Move createSwrContext in ffmpeg file

Author: NicolasHug

src/torchcodec/_core/FFMPEGCommon.cpp

@@ -116,16 +116,17 @@ void setChannelLayout(
 #endif
 }
 
-SwrContext* allocateSwrContext(
+SwrContext* createSwrContext(
     UniqueAVCodecContext& avCodecContext,
     AVSampleFormat sourceSampleFormat,
     AVSampleFormat desiredSampleFormat,
     int sourceSampleRate,
     int desiredSampleRate) {
   SwrContext* swrContext = nullptr;
+  int status = AVSUCCESS;
 #if LIBAVFILTER_VERSION_MAJOR > 7 // FFmpeg > 4
   AVChannelLayout layout = avCodecContext->ch_layout;
-  auto status = swr_alloc_set_opts2(
+  status = swr_alloc_set_opts2(
       &swrContext,
       &layout,
       desiredSampleFormat,
@@ -155,6 +156,14 @@ SwrContext* allocateSwrContext(
 #endif
 
   TORCH_CHECK(swrContext != nullptr, "Couldn't create swrContext");
+  status = swr_init(swrContext);
+  TORCH_CHECK(
+      status == AVSUCCESS,
+      "Couldn't initialize SwrContext: ",
+      getFFMPEGErrorStringFromErrorCode(status),
+      ". If the error says 'Invalid argument', it's likely that you are using "
+      "a buggy FFmpeg version. FFmpeg4 is known to fail here in some "
+      "valid scenarios. Try to upgrade FFmpeg?");
   return swrContext;
 }
 

src/torchcodec/_core/FFMPEGCommon.h

@@ -158,7 +158,7 @@ void setChannelLayout(
 void setChannelLayout(
     UniqueAVFrame& dstAVFrame,
     const UniqueAVFrame& srcAVFrame);
-SwrContext* allocateSwrContext(
+SwrContext* createSwrContext(
     UniqueAVCodecContext& avCodecContext,
     AVSampleFormat sourceSampleFormat,
     AVSampleFormat desiredSampleFormat,

src/torchcodec/_core/SingleStreamDecoder.cpp

@@ -1735,31 +1735,6 @@ void SingleStreamDecoder::createSwsContext(
   streamInfo.swsContext.reset(swsContext);
 }
 
-SwrContext* SingleStreamDecoder::createSwrContext(
-    UniqueAVCodecContext& avCodecContext,
-    AVSampleFormat sourceSampleFormat,
-    AVSampleFormat desiredSampleFormat,
-    int sourceSampleRate,
-    int desiredSampleRate) {
-  auto swrContext = allocateSwrContext(
-      avCodecContext,
-      sourceSampleFormat,
-      desiredSampleFormat,
-      sourceSampleRate,
-      desiredSampleRate);
-
-  auto status = swr_init(swrContext);
-  TORCH_CHECK(
-      status == AVSUCCESS,
-      "Couldn't initialize SwrContext: ",
-      getFFMPEGErrorStringFromErrorCode(status),
-      ". If the error says 'Invalid argument', it's likely that you are using "
-      "a buggy FFmpeg version. FFmpeg4 is known to fail here in some "
-      "valid scenarios. Try to upgrade FFmpeg?");
-  //   streamInfo.swrContext.reset(swrContext);
-  return swrContext;
-}
-
 // --------------------------------------------------------------------------
 // PTS <-> INDEX CONVERSIONS
 // --------------------------------------------------------------------------

src/torchcodec/_core/SingleStreamDecoder.h

@@ -310,13 +310,6 @@ class SingleStreamDecoder {
       const DecodedFrameContext& frameContext,
       const enum AVColorSpace colorspace);
 
-  SwrContext* createSwrContext(
-      UniqueAVCodecContext& avCodecContext,
-      AVSampleFormat sourceSampleFormat,
-      AVSampleFormat desiredSampleFormat,
-      int sourceSampleRate,
-      int desiredSampleRate);
-
   // --------------------------------------------------------------------------
   // PTS <-> INDEX CONVERSIONS
   // --------------------------------------------------------------------------