media: Add MEDIALOG_WARNING

Add a new MediaLog level so that we don't have to abuse MEDIALOG_ERROR,
which could end up in MediaError.message and should be carefully used.

Also update documentation on MediaLog levels.

Also use MEDIALOG_WARNING in audio_timestamp_validator.cc for non-fatal
issues.

Bug: 843808
Test: Manually tested and verified in about://media-internals
Cq-Include-Trybots: luci.chromium.try:android_optional_gpu_tests_rel;luci.chromium.try:linux_optional_gpu_tests_rel;luci.chromium.try:mac_optional_gpu_tests_rel;luci.chromium.try:win_optional_gpu_tests_rel
Change-Id: I20350d305b3f55d1f59e6d2324cc3be7452bcbbe
Reviewed-on: https://chromium-review.googlesource.com/1063009Reviewed-by: Dale Curtis <dalecurtis@chromium.org>
Commit-Queue: Xiaohan Wang <xhwang@chromium.org>
Cr-Commit-Position: refs/heads/master@{#559399}

media/README.md

@@ -161,6 +161,8 @@ processes. Media operations are often asynchronous running in a sandbox. These
 make attaching a debugger (e.g. GDB) sometimes less efficient than other
 mechanisms like logging.
 
+## DVLOG
+
 In media we use DVLOG() a lot. It makes filename-based filtering super easy.
 Within one file, not all logs are created equal. To make log filtering
 more convenient, use appropriate log levels. Here are some general
@@ -172,3 +174,10 @@ recommendations:
 * DVLOG(2): Recurring events per playback, e.g. seek/reset/flush, config change.
 * DVLOG(3): Frequent events, e.g. demuxer read, audio/video buffer decrypt or
   decode, audio/video frame rendering.
+
+## MediaLog
+
+MediaLog will send logs to `about://media-internals`, which is easily accessible
+by developers (including web developes), testers and even users to get detailed
+information about a playback instance. For guidance on how to use MediaLog, see
+`media/base/media_log.h`.
\ No newline at end of file

media/base/media_log.cc

@@ -21,6 +21,8 @@ std::string MediaLog::MediaLogLevelToString(MediaLogLevel level) {
   switch (level) {
     case MEDIALOG_ERROR:
       return "error";
+    case MEDIALOG_WARNING:
+      return "warning";
     case MEDIALOG_INFO:
       return "info";
     case MEDIALOG_DEBUG:
@@ -34,6 +36,8 @@ MediaLogEvent::Type MediaLog::MediaLogLevelToEventType(MediaLogLevel level) {
   switch (level) {
     case MEDIALOG_ERROR:
       return MediaLogEvent::MEDIA_ERROR_LOG_ENTRY;
+    case MEDIALOG_WARNING:
+      return MediaLogEvent::MEDIA_WARNING_LOG_ENTRY;
     case MEDIALOG_INFO:
       return MediaLogEvent::MEDIA_INFO_LOG_ENTRY;
     case MEDIALOG_DEBUG:
@@ -71,6 +75,8 @@ std::string MediaLog::EventTypeToString(MediaLogEvent::Type type) {
       return "TEXT_ENDED";
     case MediaLogEvent::MEDIA_ERROR_LOG_ENTRY:
       return "MEDIA_ERROR_LOG_ENTRY";
+    case MediaLogEvent::MEDIA_WARNING_LOG_ENTRY:
+      return "MEDIA_WARNING_LOG_ENTRY";
     case MediaLogEvent::MEDIA_INFO_LOG_ENTRY:
       return "MEDIA_INFO_LOG_ENTRY";
     case MediaLogEvent::MEDIA_DEBUG_LOG_ENTRY:

media/base/media_log.h

@@ -30,8 +30,20 @@ namespace media {
 class MEDIA_EXPORT MediaLog {
  public:
   enum MediaLogLevel {
+    // Fatal error, e.g. cause of playback failure. Since this is also used to
+    // form MediaError.message, do NOT use this for non-fatal errors to avoid
+    // contaminating MediaError.message.
     MEDIALOG_ERROR,
+
+    // Warning about non-fatal issues, e.g. quality of playback issues such as
+    // audio/video out of sync.
+    MEDIALOG_WARNING,
+
+    // General info useful for Chromium and/or web developers, testers and even
+    // users, e.g. audio/video codecs used in a playback instance.
     MEDIALOG_INFO,
+
+    // Misc debug info for Chromium developers.
     MEDIALOG_DEBUG,
   };
 

media/base/media_log_event.h

@@ -16,9 +16,7 @@ namespace media {
 struct MediaLogEvent {
   MediaLogEvent() {}
 
-  MediaLogEvent(const MediaLogEvent& event) {
-    *this = event;
-  }
+  MediaLogEvent(const MediaLogEvent& event) { *this = event; }
 
   MediaLogEvent& operator=(const MediaLogEvent& event) {
     id = event.id;
@@ -76,6 +74,10 @@ struct MediaLogEvent {
     MEDIA_ERROR_LOG_ENTRY,
     // params: "error": Error string describing the error detected.
 
+    // Warning log reported by media code such as playback quality issues.
+    MEDIA_WARNING_LOG_ENTRY,
+    // params: "warning": String describing the warning.
+
     // Informative log reported by media code.
     MEDIA_INFO_LOG_ENTRY,
     // params: "info": String with details of an informative log entry.

media/filters/audio_timestamp_validator.cc

@@ -101,7 +101,7 @@ void AudioTimestampValidator::CheckForTimestampGap(
 
       // Let developers know if their files timestamps are way off from
       if (num_unstable_audio_tries_ > limit_unstable_audio_tries_) {
-        MEDIA_LOG(ERROR, media_log_)
+        MEDIA_LOG(WARNING, media_log_)
             << "Failed to reconcile encoded audio times with decoded output.";
       }
     }
@@ -111,7 +111,7 @@ void AudioTimestampValidator::CheckForTimestampGap(
   }
 
   if (std::abs(ts_delta.InMilliseconds()) > drift_warning_threshold_msec_) {
-    MEDIA_LOG(ERROR, media_log_)
+    MEDIA_LOG(WARNING, media_log_)
         << " Large timestamp gap detected; may cause AV sync to drift."
         << " time:" << buffer.timestamp().InMicroseconds() << "us"
         << " expected:" << expected_ts.InMicroseconds() << "us"
@@ -141,4 +141,4 @@ void AudioTimestampValidator::RecordOutputDuration(
   audio_output_ts_helper_->AddFrames(audio_buffer->frame_count());
 }
 
-}  // namespace media
\ No newline at end of file
+}  // namespace media