refactor: VideoReader and videoin post-audio review cleanup

VideoReader:
- Remove unused #include <iostream>
- Remove dead AudioInfo::samples and ::channel_stride fields
- Rename have_video → has_video (consistent with has_audio)
- Rename get_next_frame → read_next (returns audio too, not just frames)
- Fix outdated comment on read_next
- Remove trailing blank line in allocate_audio_conversion_buffers

videoin:
- Remove redundant FFmpeg includes (VideoReader.hpp provides them)
- Fix bug: mxlFlowWriterGetMaxWriteLengthSamples called with invalid
  audio_writer when mxlCreateFlowWriter fails — moved inside else branch
- Rename call site: get_next_frame → read_next
- Rename have_video → has_video at call sites
- Use = nullptr for audio_writer (consistent with video_writer)

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

nodes/videoin/main.cpp

@@ -1,11 +1,3 @@
-extern "C" {
-    #include <libavformat/avformat.h>
-    #include <libavcodec/avcodec.h>
-    #include <libavutil/avutil.h>
-    #include <libswscale/swscale.h>
-    #include <libavutil/imgutils.h>
-}
-
 #include <string>
 #include <mxl/flow.h>
 #include <mxl/time.h>
@@ -21,11 +13,11 @@ class VideoInNode : public dmf::NodeBase {
         log("file: %s", filename.c_str());
 
         dmf::VideoReader video_reader(filename);
-        if (!video_reader.have_video && !video_reader.has_audio) {
+        if (!video_reader.has_video && !video_reader.has_audio) {
             log("no video or audio stream found"); return;
         }
 
-        const bool has_video = config().contains("video_flow_id") && video_reader.have_video;
+        const bool has_video = config().contains("video_flow_id") && video_reader.has_video;
         mxlFlowWriter     video_writer = nullptr;
         mxlFlowConfigInfo video_cfg{};
         uint32_t   video_stride = 0;
@@ -56,7 +48,7 @@ class VideoInNode : public dmf::NodeBase {
                 video_stride, video_stride * static_cast<uint32_t>(height), video_cfg.discrete.grainCount);
         }
 
-        mxlFlowWriter audio_writer{};
+        mxlFlowWriter audio_writer = nullptr;
         mxlFlowConfigInfo audio_cfg{};
         int  sample_rate  = video_reader.audio_info.sample_rate;
         int  channels     = video_reader.audio_info.channels;
@@ -82,12 +74,11 @@ class VideoInNode : public dmf::NodeBase {
             } else {
                 log("audio channels=%u  buffer=%u samples",
                     audio_cfg.continuous.channelCount, audio_cfg.continuous.bufferLength);
-            }
-
                 size_t max_write = 0;
                 mxlFlowWriterGetMaxWriteLengthSamples(audio_writer, &max_write);
                 max_audio_samples = static_cast<int>(max_write);
             }
+        }
         std::vector<uint8_t> audio_temp(max_audio_samples * channels * sizeof(float));
 
         const mxlRational video_rate = {fps_num, fps_den};
@@ -107,7 +98,7 @@ class VideoInNode : public dmf::NodeBase {
             }
 
             int out_samples_written = 0;
-            dmf::VideoReader::FrameKind frame_kind = video_reader.get_next_frame(
+            dmf::VideoReader::FrameKind frame_kind = video_reader.read_next(
                 has_video ? video_buf : nullptr,
                 video_stride,
                 has_audio ? audio_temp.data() : nullptr,

shared/VideoReader.hpp

@@ -16,8 +16,6 @@ extern "C" {
 #include "Signal.hpp"
 #include "V210.hpp"
 
-#include <iostream>
-
 namespace dmf {
 
 class VideoReader {
@@ -33,8 +31,6 @@ public:
     struct AudioInfo {
         int sample_rate = 0;
         int channels    = 0;
-        int samples        = 0;
-        int channel_stride = 0;  // floats between channel planes (NDI planar layout)
     };
 
     enum class FrameKind { None, Video, Audio };
@@ -42,14 +38,14 @@ public:
     VideoInfo video_info{};
     AudioInfo audio_info{};
     bool has_audio  = false;
-    bool have_video = false;
+    bool has_video = false;
 
     explicit VideoReader(const std::string& filename) {
         if (!open_file(filename))
             return;
-        if (!have_video && !has_audio) return;
+        if (!has_video && !has_audio) return;
         get_source_info();
-        if (have_video) allocate_video_conversion_buffers();
+        if (has_video) allocate_video_conversion_buffers();
         if (has_audio)  allocate_audio_conversion_buffers();
     }
 
@@ -65,12 +61,11 @@ public:
         av_packet_free(&packet);
     }
 
-    // Returns true when a frame was decoded and written into video_buf.
+    // Returns Video or Audio when a frame/packet was decoded, None when g_running goes false.
-    // Returns false when g_running goes false.
+    FrameKind read_next(uint8_t* video_buf, uint32_t mxl_stride, uint8_t* audio_buf, int max_audio_samples, int& out_samples_written) {
-    FrameKind get_next_frame(uint8_t* video_buf, uint32_t mxl_stride, uint8_t* audio_buf, int max_audio_samples, int& out_samples_written) {
         while (dmf::g_running.load(std::memory_order_relaxed)) {
             // Drain any frames buffered in the decoder first
-            if (have_video && avcodec_receive_frame(video_codec_context, video_frame) == 0) {
+            if (has_video && avcodec_receive_frame(video_codec_context, video_frame) == 0) {
                 if (!video_buf) {
                     av_frame_unref(video_frame);
                     continue;  // nowhere to write — discard frame
@@ -138,7 +133,7 @@ public:
             if (av_read_frame(format_context, packet) < 0) {
                 // EOF — loop back to start
                 avformat_seek_file(format_context, -1, 0, 0, 0, AVSEEK_FLAG_BACKWARD);
-                if (have_video) avcodec_flush_buffers(video_codec_context);
+                if (has_video) avcodec_flush_buffers(video_codec_context);
                 if (has_audio) avcodec_flush_buffers(audio_codec_context);
                 swr_close(swr_audio_ctx);
                 swr_init(swr_audio_ctx);
@@ -184,7 +179,7 @@ private:
             const AVMediaType type = format_context->streams[i]->codecpar->codec_type;
             if (type == AVMEDIA_TYPE_VIDEO && video_stream_index == -1) {
                 video_stream_index = static_cast<int>(i);
-                have_video = true;
+                has_video = true;
             } else if (type == AVMEDIA_TYPE_AUDIO && audio_stream_index == -1) {
                 audio_stream_index = static_cast<int>(i);
                 has_audio = true;
@@ -225,7 +220,7 @@ private:
             video_info.fps_den = fps.den;
             video_info.pix_fmt = video_codec_context->pix_fmt;
         } else {
-            have_video = false;
+            has_video = false;
         }
 
         // audio part
@@ -279,7 +274,6 @@ private:
         if (swr_init(swr_audio_ctx) < 0) {
             throw std::runtime_error("Failed to create SwrContext");
         }
-
     }
 };