Audio & video developmentHistorical technical note
A Simple Streaming Wrapper for FFmpeg-iOS
Builds on the preceding FFmpeg articles to set up a local nginx streaming test environment. Server configuration, a client-side streaming wrapper, and playback in VLC connect the process of sending encoded data with checking the resulting stream.
Originally credited to Bison. Content is retained as published.
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This historical illustration is currently unavailable. The original image URL is retained for reference. Building FFmpeg-iOS on a Mac H.264 Decoding with FFmpeg The previous two articles introduced some FFmpeg concepts and practical use. Next, let us learn to publish a stream. Before streaming, we need a local nginx streaming server for testing.
The main reference article An iOS Live-Streaming App: Publishing the Stream I will not elaborate here; interested readers can follow along.
Problems I encountered:
Could not symlink share/man/man8/nginx.8
/usr/local/share/man/man8 is not writable.
The main cause is missing filesystem permissions on the folder. Navigate to /usr/local/share/man/man8, open Get Info, and set system permissions to read and write.
The contents of nginx.conf for my configured nginx streaming server are:
#user nobody;
worker_processes 1;
#error_log logs/error.log;
#error_log logs/error.log notice;
#error_log logs/error.log info;
#pid logs/nginx.pid;
events {
worker_connections 1024;
}
http {
include mime.types;
default_type application/octet-stream;
#log_format main '$remote_addr - $remote_user [$time_local] "$request" '
# '$status $body_bytes_sent "$http_referer" '
# '"$http_user_agent" "$http_x_forwarded_for"';
#access_log logs/access.log main;
sendfile on;
#tcp_nopush on;
#keepalive_timeout 0;
keepalive_timeout 65;
#gzip on;
server {
listen 8080;
server_name localhost;
#charset koi8-r;
#access_log logs/host.access.log main;
location / {
root html;
index index.html index.htm;
}
#error_page 404 /404.html;
# redirect server error pages to the static page /50x.html
#
error_page 500 502 503 504 /50x.html;
location = /50x.html {
root html;
}
# proxy the PHP scripts to Apache listening on 127.0.0.1:80
#
#location ~ \.php$ {
# proxy_pass http://127.0.0.1;
#}
# pass the PHP scripts to FastCGI server listening on 127.0.0.1:9000
#
#location ~ \.php$ {
# root html;
# fastcgi_pass 127.0.0.1:9000;
# fastcgi_index index.php;
# fastcgi_param SCRIPT_FILENAME /scripts$fastcgi_script_name;
# include fastcgi_params;
#}
# deny access to .htaccess files, if Apache's document root
# concurs with nginx's one
#
#location ~ /\.ht {
# deny all;
#}
}
# another virtual host using mix of IP-, name-, and port-based configuration
#
#server {
# listen 8000;
# listen somename:8080;
# server_name somename alias another.alias;
# location / {
# root html;
# index index.html index.htm;
# }
#}
# HTTPS server
#
#server {
# listen 443 ssl;
# server_name localhost;
# ssl_certificate cert.pem;
# ssl_certificate_key cert.key;
# ssl_session_cache shared:SSL:1m;
# ssl_session_timeout 5m;
# ssl_ciphers HIGH:!aNULL:!MD5;
# ssl_prefer_server_ciphers on;
# location / {
# root html;
# index index.html index.htm;
# }
#}
include servers/*;
}
rtmp {
server {
listen 1991;
application liveApp {
live on;
record off;
}
}
}
You can copy the whole configuration. The resulting streaming-server address is:
rtmp://localhost:1991/liveApp/room
If you already completed Building FFmpeg-iOS on a Mac step, there is no need to download FFmpeg again. Proceed to the code below.
- (void)pushFlow:(NSString *)input_str output_str:(NSString *)output_rtmpStr{
char input_str_full[500]={0};
char output_str_full[500]={0};
// NSString *input_str= [NSString stringWithFormat:@"resource.bundle/%@",self.input.text];
NSString *input_nsstr=[[[NSBundle mainBundle]resourcePath] stringByAppendingPathComponent:input_str];
sprintf(input_str_full,"%s",[input_nsstr UTF8String]);
sprintf(output_str_full,"%s",[output_rtmpStr UTF8String]);
printf("Input Path:%s\n",input_str_full);
printf("Output Path:%s\n",output_str_full);
AVOutputFormat *ofmt = NULL;
//Input AVFormatContext and Output AVFormatContext
AVFormatContext *ifmt_ctx = NULL, *ofmt_ctx = NULL;
AVPacket pkt;
char in_filename[500]={0};
char out_filename[500]={0};
int ret, i;
int videoindex=-1;
int frame_index=0;
int64_t start_time=0;
//in_filename = "cuc_ieschool.mov";
//in_filename = "cuc_ieschool.h264";
//in_filename = "cuc_ieschool.flv";//Input file URL
//out_filename = "rtmp://localhost/publishlive/livestream";//Output URL[RTMP]
//out_filename = "rtp://233.233.233.233:6666";//Output URL[UDP]
strcpy(in_filename,input_str_full);
strcpy(out_filename,output_str_full);
av_register_all();
//Network
avformat_network_init();
//Input
if ((ret = avformat_open_input(&ifmt_ctx, in_filename, 0, 0)) < 0) {
printf( "Could not open input file.");
goto end;
}
if ((ret = avformat_find_stream_info(ifmt_ctx, 0)) < 0) {
printf( "Failed to retrieve input stream information");
goto end;
}
for(i=0; i<ifmt_ctx->nb_streams; i++)
if(ifmt_ctx->streams[i]->codec->codec_type==AVMEDIA_TYPE_VIDEO){
videoindex=i;
break;
}
av_dump_format(ifmt_ctx, 0, in_filename, 0);
//Output
avformat_alloc_output_context2(&ofmt_ctx, NULL, "flv", out_filename); //RTMP
//avformat_alloc_output_context2(&ofmt_ctx, NULL, "mpegts", out_filename);//UDP
if (!ofmt_ctx) {
printf( "Could not create output context\n");
ret = AVERROR_UNKNOWN;
goto end;
}
ofmt = ofmt_ctx->oformat;
for (i = 0; i < ifmt_ctx->nb_streams; i++) {
AVStream *in_stream = ifmt_ctx->streams[i];
AVStream *out_stream = avformat_new_stream(ofmt_ctx, in_stream->codec->codec);
if (!out_stream) {
printf( "Failed allocating output stream\n");
ret = AVERROR_UNKNOWN;
goto end;
}
ret = avcodec_copy_context(out_stream->codec, in_stream->codec);
if (ret < 0) {
printf( "Failed to copy context from input to output stream codec context\n");
goto end;
}
out_stream->codec->codec_tag = 0;
if (ofmt_ctx->oformat->flags & AVFMT_GLOBALHEADER)
out_stream->codec->flags |= CODEC_FLAG_GLOBAL_HEADER;
}
//Dump Format------------------
av_dump_format(ofmt_ctx, 0, out_filename, 1);
//Open output URL
if (!(ofmt->flags & AVFMT_NOFILE)) {
ret = avio_open(&ofmt_ctx->pb, out_filename, AVIO_FLAG_WRITE);
if (ret < 0) {
printf( "Could not open output URL '%s'", out_filename);
goto end;
}
}
ret = avformat_write_header(ofmt_ctx, NULL);
if (ret < 0) {
printf( "Error occurred when opening output URL\n");
goto end;
}
start_time=av_gettime();
while (1) {
AVStream *in_stream, *out_stream;
//Get an AVPacket
ret = av_read_frame(ifmt_ctx, &pkt);
if (ret < 0)
break;
//FIX：No PTS (Example: Raw H.264)
//Simple Write PTS
if(pkt.pts==AV_NOPTS_VALUE){
//Write PTS
AVRational time_base1=ifmt_ctx->streams[videoindex]->time_base;
//Duration between 2 frames (us)
int64_t calc_duration=(double)AV_TIME_BASE/av_q2d(ifmt_ctx->streams[videoindex]->r_frame_rate);
//Parameters
pkt.pts=(double)(frame_index*calc_duration)/(double)(av_q2d(time_base1)*AV_TIME_BASE);
pkt.dts=pkt.pts;
pkt.duration=(double)calc_duration/(double)(av_q2d(time_base1)*AV_TIME_BASE);
}
//Important:Delay
if(pkt.stream_index==videoindex){
AVRational time_base=ifmt_ctx->streams[videoindex]->time_base;
AVRational time_base_q={1,AV_TIME_BASE};
int64_t pts_time = av_rescale_q(pkt.dts, time_base, time_base_q);
int64_t now_time = av_gettime() - start_time;
if (pts_time > now_time)
av_usleep(pts_time - now_time);
}
in_stream = ifmt_ctx->streams[pkt.stream_index];
out_stream = ofmt_ctx->streams[pkt.stream_index];
/* copy packet */
//Convert PTS/DTS
pkt.pts = av_rescale_q_rnd(pkt.pts, in_stream->time_base, out_stream->time_base, (AV_ROUND_NEAR_INF|AV_ROUND_PASS_MINMAX));
pkt.dts = av_rescale_q_rnd(pkt.dts, in_stream->time_base, out_stream->time_base, (AV_ROUND_NEAR_INF|AV_ROUND_PASS_MINMAX));
pkt.duration = av_rescale_q(pkt.duration, in_stream->time_base, out_stream->time_base);
pkt.pos = -1;
//Print to Screen
if(pkt.stream_index==videoindex){
printf("Send %8d video frames to output URL\n",frame_index);
frame_index++;
}
//ret = av_write_frame(ofmt_ctx, &pkt);
ret = av_interleaved_write_frame(ofmt_ctx, &pkt);
if (ret < 0) {
printf( "Error muxing packet\n");
break;
}
av_packet_unref(&pkt);
}
//写文件尾（Write file trailer）
av_write_trailer(ofmt_ctx);
end:
avformat_close_input(&ifmt_ctx);
/* close output */
if (ofmt_ctx && !(ofmt->flags & AVFMT_NOFILE))
avio_close(ofmt_ctx->pb);
avformat_free_context(ofmt_ctx);
if (ret < 0 && ret != AVERROR_EOF) {
printf( "Error occurred.\n");
return;
}
return;
}
While the app runs, open the streaming address in VLC to view the stream.
This historical illustration is currently unavailable. The original image URL is retained for reference. Download LBffmpegDemo
Recommended reading: A beginner developer's review of 2015