recorder: ensure format is supported by codecs

VP8 only supports YUV420 frames, and Opus doesn't support every sample
rate, so convert to known supported formats before saving the frames to
file.

Change-Id: I27665437ea95a11ad9a08df76cf666a5f08643b8

src/media/media_recorder.cpp

@@ -306,17 +306,19 @@ MediaRecorder::setupVideoOutput()
     const MediaStream& peer = streams_[true][true];
     const MediaStream& local = streams_[true][false];
 
+    // vp8 supports only yuv420p
+    videoFilter_.reset(new MediaFilter);
     switch (nbReceivedVideoStreams_) {
-    case 1: // use a stream with a valid size
-        if (peer.width > 0 && peer.height > 0)
-            encoderStream = peer;
-        else if (local.width > 0 && local.height > 0)
-            encoderStream = local;
-        else
+    case 1:
+        encoderStream = (peer.width > 0 && peer.height > 0 ? peer : local);
+        if (videoFilter_->initialize("format=pix_fmts=yuv420p", encoderStream) < 0) {
+            RING_ERR() << "Failed to initialize video filter";
             encoderStream.format = -1; // invalidate stream
+        } else {
+            encoderStream = videoFilter_->getOutputParams();
+        }
         break;
     case 2: // overlay local video over peer video
-        videoFilter_.reset(new MediaFilter);
         if (videoFilter_->initialize(buildVideoFilter(),
                 std::vector<MediaStream>{peer, local}) < 0) {
             RING_ERR() << "Failed to initialize video filter";
@@ -327,9 +329,12 @@ MediaRecorder::setupVideoOutput()
         break;
     default:
         RING_ERR() << "Recording more than 2 video streams is not supported";
-        encoderStream.format = -1; // invalidate stream
+        break;
     }
 
+    if (encoderStream.format < 0)
+        return encoderStream;
+
     RING_DBG() << "Video recorder '"
         << (encoderStream.name.empty() ? "(null)" : encoderStream.name)
         << "' properties: "
@@ -372,22 +377,20 @@ MediaRecorder::setupAudioOutput()
     MediaStream encoderStream;
     const MediaStream& peer = streams_[false][true];
     const MediaStream& local = streams_[false][false];
-    std::stringstream aFilter;
 
+    // resample to common audio format, so any player can play the file
+    audioFilter_.reset(new MediaFilter);
     switch (nbReceivedAudioStreams_) {
-    case 1: // use a stream with a valid sample rate and channel count
-        if (peer.sampleRate > 0 && peer.nbChannels > 0)
-            encoderStream = peer;
-        else if (local.sampleRate > 0 && local.nbChannels > 0)
-            encoderStream = local;
-        else
+    case 1:
+        encoderStream = (peer.sampleRate > 0 && peer.nbChannels > 0 ? peer : local);
+        if (audioFilter_->initialize("aresample=osr=48000:ocl=stereo:osf=s16",
+                encoderStream) < 0) {
+            RING_ERR() << "Failed to initialize audio filter";
             encoderStream.format = -1; // invalidate stream
+        }
         break;
     case 2: // mix both audio streams
-        audioFilter_.reset(new MediaFilter);
-        // resample to common audio format, so any player can play the file
-        aFilter << "[a:1] [a:2] amix, aresample=osr=48000:ocl=stereo:osf=s16";
-        if (audioFilter_->initialize(aFilter.str(),
+        if (audioFilter_->initialize("[a:1][a:2] amix,aresample=osr=48000:ocl=stereo:osf=s16",
                 std::vector<MediaStream>{peer, local}) < 0) {
             RING_ERR() << "Failed to initialize audio filter";
             encoderStream.format = -1; // invalidate stream
@@ -401,6 +404,9 @@ MediaRecorder::setupAudioOutput()
         break;
     }
 
+    if (encoderStream.format < 0)
+        return encoderStream;
+
     RING_DBG() << "Audio recorder '"
         << (encoderStream.name.empty() ? "(null)" : encoderStream.name)
         << "' properties: "
@@ -473,7 +479,7 @@ MediaRecorder::process()
     }
 
     // get filter input name if frame needs filtering
-    std::string inputName;
+    std::string inputName = "default";
     if (recframe.isVideo && nbReceivedVideoStreams_ == 2)
         inputName = (recframe.fromPeer ? "v:main" : "v:overlay");
     if (!recframe.isVideo && nbReceivedAudioStreams_ == 2)
@@ -482,10 +488,6 @@ MediaRecorder::process()
     emptyFilterGraph();
     if (filter) {
         filter->feedInput(input, inputName);
-    } else if (inputName.empty()) { // #nofilters
-        if (sendToEncoder(input, streamIdx) < 0) {
-            RING_ERR() << "Failed to encode frame";
-        }
     }
 
     av_frame_free(&input);