Initial commit.

2 files changed, 172 insertions, 0 deletions

diff --git a/Makefile b/Makefile
new file mode 100644
index 00000000..a95ccfd4
--- /dev/null
+++ b/Makefile
@@ -0,0 +1,2 @@
+ffcmp:	ffcmp.c
+	gcc -o $@ $< `pkg-config --cflags --libs libavformat libavcodec libavutil` -Wno-deprecated-declarations -Wall -g -std=c99
diff --git a/ffcmp.c b/ffcmp.c
new file mode 100644
index 00000000..28713d62
--- /dev/null
+++ b/ffcmp.c
@@ -0,0 +1,170 @@
+#include <libavformat/avformat.h>
+#include <libavutil/frame.h>
+#include <stdbool.h>
+
+#define MAX_COMPLETE_FRAMES 64
+
+typedef struct
+{
+	AVFrame* frame;
+	int stream_index;
+} Frame;
+
+typedef struct
+{
+	AVFormatContext* format_context;
+	AVCodec* codec;
+	AVPacket packet;
+	AVFrame* current_frame;
+	Frame complete_frames[MAX_COMPLETE_FRAMES];
+	int n_complete_frames;
+} File;
+
+static File
+open_file(char* filename)
+{
+	File file;
+
+	file.format_context = avformat_alloc_context();
+	if (!file.format_context) {
+		fprintf(stderr, "Could not create format context.\n");
+		exit(EXIT_FAILURE);
+	}
+	int e = avformat_open_input(&file.format_context, filename, 0, 0);
+	if (e < 0) {
+		fprintf(stderr, "Failed to open %s\n", filename);
+		exit(EXIT_FAILURE);
+	}
+	for (int i = 0; i < file.format_context->nb_streams; ++i) {
+		file.codec = avcodec_find_decoder(file.format_context->streams[i]->codec->codec_id);
+		if (!file.codec) {
+			fprintf(stderr, "Could not find codec.\n");
+			exit(EXIT_FAILURE);
+		}
+		if (avcodec_open2(file.format_context->streams[i]->codec, file.codec, 0) < 0) {
+			fprintf(stderr, "Could not open codec.\n");
+			exit(EXIT_FAILURE);
+		}
+	}
+
+	file.current_frame = av_frame_alloc();
+	if (!file.current_frame) {
+		fprintf(stderr, "Could not allocate frame.\n");
+		exit(EXIT_FAILURE);
+	}
+
+	file.n_complete_frames = 0;
+
+	return file;
+}
+
+bool
+read_frame(File* file)
+{
+	int r = av_read_frame(file->format_context, &file->packet);
+	if (r == AVERROR_EOF) {
+		return true;
+	}
+
+	if (r < 0) {
+		fprintf(stderr, "Failed to read frame.\n");
+		exit(EXIT_FAILURE);
+	}
+
+	switch (file->format_context->streams[file->packet.stream_index]->codec->codec_type) {
+	case AVMEDIA_TYPE_VIDEO:
+		fprintf(stderr, "Warning: ignoring video frame.\n");
+		break;
+	case AVMEDIA_TYPE_AUDIO:
+	{
+		AVPacket copy_packet = file->packet;
+		while (copy_packet.size > 0) {
+			int frame_finished;
+			int decode_result = avcodec_decode_audio4(file->format_context->streams[file->packet.stream_index]->codec, file->current_frame, &frame_finished, &copy_packet);
+			if (decode_result < 0) {
+				fprintf(stderr, "Failed to decode audio.\n");
+				exit(EXIT_FAILURE);
+			}
+
+			if (frame_finished) {
+				file->complete_frames[file->n_complete_frames].frame = file->current_frame;
+				file->complete_frames[file->n_complete_frames].stream_index = file->packet.stream_index;
+				++file->n_complete_frames;
+				file->current_frame = av_frame_alloc();
+				if (!file->current_frame) {
+					fprintf(stderr, "Could not allocate frame.\n");
+					exit(EXIT_FAILURE);
+				}
+			}
+
+			copy_packet.data -= decode_result;
+			copy_packet.size -= decode_result;
+		}
+		break;
+	default:
+		fprintf(stderr, "Warning: ignoring other frame.\n");
+		break;
+	}
+	}
+
+	return false;
+}
+
+int main(int argc, char** argv)
+{
+	av_register_all();
+
+	File file[2] = {
+		open_file(argv[1]),
+		open_file(argv[2])
+	};
+
+	if (file[0].format_context->nb_streams != file[1].format_context->nb_streams) {
+		fprintf(stderr, "Files have different stream counts.\n");
+		exit(EXIT_FAILURE);
+	}
+
+	for (int i = 0; i < file[0].format_context->nb_streams; ++i) {
+		if (file[0].format_context->streams[i]->codec->codec_type != file[1].format_context->streams[i]->codec->codec_type) {
+			fprintf(stderr, "Stream %d has different code type.\n", i);
+			exit(EXIT_FAILURE);
+		}
+	}
+
+	while (true) {
+		bool done[2] = {
+			read_frame(&file[0]),
+			read_frame(&file[1])
+		};
+
+		if (done[0] != done[1]) {
+			fprintf(stderr, "Files are different lengths.\n");
+			exit(EXIT_FAILURE);
+		}
+
+		while (file[0].n_complete_frames > 0 && file[1].n_complete_frames > 0) {
+			Frame frame = file[0].complete_frames[0];
+			AVStream* stream = file[0].format_context->streams[frame.stream_index];
+
+			int const size = av_samples_get_buffer_size(0, stream->codec->channels, frame.frame->nb_samples, stream->codec->sample_fmt, 1);
+			int const check = av_sample_fmt_is_planar(stream->codec->sample_fmt) ? stream->codec->channels : 1;
+			for (int i = 0; i < check; ++i) {
+				if (memcmp(file[0].complete_frames[0].frame->data[i], file[1].complete_frames[0].frame->data[i], size) != 0) {
+					fprintf(stderr, "Audio frames differ.\n");
+					exit(EXIT_FAILURE);
+				}
+			}
+
+			memmove(file[0].complete_frames, file[0].complete_frames + 1, (MAX_COMPLETE_FRAMES - 1) * sizeof(Frame));
+			memmove(file[1].complete_frames, file[1].complete_frames + 1, (MAX_COMPLETE_FRAMES - 1) * sizeof(Frame));
+			--file[0].n_complete_frames;
+			--file[1].n_complete_frames;
+		}
+
+		if (done[0]) {
+			break;
+		}
+	}
+
+	return 0;
+}