Add VideoIO.framerate(f) to the manual and expand tests (#393)

Co-authored-by: AbelHo <[email protected]>

Author: IanButterworth

docs/src/reading.md

@@ -89,6 +89,11 @@ Total available frame count is available via `counttotalframes(f)`
 VideoIO.counttotalframes
 ```
 
+The video framerate can be read via `framerate(f)`
+```@docs
+VideoIO.framerate
+```
+
 !!! note H264 videos encoded with `crf>0` have been observed to have 4-fewer frames
 available for reading.
 

src/avio.jl

@@ -429,6 +429,11 @@ For some codecs, the time base is closer to the field rate than the frame rate.
 Most notably, H.264 and MPEG-2 specify time_base as half of frame duration if no telecine is used ...
 Set to time_base ticks per frame. Default 1, e.g., H.264/MPEG-2 set it to 2.
 =#
+"""
+    framerate(f::VideoReader)
+
+Read the framerate of a VideoReader object.
+"""
 function framerate(f::VideoReader)
     # Try codec_context time_base first
     # NOTE: In modern FFmpeg (4+), codec_context.time_base is primarily used for encoding

src/testvideos.jl

@@ -31,25 +31,10 @@ mutable struct VideoFile{compression}
     source::AbstractString
     download_url::AbstractString
     numframes::Int
+    framerate::Rational
     testframe::Int
     summarysize::Int
 
-    fps::Union{Nothing,Rational}
-
-    VideoFile{compression}(
-        name::AbstractString,
-        description::AbstractString,
-        license::AbstractString,
-        credit::AbstractString,
-        source::AbstractString,
-        download_url::AbstractString,
-        numframes::Int,
-        testframe::Int,
-        summarysize::Int,
-        fps::Rational,
-    ) where {compression} =
-        new(name, description, license, credit, source, download_url, numframes, testframe, summarysize, fps)
-
     VideoFile{compression}(
         name::AbstractString,
         description::AbstractString,
@@ -58,10 +43,11 @@ mutable struct VideoFile{compression}
         source::AbstractString,
         download_url::AbstractString,
         numframes::Int,
+        framerate::Rational,
         testframe::Int,
         summarysize::Int,
     ) where {compression} =
-        new(name, description, license, credit, source, download_url, numframes, testframe, summarysize, nothing)
+        new(name, description, license, credit, source, download_url, numframes, framerate, testframe, summarysize)
 end
 
 show(io::IO, v::VideoFile) = print(
@@ -75,15 +61,13 @@ VideoFile:
    source:       $(v.source)
    download_url: $(v.download_url)
    numframes:    $(v.numframes)
+   framerate:    $(v.framerate)
    summarysize:  $(v.summarysize)
  """,
 )
 
-VideoFile(name, description, license, credit, source, download_url, numframes, testframe, summarysize) =
-    VideoFile{:raw}(name, description, license, credit, source, download_url, numframes, testframe, summarysize)
-
-VideoFile(name, description, license, credit, source, download_url, numframes, testframe, summarysize, fps) =
-    VideoFile{:raw}(name, description, license, credit, source, download_url, numframes, testframe, summarysize, fps)
+VideoFile(name, description, license, credit, source, download_url, numframes, framerate, testframe, summarysize) =
+    VideoFile{:raw}(name, description, license, credit, source, download_url, numframes, framerate, testframe, summarysize)
 
 # Standard test videos
 const videofiles = Dict(
@@ -95,6 +79,7 @@ const videofiles = Dict(
         "https://downloadnatureclip.blogspot.com/p/download-links.html",
         "https://archive.org/download/LadybirdOpeningWingsCCBYNatureClip/Ladybird%20opening%20wings%20CC-BY%20NatureClip.mp4",
         397,
+        30000//1001,
         13,
         3216,
     ),
@@ -106,6 +91,7 @@ const videofiles = Dict(
         "https://commons.wikimedia.org/wiki/File:Annie_Oakley_shooting_glass_balls,_1894.ogg",
         "https://upload.wikimedia.org/wikipedia/commons/8/87/Annie_Oakley_shooting_glass_balls%2C_1894.ogv",
         726,
+        30000//1001,
         2,
         167311096,
     ),
@@ -117,6 +103,7 @@ const videofiles = Dict(
         "https://commons.wikimedia.org/wiki/File:2010-10-10-Lune.ogv",
         "https://upload.wikimedia.org/wikipedia/commons/e/ef/2010-10-10-Lune.ogv",
         1213,
+        25//1,
         1,
         9744,
     ),
@@ -128,6 +115,7 @@ const videofiles = Dict(
         "https://www.eso.org/public/videos/eso1004a/",
         "https://upload.wikimedia.org/wikipedia/commons/1/13/Artist%E2%80%99s_impression_of_the_black_hole_inside_NGC_300_X-1_%28ESO_1004c%29.webm",
         597,
+        25//1,
         1,
         4816,
     ),

test/reading.jl

@@ -11,6 +11,8 @@
             try
                 time_seconds = VideoIO.gettime(v)
                 @test time_seconds == 0
+                @test VideoIO.framerate(v) == testvid.framerate
+                @test get_fps(testvid_path) == testvid.framerate # ffprobe sanity check
                 width, height = VideoIO.out_frame_size(v)
                 @test VideoIO.width(v) == width
                 @test VideoIO.height(v) == height
@@ -21,24 +23,22 @@
                     trimmed_comparison_frame = comparison_frame
                 end
 
+                fps1 = VideoIO.framerate(v)
+
                 # Find the first non-trivial image
                 first_img = read(v)
+
+                # fps should be the same before and after first read
+                fps2 = VideoIO.framerate(v)
+                @test fps1 == fps2
+
                 first_time = VideoIO.gettime(v)
                 seekstart(v)
                 img = read(v)
                 @test VideoIO.gettime(v) == first_time
                 @test img == first_img
                 @test size(img) == VideoIO.out_frame_size(v)[[2, 1]]
 
-
-                # First read(v) then framerate(v)
-                # https://github.com/JuliaIO/VideoIO.jl/issues/349
-                if !isnothing(testvid.fps)
-                    @test isapprox(VideoIO.framerate(v), testvid.fps, rtol=0.01)
-                else
-                    @test VideoIO.framerate(v) != 0
-                end
-
                 # no scaling currently
                 @test VideoIO.out_frame_size(v) == VideoIO.raw_frame_size(v)
                 @test VideoIO.raw_pixel_format(v) == 0 # true for current test videos

test/utils.jl

@@ -169,3 +169,26 @@ macro memory_profile()
         end
     end
 end
+
+"""
+    get_fps(file [, streamno])
+
+Query the container `file` for the frame per second(fps) of the video stream
+`streamno` if applicable, instead returning `nothing`.
+"""
+function get_fps(file::AbstractString, streamno::Integer = 0)
+    streamno >= 0 || throw(ArgumentError("streamno must be non-negative"))
+    fps_strs = FFMPEG.exe(
+        `-v 0 -of compact=p=0 -select_streams v:$(streamno) -show_entries stream=r_frame_rate $file`,
+        command = FFMPEG.ffprobe,
+        collect = true,
+    )
+    fps = split(fps_strs[1], '=')[2]
+    if occursin("No such file or directory", fps)
+        error("Could not find file $file")
+    elseif occursin("N/A", fps)
+        return nothing
+    end
+
+    return reduce(//, parse.(Int, split(fps,'/')) )
+end

test/writing.jl

@@ -25,6 +25,7 @@ end
                     VideoIO.save(
                         tempvidpath,
                         img_stack;
+                        framerate = 24,
                         codec_name = codec_name,
                         encoder_private_options = encoder_private_options,
                         encoder_options = encoder_options,
@@ -36,6 +37,7 @@ end
                     try
                         notempty = !eof(f)
                         @test notempty
+                        @test VideoIO.framerate(f) == 24
                         if notempty
                             img = read(f)
                             test_img = scanline_arg ? parent(img) : img
@@ -184,6 +186,30 @@ end
     end
 end
 
+@testset "Encoding video with integer frame rates" begin
+    n = 100
+    for fr in 20:30
+        target_dur = n / fr
+        @testset "Encoding with frame rate $(fr)" begin
+            imgstack = map(x -> rand(UInt8, 100, 100), 1:n)
+            encoder_options = (color_range = 2, crf = 0, preset = "medium")
+            VideoIO.save(tempvidpath, imgstack, framerate = fr, encoder_options = encoder_options)
+            @test stat(tempvidpath).size > 100
+            measured_dur_str = VideoIO.FFMPEG.exe(
+                `-v error -show_entries format=duration -of default=noprint_wrappers=1:nokey=1 $(tempvidpath)`,
+                command = VideoIO.FFMPEG.ffprobe,
+                collect = true,
+            )
+            @test parse(Float64, measured_dur_str[1]) ≈ target_dur rtol = 0.01
+            @testset "Reading framerate" begin
+                f = VideoIO.openvideo(tempvidpath)
+                @test VideoIO.framerate(f) == fr
+                @test get_fps(tempvidpath) == fr # ffprobe sanity check
+            end
+        end
+    end
+end
+
 @testset "Encoding video with rational frame rates" begin
     n = 100
     fr = 59 // 2 # 29.5
@@ -199,6 +225,11 @@ end
             collect = true,
         )
         @test parse(Float64, measured_dur_str[1]) == target_dur
+        @testset "Reading framerate" begin
+            f = VideoIO.openvideo(tempvidpath)
+            @test VideoIO.framerate(f) == fr
+            @test get_fps(tempvidpath) == fr # ffprobe sanity check
+        end
     end
 end
 
@@ -217,5 +248,10 @@ end
             collect = true,
         )
         @test parse(Float64, measured_dur_str[1]) == target_dur
+        @testset "Reading framerate" begin
+            f = VideoIO.openvideo(tempvidpath)
+            @test VideoIO.framerate(f) == fr
+            @test get_fps(tempvidpath) == fr # ffprobe sanity check
+        end
     end
 end