AviSynth Chaitanya Ghone [email protected] Introduction • Website – http://avisynth.org/mediawiki/Main_Page – Downloads links available on above page • What is it? – AviSynth is a powerful tool for video post-production. It provides ways of editing and processing videos – AviSynth works as a frameserver, providing instant editing without the need for temporary files – AviSynth itself does not provide a graphical user interface (GUI), but instead relies on a script system that allows advanced non-linear editing – Text-based scripts are human readable, projects are inherently self-documenting. The scripting language is simple yet powerful, and complex filters can be created from basic operations to develop a sophisticated palette of useful and unique effects. Common applications • Some typical video operations that can be done using AviSynth – Extracting individual fields – Overlaying frame numbers – Side-by-side stacking of videos – Dropping / Duplicating frames – Applying simple blur filters, noise addition/removal filters How to use? • Create a script (text file) – example.avs • Using mplayer – “mplayer example.avs” – This will display the output of your script • Using FFMPEG – “ffmpeg -i example.avs output.yuv” – The output of your script will be given as input to ffmpeg – This may be dumped out as raw YUV using above command or encoded into any other format that ffmpeg supports AviSynth Filters • Internal Filters – – – http://avisynth.org/mediawiki/Internal_filters This are part of default AviSynth installation Provides very common functionalities required for video processing like • • • • External Filters – – – – http://avisynth.org/mediawiki/External_filters http://avisynth.org/warpenterprises/ This are available separately for download from the link above These provide more advanced features like • • • • • – • Resizing Display frame numbers Field operation for interlaced streams Anti-aliasing filters Noise filters De-interlacers Support for different RAW YUV video Support for different containers Some of these may not be free Some important filters are available at – – – – RawSource: http://avisynth.org/warpenterprises/#rawsource ffmpegSource2: http://code.google.com/p/ffmpegsource/downloads/list These need to be copied to your AviSynth plugins directory These are required to run the examples in next slides Example 1: Using RAW video #Read YUV: Specify width, height, format, offset in bytes to first data to read) V1 = RawSource("test.yuv",176,144,"I420“, offset= 38016) #Read from second frame #Display frame number or SMPTE style timing from any offset as required V1 = ShowFrameNumber(V1, x=90, y=30, offset=100) V1 = ShowSMPTE(V1,x=90,y=60,offset="00:01:00:00") #Only sets the frame-rate property, no change to actual data V1 = AssumeFPS(V1,30) V1 = ShowFrameNumber(V1, x=90, y=90, offset=100) #Duplicates or drops frames to get specified frame rate V1 = ChangeFPS(V1, 60) V1 = ShowFrameNumber(V1, x=90, y=120, offset=100) #Changes frame rate by blending consecutive frames (Range originalFPS*0.66 to inf) V1 = ConvertFPS(V1,120) V1 = ShowFrameNumber(V1, x=90, y=150, offset=100) #Return video to application return V1 Example 1: Output using mplayer Frame 0 Frame 1 Frame 2 Resolution is 176x144 Frame 3 Frame 4 Example 2: Using compressed data #Reading encoded data, this needs to be in a container like AVI or MOV or MP4 or TS V1 = ffmpegSource2("test.mp4") V1 = ShowFrameNumber(V1, x=90, y=30, offset=100) V1 = ShowSMPTE(V1,x=90,y=60,offset="00:01:00:00") V1 = AssumeFPS(V1,30) V1 = ShowFrameNumber(V1, x=90, y=90, offset=100) #Duplicates or drops frames to get specified frame rate V1 = ChangeFPS(V1, 60) V1 = ShowFrameNumber(V1, x=90, y=120, offset=100) #Changes frame rate by blending consecutive frames (Range originalFPS*0.66 to inf) V1 = ConvertFPS(V1,120) V1 = ShowFrameNumber(V1, x=90, y=150, offset=100) return V1 Example 2: Output using mplayer Frame 0 Frame 1 Frame 2 Resolution is 176x144 Frame 3 Frame 4 Example 3: Handling multiple inputs #Reading encoded data, this needs to be in a container like AVI or MOV or MP4 or TS V1 = RawSource("test.yuv",176,144,"I420") V2 = ffmpegsource2("test.mp4") #Cropping examples #Extract left half V1_L = crop(V1, 0, 0, -(V1.width/2), 0) #Extract right half V1_R = crop(V1, (V1.width/2), 0, 0, 0) #Extract top half V2_T = crop(V2, 0, 0, 0, -(V1.Height/2)) #Extract bottom half V2_B = crop(V2, 0, (V1.Height/2), 0, 0) #Stacking multiple frame data V3 = StackHorizontal(V1_R, V1_L) V4 = StackVertical(V2_B, V2_T) V = StackVertical(V3,V4) return V Example 3: Output using mplayer Resolution is 176x288 Example 4: Handling interlaced data #Read input assuming Top Field and Bottom Field in interleaved in one frame data V1 = RawSource("test.yuv",176,144,"I420") V1 = ShowFrameNumber(V1, x=30, y=30, offset=100) V1 = AssumeFrameBased(V1) #Set property of original stream to TopFieldFirst (TFF) V1 = AssumeTFF(V1) #Extract individual fields V_Fld = SeparateFields(V1) V1_TF = V_Fld.SelectEven() V1_TF = ShowFrameNumber(V1_TF, x=30, y=60, offset=100) V1_BF = V_Fld.SelectOdd() V1_BF = ShowFrameNumber(V1_BF, x=30, y=60, offset=100) #Explicit swap fields by forcing BottomFieldFirst(BFF) on TFF stream V2 = Interleave(V1_TF, V1_BF) V2 = AssumeFieldBased(V2) V2 = AssumeBFF(V2) V2 = Weave(V2) #Simple Swap Fields V5 = SwapFields(V1) V3 V4 V4 V4 = = = = StackVertical(V1_TF, V1_BF) StackHorizontal(V3, V2) StackHorizontal(V4, V5) StackHorizontal(V1, V4) return V4 Example 4: Output using mplayer Frame 0 Field Separated Field merged but swapped Resolution is 704x144 Direct field swapping using original Example 5: Generating standard Inputs #Generate Black Frame V1 = BlankClip(width=176, height=144) #Convert to YUV420P since default is RGB V1 = ConvertToYV12(V1) #Generate standard SMPTE color chart V2 = ColorBars(width=176, height=144) #Convert to YUV420P since default is RGB V2 = ConvertToYV12(V2) #Interleave the two data in time and return to application V3 = Interleave(V1,V2) V3 = ShowFrameNumber(V3, x=30, y=30) return V3 Number of frames are controlled using application: ffmpeg –vframes 10 –i example4.avs output.yuv mplayer –frames 10 example4.avs Example 5: Output using mplayer Frame 0 Frame 1 Frame 2 Resolution is 176x144 Frame 3 Frame 4 Example 6: More filters! V1 = RawSource("test.yuv",176,144,"I420") #Resize to 352x288 V2 = Lanczos4Resize(V1, 352, 288) #Resize back to 176x144 V2 = Lanczos4Resize(V2, 176, 144) #Overlays comparison details on V1 V3 = Compare(V1,V2) #Writes comparison data to file V4 = Compare(V1,V2,"Y","compareY.log") V5 = Compare(V1,V2,"U","compareU.log") V6 = Compare(V1,V2,"V","compareV.log") V8 = Compare(V1,V2,"","compare.log") #Compares all Y,U,V #Generate Histogram V7 = Histogram(V1) #Need to use all output to actually dump the log files return stackHorizontal(V3, FlipHorizontal(V4), FlipVertical(V5), V6, V7, V8) Example 6: Output using mplayer Total Resolution is 1312x144 Histogram is 256x144 compareY.log compareU.log compareV.log compare.log Comparing channel(s) Y Comparing channel(s) U Comparing channel(s) V Comparing channel(s) YUV Mean Max Max Absolute Mean Pos. Neg. Frame Dev. Dev. Dev. Dev. PSNR (dB) ----------------------------------------------------0 0.5449 -0.0392 10 -15 46.9531 1 0.4162 -0.0278 10 -15 48.1197 2 0.4503 -0.0368 10 -15 47.8962 3 0.3937 -0.0344 11 -14 48.6711 4 0.4221 -0.0333 12 -13 48.3770 Mean Max Max Absolute Mean Pos. Neg. Frame Dev. Dev. Dev. Dev. PSNR (dB) ----------------------------------------------------0 0.0137 -0.0002 1 -1 66.7538 1 0.0199 -0.0022 1 -1 65.1452 2 0.0262 -0.0028 1 -1 63.9479 3 0.0238 +0.0024 1 -1 64.3592 4 0.0271 +0.0006 2 -1 63.7435 Mean Max Max Absolute Mean Pos. Neg. Frame Dev. Dev. Dev. Dev. PSNR (dB) ----------------------------------------------------0 0.0535 +0.0055 4 -4 59.0309 1 0.0461 +0.0076 4 -4 59.5976 2 0.0527 +0.0044 4 -4 59.1767 3 0.0456 +0.0077 4 -4 59.7441 4 0.0443 +0.0011 4 -5 59.9061 Mean Max Max Absolute Mean Pos. Neg. Frame Dev. Dev. Dev. Dev. PSNR (dB) ----------------------------------------------------0 0.3744 -0.0252 10 -4 48.6360 1 0.2884 -0.0177 10 -4 49.7829 2 0.3134 -0.0243 10 -4 49.5506 3 0.2741 -0.0213 11 -4 50.3194 4 0.2933 -0.0219 12 -5 50.0314 Debugging scripts • • Everything is case-insensitive Semi-colons at end of line cause scripts to crash • Arbitrarily cut files with containers may not work – – – • To debug scripts use mplayer command as follows – – • In this case, use ffmpeg to sync to nearest key frame ffmpeg –i input.avi –vcodec copy output.avi Any other container may also be used instead of avi mplayer input.avs –demuxer avs –v This will point out where the script faced problems Number of frame to process – Number of frames can be controlled by mplayer or ffmpeg in all scenarios • • ffmpeg –vframes 100 –i input.avs output.yuv mplayer –frames 100 –i input.avs • All mplayer and ffmpeg options works normally as it does for any other file • Handling elementary streams – – RAW H264 streams are not supported by the default filters These need to be embedded in a container format like AVI/MP4/MOV/MKV using ffmpeg or any other means • ffmpeg –i input.h264 –vcodec copy output.avi Other features • • Supports audio filters like resampling, equalizers, etc Complex filters like increasing FPS using temporal interpolation for intermediate frames • Lot of plugins available – – – • Scripting reference – • http://avisynth.org/warpenterprises/ http://avisynth.org/mediawiki/External_filters http://avisynth.org/mediawiki/Internal_filters http://avisynth.org/mediawiki/Scripting_reference Advanced features – Runtime filters • • • http://avisynth.org/mediawiki/Runtime_environment Provides features like conditionally running filters Editors for AVS script with features like auto-completion, etc.. – http://avisynth.org/qwerpoi/