HLS: Remove deprecated hls_acodec/hls_vcodec configs. v7.0.53 (#4225)

## Summary
Removes the deprecated `hls_acodec` and `hls_vcodec` configuration
options and implements automatic codec detection for HLS streams, fixing
issues with video-only streams incorrectly showing audio information.

## Problem
- When streaming video-only content via RTMP, HLS output incorrectly
contained audio track information due to hardcoded default codec
settings
- The static `hls_acodec` and `hls_vcodec` configurations were
inflexible and caused compatibility issues with some players
- Users had to manually configure `hls_acodec an` to fix video-only
streams

## Solution
- **Remove deprecated configs**: Eliminates `hls_acodec` and
`hls_vcodec` configuration options entirely
- **Dynamic codec detection**: HLS muxer now automatically detects and
uses actual stream codecs in real-time
- **Improved defaults**: Changes from hardcoded AAC/H.264 defaults to
disabled state, letting actual stream content determine codec
information
- **Real-time codec switching**: Supports codec changes during streaming
with proper logging

## Changes
- Remove `get_hls_acodec()` and `get_hls_vcodec()` from SrsConfig
- Update HLS muxer to use `latest_acodec_`/`latest_vcodec_` for codec
detection
- Add codec detection logic in `write_audio()` and `write_video()`
methods
- Remove deprecated config options from all configuration files
- Add comprehensive unit tests for codec detection functionality

Fixes #4223

---------

Co-authored-by: Haibo Chen <495810242@qq.com>
Co-authored-by: OSSRS-AI <winlinam@gmail.com>

trunk/conf/full.conf

@@ -1941,22 +1941,6 @@ vhost hls.srs.com {
         # Overwrite by env SRS_VHOST_HLS_HLS_ENTRY_PREFIX for all vhosts.
         # optional, default to empty string.
         hls_entry_prefix http://your-server;
-        # the default audio codec of hls.
-        # when codec changed, write the PAT/PMT table, but maybe ok util next ts.
-        # so user can set the default codec for mp3.
-        # the available audio codec:
-        #       aac, mp3, an
-        # Overwrite by env SRS_VHOST_HLS_HLS_ACODEC for all vhosts.
-        # default: aac
-        hls_acodec aac;
-        # the default video codec of hls.
-        # when codec changed, write the PAT/PMT table, but maybe ok util next ts.
-        # so user can set the default codec for pure audio(without video) to vn.
-        # the available video codec:
-        #       h264, vn
-        # Overwrite by env SRS_VHOST_HLS_HLS_VCODEC for all vhosts.
-        # default: h264
-        hls_vcodec h264;
         # whether cleanup the old expired ts files.
         # Overwrite by env SRS_VHOST_HLS_HLS_CLEANUP for all vhosts.
         # default: on

trunk/conf/mp3.conf

@@ -14,6 +14,5 @@ vhost __defaultVhost__ {
     }
     hls {
         enabled on;
-        hls_acodec mp3;
     }
 }

trunk/conf/mp3.rtc.conf

@@ -20,7 +20,6 @@ vhost __defaultVhost__ {
     }
     hls {
         enabled on;
-        hls_acodec mp3;
     }
     rtc {
         enabled     on;

trunk/doc/CHANGELOG.md

@@ -7,6 +7,7 @@ The changelog for SRS.
 <a name="v7-changes"></a>
 
 ## SRS 7.0 Changelog
+* v7.0, 2025-08-13, Merge [#4225](https://github.com/ossrs/srs/pull/4225): issue #4223: remove hls_acodec and hls_vcodec config. v7.0.53 (#4225)
 * v7.0, 2025-08-12, Merge [#4230](https://github.com/ossrs/srs/pull/4230): MP4 DVR: Fix audio/video synchronization issues in WebRTC recordings. v7.0.52 (#4230)
 * v7.0, 2025-08-12, Merge [#4301](https://github.com/ossrs/srs/pull/4301): Valgrind: Return error for unsupported check=new on Valgrind < 3.21. v7.0.52 (#4301)
 * v7.0, 2025-08-12, Merge [#4431](https://github.com/ossrs/srs/pull/4431): fix srt cmake 4.x compiling error. v7.0.52 (#4431)

trunk/src/app/srs_app_config.cpp

@@ -7284,44 +7284,6 @@ string SrsConfig::get_hls_on_error(string vhost)
     return conf->arg0();
 }
 
-string SrsConfig::get_hls_acodec(string vhost)
-{
-    SRS_OVERWRITE_BY_ENV_STRING("srs.vhost.hls.hls_acodec"); // SRS_VHOST_HLS_HLS_ACODEC
-
-    static string DEFAULT = "aac";
-
-    SrsConfDirective *conf = get_hls(vhost);
-    if (!conf) {
-        return DEFAULT;
-    }
-
-    conf = conf->get("hls_acodec");
-    if (!conf || conf->arg0().empty()) {
-        return DEFAULT;
-    }
-
-    return conf->arg0();
-}
-
-string SrsConfig::get_hls_vcodec(string vhost)
-{
-    SRS_OVERWRITE_BY_ENV_STRING("srs.vhost.hls.hls_vcodec"); // SRS_VHOST_HLS_HLS_VCODEC
-
-    static string DEFAULT = "h264";
-
-    SrsConfDirective *conf = get_hls(vhost);
-    if (!conf) {
-        return DEFAULT;
-    }
-
-    conf = conf->get("hls_vcodec");
-    if (!conf || conf->arg0().empty()) {
-        return DEFAULT;
-    }
-
-    return conf->arg0();
-}
-
 int SrsConfig::get_vhost_hls_nb_notify(string vhost)
 {
     SRS_OVERWRITE_BY_ENV_INT("srs.vhost.hls.hls_nb_notify"); // SRS_VHOST_HLS_HLS_NB_NOTIFY

trunk/src/app/srs_app_config.hpp

@@ -1006,10 +1006,6 @@ public:
     // The ignore will ignore error and disable hls.
     // The disconnect will disconnect publish connection.
     virtual std::string get_hls_on_error(std::string vhost);
-    // Get the HLS default audio codec.
-    virtual std::string get_hls_acodec(std::string vhost);
-    // Get the HLS default video codec.
-    virtual std::string get_hls_vcodec(std::string vhost);
     // Whether cleanup the old ts files.
     virtual bool get_hls_cleanup(std::string vhost);
     // The timeout in srs_utime_t to dispose the hls.

trunk/src/app/srs_app_hls.cpp

@@ -1267,37 +1267,15 @@ srs_error_t SrsHlsMuxer::segment_open()
     srs_assert(!current);
 
     // load the default acodec from config.
-    SrsAudioCodecId default_acodec = SrsAudioCodecIdAAC;
-    if (true) {
-        std::string default_acodec_str = _srs_config->get_hls_acodec(req->vhost);
-        if (default_acodec_str == "mp3") {
-            default_acodec = SrsAudioCodecIdMP3;
-        } else if (default_acodec_str == "aac") {
-            default_acodec = SrsAudioCodecIdAAC;
-        } else if (default_acodec_str == "an") {
-            default_acodec = SrsAudioCodecIdDisabled;
-        } else {
-            srs_warn("hls: use aac for other codec=%s", default_acodec_str.c_str());
-        }
-    }
+    SrsAudioCodecId default_acodec = SrsAudioCodecIdDisabled;
+
     // Now that we know the latest audio codec in stream, use it.
     if (latest_acodec_ != SrsAudioCodecIdForbidden)
         default_acodec = latest_acodec_;
 
     // load the default vcodec from config.
-    SrsVideoCodecId default_vcodec = SrsVideoCodecIdAVC;
-    if (true) {
-        std::string default_vcodec_str = _srs_config->get_hls_vcodec(req->vhost);
-        if (default_vcodec_str == "h264") {
-            default_vcodec = SrsVideoCodecIdAVC;
-        } else if (default_vcodec_str == "h265") {
-            default_vcodec = SrsVideoCodecIdHEVC;
-        } else if (default_vcodec_str == "vn") {
-            default_vcodec = SrsVideoCodecIdDisabled;
-        } else {
-            srs_warn("hls: use h264 for other codec=%s", default_vcodec_str.c_str());
-        }
-    }
+    SrsVideoCodecId default_vcodec = SrsVideoCodecIdDisabled;
+
     // Now that we know the latest video codec in stream, use it.
     if (latest_vcodec_ != SrsVideoCodecIdForbidden)
         default_vcodec = latest_vcodec_;
@@ -2156,12 +2134,20 @@ srs_error_t SrsHlsMp4Controller::on_unpublish()
 srs_error_t SrsHlsMp4Controller::write_audio(SrsSharedPtrMessage *shared_audio, SrsFormat *format)
 {
     srs_error_t err = srs_success;
+    SrsAudioFrame *frame = format->audio;
 
     // Ignore audio sequence header
     if (format->is_aac_sequence_header() || format->is_mp3_sequence_header()) {
         return err;
     }
 
+    // Refresh the codec ASAP.
+    if (muxer_->latest_acodec() != frame->acodec()->id) {
+        srs_trace("HLS: Switch audio codec %d(%s) to %d(%s)", muxer_->latest_acodec(), srs_audio_codec_id2str(muxer_->latest_acodec()).c_str(),
+                  frame->acodec()->id, srs_audio_codec_id2str(frame->acodec()->id).c_str());
+        muxer_->set_latest_acodec(frame->acodec()->id);
+    }
+
     audio_dts_ = shared_audio->timestamp;
 
     if ((err = muxer_->write_audio(shared_audio, format)) != srs_success) {
@@ -2178,7 +2164,7 @@ srs_error_t SrsHlsMp4Controller::write_video(SrsSharedPtrMessage *shared_video,
 
     // Refresh the codec ASAP.
     if (muxer_->latest_vcodec() != frame->vcodec()->id) {
-        srs_trace("HLS: Switch video codec %d(%s) to %d(%s)", muxer_->latest_acodec(), srs_video_codec_id2str(muxer_->latest_vcodec()).c_str(),
+        srs_trace("HLS: Switch video codec %d(%s) to %d(%s)", muxer_->latest_vcodec(), srs_video_codec_id2str(muxer_->latest_vcodec()).c_str(),
                   frame->vcodec()->id, srs_video_codec_id2str(frame->vcodec()->id).c_str());
         muxer_->set_latest_vcodec(frame->vcodec()->id);
     }

trunk/src/core/srs_core_version7.hpp

@@ -9,6 +9,6 @@
 
 #define VERSION_MAJOR 7
 #define VERSION_MINOR 0
-#define VERSION_REVISION 52
+#define VERSION_REVISION 53
 
 #endif

trunk/src/utest/srs_utest_config.cpp

@@ -3742,13 +3742,11 @@ VOID TEST(ConfigMainTest, CheckVhostConfig5)
 
     if (true) {
         MockSrsConfig conf;
-        HELPER_ASSERT_SUCCESS(conf.parse(_MIN_OK_CONF "vhost ossrs.net{hls{hls_td_ratio 2.1;hls_aof_ratio 3.1;hls_window 10;hls_on_error xxx;hls_acodec xxx2;hls_vcodec xxx3;hls_nb_notify 5;hls_dts_directly off;hls_cleanup off;hls_dispose 10;hls_wait_keyframe off;}}"));
+        HELPER_ASSERT_SUCCESS(conf.parse(_MIN_OK_CONF "vhost ossrs.net{hls{hls_td_ratio 2.1;hls_aof_ratio 3.1;hls_window 10;hls_on_error xxx;hls_nb_notify 5;hls_dts_directly off;hls_cleanup off;hls_dispose 10;hls_wait_keyframe off;}}"));
         EXPECT_EQ(2.1, conf.get_hls_td_ratio("ossrs.net"));
         EXPECT_EQ(3.1, conf.get_hls_aof_ratio("ossrs.net"));
         EXPECT_EQ(10 * SRS_UTIME_SECONDS, conf.get_hls_window("ossrs.net"));
         EXPECT_STREQ("xxx", conf.get_hls_on_error("ossrs.net").c_str());
-        EXPECT_STREQ("xxx2", conf.get_hls_acodec("ossrs.net").c_str());
-        EXPECT_STREQ("xxx3", conf.get_hls_vcodec("ossrs.net").c_str());
         EXPECT_EQ(5, conf.get_vhost_hls_nb_notify("ossrs.net"));
         EXPECT_FALSE(conf.get_vhost_hls_dts_directly("ossrs.net"));
         EXPECT_FALSE(conf.get_hls_cleanup("ossrs.net"));
@@ -5118,12 +5116,6 @@ VOID TEST(ConfigEnvTest, CheckEnvValuesHls)
         SrsSetEnvConfig(conf, hls_entry_prefix, "SRS_VHOST_HLS_HLS_ENTRY_PREFIX", "yyy");
         EXPECT_STREQ("yyy", conf.get_hls_entry_prefix("__defaultVhost__").c_str());
 
-        SrsSetEnvConfig(conf, hls_acodec, "SRS_VHOST_HLS_HLS_ACODEC", "yyy2");
-        EXPECT_STREQ("yyy2", conf.get_hls_acodec("__defaultVhost__").c_str());
-
-        SrsSetEnvConfig(conf, hls_vcodec, "SRS_VHOST_HLS_HLS_VCODEC", "yyy3");
-        EXPECT_STREQ("yyy3", conf.get_hls_vcodec("__defaultVhost__").c_str());
-
         SrsSetEnvConfig(conf, hls_cleanup, "SRS_VHOST_HLS_HLS_CLEANUP", "off");
         EXPECT_FALSE(conf.get_hls_cleanup("__defaultVhost__"));
 

trunk/src/utest/srs_utest_fmp4.cpp

@@ -751,6 +751,84 @@ VOID TEST(Fmp4Test, Configuration_SequenceHeaderValidation)
     controller.dispose();
 }
 
+VOID TEST(Fmp4Test, CodecDetection_AudioCodecUpdate)
+{
+    srs_error_t err;
+
+    SrsHlsMp4Controller controller;
+    HELPER_ASSERT_SUCCESS(controller.initialize());
+
+    MockSrsRequest req;
+    HELPER_ASSERT_SUCCESS(controller.on_publish(&req));
+
+    // Create mock format with AAC audio codec
+    MockSrsFormat fmt;
+    fmt.acodec = new SrsAudioCodecConfig();
+    fmt.acodec->id = SrsAudioCodecIdAAC;
+    fmt.audio = new SrsAudioFrame();
+    fmt.audio->codec = fmt.acodec;
+
+    // Initial codec should be forbidden (not set)
+    EXPECT_EQ(SrsAudioCodecIdForbidden, controller.muxer_->latest_acodec());
+
+    // Write audio frame - should detect and update codec
+    MockSrsSharedPtrMessage audio_msg(false, 1000);
+    HELPER_ASSERT_SUCCESS(controller.write_audio(&audio_msg, &fmt));
+
+    // Codec should now be detected as AAC
+    EXPECT_EQ(SrsAudioCodecIdAAC, controller.muxer_->latest_acodec());
+
+    // Test codec change from AAC to MP3
+    fmt.acodec->id = SrsAudioCodecIdMP3;
+    HELPER_ASSERT_SUCCESS(controller.write_audio(&audio_msg, &fmt));
+
+    // Codec should now be updated to MP3
+    EXPECT_EQ(SrsAudioCodecIdMP3, controller.muxer_->latest_acodec());
+
+    controller.dispose();
+    srs_freep(fmt.acodec);
+    srs_freep(fmt.audio);
+}
+
+VOID TEST(Fmp4Test, CodecDetection_VideoCodecUpdate)
+{
+    srs_error_t err;
+
+    SrsHlsMp4Controller controller;
+    HELPER_ASSERT_SUCCESS(controller.initialize());
+
+    MockSrsRequest req;
+    HELPER_ASSERT_SUCCESS(controller.on_publish(&req));
+
+    // Create mock format with H.264 video codec
+    MockSrsFormat fmt;
+    fmt.vcodec = new SrsVideoCodecConfig();
+    fmt.vcodec->id = SrsVideoCodecIdAVC;
+    fmt.video = new SrsVideoFrame();
+    fmt.video->codec = fmt.vcodec;
+
+    // Initial codec should be forbidden (not set)
+    EXPECT_EQ(SrsVideoCodecIdForbidden, controller.muxer_->latest_vcodec());
+
+    // Write video frame - should detect and update codec
+    MockSrsSharedPtrMessage video_msg(true, 1000);
+    HELPER_ASSERT_SUCCESS(controller.write_video(&video_msg, &fmt));
+
+    // Codec should now be detected as H.264
+    EXPECT_EQ(SrsVideoCodecIdAVC, controller.muxer_->latest_vcodec());
+
+    // Test codec change from H.264 to HEVC
+    fmt.vcodec->id = SrsVideoCodecIdHEVC;
+    HELPER_ASSERT_SUCCESS(controller.write_video(&video_msg, &fmt));
+
+    // Codec should now be updated to HEVC
+    EXPECT_EQ(SrsVideoCodecIdHEVC, controller.muxer_->latest_vcodec());
+
+    controller.dispose();
+    srs_freep(fmt.vcodec);
+    srs_freep(fmt.video);
+}
+
 VOID TEST(Fmp4Test, Performance_MultipleSegments)
 {
     srs_error_t err;