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• Saying Goodbye To Old Machines

  1er décembre 2014, par Multimedia Mike — General, powerpc, via

  I recently sent a few old machines off for recycling. Both had relevance to the early days of the FATE testing effort. As is my custom, I photographed them (poorly, of course).

  First, there’s the PowerPC-based Mac Mini I procured thanks to a Craigslist ad in late 2006. I had plans to develop automated FFmpeg building and testing and was already looking ahead toward testing multiple CPU architectures. Again, this was 2006 and PowerPC wasn’t completely on the outs yet– although Apple’s MacTel transition was in full swing, the entire new generation of video game consoles was based on PowerPC.

  
  

  

  Click for larger image

  
  

  I remember trying to find a Mac Mini PPC on Craigslist. Many were to be found, but all asked more than the price of even a new Mac Mini Intel, always because the seller was leaving all of last year’s applications and perhaps including a monitor, neither of which I needed. Fortunately, I found this bare Mac Mini. Also fortunate was the fact that it was far easier to install Linux on it than the first PowerPC machine I owned.

  After FATE operation transitioned away from me, I still kept the machine in service as an edge server and automated backup machine. That is, until the hard drive failed on reboot one day. Thus, when it was finally time to recycle the computer, I felt it necessary to disassemble the machine and remove the hard drive for possible salvage and then for destruction.
  

  If you’ve ever attempted to upgrade or otherwise service this style of Mac Mini, you will no doubt recognize the pictured paint scraper tool as standard kit. I have had that tool since I first endeavored to upgrade the RAM to 1 GB from the standard 1/2 GB. Performing such activities on a Mac Mini is tedious, but only if you care about putting it back together afterwards.

  The next machine is a bit older. I put it together nearly a decade ago, early in 2005. This machine’s original duty was “download agent”– this would be more specifically called a BitTorrent machine in modern tech parlance. Back then, I placed it on someone else’s woefully underutilized home broadband connection (with their permission, of course) when I was too cheap to upgrade from dialup.

  
  

  

  Click for larger image

  
  

  This is a small form factor system from VIA that was clearly designed with home theater PC (HTPC) use cases in mind. It has a VIA C3 x86-compatible CPU (according to my notes, Centaur VIA Samuel 2 stepping 03, flags : fpu de tsc msr cx8 mtrr pge mmx 3dnow) and 128 MB of RAM (initially ; I upgraded it to 512 MB some years later, just for the sake of doing it). And then there was the 120 GB PATA HD for all that downloaded goodness.

  
  

  

  Click for larger image

  
  

  I have specific memories of a time when my main computer at home wasn’t working correctly for one reason or another. Instead, I logged into this machine remotely via SSH to make several optimizations and fixes on FFmpeg’s VP3/Theora video decoder, all from the terminal, without being able to see the decoded images with my own eyes (which is why I insist that even blind people could work on video codecs).

  By the time I got my own broadband, I had become inspired to attempt the automated build and test system for FFmpeg. This was the machine I used for prototyping early brainstorms of FATE. By the time I put a basic build/test system into place in early 2008, I had much faster computers that could build and test the project– obvious limitation of this machine is that it could take at least 1/2 hour to build the entire codebase, and that was the project from 8 years ago.

  So the machine got stuffed in a closet somewhere along the line. The next time I pulled it out was in 2010 when I wanted to toy with Dreamcast programming once more (the machine appears in one of the photos in this post). This was the only machine I still owned which still had an RS-232 serial port (I didn’t know much about USB serial converters yet), plus it still had a bunch of pre-compiled DC homebrew binaries (I was having trouble getting the toolchain to work right).

  The next time I dusted off this machine was late last year when I was trying some experiments with the Microsoft Xbox’s IDE drive (a photo in that post also shows the machine ; this thing shows up a lot on this blog). The VIA machine was the only machine I still owned which had 40-pin IDE connectors which was crucial to my experiment.

  At this point, I was trying to make the machine more useful which meant replacing the ancient Gentoo Linux distribution as well as simply interacting with it via a keyboard and mouse. I have a long Evernote entry documenting a comedy of errors revolving around this little box. The interaction troubles were due to the fact that I didn’t have any PS/2 keyboards left and I couldn’t make a USB keyboard work with it. Diego was able to explain that I needed to flip a bit in the BIOS to address this which worked. As for upgrading the OS, I tried numerous Linux distributions large and small, mostly focusing on the small. None worked. I eventually learned that, while I was trying to use i686 distributions, this machine did not actually qualify as an i686 CPU ; installations usually booted but failed because the default kernel required the cmov instruction. I was advised to try i386 distros instead. My notes don’t indicate whether I had any luck on this front before I gave up and moved on.

  I just made the connection that this VIA machine has two 40-pin IDE connectors which means that the thing was technically capable of supporting up to 4 IDE devices. Obviously, the computer couldn’t really accommodate that in terms of space or power. When I wanted to try installing a new OS, I needed take off the top and connect a rather bulky IDE CD-ROM drive. This computer’s casing was supposed to be able to support a slimline optical drive (perhaps like the type found in laptops), but I could never quite visualize how that was supposed to work, space-wise. When I disassembled the PowerPC Mac Mini, I realized I might be able to repurpose that machines optical drive for this computer. Obviously, I thought better of trying since both machines are off to the recycle pile.

  I would still like to work on the Xbox project a bit more, but I procured a different, unused, much more powerful yet still old computer that has a motherboard with 1 PATA connector in addition to 6 SATA connectors. If I ever get around to toying with Linux kernel development, this should be a much more appropriate platform to use.

  I thought about turning this machine into an old Windows XP (and lower, down to Windows 3.1) gaming platform ; the capabilities of the machine would probably be perfect for a huge portion of my Windows game collection. But I think the lack of an optical drive renders this idea intractable. External USB drives are likely out of the question since there is very little chance that this motherboard featured USB 2.0 (the specs don’t mention 2.0, so the USB ports are probably 1.1).

  So it is with fond memories that I send off both machines, sans hard drives, to the recycle pile. I’m still deciding on an appropriate course of action for failed hard drives, though.

• HLS script has been lost to time, previous content was made in specific format, attempting to recreate using FFMPEG primitives

  28 février, par Wungo

  Looking to add this video to a stitched playlist. The variants, encoding, and everything must match exactly. We have no access to how things were done previously, so I am literally vibing through this as best as I can.

  


  I recommend using a clip of buck bunny that's 30 seconds long, or the original buck bunny 1080p video.

  


  #!/bin/bash
ffmpeg -i bbb_30s.mp4 -filter_complex "
[0:v]split=7[v1][v2][v3][v4][v5][v6][v7];
[v1]scale=416:234[v1out];
[v2]scale=416:234[v2out];
[v3]scale=640:360[v3out];
[v4]scale=768:432[v4out];
[v5]scale=960:540[v5out];
[v6]scale=1280:720[v6out];
[v7]scale=1920:1080[v7out]
" \
-map "[v1out]" -c:v:0 libx264 -b:v:0 200k -maxrate 361k -bufsize 400k -r 29.97 -g 60 -keyint_min 60 -sc_threshold 0 -preset veryfast -profile:v baseline -level 3.0 \
-map "[v2out]" -c:v:1 libx264 -b:v:1 500k -maxrate 677k -bufsize 700k -r 29.97 -g 60 -keyint_min 60 -sc_threshold 0 -preset veryfast -profile:v baseline -level 3.0 \
-map "[v3out]" -c:v:2 libx264 -b:v:2 1000k -maxrate 1203k -bufsize 1300k -r 29.97 -g 60 -keyint_min 60 -sc_threshold 0 -preset veryfast -profile:v main -level 3.1 \
-map "[v4out]" -c:v:3 libx264 -b:v:3 1800k -maxrate 2057k -bufsize 2200k -r 29.97 -g 60 -keyint_min 60 -sc_threshold 0 -preset veryfast -profile:v main -level 3.1 \
-map "[v5out]" -c:v:4 libx264 -b:v:4 2500k -maxrate 2825k -bufsize 3000k -r 29.97 -g 60 -keyint_min 60 -sc_threshold 0 -preset veryfast -profile:v main -level 4.0 \
-map "[v6out]" -c:v:5 libx264 -b:v:5 5000k -maxrate 5525k -bufsize 6000k -r 29.97 -g 60 -keyint_min 60 -sc_threshold 0 -preset veryfast -profile:v high -level 4.1 \
-map "[v7out]" -c:v:6 libx264 -b:v:6 8000k -maxrate 9052k -bufsize 10000k -r 29.97 -g 60 -keyint_min 60 -sc_threshold 0 -preset veryfast -profile:v high -level 4.2 \
-map a:0 -c:a:0 aac -b:a:0 128k -ar 48000 -ac 2 \
-f hls -hls_time 6 -hls_playlist_type vod -hls_flags independent_segments \
-hls_segment_type fmp4 \
-hls_segment_filename "output_%v_%03d.mp4" \
-master_pl_name master.m3u8 \
-var_stream_map "v:0,name:layer-416x234-200k v:1,name:layer-416x234-500k v:2,name:layer-640x360-1000k v:3,name:layer-768x432-1800k v:4,name:layer-960x540-2500k v:5,name:layer-1280x720-5000k v:6,name:layer-1920x1080-8000k a:0,name:layer-audio-128k" \
output_%v.m3u8



  


  Above is what i've put together over the past few days.

  


  I consistently run into the same issues :

  


  

  1. my variants must match identically, the bit rate etc. must match identically no excuses. No variance allowed.

  


  2. When I did it a different way previously, it became impossible to sync the variants timing, thus making the project not stitchable, making the asset useless.The variants are encoded to last longer than the master.m3u8 says it will last. Rejecting the asset downstream.

  


  3. I end up either having variants mismatched with timing, or no audio/audio channels synced properly. Here is what the master.m3u8 should look like.

  


  


  #EXTM3U
#EXT-X-VERSION:7

#EXT-X-STREAM-INF:AUDIO="aac",AVERAGE-BANDWIDTH=333000,BANDWIDTH=361000,CLOSED-CAPTIONS="cc1",CODECS="avc1.4d400d,mp4a.40.2",FRAME-RATE=29.97,RESOLUTION=416x234
placeholder.m3u8
#EXT-X-STREAM-INF:AUDIO="aac",AVERAGE-BANDWIDTH=632000,BANDWIDTH=677000,CLOSED-CAPTIONS="cc1",CODECS="avc1.4d400d,mp4a.40.2",FRAME-RATE=29.97,RESOLUTION=416x234
placeholder2.m3u8
#EXT-X-STREAM-INF:AUDIO="aac",AVERAGE-BANDWIDTH=1133000,BANDWIDTH=1203000,CLOSED-CAPTIONS="cc1",CODECS="avc1.4d401e,mp4a.40.2",FRAME-RATE=29.97,RESOLUTION=640x360
placeholder3.m3u8

#EXT-X-STREAM-INF:AUDIO="aac",AVERAGE-BANDWIDTH=1933000,BANDWIDTH=2057000,CLOSED-CAPTIONS="cc1",CODECS="avc1.4d401f,mp4a.40.2",FRAME-RATE=29.97,RESOLUTION=768x432
placeholder4.m3u8

#EXT-X-STREAM-INF:AUDIO="aac",AVERAGE-BANDWIDTH=2633000,BANDWIDTH=2825000,CLOSED-CAPTIONS="cc1",CODECS="avc1.4d401f,mp4a.40.2",FRAME-RATE=29.97,RESOLUTION=960x540
placeholder5.m3u8

#EXT-X-STREAM-INF:AUDIO="aac",AVERAGE-BANDWIDTH=5134000,BANDWIDTH=5525000,CLOSED-CAPTIONS="cc1",CODECS="avc1.4d401f,mp4a.40.2",FRAME-RATE=29.97,RESOLUTION=1280x720
placeholder6.m3u8

#EXT-X-STREAM-INF:AUDIO="aac",AVERAGE-BANDWIDTH=8135000,BANDWIDTH=9052000,CLOSED-CAPTIONS="cc1",CODECS="avc1.640028,mp4a.40.2",FRAME-RATE=29.97,RESOLUTION=1920x1080
placeholder7.m3u8

#EXT-X-STREAM-INF:AUDIO="aac",AVERAGE-BANDWIDTH=129000,BANDWIDTH=130000,CLOSED-CAPTIONS="cc1",CODECS="mp4a.40.2"
placeholder8.m3u8

#EXT-X-MEDIA:AUTOSELECT=YES,CHANNELS="2",DEFAULT=YES,GROUP-ID="aac",LANGUAGE="en",NAME="English",TYPE=AUDIO,URI="placeholder8.m3u8"
#EXT-X-MEDIA:AUTOSELECT=YES,DEFAULT=YES,GROUP-ID="cc1",INSTREAM-ID="CC1",LANGUAGE="en",NAME="English",TYPE=CLOSED-CAPTIONS


  


  Underlying playlist clips should be *.mp4 not *.m4s or anything like that. Audio must be on a single channel by itself, closed captions are handled by a remote server and aren't a concern.

  


  as mentioned above :

  


  

  1. I have tried transcoding separately and then combining manually or later. Here is an example of that.

  


  


  #!/bin/bash
set -e

# Input file
INPUT_FILE="bbb_30.mp4"

# Output directory
OUTPUT_DIR="hls_output"
mkdir -p "$OUTPUT_DIR"

# First, extract exact duration from master.m3u8 (if it exists)
MASTER_M3U8="master.m3u8"  # Change if needed

echo "Extracting exact duration from the source MP4..."
EXACT_DURATION=$(ffprobe -v error -show_entries format=duration -of default=noprint_wrappers=1:nokey=1 "$INPUT_FILE")
echo "Using exact duration: $EXACT_DURATION seconds"
# Create a reference file with exact duration from the source
echo "Creating reference file with exact duration..."
ffmpeg -y -i "$INPUT_FILE" -c copy -t "$EXACT_DURATION" "$OUTPUT_DIR/exact_reference.mp4"

# Calculate exact GOP size for segment alignment (for 6-second segments at 29.97fps)
FPS=29.97
SEGMENT_DURATION=6
GOP_SIZE=$(echo "$FPS * $SEGMENT_DURATION" | bc | awk '{print int($1)}')
echo "Using GOP size of $GOP_SIZE frames for $SEGMENT_DURATION-second segments at $FPS fps"

# Function to encode a variant with exact duration
encode_variant() {
  local resolution="$1"
  local bitrate="$2"
  local maxrate="$3"
  local bufsize="$4"
  local profile="$5"
  local level="$6"
  local audiorate="$7"
  local name_suffix="$8"
  
  echo "Encoding $resolution variant with video bitrate $bitrate kbps and audio bitrate ${audiorate}k..."
  
  # Step 1: Create an intermediate file with exact duration and GOP alignment
  ffmpeg -y -i "$OUTPUT_DIR/exact_reference.mp4" \
    -c:v libx264 -profile:v "$profile" -level "$level" \
    -x264-params "bitrate=$bitrate:vbv-maxrate=$maxrate:vbv-bufsize=$bufsize:keyint=$GOP_SIZE:min-keyint=$GOP_SIZE:no-scenecut=1" \
    -s "$resolution" -r "$FPS" \
    -c:a aac -b:a "${audiorate}k" \
    -vsync cfr -start_at_zero -reset_timestamps 1 \
    -map 0:v:0 -map 0:a:0 \
    -t "$EXACT_DURATION" \
    -force_key_frames "expr:gte(t,n_forced*6)" \
    "$OUTPUT_DIR/temp_${name_suffix}.mp4"
  
  # Step 2: Create HLS segments with exact boundaries from the intermediate file.
  ffmpeg -y -i "$OUTPUT_DIR/temp_${name_suffix}.mp4" \
    -c copy \
    -f hls \
    -hls_time "$SEGMENT_DURATION" \
    -hls_playlist_type vod \
    -hls_segment_filename "$OUTPUT_DIR/layer-${name_suffix}-segment-%03d.mp4" \
    -hls_flags independent_segments+program_date_time+round_durations \
    -hls_list_size 0 \
    "$OUTPUT_DIR/layer-${name_suffix}.m3u8"
  
  # Verify duration
  VARIANT_DURATION=$(ffprobe -v error -show_entries format=duration -of default=noprint_wrappers=1:nokey=1 "$OUTPUT_DIR/temp_${name_suffix}.mp4")
  echo "Variant $name_suffix duration: $VARIANT_DURATION (target: $EXACT_DURATION, diff: $(echo "$VARIANT_DURATION - $EXACT_DURATION" | bc))"
  
  # Clean up temporary file
  rm "$OUTPUT_DIR/temp_${name_suffix}.mp4"
}

# Process each variant with exact duration matching
# Format: resolution, bitrate, maxrate, bufsize, profile, level, audio bitrate, name suffix
encode_variant "416x234" "333" "361" "722" "baseline" "3.0" "64" "416x234-200k"
encode_variant "416x234" "632" "677" "1354" "baseline" "3.0" "64" "416x234-500k"
encode_variant "640x360" "1133" "1203" "2406" "main" "3.0" "96" "640x360-1000k"
encode_variant "768x432" "1933" "2057" "4114" "main" "3.1" "96" "768x432-1800k"
encode_variant "960x540" "2633" "2825" "5650" "main" "3.1" "128" "960x540-2500k"
encode_variant "1280x720" "5134" "5525" "11050" "main" "3.1" "128" "1280x720-5000k"
encode_variant "1920x1080" "8135" "9052" "18104" "high" "4.0" "128" "1920x1080-8000k"

# 8. Audio-only variant
echo "Creating audio-only variant..."


# ffmpeg -y -i "$INPUT_FILE" \
#   -vn -map 0:a \
#   -c:a aac -b:a 128k -ac 2 \ 
#   -t "$EXACT_DURATION" \
#   -f hls \
#   -hls_time "$SEGMENT_DURATION" \
#   -hls_playlist_type vod \
#   -hls_flags independent_segments+program_date_time+round_durations \
#   -hls_segment_filename "$OUTPUT_DIR/layer-audio-128k-segment-%03d.ts" \
#   -hls_list_size 0 \
#   "$OUTPUT_DIR/layer-audio-128k.m3u8"

ffmpeg -y -i "$INPUT_FILE" \
  -vn \
  -map 0:a \
  -c:a aac -b:a 128k \
  -t "$EXACT_DURATION" \
  -f hls \
  -hls_time "$SEGMENT_DURATION" \
  -hls_playlist_type vod \
  -hls_segment_type fmp4 \
  -hls_flags independent_segments+program_date_time+round_durations \
  -hls_list_size 0 \
  -hls_segment_filename "$OUTPUT_DIR/layer-audio-128k-segment-%03d.m4s" \
  "$OUTPUT_DIR/layer-audio-128k.m3u8"


# Create master playlist
cat > "$OUTPUT_DIR/master.m3u8" << EOF
#EXTM3U
#EXT-X-VERSION:7
#EXT-X-INDEPENDENT-SEGMENTS

#EXT-X-STREAM-INF:BANDWIDTH=361000,AVERAGE-BANDWIDTH=333000,CODECS="avc1.4d400d,mp4a.40.2",RESOLUTION=416x234,FRAME-RATE=29.97
layer-416x234-200k.m3u8
#EXT-X-STREAM-INF:BANDWIDTH=677000,AVERAGE-BANDWIDTH=632000,CODECS="avc1.4d400d,mp4a.40.2",RESOLUTION=416x234,FRAME-RATE=29.97
layer-416x234-500k.m3u8
#EXT-X-STREAM-INF:BANDWIDTH=1203000,AVERAGE-BANDWIDTH=1133000,CODECS="avc1.4d401e,mp4a.40.2",RESOLUTION=640x360,FRAME-RATE=29.97
layer-640x360-1000k.m3u8
#EXT-X-STREAM-INF:BANDWIDTH=2057000,AVERAGE-BANDWIDTH=1933000,CODECS="avc1.4d401f,mp4a.40.2",RESOLUTION=768x432,FRAME-RATE=29.97
layer-768x432-1800k.m3u8
#EXT-X-STREAM-INF:BANDWIDTH=2825000,AVERAGE-BANDWIDTH=2633000,CODECS="avc1.4d401f,mp4a.40.2",RESOLUTION=960x540,FRAME-RATE=29.97
layer-960x540-2500k.m3u8
#EXT-X-STREAM-INF:BANDWIDTH=5525000,AVERAGE-BANDWIDTH=5134000,CODECS="avc1.4d401f,mp4a.40.2",RESOLUTION=1280x720,FRAME-RATE=29.97
layer-1280x720-5000k.m3u8
#EXT-X-STREAM-INF:BANDWIDTH=9052000,AVERAGE-BANDWIDTH=8135000,CODECS="avc1.640028,mp4a.40.2",RESOLUTION=1920x1080,FRAME-RATE=29.97
layer-1920x1080-8000k.m3u8
#EXT-X-STREAM-INF:BANDWIDTH=130000,AVERAGE-BANDWIDTH=129000,CODECS="mp4a.40.2"
layer-audio-128k.m3u8
EOF

# Verify all durations match
cat > "$OUTPUT_DIR/verify_all.sh" << 'EOF'
#!/bin/bash

# Get exact reference duration from the exact reference file
REFERENCE_DURATION=$(ffprobe -v error -show_entries format=duration -of default=noprint_wrappers=1:nokey=1 "exact_reference.mp4")
echo "Reference duration: $REFERENCE_DURATION seconds"

# Check each segment's duration
echo -e "\nChecking individual segments..."
for seg in layer-*-segment-*.mp4 layer-audio-128k-segment-*.ts; do
  dur=$(ffprobe -v error -show_entries format=duration -of default=noprint_wrappers=1:nokey=1 "$seg")
  echo "$seg: $dur seconds"
done

# Get total duration for each variant by summing segment EXTINF durations from each playlist
echo -e "\nChecking combined variant durations..."
for variant in layer-*.m3u8; do
  total=0
  while read -r line; do
    if [[ $line == "#EXTINF:"* ]]; then
      dur=$(echo "$line" | sed 's/#EXTINF:\([0-9.]*\).*/\1/')
      total=$(echo "$total + $dur" | bc)
    fi
  done < "$variant"
  echo "$variant: $total seconds (reference: $REFERENCE_DURATION, diff: $(echo "$total - $REFERENCE_DURATION" | bc))"
done
EOF

chmod +x "$OUTPUT_DIR/verify_all.sh"

echo "HLS packaging complete with exact duration matching."
echo "Master playlist available at: $OUTPUT_DIR/master.m3u8"
echo "Run $OUTPUT_DIR/verify_all.sh to verify durations."
rm "$OUTPUT_DIR/exact_reference.mp4"



  


  I end up with weird audio in vlc which can't be right, and I also end up with variants being longer than the master.m3u8 playlist which is wonky.

  


  I tried using AI to fix the audio sync issue, and honestly I'm more confused than when I started.

  


• Revision 33458 : retablir le pied de la dist

  1er décembre 2009, par cedric@… — Log

  retablir le pied de la dist