col_sn = 0;
s->rtp_row_sn = 0;
} else {
seed = av_get_random_seed();
s->rtp_col_sn = seed & 0x0fff;
s->rtp_row_sn = (seed >> 16) & 0x0fff;
}
s->fec_arr = av_malloc_array(s->fec_arr_len, sizeof (PrompegFec*));
if (!s->fec_arr) {
goto fail;
}
for (i = 0; i < s->fec_arr_len; i++) {
s->fec_arr[i] = av_malloc(sizeof (PrompegFec));
if (!s->fec_arr[i]) {
goto fail;
}
s->fec_arr[i]->bitstring = av_malloc_array(s->bitstring_size, sizeof (uint8_t));
if (!s->fec_arr[i]->bitstring) {
av_freep(&s->fec_arr[i]);
goto fail;
}
}
s->fec_row = *s->fec_arr;
s->fec_col = s->fec_arr + 1;
s->fec_col_tmp = s->fec_arr + 1 + s->l;
s->rtp_buf = av_malloc_array(s->rtp_buf_size, sizeof (uint8_t));
if (!s->rtp_buf) {
goto fail;
}
memset(s->rtp_buf, 0, s->rtp_buf_size);
s->init = 0;
s->first = 1;
return 0;
fail:
av_log(h, AV_LOG_ERROR, "Failed to allocate the FEC buffer\n");
return AVERROR(ENOMEM);
}
static int prompeg_write(URLContext *h, const uint8_t *buf, int size) {
PrompegContext *s = h->priv_data;
PrompegFec *fec_tmp;
uint8_t *bitstring = NULL;
int col_idx, col_out_idx, row_idx;
int ret = 0;
if (s->init && ((ret = prompeg_init(h, buf, size)) < 0))
goto end;
if ((ret = prompeg_create_bitstring(h, buf, size, &bitstring)) < 0)
goto end;
col_idx = s->packet_idx % s->l;
row_idx = s->packet_idx / s->l % s->d;
// FEC' (row) send block-aligned, xor
if (col_idx == 0) {
if (!s->first || s->packet_idx > 0) {
if ((ret = prompeg_write_fec(h, s->fec_row, PROMPEG_FEC_ROW)) < 0)
goto end;
}
memcpy(s->fec_row->bitstring, bitstring, s->bitstring_size);
s->fec_row->sn = AV_RB16(buf + 2);
s->fec_row->ts = AV_RB32(buf + 4);
} else {
xor_fast(s->fec_row->bitstring, bitstring, s->fec_row->bitstring,
s->bitstring_size);
}
// FEC (column) xor
if (row_idx == 0) {
if (!s->first) {
// swap fec_col and fec_col_tmp
fec_tmp = s->fec_col[col_idx];
s->fec_col[col_idx] = s->fec_col_tmp[col_idx];
s->fec_col_tmp[col_idx] = fec_tmp;
}
memcpy(s->fec_col_tmp[col_idx]->bitstring, bitstring, s->bitstring_size);
s->fec_col_tmp[col_idx]->sn = AV_RB16(buf + 2);
s->fec_col_tmp[col_idx]->ts = AV_RB32(buf + 4);
} else {
xor_fast(s->fec_col_tmp[col_idx]->bitstring, bitstring,
s->fec_col_tmp[col_idx]->bitstring, s->bitstring_size);
}
// FEC (column) send block-aligned
if (!s->first && s->packet_idx % s->d == 0) {
col_out_idx = s->packet_idx / s->d;
if ((ret = prompeg_write_fec(h, s->fec_col[col_out_idx], PROMPEG_FEC_COL)) < 0)
goto end;
}
if (++s->packet_idx >= s->packet_idx_max) {
s->packet_idx = 0;
if (s->first)
s->first = 0;
}
ret = size;
end:
av_free(bitstring);
return ret;
}
static int prompeg_close(URLContext *h) {
PrompegContext *s = h->priv_data;
int i;
ffurl_closep(&s->fec_col_hd);
ffurl_closep(&s->fec_row_hd);
if (s->fec_arr) {
for (i = 0; i < s->fec_arr_len; i++) {
av_free(s->fec_arr[i]->bitstring);
av_freep(&s->fec_arr[i]);
}
av_freep(&s->fec_arr);
}
av_freep(&s->rtp_buf);
return 0;
}
const URLProtocol ff_prompeg_protocol = {
.name = "prompeg",
.url_open = prompeg_open,
.url_write = prompeg_write,
.url_close = prompeg_close,
.priv_data_size = sizeof(PrompegContext),
.flags = URL_PROTOCOL_FLAG_NETWORK,
.priv_data_class = &prompeg_class,
};
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