Reed-Solomon: add defaults for audio

For unsompreesed audio, where it has only the advantage, set default R-S values to k=160 n=240 (50 % redundancy). For uncompressed audio, the number of packets per frmae start at 3 (for 16-bit 30p), for which the value is appropriate. Not for the audio captured at 60 Hz, however. Here it, is 1600 B with 16-bit samples, with the R-S FEC this yields 2 packets only.
CESNET · Sep 11, 2024 · 215b823 · 215b823
1 parent 5bae31f
commit 215b823
Show file tree

Hide file tree

Showing 6 changed files with 14 additions and 11 deletions.
diff --git a/src/audio/audio.cpp b/src/audio/audio.cpp
@@ -873,7 +873,7 @@ static struct response *audio_sender_process_message(struct state_audio *s, stru
                         delete old_fec_state;
                         break;
                 }
-                s->fec_state = fec::create_from_config(msg->fec_cfg);
+                s->fec_state = fec::create_from_config(msg->fec_cfg, true);
                 if (s->fec_state == nullptr) {
                         s->fec_state = old_fec_state;
                         if (strstr(msg->fec_cfg, "help") !=

diff --git a/src/rtp/fec.cpp b/src/rtp/fec.cpp
@@ -59,7 +59,7 @@ using std::stof;
 using std::stoi;
 using std::string;
 
-fec *fec::create_from_config(const char *c_str) noexcept
+fec *fec::create_from_config(const char *c_str, bool is_audio) noexcept
 {
         try {
                 if (strncmp(c_str, "LDGM percents ", strlen("LDGM percents ")) == 0) {
@@ -87,7 +87,7 @@ fec *fec::create_from_config(const char *c_str) noexcept
                         return new ldgm(c_str + strlen("LDGM cfg "));
                 }
                 if (strncmp(c_str, "RS cfg ", strlen("RS cfg ")) == 0) {
-                        return new rs(c_str + strlen("rs cfg "));
+                        return new rs(c_str + strlen("rs cfg "), is_audio);
                 }
                 throw ug_runtime_error("Unrecognized FEC configuration!");
         } catch (string const &s) {

diff --git a/src/rtp/fec.h b/src/rtp/fec.h
@@ -64,7 +64,7 @@ struct fec {
                         const std::map<int, int> &) = 0;
         virtual ~fec() {}
 
-        static fec *create_from_config(const char *str) noexcept;
+        static fec *create_from_config(const char *str, bool is_audio) noexcept;
         static fec *create_from_desc(struct fec_desc) noexcept;
         static int pt_from_fec_type(enum tx_media_type media_type, enum fec_type fec_type, bool encrypted) throw();
         static enum fec_type fec_type_from_pt(int pt) throw();

diff --git a/src/rtp/rs.cpp b/src/rtp/rs.cpp
@@ -51,8 +51,11 @@
 #include "utils/text.h"
 #include "video.h"
 
-#define DEFAULT_K 200
-#define DEFAULT_N 240
+enum {
+        DEFAULT_K_AUDIO = 160,
+        DEFAULT_K_VIDEO = 200,
+        DEFAULT_N       = 240,
+};
 
 #define MAX_K 255
 #define MAX_N 255
@@ -90,7 +93,7 @@ rs::rs(unsigned int k, unsigned int n)
 #endif
 }
 
-rs::rs(const char *c_cfg)
+rs::rs(const char *c_cfg, bool is_audio)
 {
         if (strcmp(c_cfg, "help") == 0) {
                 usage();
@@ -105,7 +108,7 @@ rs::rs(const char *c_cfg)
                 assert(item != NULL);
                 m_n = atoi(item);
         } else {
-                m_k = DEFAULT_K;
+                m_k = is_audio ? DEFAULT_K_AUDIO : DEFAULT_K_VIDEO;
                 m_n = DEFAULT_N;
         }
         free(cfg);
@@ -424,7 +427,7 @@ static void usage() {
                 "\t" TBOLD("<n>") " - length of block + parity "
                 "(default " TBOLD("%d") ", max %d),\n"
                 "\t\t\tmust be > <k>\n\n",
-                DEFAULT_K, MAX_K, DEFAULT_N, MAX_N);
+                DEFAULT_K_VIDEO, MAX_K, DEFAULT_N, MAX_N);
 
         char desc[] =
             "The n/k ratio determines the redundancy that the FEC provides. "

diff --git a/src/rtp/rs.h b/src/rtp/rs.h
@@ -48,7 +48,7 @@ struct video_frame;
 
 struct rs : public fec {
         rs(unsigned int k, unsigned int n);
-        rs(const char *cfg);
+        rs(const char *cfg, bool is_audio);
         virtual ~rs();
         std::shared_ptr<video_frame> encode(std::shared_ptr<video_frame> frame) override;
         virtual audio_frame2 encode(audio_frame2 const &) override;

diff --git a/src/video_rxtx/rtp.cpp b/src/video_rxtx/rtp.cpp
@@ -129,7 +129,7 @@ rtp_video_rxtx::process_sender_message(struct msg_sender *msg)
                         delete old_fec_state;
                         break;
                 }
-                m_fec_state = fec::create_from_config(msg->fec_cfg);
+                m_fec_state = fec::create_from_config(msg->fec_cfg, false);
                 if (m_fec_state == nullptr) {
                         int rc = 0;
                         if (strstr(msg->fec_cfg, "help") == nullptr) {