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WHIP: Refine code.
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@winlinvip
winlinvip committed May 1, 2023
1 parent 2e26baf commit 58821db
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Showing 2 changed files with 71 additions and 41 deletions.
1 change: 1 addition & 0 deletions .gitignore
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Original file line number Diff line number Diff line change
Expand Up @@ -42,3 +42,4 @@
/mapfile
/tools/python/__pycache__/
.idea
patcheck.*
111 changes: 70 additions & 41 deletions libavformat/rtcenc.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -33,6 +33,8 @@
#include "url.h"
#include "libavutil/random_seed.h"

#define MAX_SDP_SIZE 8192

typedef struct RTCContext {
AVClass *av_class;

Expand All @@ -58,16 +60,16 @@ typedef struct RTCContext {
/* The ICE username and pwd from remote server. */
char *ice_ufrag_remote;
char *ice_pwd_remote;
/* The ICE candidate protocol, priority, host and port. */
/**
* The ICE candidate protocol, priority, host and port. Note that only
* support one candidate for now. We will choose the first udp candidate.
* We will support multiple candidates in the future.
*/
char *ice_protocol;
int ice_priority;
char *ice_host;
int ice_port;
/* The SDP answer received from the WebRTC server. */
char *sdp_answer;

/* The HTTP URL context is the transport layer for the WHIP protocol. */
URLContext *whip_uc;
} RTCContext;

/**
Expand Down Expand Up @@ -186,9 +188,15 @@ static int check_codec(AVFormatContext *s)
*/
static int generate_sdp_offer(AVFormatContext *s)
{
int profile_iop;
int ret, profile_iop;
RTCContext *rtc = s->priv_data;

char *tmp = av_mallocz(MAX_SDP_SIZE);
if (!tmp) {
av_log(s, AV_LOG_ERROR, "Failed to alloc answer: %s", s->url);
return AVERROR(EINVAL);
}

if (rtc->sdp_offer) {
av_log(s, AV_LOG_ERROR, "SDP offer is already set\n");
return AVERROR(EINVAL);
Expand All @@ -207,7 +215,8 @@ static int generate_sdp_offer(AVFormatContext *s)
rtc->video_payload_type = 106;

profile_iop = rtc->video_par->profile & FF_PROFILE_H264_CONSTRAINED ? 0xe0 : 0x00;
rtc->sdp_offer = av_asprintf(

ret = av_strlcatf(tmp, MAX_SDP_SIZE,
"v=0\r\n"
"o=FFmpeg 4489045141692799359 2 IN IP4 127.0.0.1\r\n"
"s=FFmpegPublishSession\r\n"
Expand Down Expand Up @@ -262,11 +271,19 @@ static int generate_sdp_offer(AVFormatContext *s)
profile_iop,
rtc->video_par->level,
rtc->video_ssrc,
rtc->video_ssrc
);
rtc->video_ssrc);
if (ret >= MAX_SDP_SIZE) {
av_log(s, AV_LOG_ERROR, "Offer %d exceed max %d, %s", ret, MAX_SDP_SIZE, tmp);
ret = AVERROR(EINVAL);
goto end;
}

rtc->sdp_offer = av_strdup(tmp);
av_log(s, AV_LOG_VERBOSE, "Generated offer: %s", rtc->sdp_offer);

return 0;
end:
av_free(tmp);
return ret;
}

/**
Expand Down Expand Up @@ -313,31 +330,38 @@ static int generate_sdp_offer(AVFormatContext *s)
static int exchange_sdp(AVFormatContext *s)
{
int ret;
char headers[MAX_URL_SIZE], buf[MAX_URL_SIZE];
char *p;
char buf[MAX_URL_SIZE];
RTCContext *rtc = s->priv_data;
/* The URL context is an HTTP transport layer for the WHIP protocol. */
URLContext *whip_uc = NULL;

char *tmp = av_mallocz(MAX_SDP_SIZE);
if (!tmp) {
av_log(s, AV_LOG_ERROR, "Failed to alloc answer: %s", s->url);
return AVERROR(EINVAL);
}

ret = ffurl_alloc(&rtc->whip_uc, s->url, AVIO_FLAG_READ_WRITE, &s->interrupt_callback);
ret = ffurl_alloc(&whip_uc, s->url, AVIO_FLAG_READ_WRITE, &s->interrupt_callback);
if (ret < 0) {
av_log(s, AV_LOG_ERROR, "Failed to alloc HTTP context: %s", s->url);
return ret;
goto end;
}

snprintf(headers, sizeof(headers),
snprintf(buf, sizeof(buf),
"Cache-Control: no-cache\r\n"
"Content-Type: application/sdp\r\n");
av_opt_set(rtc->whip_uc->priv_data, "headers", headers, 0);
av_opt_set(rtc->whip_uc->priv_data, "chunked_post", "0", 0);
av_opt_set_bin(rtc->whip_uc->priv_data, "post_data", rtc->sdp_offer, (int)strlen(rtc->sdp_offer), 0);
av_opt_set(whip_uc->priv_data, "headers", buf, 0);
av_opt_set(whip_uc->priv_data, "chunked_post", "0", 0);
av_opt_set_bin(whip_uc->priv_data, "post_data", rtc->sdp_offer, (int)strlen(rtc->sdp_offer), 0);

ret = ffurl_connect(rtc->whip_uc, NULL);
ret = ffurl_connect(whip_uc, NULL);
if (ret < 0) {
av_log(s, AV_LOG_ERROR, "Failed to request url=%s, offer: %s", s->url, rtc->sdp_offer);
return ret;
goto end;
}

for (;;) {
ret = ffurl_read(rtc->whip_uc, buf, sizeof(buf));
while (1) {
ret = ffurl_read(whip_uc, buf, sizeof(buf));
if (ret == AVERROR_EOF) {
/* Reset the error because we read all response as answer util EOF. */
ret = 0;
Expand All @@ -346,15 +370,23 @@ static int exchange_sdp(AVFormatContext *s)
if (ret <= 0) {
av_log(s, AV_LOG_ERROR, "Failed to read response from url=%s, offer is %s, answer is %s",
s->url, rtc->sdp_offer, rtc->sdp_answer);
return ret;
goto end;
}

p = rtc->sdp_answer;
rtc->sdp_answer = av_asprintf("%s%.*s", p ? p : "", ret, buf);
av_free(p);
ret = av_strlcatf(tmp, MAX_SDP_SIZE, "%.*s", ret, buf);
if (ret >= MAX_SDP_SIZE) {
av_log(s, AV_LOG_ERROR, "Answer %d exceed max size %d, %s", ret, MAX_SDP_SIZE, tmp);
ret = AVERROR(EINVAL);
goto end;
}
}

rtc->sdp_answer = av_strdup(tmp);
av_log(s, AV_LOG_VERBOSE, "Got answer: %s", rtc->sdp_answer);

end:
ffurl_closep(&whip_uc);
av_free(tmp);
return ret;
}

Expand All @@ -372,9 +404,7 @@ static int parse_answer(AVFormatContext *s)
int i;
RTCContext *rtc = s->priv_data;

pb = avio_alloc_context(
(unsigned char *)rtc->sdp_answer, (int)strlen(rtc->sdp_answer),
AVIO_FLAG_READ, NULL, NULL, NULL, NULL);
pb = avio_alloc_context(rtc->sdp_answer, strlen(rtc->sdp_answer), AVIO_FLAG_READ, NULL, NULL, NULL, NULL);
if (!pb) {
av_log(s, AV_LOG_ERROR, "Failed to alloc AVIOContext for answer: %s", rtc->sdp_answer);
ret = AVERROR(ENOMEM);
Expand All @@ -383,13 +413,11 @@ static int parse_answer(AVFormatContext *s)

for (i = 0; !avio_feof(pb); i++) {
ff_get_chomp_line(pb, line, sizeof(line));
if (av_strstart(line, "a=ice-ufrag:", &ptr)) {
av_freep(&rtc->ice_ufrag_remote);
if (av_strstart(line, "a=ice-ufrag:", &ptr) && !rtc->ice_ufrag_remote) {
rtc->ice_ufrag_remote = av_strdup(ptr);
} else if (av_strstart(line, "a=ice-pwd:", &ptr)) {
av_freep(&rtc->ice_pwd_remote);
} else if (av_strstart(line, "a=ice-pwd:", &ptr) && !rtc->ice_pwd_remote) {
rtc->ice_pwd_remote = av_strdup(ptr);
} else if (av_strstart(line, "a=candidate:", &ptr)) {
} else if (av_strstart(line, "a=candidate:", &ptr) && !rtc->ice_protocol) {
ptr = av_stristr(ptr, "udp");
if (ptr && av_stristr(ptr, "host")) {
char protocol[17], host[129];
Expand All @@ -403,27 +431,29 @@ static int parse_answer(AVFormatContext *s)
}

if (av_strcasecmp(protocol, "udp")) {
av_log(s, AV_LOG_ERROR, "Protocol %s is not supported by RTC, choose udp", protocol);
av_log(s, AV_LOG_ERROR, "Protocol %s is not supported by RTC, choose udp, line %d %s of %s",
protocol, i, line, rtc->sdp_answer);
ret = AVERROR(EINVAL);
goto end;
}

av_freep(&rtc->ice_protocol);
rtc->ice_protocol = av_strdup(protocol);
av_freep(&rtc->ice_host);
rtc->ice_host = av_strdup(host);
rtc->ice_priority = priority;
rtc->ice_port = port;
}
}
}

av_log(s, AV_LOG_VERBOSE, "SDP offer=%luB, answer=%luB, ufrag=%s, pwd=%luB, transport=%s://%s:%d\n",
strlen(rtc->sdp_offer), strlen(rtc->sdp_answer), rtc->ice_ufrag_remote, strlen(rtc->ice_pwd_remote),
rtc->ice_protocol, rtc->ice_host, rtc->ice_port);

end:
avio_context_free(&pb);
return ret;
}

static int rtc_init(AVFormatContext *s)
static av_cold int rtc_init(AVFormatContext *s)
{
int ret;

Expand Down Expand Up @@ -457,12 +487,11 @@ static int rtc_write_trailer(AVFormatContext *s)
return 0;
}

static void rtc_deinit(AVFormatContext *s)
static av_cold void rtc_deinit(AVFormatContext *s)
{
RTCContext *rtc = s->priv_data;
av_freep(&rtc->sdp_offer);
av_freep(&rtc->sdp_answer);
ffurl_closep(&rtc->whip_uc);
av_freep(&rtc->ice_ufrag_remote);
av_freep(&rtc->ice_pwd_remote);
av_freep(&rtc->ice_protocol);
Expand Down

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