media validator

Makefile

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+RM      := rm -f
+CC      := gcc
+CFLAGS  := -O3 -Wall -Isrc -I/usr/include/ffmpeg
+LIBS    := -lavformat -lavutil -lavcodec
+LDFLAGS :=
+INSTALL ?= install
+PREFIX  ?= /usr/local
+
+COMMON_OBJECTS     := build/validation.o
+MEDIASTAT_OBJECTS  := build/stat.o
+
+# Phony rules
+.PHONY: all mediastat clean
+
+all: mediastat 
+
+install: all
+	$(INSTALL) build/mediastat $(PREFIX)/bin/mediastat
+
+uninstall:
+	$(RM) -rf $(PREFIX)/bin/mediastat
+
+mediastat: build/mediastat
+
+clean:
+	$(RM) $(COMMON_OBJECTS) $(MEDIASTAT_OBJECTS)
+
+# Build rules
+build/mediastat: $(COMMON_OBJECTS) $(MEDIASTAT_OBJECTS)
+	$(CC) $^ $(LDFLAGS) $(LIBS) -o $@
+
+build/%.o: src/%.c
+	$(CC) $(CFLAGS) -MMD -c $< -o $@
+
+# Declare dependencies
+-include $(COMMON_OBJECTS:.o=.d)
+-include $(MEDIASTAT_OBJECTS:.o=.d)

build/.gitignore

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+*
+*/
+!.gitignore

src/stat.c

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+#include <libavformat/avformat.h>
+#include <stdio.h>
+
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <unistd.h>
+
+#include "validation.h"
+
+int main(int argc, char *argv[])
+{
+    AVFormatContext *format = NULL;
+    struct stat statbuf;
+    AVPacket pkt;
+
+    if (argc != 2) {
+        printf("No input specified\n");
+        return -1;
+    }
+
+    av_log_set_level(AV_LOG_QUIET);
+
+    if (stat(argv[1], &statbuf) != 0) {
+        printf("Couldn't read file\n");
+        return -1;
+    }
+
+    if (avformat_open_input(&format, argv[1], NULL, NULL) != 0) {
+        printf("Couldn't read file\n");
+        return -1;
+    }
+
+    if (!mediatools_validate_video(format)) {
+        // Error is printed by validation function
+        return -1;
+    }
+
+    if (av_seek_frame(format, -1, 0, AVSEEK_FLAG_BACKWARD) != 0) {
+        printf("Couldn't read file\n");
+        return -1;
+    }
+
+    int vstream_idx = av_find_best_stream(format, AVMEDIA_TYPE_VIDEO, -1, -1, NULL, 0);
+    if (vstream_idx < 0) {
+        printf("Couldn't read file\n");
+        return -1;
+    }
+
+    uint64_t frames = 0;
+    int64_t last_pts = 0;
+    int last_stream = 0;
+
+    while (av_read_frame(format, &pkt) >= 0) {
+        int64_t new_pts = pkt.pts + pkt.duration;
+
+        if (last_pts < new_pts) {
+            last_pts = new_pts;
+            last_stream = pkt.stream_index;
+        }
+
+        if (pkt.stream_index == vstream_idx)
+            ++frames;
+
+        av_packet_unref(&pkt);
+    }
+
+    AVRational tb  = format->streams[last_stream]->time_base;
+    AVRational dur = av_mul_q(av_make_q(last_pts, 1), tb);
+
+    if (!mediatools_validate_duration(dur))
+        return -1;
+
+    AVCodecParameters *vpar = format->streams[vstream_idx]->codecpar;
+
+    printf("%ld %lu %d %d %d %d\n", statbuf.st_size, frames, vpar->width, vpar->height, dur.num, dur.den);
+
+    avformat_close_input(&format);
+
+    return 0;
+}

src/validation.c

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+#include <libavformat/avformat.h>
+#include <stdbool.h>
+#include <string.h>
+
+#include "validation.h"
+
+const AVRational t_1h = { 3600, 1 };
+const AVRational t_0h  = { 0, 1 };
+
+int mediatools_validate_video(AVFormatContext *format)
+{
+    uint64_t num_vstreams = 0;
+    uint64_t num_astreams = 0;
+    int64_t vstream_idx = -1;
+    int64_t astream_idx = -1;
+
+    for (size_t i = 0; i < format->nb_streams; ++i) {
+        if (format->streams[i]->codecpar->codec_type == AVMEDIA_TYPE_VIDEO) {
+            num_vstreams++;
+            vstream_idx = i;
+        }
+        if (format->streams[i]->codecpar->codec_type == AVMEDIA_TYPE_AUDIO) {
+            num_astreams++;
+            astream_idx = i;
+        }
+    }
+
+    if (num_vstreams != 1) {
+        printf("Found %lu video streams (must be 1)\n", num_vstreams);
+        return false;
+    }
+
+    if (num_astreams > 1) {
+        printf("Found %lu audio streams (must be 0 or 1)\n", num_astreams);
+        return false;
+    }
+
+    AVInputFormat *iformat = format->iformat;
+    AVCodecParameters *vpar = format->streams[vstream_idx]->codecpar;
+    AVCodecParameters *apar = NULL;
+
+    if (astream_idx != -1)
+        apar = format->streams[astream_idx]->codecpar;
+
+    if (strstr(iformat->name, "matroska")) {
+        switch (vpar->codec_id) {
+        default:
+            printf("Bad video codec for WebM container (must be VP8, or VP9)\n");
+            return false;
+        case AV_CODEC_ID_VP8:
+        case AV_CODEC_ID_VP9:
+            ;
+        }
+
+        if (apar) {
+            switch (apar->codec_id) {
+            default:
+                printf("Bad audio codec for WebM container (must be Opus or Vorbis)\n");
+                return false;
+            case AV_CODEC_ID_VORBIS:
+            case AV_CODEC_ID_OPUS:
+                ;
+            }
+        }
+    } else {
+        printf("Unknown input format\n");
+        return false;
+    }
+
+    if (vpar->width < 32 || vpar->width > 4096) {
+        printf("Bad width %d (must be 32..4096)\n", vpar->width);
+        return false;
+    }
+
+    if (vpar->height < 32 || vpar->height > 4096) {
+        printf("Bad height %d (must be 32..4096)\n", vpar->height);
+        return false;
+    }
+
+    return true;
+}
+
+int mediatools_validate_duration(AVRational dur)
+{
+    if (av_cmp_q(dur, t_0h) < 0 || av_cmp_q(dur, t_1h) > 0) {
+        printf("Bad duration (must be 0..1 hour)\n");
+        return false;
+    }
+
+    return true;
+}

src/validation.h

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+#ifndef _VALIDATION_H_DEFINED
+#define _VALIDATION_H_DEFINED
+
+#include <libavformat/avformat.h>
+
+int mediatools_validate_video(AVFormatContext *format);
+int mediatools_validate_duration(AVRational dur);
+
+#endif