various: conformed frame usages to respect stride

app/codec/ffmpeg/ffmpegdecoder.cpp

@@ -324,7 +324,7 @@ FramePtr FFmpegDecoder::RetrieveVideo(const rational &timecode, const int &divid
 
     // Convert frame to RGB/A for the rest of the pipeline
     uint8_t* output_data = reinterpret_cast<uint8_t*>(copy->data());
-    int output_linesize = copy->width() * PixelFormat::BytesPerPixel(native_pix_fmt_);
+    int output_linesize = copy->linesize_bytes();
 
     sws_scale(scale_ctx_,
               input_data,

app/codec/ffmpeg/ffmpegencoder.cpp

@@ -254,7 +254,7 @@ void FFmpegEncoder::WriteInternal(FramePtr frame)
 
   // Use swscale context to convert formats/linesizes
   input_data = frame->const_data();
-  input_linesize = frame->width() * PixelFormat::BytesPerPixel(video_conversion_fmt_);
+  input_linesize = frame->linesize_bytes();
   error_code = sws_scale(video_scale_ctx_,
                          reinterpret_cast<const uint8_t**>(&input_data),
                          &input_linesize,