]> git.sesse.net Git - nageru/blobdiff - nageru/ffmpeg_capture.cpp
Fix a Clang 19 warning.
[nageru] / nageru / ffmpeg_capture.cpp
index 4bc277af61fc05405c8c264fbecc134de2ce59ef..14ad91f0c64baa01b686680baada50d7b5d96977 100644 (file)
@@ -1,24 +1,49 @@
 #include "ffmpeg_capture.h"
+#include "defs.h"
+#include "shared/shared_defs.h"
 
 #include <assert.h>
+#include <errno.h>
+#include <epoxy/egl.h>
+#include <limits>
+#include <map>
+#include <memory>
+#include <movit/effect.h>
+#include <movit/image_format.h>
+#include <movit/ycbcr.h>
+#include <mutex>
 #include <pthread.h>
+#include <time.h>
 #include <stdint.h>
 #include <stdio.h>
 #include <stdlib.h>
 #include <string.h>
+#include <string>
 #include <sys/stat.h>
-#include <unistd.h>
+#include <thread>
+#include <QSurface>
 
 extern "C" {
 #include <libavcodec/avcodec.h>
+#include <libavcodec/codec.h>
+#include <libavcodec/codec_id.h>
+#include <libavcodec/codec_par.h>
 #include <libavformat/avformat.h>
 #include <libavutil/avutil.h>
+#include <libavutil/buffer.h>
+#include <libavutil/channel_layout.h>
+#include <libavutil/common.h>
+#include <libavutil/dict.h>
 #include <libavutil/error.h>
 #include <libavutil/frame.h>
-#include <libavutil/imgutils.h>
-#include <libavutil/mem.h>
+#include <libavutil/hwcontext.h>
+#include <libavutil/mathematics.h>
+#include <libavutil/pixdesc.h>
 #include <libavutil/pixfmt.h>
-#include <libavutil/opt.h>
+#include <libavutil/rational.h>
+#include <libavutil/samplefmt.h>
+#include <libavutil/version.h>
+#include <libswresample/swresample.h>
 #include <libswscale/swscale.h>
 }
 
@@ -26,16 +51,17 @@ extern "C" {
 #include <cstdint>
 #include <utility>
 #include <vector>
+#include <unordered_set>
 
 #include <Eigen/Core>
 #include <Eigen/LU>
 #include <movit/colorspace_conversion_effect.h>
 
 #include "bmusb/bmusb.h"
+#include "shared/context.h"
 #include "shared/ffmpeg_raii.h"
 #include "ffmpeg_util.h"
 #include "flags.h"
-#include "image_input.h"
 #include "ref_counted_frame.h"
 #include "shared/timebase.h"
 
@@ -43,14 +69,17 @@ extern "C" {
 #include <srt/srt.h>
 #endif
 
-#define FRAME_SIZE (8 << 20)  // 8 MB.
-
 using namespace std;
 using namespace std::chrono;
 using namespace bmusb;
 using namespace movit;
 using namespace Eigen;
 
+// Avoid deprecation warnings, but we don't want to drop FFmpeg 5.1 support just yet.
+#if LIBAVUTIL_VERSION_INT >= AV_VERSION_INT(57, 30, 100)
+#define pkt_duration duration
+#endif
+
 namespace {
 
 steady_clock::time_point compute_frame_start(int64_t frame_pts, int64_t pts_origin, const AVRational &video_timebase, const steady_clock::time_point &origin, double rate)
@@ -124,8 +153,8 @@ AVPixelFormat decide_dst_format(AVPixelFormat src_format, bmusb::PixelFormat dst
                if (desc->comp[0].depth != 8) continue;
 
                // Same or better chroma resolution only.
-               int chroma_w_diff = desc->log2_chroma_w - src_desc->log2_chroma_w;
-               int chroma_h_diff = desc->log2_chroma_h - src_desc->log2_chroma_h;
+               int chroma_w_diff = src_desc->log2_chroma_w - desc->log2_chroma_w;
+               int chroma_h_diff = src_desc->log2_chroma_h - desc->log2_chroma_h;
                if (chroma_w_diff < 0 || chroma_h_diff < 0)
                        continue;
 
@@ -143,7 +172,7 @@ AVPixelFormat decide_dst_format(AVPixelFormat src_format, bmusb::PixelFormat dst
        return av_get_pix_fmt(best_format);
 }
 
-YCbCrFormat decode_ycbcr_format(const AVPixFmtDescriptor *desc, const AVFrame *frame, bool is_mjpeg)
+YCbCrFormat decode_ycbcr_format(const AVPixFmtDescriptor *desc, const AVFrame *frame, bool is_mjpeg, AVColorSpace *last_colorspace, AVChromaLocation *last_chroma_location)
 {
        YCbCrFormat format;
        AVColorSpace colorspace = frame->colorspace;
@@ -163,11 +192,14 @@ YCbCrFormat decode_ycbcr_format(const AVPixFmtDescriptor *desc, const AVFrame *f
                format.luma_coefficients = (frame->height >= 720 ? YCBCR_REC_709 : YCBCR_REC_601);
                break;
        default:
-               fprintf(stderr, "Unknown Y'CbCr coefficient enum %d from FFmpeg; choosing Rec. 709.\n",
-                       colorspace);
+               if (colorspace != *last_colorspace) {
+                       fprintf(stderr, "Unknown Y'CbCr coefficient enum %d from FFmpeg; choosing Rec. 709.\n",
+                               colorspace);
+               }
                format.luma_coefficients = YCBCR_REC_709;
                break;
        }
+       *last_colorspace = colorspace;
 
        format.full_range = is_full_range(desc);
        format.num_levels = 1 << desc->comp[0].depth;
@@ -200,12 +232,15 @@ YCbCrFormat decode_ycbcr_format(const AVPixFmtDescriptor *desc, const AVFrame *f
                format.cb_y_position = 1.0;
                break;
        default:
-               fprintf(stderr, "Unknown chroma location coefficient enum %d from FFmpeg; choosing center.\n",
-                       frame->chroma_location);
+               if (frame->chroma_location != *last_chroma_location) {
+                       fprintf(stderr, "Unknown chroma location coefficient enum %d from FFmpeg; choosing center.\n",
+                               frame->chroma_location);
+               }
                format.cb_x_position = 0.5;
                format.cb_y_position = 0.5;
                break;
        }
+       *last_chroma_location = frame->chroma_location;
 
        if (is_mjpeg && !format.full_range) {
                // Limited-range MJPEG is only detected by FFmpeg whenever a special
@@ -251,8 +286,8 @@ RGBTriplet get_neutral_color(AVDictionary *metadata)
 
 }  // namespace
 
-FFmpegCapture::FFmpegCapture(const string &filename, unsigned width, unsigned height)
-       : filename(filename), width(width), height(height), video_timebase{1, 1}
+FFmpegCapture::FFmpegCapture(const string &filename, unsigned width, unsigned height, QSurface *surface)
+       : filename(filename), width(width), height(height), video_timebase{1, 1}, surface(surface)
 {
        description = "Video: " + filename;
 
@@ -262,12 +297,13 @@ FFmpegCapture::FFmpegCapture(const string &filename, unsigned width, unsigned he
 }
 
 #ifdef HAVE_SRT
-FFmpegCapture::FFmpegCapture(int srt_sock, const string &stream_id)
+FFmpegCapture::FFmpegCapture(int srt_sock, const string &stream_id, QSurface *surface)
        : srt_sock(srt_sock),
-         width(global_flags.width),
-         height(global_flags.height),
+         width(0),  // Don't resize; SRT streams typically have stable resolution, and should behave much like regular cards in general.
+         height(0),
          pixel_format(bmusb::PixelFormat_8BitYCbCrPlanar),
-         video_timebase{1, 1}
+         video_timebase{1, 1},
+         surface(surface)
 {
        if (stream_id.empty()) {
                description = "SRT stream";
@@ -286,6 +322,12 @@ FFmpegCapture::~FFmpegCapture()
                dequeue_cleanup_callback();
        }
        swr_free(&resampler);
+#ifdef HAVE_SRT
+       if (srt_sock != -1) {
+               srt_close(srt_sock);
+       }
+#endif
+       delete surface;
 }
 
 void FFmpegCapture::configure_card()
@@ -327,12 +369,12 @@ std::map<uint32_t, VideoMode> FFmpegCapture::get_available_video_modes() const
        VideoMode mode;
 
        char buf[256];
-       snprintf(buf, sizeof(buf), "%ux%u", width, height);
+       snprintf(buf, sizeof(buf), "%ux%u", sws_last_width, sws_last_height);
        mode.name = buf;
        
        mode.autodetect = false;
-       mode.width = width;
-       mode.height = height;
+       mode.width = sws_last_width;
+       mode.height = sws_last_height;
        mode.frame_rate_num = 60;
        mode.frame_rate_den = 1;
        mode.interlaced = false;
@@ -346,6 +388,21 @@ void FFmpegCapture::producer_thread_func()
        snprintf(thread_name, sizeof(thread_name), "FFmpeg_C_%d", card_index);
        pthread_setname_np(pthread_self(), thread_name);
 
+       // We need a context in case create_frame() needs to reallocate something.
+       // (If none is given, we are probably in Kaeru, which uses MallocFrameAllocator
+       // anyway, which doesn't reallocate currently and definitely doesn't need
+       // an active OpenGL context to do so.)
+       QOpenGLContext *context = nullptr;
+       if (surface != nullptr) {
+               context = create_context(this->surface);
+               eglBindAPI(EGL_OPENGL_API);
+               if (!make_current(context, this->surface)) {
+                       printf("display=%p surface=%p context=%p curr=%p err=%d\n", eglGetCurrentDisplay(), this->surface, context, eglGetCurrentContext(),
+                               eglGetError());
+                       abort();
+               }
+       }
+
        while (!producer_thread_should_quit.should_quit()) {
                string filename_copy;
                {
@@ -389,28 +446,32 @@ void FFmpegCapture::producer_thread_func()
        }
 
        if (has_dequeue_callbacks) {
-                dequeue_cleanup_callback();
+               dequeue_cleanup_callback();
                has_dequeue_callbacks = false;
-        }
+       }
+
+       delete_context(context);
 }
 
 void FFmpegCapture::send_disconnected_frame()
 {
        // Send an empty frame to signal that we have no signal anymore.
        FrameAllocator::Frame video_frame = video_frame_allocator->alloc_frame();
+       size_t frame_width = width == 0 ? global_flags.width : width;
+       size_t frame_height = height == 0 ? global_flags.height : height;
        if (video_frame.data) {
                VideoFormat video_format;
-               video_format.width = width;
-               video_format.height = height;
+               video_format.width = frame_width;
+               video_format.height = frame_height;
                video_format.frame_rate_nom = 60;
                video_format.frame_rate_den = 1;
                video_format.is_connected = false;
                if (pixel_format == bmusb::PixelFormat_8BitBGRA) {
-                       video_format.stride = width * 4;
-                       video_frame.len = width * height * 4;
+                       video_format.stride = frame_width * 4;
+                       video_frame.len = frame_width * frame_height * 4;
                        memset(video_frame.data, 0, video_frame.len);
                } else {
-                       video_format.stride = width;
+                       video_format.stride = frame_width;
                        current_frame_ycbcr_format.luma_coefficients = YCBCR_REC_709;
                        current_frame_ycbcr_format.full_range = true;
                        current_frame_ycbcr_format.num_levels = 256;
@@ -420,14 +481,16 @@ void FFmpegCapture::send_disconnected_frame()
                        current_frame_ycbcr_format.cb_y_position = 0.0f;
                        current_frame_ycbcr_format.cr_x_position = 0.0f;
                        current_frame_ycbcr_format.cr_y_position = 0.0f;
-                       video_frame.len = width * height * 2;
-                       memset(video_frame.data, 0, width * height);
-                       memset(video_frame.data + width * height, 128, width * height);  // Valid for both NV12 and planar.
+                       video_frame.len = frame_width * frame_height * 2;
+                       memset(video_frame.data, 0, frame_width * frame_height);
+                       memset(video_frame.data + frame_width * frame_height, 128, frame_width * frame_height);  // Valid for both NV12 and planar.
                }
 
-               frame_callback(-1, AVRational{1, TIMEBASE}, -1, AVRational{1, TIMEBASE}, timecode++,
-                       video_frame, /*video_offset=*/0, video_format,
-                       FrameAllocator::Frame(), /*audio_offset=*/0, AudioFormat());
+               if (frame_callback != nullptr) {
+                       frame_callback(-1, AVRational{1, TIMEBASE}, -1, AVRational{1, TIMEBASE}, timecode++,
+                               video_frame, /*video_offset=*/0, video_format,
+                               FrameAllocator::Frame(), /*audio_offset=*/0, AudioFormat());
+               }
                last_frame_was_connected = false;
        }
 
@@ -439,6 +502,66 @@ void FFmpegCapture::send_disconnected_frame()
        }
 }
 
+template<AVHWDeviceType type>
+AVPixelFormat get_hw_format(AVCodecContext *ctx, const AVPixelFormat *fmt)
+{
+       bool found_config_of_right_type = false;
+       for (int i = 0;; ++i) {  // Termination condition inside loop.
+               const AVCodecHWConfig *config = avcodec_get_hw_config(ctx->codec, i);
+               if (config == nullptr) {  // End of list.
+                       break;
+               }
+               if (!(config->methods & AV_CODEC_HW_CONFIG_METHOD_HW_DEVICE_CTX) ||
+                   config->device_type != type) {
+                       // Not interesting for us.
+                       continue;
+               }
+
+               // We have a config of the right type, but does it actually support
+               // the pixel format we want? (Seemingly, FFmpeg's way of signaling errors
+               // is to just replace the pixel format with a software-decoded one,
+               // such as yuv420p.)
+               found_config_of_right_type = true;
+               for (const AVPixelFormat *fmt_ptr = fmt; *fmt_ptr != -1; ++fmt_ptr) {
+                       if (config->pix_fmt == *fmt_ptr) {
+                               fprintf(stderr, "Initialized '%s' hardware decoding for codec '%s'.\n",
+                                       av_hwdevice_get_type_name(type), ctx->codec->name);
+                               if (ctx->profile == FF_PROFILE_H264_BASELINE) {
+                                       fprintf(stderr, "WARNING: Stream claims to be H.264 Baseline, which is generally poorly supported in hardware decoders.\n");
+                                       fprintf(stderr, "         Consider encoding it as Constrained Baseline, Main or High instead.\n");
+                                       fprintf(stderr, "         Decoding might fail and fall back to software.\n");
+                               }
+                               return config->pix_fmt;
+                       }
+               }
+               fprintf(stderr, "Decoder '%s' supports only these pixel formats:", ctx->codec->name);
+               unordered_set<AVPixelFormat> seen;
+               for (const AVPixelFormat *fmt_ptr = fmt; *fmt_ptr != -1; ++fmt_ptr) {
+                       if (!seen.count(*fmt_ptr)) {
+                               fprintf(stderr, " %s", av_get_pix_fmt_name(*fmt_ptr));
+                               seen.insert(*fmt_ptr);
+                       }
+               }
+               fprintf(stderr, " (wanted %s for hardware acceleration)\n", av_get_pix_fmt_name(config->pix_fmt));
+
+       }
+
+       if (!found_config_of_right_type) {
+               fprintf(stderr, "Decoder '%s' does not support device type '%s'.\n", ctx->codec->name, av_hwdevice_get_type_name(type));
+       }
+
+       // We found no VA-API formats, so take the first software format.
+       for (const AVPixelFormat *fmt_ptr = fmt; *fmt_ptr != -1; ++fmt_ptr) {
+               if ((av_pix_fmt_desc_get(*fmt_ptr)->flags & AV_PIX_FMT_FLAG_HWACCEL) == 0) {
+                       fprintf(stderr, "Falling back to software format %s.\n", av_get_pix_fmt_name(*fmt_ptr));
+                       return *fmt_ptr;
+               }
+       }
+
+       // Fallback: Just return anything. (Should never really happen.)
+       return fmt[0];
+}
+
 bool FFmpegCapture::play_video(const string &pathname)
 {
        // Note: Call before open, not after; otherwise, there's a race.
@@ -452,17 +575,22 @@ bool FFmpegCapture::play_video(const string &pathname)
        } else {
                last_modified = buf.st_mtim;
        }
+       last_colorspace = static_cast<AVColorSpace>(-1);
+       last_chroma_location = static_cast<AVChromaLocation>(-1);
 
        AVFormatContextWithCloser format_ctx;
        if (srt_sock == -1) {
-               // Regular file.
+               // Regular file (or stream).
+               frame_timeout_started = steady_clock::now();
+               frame_timeout_valid = true;
                format_ctx = avformat_open_input_unique(pathname.c_str(), /*fmt=*/nullptr,
                        /*options=*/nullptr,
                        AVIOInterruptCB{ &FFmpegCapture::interrupt_cb_thunk, this });
+               frame_timeout_valid = false;
        } else {
 #ifdef HAVE_SRT
                // SRT socket, already opened.
-               AVInputFormat *mpegts_fmt = av_find_input_format("mpegts");
+               const AVInputFormat *mpegts_fmt = av_find_input_format("mpegts");
                format_ctx = avformat_open_input_unique(&FFmpegCapture::read_srt_thunk, this,
                        mpegts_fmt, /*options=*/nullptr,
                        AVIOInterruptCB{ &FFmpegCapture::interrupt_cb_thunk, this });
@@ -492,7 +620,8 @@ bool FFmpegCapture::play_video(const string &pathname)
 
        // Open video decoder.
        const AVCodecParameters *video_codecpar = format_ctx->streams[video_stream_index]->codecpar;
-       AVCodec *video_codec = avcodec_find_decoder(video_codecpar->codec_id);
+       const AVCodec *video_codec = avcodec_find_decoder(video_codecpar->codec_id);
+
        video_timebase = format_ctx->streams[video_stream_index]->time_base;
        AVCodecContextWithDeleter video_codec_ctx = avcodec_alloc_context3_unique(nullptr);
        if (avcodec_parameters_to_context(video_codec_ctx.get(), video_codecpar) < 0) {
@@ -503,6 +632,28 @@ bool FFmpegCapture::play_video(const string &pathname)
                fprintf(stderr, "%s: Cannot find video decoder\n", pathname.c_str());
                return false;
        }
+
+       // Seemingly, it's not too easy to make something that just initializes
+       // “whatever goes”, so we don't get CUDA or VULKAN or whatever here
+       // without enumerating through several different types.
+       // VA-API and VDPAU will do for now. We prioritize VDPAU for the
+       // simple reason that there's a VA-API-via-VDPAU emulation for NVidia
+       // cards that seems to work, but just hangs when trying to transfer the frame.
+       //
+       // Note that we don't actually check codec support beforehand,
+       // so if you have a low-end VDPAU device but a high-end VA-API device,
+       // you lose out on the extra codec support from the latter.
+       AVBufferRef *hw_device_ctx = nullptr;
+       if (av_hwdevice_ctx_create(&hw_device_ctx, AV_HWDEVICE_TYPE_VDPAU, nullptr, nullptr, 0) >= 0) {
+               video_codec_ctx->hw_device_ctx = av_buffer_ref(hw_device_ctx);
+               video_codec_ctx->get_format = get_hw_format<AV_HWDEVICE_TYPE_VDPAU>;
+       } else if (av_hwdevice_ctx_create(&hw_device_ctx, AV_HWDEVICE_TYPE_VAAPI, nullptr, nullptr, 0) >= 0) {
+               video_codec_ctx->hw_device_ctx = av_buffer_ref(hw_device_ctx);
+               video_codec_ctx->get_format = get_hw_format<AV_HWDEVICE_TYPE_VAAPI>;
+       } else {
+               fprintf(stderr, "Failed to initialize VA-API or VDPAU for FFmpeg acceleration. Decoding video in software.\n");
+       }
+
        if (avcodec_open2(video_codec_ctx.get(), video_codec, nullptr) < 0) {
                fprintf(stderr, "%s: Cannot open video decoder\n", pathname.c_str());
                return false;
@@ -523,7 +674,7 @@ bool FFmpegCapture::play_video(const string &pathname)
                        fprintf(stderr, "%s: Cannot fill audio codec parameters\n", pathname.c_str());
                        return false;
                }
-               AVCodec *audio_codec = avcodec_find_decoder(audio_codecpar->codec_id);
+               const AVCodec *audio_codec = avcodec_find_decoder(audio_codecpar->codec_id);
                if (audio_codec == nullptr) {
                        fprintf(stderr, "%s: Cannot find audio decoder\n", pathname.c_str());
                        return false;
@@ -540,6 +691,7 @@ bool FFmpegCapture::play_video(const string &pathname)
 
        // Main loop.
        bool first_frame = true;
+       int consecutive_errors = 0;
        while (!producer_thread_should_quit.should_quit()) {
                if (process_queued_commands(format_ctx.get(), pathname, last_modified, /*rewound=*/nullptr)) {
                        return true;
@@ -553,11 +705,25 @@ bool FFmpegCapture::play_video(const string &pathname)
 
                int64_t audio_pts;
                bool error;
+               frame_timeout_started = steady_clock::now();
+               frame_timeout_valid = true;
                AVFrameWithDeleter frame = decode_frame(format_ctx.get(), video_codec_ctx.get(), audio_codec_ctx.get(),
                        pathname, video_stream_index, audio_stream_index, subtitle_stream_index, audio_frame.get(), &audio_format, &audio_pts, &error);
-               if (error) {
+               frame_timeout_valid = false;
+               if (should_interrupt.load()) {
+                       // Abort no matter whether we got a frame or not.
                        return false;
                }
+               if (error) {
+                       if (++consecutive_errors >= 100) {
+                               fprintf(stderr, "More than 100 consecutive error video frames, aborting playback.\n");
+                               return false;
+                       } else {
+                               continue;
+                       }
+               } else {
+                       consecutive_errors = 0;
+               }
                if (frame == nullptr) {
                        // EOF. Loop back to the start if we can.
                        if (format_ctx->pb != nullptr && format_ctx->pb->seekable == 0) {
@@ -587,6 +753,22 @@ bool FFmpegCapture::play_video(const string &pathname)
                }
 
                VideoFormat video_format = construct_video_format(frame.get(), video_timebase);
+               if (video_format.frame_rate_nom == 0 || video_format.frame_rate_den == 0) {
+                       // Invalid frame rate; try constructing it from the previous frame length.
+                       // (This is especially important if we are the master card, for SRT,
+                       // since it affects audio. Not all senders have good timebases
+                       // (e.g., Larix rounds first to timebase 1000 and then multiplies by
+                       // 90 from there, it seems), but it's much better to have an oscillating
+                       // value than just locking at 60.
+                       if (last_pts != 0 && frame->pts > last_pts) {
+                               int64_t pts_diff = frame->pts - last_pts;
+                               video_format.frame_rate_nom = video_timebase.den;
+                               video_format.frame_rate_den = video_timebase.num * pts_diff;
+                       } else {
+                               video_format.frame_rate_nom = 60;
+                               video_format.frame_rate_den = 1;
+                       }
+               }
                UniqueFrame video_frame = make_video_frame(frame.get(), pathname, &error);
                if (error) {
                        return false;
@@ -648,7 +830,7 @@ bool FFmpegCapture::play_video(const string &pathname)
                                                1e3 * duration<double>(now - next_frame_start).count());
                                        pts_origin = frame->pts;
                                        start = next_frame_start = now;
-                                       timecode += MAX_FPS * 2 + 1;
+                                       timecode += TYPICAL_FPS * 2 + 1;
                                }
                        }
                        bool finished_wakeup;
@@ -666,12 +848,14 @@ bool FFmpegCapture::play_video(const string &pathname)
                                        // Make sure to get the audio resampler reset. (This is a hack;
                                        // ideally, the frame callback should just accept a way to signal
                                        // audio discontinuity.)
-                                       timecode += MAX_FPS * 2 + 1;
+                                       timecode += TYPICAL_FPS * 2 + 1;
                                }
                                last_neutral_color = get_neutral_color(frame->metadata);
-                               frame_callback(frame->pts, video_timebase, audio_pts, audio_timebase, timecode++,
-                                       video_frame.get_and_release(), 0, video_format,
-                                       audio_frame.get_and_release(), 0, audio_format);
+                               if (frame_callback != nullptr) {
+                                       frame_callback(frame->pts, video_timebase, audio_pts, audio_timebase, timecode++,
+                                               video_frame.get_and_release(), 0, video_format,
+                                               audio_frame.get_and_release(), 0, audio_format);
+                               }
                                first_frame = false;
                                last_frame = steady_clock::now();
                                last_frame_was_connected = true;
@@ -766,31 +950,31 @@ AVFrameWithDeleter FFmpegCapture::decode_frame(AVFormatContext *format_ctx, AVCo
        *audio_pts = -1;
        bool has_audio = false;
        do {
-               AVPacket pkt;
-               unique_ptr<AVPacket, decltype(av_packet_unref)*> pkt_cleanup(
-                       &pkt, av_packet_unref);
-               av_init_packet(&pkt);
-               pkt.data = nullptr;
-               pkt.size = 0;
-               if (av_read_frame(format_ctx, &pkt) == 0) {
-                       if (pkt.stream_index == audio_stream_index && audio_callback != nullptr) {
-                               audio_callback(&pkt, format_ctx->streams[audio_stream_index]->time_base);
+               AVPacketWithDeleter pkt = av_packet_alloc_unique();
+               pkt->data = nullptr;
+               pkt->size = 0;
+               if (av_read_frame(format_ctx, pkt.get()) == 0) {
+                       if (pkt->stream_index == audio_stream_index && audio_callback != nullptr) {
+                               audio_callback(pkt.get(), format_ctx->streams[audio_stream_index]->time_base);
                        }
-                       if (pkt.stream_index == video_stream_index) {
-                               if (avcodec_send_packet(video_codec_ctx, &pkt) < 0) {
+                       if (pkt->stream_index == video_stream_index && video_callback != nullptr) {
+                               video_callback(pkt.get(), format_ctx->streams[video_stream_index]->time_base);
+                       }
+                       if (pkt->stream_index == video_stream_index && global_flags.transcode_video) {
+                               if (avcodec_send_packet(video_codec_ctx, pkt.get()) < 0) {
                                        fprintf(stderr, "%s: Cannot send packet to video codec.\n", pathname.c_str());
                                        *error = true;
                                        return AVFrameWithDeleter(nullptr);
                                }
-                       } else if (pkt.stream_index == audio_stream_index) {
+                       } else if (pkt->stream_index == audio_stream_index && global_flags.transcode_audio) {
                                has_audio = true;
-                               if (avcodec_send_packet(audio_codec_ctx, &pkt) < 0) {
+                               if (avcodec_send_packet(audio_codec_ctx, pkt.get()) < 0) {
                                        fprintf(stderr, "%s: Cannot send packet to audio codec.\n", pathname.c_str());
                                        *error = true;
                                        return AVFrameWithDeleter(nullptr);
                                }
-                       } else if (pkt.stream_index == subtitle_stream_index) {
-                               last_subtitle = string(reinterpret_cast<const char *>(pkt.data), pkt.size);
+                       } else if (pkt->stream_index == subtitle_stream_index) {
+                               last_subtitle = string(reinterpret_cast<const char *>(pkt->data), pkt->size);
                                has_last_subtitle = true;
                        }
                } else {
@@ -819,6 +1003,22 @@ AVFrameWithDeleter FFmpegCapture::decode_frame(AVFormatContext *format_ctx, AVCo
                // Decode video, if we have a frame.
                int err = avcodec_receive_frame(video_codec_ctx, video_avframe.get());
                if (err == 0) {
+                       if (video_avframe->format == AV_PIX_FMT_VAAPI ||
+                           video_avframe->format == AV_PIX_FMT_VDPAU) {
+                               // Get the frame down to the CPU. (TODO: See if we can keep it
+                               // on the GPU all the way, since it will be going up again later.
+                               // However, this only works if the OpenGL GPU is the same one.)
+                               AVFrameWithDeleter sw_frame = av_frame_alloc_unique();
+                               int err = av_hwframe_transfer_data(sw_frame.get(), video_avframe.get(), 0);
+                               if (err != 0) {
+                                       fprintf(stderr, "%s: Cannot transfer hardware video frame to software.\n", pathname.c_str());
+                                       *error = true;
+                                       return AVFrameWithDeleter(nullptr);
+                               }
+                               sw_frame->pts = video_avframe->pts;
+                               sw_frame->pkt_duration = video_avframe->pkt_duration;
+                               video_avframe = move(sw_frame);
+                       }
                        frame_finished = true;
                        break;
                } else if (err != AVERROR(EAGAIN)) {
@@ -864,28 +1064,36 @@ void FFmpegCapture::convert_audio(const AVFrame *audio_avframe, FrameAllocator::
        }
        audio_format->num_channels = 2;
 
-       int64_t channel_layout = audio_avframe->channel_layout;
-       if (channel_layout == 0) {
-               channel_layout = av_get_default_channel_layout(audio_avframe->channels);
+       AVChannelLayout channel_layout = audio_avframe->ch_layout;
+       if (!av_channel_layout_check(&channel_layout) ||
+           channel_layout.order == AV_CHANNEL_ORDER_UNSPEC) {
+               av_channel_layout_default(&channel_layout, audio_avframe->ch_layout.nb_channels);
        }
 
        if (resampler == nullptr ||
            audio_avframe->format != last_src_format ||
            dst_format != last_dst_format ||
-           channel_layout != last_channel_layout ||
+           av_channel_layout_compare(&channel_layout, &last_channel_layout) !=  0||
            audio_avframe->sample_rate != last_sample_rate) {
+               // TODO: When we get C++20, use AV_CHANNEL_LAYOUT_STEREO_DOWNMIX.
+               AVChannelLayout stereo_downmix;
+               stereo_downmix.order = AV_CHANNEL_ORDER_NATIVE;
+               stereo_downmix.nb_channels = 2;
+               stereo_downmix.u.mask = AV_CH_LAYOUT_STEREO_DOWNMIX;
+
                swr_free(&resampler);
-               resampler = swr_alloc_set_opts(nullptr,
-                                              /*out_ch_layout=*/AV_CH_LAYOUT_STEREO_DOWNMIX,
-                                              /*out_sample_fmt=*/dst_format,
-                                              /*out_sample_rate=*/OUTPUT_FREQUENCY,
-                                              /*in_ch_layout=*/channel_layout,
-                                              /*in_sample_fmt=*/AVSampleFormat(audio_avframe->format),
-                                              /*in_sample_rate=*/audio_avframe->sample_rate,
-                                              /*log_offset=*/0,
-                                              /*log_ctx=*/nullptr);
-
-               if (resampler == nullptr) {
+               resampler = nullptr;
+               int err = swr_alloc_set_opts2(&resampler,
+                                             /*out_ch_layout=*/&stereo_downmix,
+                                             /*out_sample_fmt=*/dst_format,
+                                             /*out_sample_rate=*/OUTPUT_FREQUENCY,
+                                             /*in_ch_layout=*/&channel_layout,
+                                             /*in_sample_fmt=*/AVSampleFormat(audio_avframe->format),
+                                             /*in_sample_rate=*/audio_avframe->sample_rate,
+                                             /*log_offset=*/0,
+                                             /*log_ctx=*/nullptr);
+
+               if (err != 0 || resampler == nullptr) {
                        fprintf(stderr, "Allocating resampler failed.\n");
                        abort();
                }
@@ -908,9 +1116,9 @@ void FFmpegCapture::convert_audio(const AVFrame *audio_avframe, FrameAllocator::
        int out_samples = swr_convert(resampler, &data, num_samples_room,
                const_cast<const uint8_t **>(audio_avframe->data), audio_avframe->nb_samples);
        if (out_samples < 0) {
-                fprintf(stderr, "Audio conversion failed.\n");
-                abort();
-        }
+               fprintf(stderr, "Audio conversion failed.\n");
+               abort();
+       }
 
        audio_frame->len += out_samples * bytes_per_sample;
 }
@@ -918,23 +1126,18 @@ void FFmpegCapture::convert_audio(const AVFrame *audio_avframe, FrameAllocator::
 VideoFormat FFmpegCapture::construct_video_format(const AVFrame *frame, AVRational video_timebase)
 {
        VideoFormat video_format;
-       video_format.width = width;
-       video_format.height = height;
+       video_format.width = frame_width(frame);
+       video_format.height = frame_height(frame);
        if (pixel_format == bmusb::PixelFormat_8BitBGRA) {
-               video_format.stride = width * 4;
+               video_format.stride = frame_width(frame) * 4;
        } else if (pixel_format == FFmpegCapture::PixelFormat_NV12) {
-               video_format.stride = width;
+               video_format.stride = frame_width(frame);
        } else {
                assert(pixel_format == bmusb::PixelFormat_8BitYCbCrPlanar);
-               video_format.stride = width;
+               video_format.stride = frame_width(frame);
        }
        video_format.frame_rate_nom = video_timebase.den;
        video_format.frame_rate_den = frame->pkt_duration * video_timebase.num;
-       if (video_format.frame_rate_nom == 0 || video_format.frame_rate_den == 0) {
-               // Invalid frame rate.
-               video_format.frame_rate_nom = 60;
-               video_format.frame_rate_den = 1;
-       }
        video_format.has_signal = true;
        video_format.is_connected = true;
        return video_format;
@@ -944,7 +1147,7 @@ UniqueFrame FFmpegCapture::make_video_frame(const AVFrame *frame, const string &
 {
        *error = false;
 
-       UniqueFrame video_frame(video_frame_allocator->alloc_frame());
+       UniqueFrame video_frame(video_frame_allocator->create_frame(frame->width, frame->height, frame->width));
        if (video_frame->data == nullptr) {
                return video_frame;
        }
@@ -956,7 +1159,7 @@ UniqueFrame FFmpegCapture::make_video_frame(const AVFrame *frame, const string &
                sws_dst_format = decide_dst_format(AVPixelFormat(frame->format), pixel_format);
                sws_ctx.reset(
                        sws_getContext(frame->width, frame->height, AVPixelFormat(frame->format),
-                               width, height, sws_dst_format,
+                               frame_width(frame), frame_height(frame), sws_dst_format,
                                SWS_BICUBIC, nullptr, nullptr, nullptr));
                sws_last_width = frame->width;
                sws_last_height = frame->height;
@@ -972,39 +1175,49 @@ UniqueFrame FFmpegCapture::make_video_frame(const AVFrame *frame, const string &
        int linesizes[4] = { 0, 0, 0, 0 };
        if (pixel_format == bmusb::PixelFormat_8BitBGRA) {
                pic_data[0] = video_frame->data;
-               linesizes[0] = width * 4;
-               video_frame->len = (width * 4) * height;
+               linesizes[0] = frame_width(frame) * 4;
+               video_frame->len = (frame_width(frame) * 4) * frame_height(frame);
        } else if (pixel_format == PixelFormat_NV12) {
                pic_data[0] = video_frame->data;
-               linesizes[0] = width;
+               linesizes[0] = frame_width(frame);
 
-               pic_data[1] = pic_data[0] + width * height;
-               linesizes[1] = width;
+               pic_data[1] = pic_data[0] + frame_width(frame) * frame_height(frame);
+               linesizes[1] = frame_width(frame);
 
-               video_frame->len = (width * 2) * height;
+               video_frame->len = (frame_width(frame) * 2) * frame_height(frame);
 
                const AVPixFmtDescriptor *desc = av_pix_fmt_desc_get(sws_dst_format);
-               current_frame_ycbcr_format = decode_ycbcr_format(desc, frame, is_mjpeg);
+               current_frame_ycbcr_format = decode_ycbcr_format(desc, frame, is_mjpeg, &last_colorspace, &last_chroma_location);
        } else {
                assert(pixel_format == bmusb::PixelFormat_8BitYCbCrPlanar);
                const AVPixFmtDescriptor *desc = av_pix_fmt_desc_get(sws_dst_format);
 
-               int chroma_width = AV_CEIL_RSHIFT(int(width), desc->log2_chroma_w);
-               int chroma_height = AV_CEIL_RSHIFT(int(height), desc->log2_chroma_h);
+               int chroma_width = AV_CEIL_RSHIFT(int(frame_width(frame)), desc->log2_chroma_w);
+               int chroma_height = AV_CEIL_RSHIFT(int(frame_height(frame)), desc->log2_chroma_h);
 
                pic_data[0] = video_frame->data;
-               linesizes[0] = width;
+               linesizes[0] = frame_width(frame);
 
-               pic_data[1] = pic_data[0] + width * height;
+               pic_data[1] = pic_data[0] + frame_width(frame) * frame_height(frame);
                linesizes[1] = chroma_width;
 
                pic_data[2] = pic_data[1] + chroma_width * chroma_height;
                linesizes[2] = chroma_width;
 
-               video_frame->len = width * height + 2 * chroma_width * chroma_height;
+               video_frame->len = frame_width(frame) * frame_height(frame) + 2 * chroma_width * chroma_height;
 
-               current_frame_ycbcr_format = decode_ycbcr_format(desc, frame, is_mjpeg);
+               current_frame_ycbcr_format = decode_ycbcr_format(desc, frame, is_mjpeg, &last_colorspace, &last_chroma_location);
        }
+
+       // FIXME: Currently, if the video is too high-res for one of the allocated
+       // frames, we simply refuse to scale it here to avoid crashes. It would be better
+       // if we could somehow signal getting larger frames, especially as 4K is a thing now.
+       if (video_frame->len > video_frame->size) {
+               fprintf(stderr, "%s: Decoded frame would be larger than supported frame size (%zu > %zu), not decoding.\n", pathname.c_str(), video_frame->len, video_frame->size);
+               *error = true;
+               return video_frame;
+       }
+
        sws_scale(sws_ctx.get(), frame->data, frame->linesize, 0, frame->height, pic_data, linesizes);
 
        return video_frame;
@@ -1017,9 +1230,42 @@ int FFmpegCapture::interrupt_cb_thunk(void *opaque)
 
 int FFmpegCapture::interrupt_cb()
 {
+       // If ten seconds is gone without anything happening, we assume that
+       // we are in a network stream that died and FFmpeg just didn't
+       // pick it up (or perhaps it just hung, keeping the connection open).
+       // Called back approximately every 100 ms if something is hanging,
+       // so we get more than enough accuracy for our purposes.
+       if (!should_interrupt && frame_timeout_valid &&
+           duration<double>(steady_clock::now() - frame_timeout_started).count() >= 10.0) {
+               string filename_copy;
+               {
+                       lock_guard<mutex> lock(filename_mu);
+                       filename_copy = filename;
+               }
+               fprintf(stderr, "%s: No frame for more than 10 seconds, restarting stream.\n", filename.c_str());
+               should_interrupt = true;
+       }
        return should_interrupt.load();
 }
 
+unsigned FFmpegCapture::frame_width(const AVFrame *frame) const
+{
+       if (width == 0) {
+               return frame->width;
+       } else {
+               return width;
+       }
+}
+
+unsigned FFmpegCapture::frame_height(const AVFrame *frame) const
+{
+       if (height == 0) {
+               return frame->height;
+       } else {
+               return height;
+       }
+}
+
 #ifdef HAVE_SRT
 int FFmpegCapture::read_srt_thunk(void *opaque, uint8_t *buf, int buf_size)
 {