Detect: Basic hwaccel detection based on OS and GPU, Linux only ATM

Makefile

@@ -0,0 +1,19 @@
+## Automate common development tasks
+
+
+.PHONY: default
+defalt: ffmpeg/detect.json
+
+
+.tox/py35/bin/python:
+	tox -e py35
+	touch "$(@)"
+
+.tox/py35/lib/python3.5/site-packages/pandas: .tox/py35/bin/python
+	.tox/py35/bin/pip install requests lxml pandas
+	touch "$(@)"
+
+.PHONY: ffmpeg/detect.json
+ffmpeg/detect.json: .tox/py35/lib/python3.5/site-packages/pandas
+	.tox/py35/bin/python examples/get_detect_data.py >"$(@)"
+

examples/get_detect_data.py

@@ -0,0 +1,59 @@
+#!/usr/bin/env python
+"""
+Retrieve and process all the external data for hardware detection.
+"""
+
+import sys
+import json
+
+import requests
+import pandas
+
+HWACCELINTRO_URL = 'https://trac.ffmpeg.org/wiki/HWAccelIntro'
+API_TO_HWACCEL = {
+    'AMF': 'amf',
+    'NVENC/NVDEC/CUVID': 'cuvid',
+    'Direct3D 11': 'd3d11va',
+    'Direct3D 9 (DXVA2)': 'dxva2',
+    'libmfx': 'libmfx',
+    'MediaCodec': 'mediacodec',
+    'Media Foundation': 'mediafoundation',
+    'MMAL': 'mmal',
+    'OpenCL': 'opencl',
+    'OpenMAX': 'omx',
+    'V4L2 M2M': 'v4l2m2m',
+    'VAAPI': 'vaapi',
+    'VDPAU': 'vdpau',
+    'VideoToolbox': 'videotoolbox',
+}
+PLATFORM_TO_PY = {
+    'Apple': 'Darwin',
+}
+
+
+def main():
+    data = {}
+
+    data['hwaccels'] = hwaccels = {}
+    response = requests.get(HWACCELINTRO_URL)
+    api_avail_table, impl_table = pandas.read_html(response.content)
+
+    gpu_vendor_cols = api_avail_table.loc[1][1:]
+    platform_cols = api_avail_table.loc[0][1:]
+    api_rows = api_avail_table[0][2:]
+
+    hwaccels['api_avail'] = platforms = {}
+    for gpu_vendor_idx, gpu_vendor in enumerate(gpu_vendor_cols):
+        platform = platform_cols[gpu_vendor_idx + 1]
+        platform = PLATFORM_TO_PY.get(platform, platform)
+        gpu_vendors = platforms.setdefault(platform, {})
+        avail_hwaccels = gpu_vendors.setdefault(gpu_vendor, [])
+        for api_idx, api in enumerate(api_rows):
+            if api_avail_table[gpu_vendor_idx + 1][api_idx + 2] != 'N':
+                avail_hwaccels.append(API_TO_HWACCEL[api])
+
+    json.dump(data, sys.stdout, indent=2)
+
+
+if __name__ == '__main__':
+    main()

ffmpeg/__init__.py

@@ -1,6 +1,7 @@
 from __future__ import unicode_literals
 from . import nodes
 from . import _build
+from . import _detect
 from . import _ffmpeg
 from . import _filters
 from . import _probe
@@ -8,6 +9,7 @@ from . import _run
 from . import _view
 from .nodes import *
 from ._build import *
+from ._detect import *
 from ._ffmpeg import *
 from ._filters import *
 from ._probe import *
@@ -17,6 +19,7 @@ from ._view import *
 __all__ = (
     nodes.__all__
     + _build.__all__
+    + _detect.__all__
     + _ffmpeg.__all__
     + _probe.__all__
     + _run.__all__

ffmpeg/_detect.py

@@ -0,0 +1,121 @@
+"""Detect optimal arguments for various options.
+
+This module includes a number of constants used to attempt to detect the
+options which will provide the best performance for a given OS/GPU/etc..
+
+For most of these constants, it only matters that the best performing option
+available for a given OS/platform/hardware rank first for that
+OS/platform/hardware, not which OS/platform/hardware performs better.  For
+example, it doesn't matter if `vdpau` is lower than `cuvid` or vice versa,
+because one is only available for Linux and the other for Windows. Similarly,
+it doesn't matter how `amf` is ranked with respect to `cuvid` because one is
+only available on NVidia GPUs and the other AMD.  It *does* matter how
+`cuvid`/`amf` are ranked with respect to `dxva2` because those could both be
+available on the same OS and GPU.
+
+Additions and suggestions for these constants are very much welcome,
+especially if they come with benchmarks and/or good explanations from those
+who understand this domain well.  Contributions of more complicated or
+involved detection logic may also be welcome, though the case will have to be
+made more rigorously.
+"""
+
+import sys
+import platform
+import os
+import json
+import logging
+import argparse
+import subprocess
+
+import ffmpeg
+
+logger = logging.getLogger(__name__)
+
+parser = argparse.ArgumentParser(description=__doc__)
+parser.add_argument(
+    '--ffmpeg', default='ffmpeg',
+    help='The path to the ffmpeg execuatble')
+
+# List `hwaccel` options by order of expected performance when available.
+HWACCELS_BY_PERFORMANCE = [
+    'cuvid', 'amf', 'vdpau',
+    'qsv', 'd3d11va', 'dxva2', 'vaapi', 'drm']
+# Loaded from JSON
+DATA = None
+
+
+def detect_gpu():
+    """
+    Detect the GPU vendor, generation and model if possible.
+    """
+    plat_sys = platform.system()
+    if plat_sys == 'Linux':
+        display_output = subprocess.check_output(
+            ['lshw', '-class', 'display', '-json'])
+        return json.loads(display_output.decode().strip().strip(','))
+
+
+def detect_hwaccels(hwaccels=None, cmd='ffmpeg'):
+    """
+    Extract details about the ffmpeg build.
+    """
+    # Filter against what's available in the ffmpeg build
+    build_hwaccels = ffmpeg.get_hwaccels(cmd=cmd)
+    if hwaccels is None:
+        # Consider all the available hwaccels
+        hwaccels = build_hwaccels
+    else:
+        # Support passing in a restricted set of hwaccels
+        hwaccels = [
+            hwaccel for hwaccel in hwaccels if hwaccel in build_hwaccels]
+
+    # Filter against which APIs are available on this OS+GPU
+    data = _get_data()
+    plat_sys = platform.system()
+    gpu = detect_gpu()
+    api_avail = data['hwaccels']['api_avail'][plat_sys][
+        gpu['vendor'].replace(' Corporation', '')]
+    hwaccels = [hwaccel for hwaccel in hwaccels if hwaccel in api_avail]
+
+    hwaccels.sort(key=lambda hwaccel: (
+        # Sort unranked hwaccels last, but in the order given by ffmpeg
+        hwaccel not in HWACCELS_BY_PERFORMANCE,
+        (
+            # Sort ranked hwaccels per the constant
+            hwaccel in HWACCELS_BY_PERFORMANCE and
+            HWACCELS_BY_PERFORMANCE.index(hwaccel))))
+    return hwaccels
+
+
+__all__ = [
+    'detect_gpu',
+    'detect_hwaccels',
+]
+
+
+def _get_data():
+    """
+    Don't load the data JSON unless needed, cache in a global.
+    """
+    global DATA
+    if DATA is None:
+        with open(os.path.join(
+                os.path.dirname(__file__), 'detect.json')) as data_opened:
+            DATA = json.load(data_opened)
+    return DATA
+
+
+def main(args=None):
+    """
+    Dump all ffmpeg build data to json.
+    """
+    args = parser.parse_args(args)
+    data = dict(
+        gpu=detect_gpu(),
+        hwaccels=detect_hwaccels(args.ffmpeg))
+    json.dump(data, sys.stdout, indent=2)
+
+
+if __name__ == '__main__':
+    main()

ffmpeg/detect.json

@@ -0,0 +1,71 @@
+{
+  "hwaccels": {
+    "api_avail": {
+      "Linux": {
+        "AMD": [
+          "opencl",
+          "omx",
+          "vaapi",
+          "vdpau"
+        ],
+        "NVIDIA": [
+          "cuvid",
+          "opencl",
+          "vaapi",
+          "vdpau"
+        ],
+        "Intel": [
+          "libmfx",
+          "opencl",
+          "vaapi"
+        ]
+      },
+      "Darwin": {
+        "iOS": [
+          "videotoolbox"
+        ],
+        "macOS": [
+          "opencl",
+          "videotoolbox"
+        ]
+      },
+      "Android": {
+        "NaN": [
+          "mediacodec",
+          "opencl",
+          "omx",
+          "v4l2m2m"
+        ]
+      },
+      "Other": {
+        "Raspberry Pi": [
+          "mmal",
+          "omx"
+        ]
+      },
+      "Windows": {
+        "AMD": [
+          "amf",
+          "d3d11va",
+          "dxva2",
+          "mediafoundation",
+          "opencl"
+        ],
+        "NVIDIA": [
+          "cuvid",
+          "d3d11va",
+          "dxva2",
+          "mediafoundation",
+          "opencl"
+        ],
+        "Intel": [
+          "d3d11va",
+          "dxva2",
+          "libmfx",
+          "mediafoundation",
+          "opencl"
+        ]
+      }
+    }
+  }
+}

setup.py

@@ -95,8 +95,9 @@ setup(
         'Programming Language :: Python :: 3.5',
         'Programming Language :: Python :: 3.6',
     ],
-    entry_points = {
+    entry_points={
         'console_scripts': [
-            'ffmpeg-build-json=ffmpeg._build:main'],
+            'ffmpeg-build-json=ffmpeg._build:main',
+            'ffmpeg-detect=ffmpeg._detect:main'],
     },
 )