[youtube|ffmpeg] Automatically correct video with non-square pixels (Fixes #4674)

7 files changed, 89 insertions, 0 deletions

diff --git a/youtube_dl/YoutubeDL.py b/youtube_dl/YoutubeDL.py
index 61675d8ec..4cc3ec2fb 100755
--- a/youtube_dl/YoutubeDL.py
+++ b/youtube_dl/YoutubeDL.py
@@ -70,6 +70,7 @@ from .extractor import get_info_extractor, gen_extractors
 from .downloader import get_suitable_downloader
 from .downloader.rtmp import rtmpdump_version
 from .postprocessor import (
+    FFmpegFixupStretchedPP,
     FFmpegMergerPP,
     FFmpegPostProcessor,
     get_postprocessor,
@@ -204,6 +205,12 @@ class YoutubeDL(object):
                        Progress hooks are guaranteed to be called at least once
                        (with status "finished") if the download is successful.
     merge_output_format: Extension to use when merging formats.
+    fixup:             Automatically correct known faults of the file.
+                       One of:
+                       - "never": do nothing
+                       - "warn": only emit a warning
+                       - "detect_or_warn": check whether we can do anything
+                                           about it, warn otherwise
 
 
     The following parameters are not used by YoutubeDL itself, they are used by
@@ -924,6 +931,7 @@ class YoutubeDL(object):
                                 'fps': formats_info[0].get('fps'),
                                 'vcodec': formats_info[0].get('vcodec'),
                                 'vbr': formats_info[0].get('vbr'),
+                                'stretched_ratio': formats_info[0].get('stretched_ratio'),
                                 'acodec': formats_info[1].get('acodec'),
                                 'abr': formats_info[1].get('abr'),
                                 'ext': output_ext,
@@ -1154,6 +1162,27 @@ class YoutubeDL(object):
                     return
 
             if success:
+                # Fixup content
+                stretched_ratio = info_dict.get('stretched_ratio')
+                if stretched_ratio is not None and stretched_ratio != 1:
+                    fixup_policy = self.params.get('fixup')
+                    if fixup_policy is None:
+                        fixup_policy = 'detect_or_warn'
+                    if fixup_policy == 'warn':
+                        self.report_warning('%s: Non-uniform pixel ratio (%s)' % (
+                            info_dict['id'], stretched_ratio))
+                    elif fixup_policy == 'detect_or_warn':
+                        stretched_pp = FFmpegFixupStretchedPP(self)
+                        if stretched_pp.available:
+                            info_dict.setdefault('__postprocessors', [])
+                            info_dict['__postprocessors'].append(stretched_pp)
+                        else:
+                            self.report_warning(
+                                '%s: Non-uniform pixel ratio (%s). Install ffmpeg or avconv to fix this automatically.' % (
+                                    info_dict['id'], stretched_ratio))
+                    else:
+                        assert fixup_policy == 'ignore'
+
                 try:
                     self.post_process(filename, info_dict)
                 except (PostProcessingError) as err:
diff --git a/youtube_dl/__init__.py b/youtube_dl/__init__.py
index 8e7b74466..659a92a3b 100644
--- a/youtube_dl/__init__.py
+++ b/youtube_dl/__init__.py
@@ -326,6 +326,7 @@ def _real_main(argv=None):
         'extract_flat': opts.extract_flat,
         'merge_output_format': opts.merge_output_format,
         'postprocessors': postprocessors,
+        'fixup': opts.fixup,
     }
 
     with YoutubeDL(ydl_opts) as ydl:
diff --git a/youtube_dl/extractor/common.py b/youtube_dl/extractor/common.py
index cd155a090..363e2000c 100644
--- a/youtube_dl/extractor/common.py
+++ b/youtube_dl/extractor/common.py
@@ -114,6 +114,9 @@ class InfoExtractor(object):
                                  to add to the request.
                     * http_post_data  Additional data to send with a POST
                                  request.
+                    * stretched_ratio  If given and not 1, indicates that the
+                                       video's pixels are not square.
+                                       width : height ratio as float.
     url:            Final video URL.
     ext:            Video filename extension.
     format:         The video format, defaults to ext (used for --get-format)
diff --git a/youtube_dl/extractor/youtube.py b/youtube_dl/extractor/youtube.py
index bc18276d6..c7611a3a0 100644
--- a/youtube_dl/extractor/youtube.py
+++ b/youtube_dl/extractor/youtube.py
@@ -465,6 +465,20 @@ class YoutubeIE(YoutubeBaseInfoExtractor, SubtitlesInfoExtractor):
                 'skip_download': 'requires avconv',
             }
         },
+        # Non-square pixels
+        {
+            'url': 'https://www.youtube.com/watch?v=_b-2C3KPAM0',
+            'info_dict': {
+                'id': '_b-2C3KPAM0',
+                'ext': 'mp4',
+                'stretched_ratio': 16 / 9.,
+                'upload_date': '20110310',
+                'uploader_id': 'AllenMeow',
+                'description': 'made by Wacom from Korea | 字幕&加油添醋 by TY\'s Allen | 感謝heylisa00cavey1001同學熱情提供梗及翻譯',
+                'uploader': '孫艾倫',
+                'title': '[A-made] 變態妍字幕版 太妍 我就是這樣的人',
+            },
+        }
     ]
 
     def __init__(self, *args, **kwargs):
@@ -1051,6 +1065,16 @@ class YoutubeIE(YoutubeBaseInfoExtractor, SubtitlesInfoExtractor):
                             f['preference'] = f.get('preference', 0) - 10000
                     formats.extend(dash_formats)
 
+        # Check for malformed aspect ratio
+        stretched_m = re.search(
+            r'<meta\s+property="og:video:tag".*?content="yt:stretch=(?P<w>[0-9]+):(?P<h>[0-9]+)">',
+            video_webpage)
+        if stretched_m:
+            ratio = float(stretched_m.group('w')) / float(stretched_m.group('h'))
+            for f in formats:
+                if f.get('vcodec') != 'none':
+                    f['stretched_ratio'] = ratio
+
         self._sort_formats(formats)
 
         return {
diff --git a/youtube_dl/options.py b/youtube_dl/options.py
index 14006178d..e5602bb3a 100644
--- a/youtube_dl/options.py
+++ b/youtube_dl/options.py
@@ -632,6 +632,13 @@ def parseOpts(overrideArguments=None):
         action='store_true', dest='xattrs', default=False,
         help='write metadata to the video file\'s xattrs (using dublin core and xdg standards)')
     postproc.add_option(
+        '--fixup',
+        metavar='POLICY', dest='fixup', default='detect_or_warn',
+        help='(experimental) Automatically correct known faults of the file. '
+             'One of never (do nothing), warn (only emit a warning), '
+             'detect_or_warn(check whether we can do anything about it, warn '
+             'otherwise')
+    postproc.add_option(
         '--prefer-avconv',
         action='store_false', dest='prefer_ffmpeg',
         help='Prefer avconv over ffmpeg for running the postprocessors (default)')
diff --git a/youtube_dl/postprocessor/__init__.py b/youtube_dl/postprocessor/__init__.py
index 7f505b58e..f8507951c 100644
--- a/youtube_dl/postprocessor/__init__.py
+++ b/youtube_dl/postprocessor/__init__.py
@@ -6,6 +6,7 @@ from .ffmpeg import (
     FFmpegAudioFixPP,
     FFmpegEmbedSubtitlePP,
     FFmpegExtractAudioPP,
+    FFmpegFixupStretchedPP,
     FFmpegMergerPP,
     FFmpegMetadataPP,
     FFmpegVideoConvertorPP,
@@ -24,6 +25,7 @@ __all__ = [
     'FFmpegAudioFixPP',
     'FFmpegEmbedSubtitlePP',
     'FFmpegExtractAudioPP',
+    'FFmpegFixupStretchedPP',
     'FFmpegMergerPP',
     'FFmpegMetadataPP',
     'FFmpegPostProcessor',
diff --git a/youtube_dl/postprocessor/ffmpeg.py b/youtube_dl/postprocessor/ffmpeg.py
index d1b342c7a..6e9194fa6 100644
--- a/youtube_dl/postprocessor/ffmpeg.py
+++ b/youtube_dl/postprocessor/ffmpeg.py
@@ -51,6 +51,10 @@ class FFmpegPostProcessor(PostProcessor):
         return dict((p, get_exe_version(p, args=['-version'])) for p in programs)
 
     @property
+    def available(self):
+        return self._executable is not None
+
+    @property
     def _executable(self):
         if self._downloader.params.get('prefer_ffmpeg', False):
             prefs = ('ffmpeg', 'avconv')
@@ -540,3 +544,22 @@ class FFmpegAudioFixPP(FFmpegPostProcessor):
         os.rename(encodeFilename(temp_filename), encodeFilename(filename))
 
         return True, info
+
+
+class FFmpegFixupStretchedPP(FFmpegPostProcessor):
+    def run(self, info):
+        stretched_ratio = info.get('stretched_ratio')
+        if stretched_ratio is None or stretched_ratio == 1:
+            return
+
+        filename = info['filepath']
+        temp_filename = prepend_extension(filename, 'temp')
+
+        options = ['-c', 'copy', '-aspect', '%f' % stretched_ratio]
+        self._downloader.to_screen('[ffmpeg] Fixing aspect ratio in "%s"' % filename)
+        self.run_ffmpeg(filename, temp_filename, options)
+
+        os.remove(encodeFilename(filename))
+        os.rename(encodeFilename(temp_filename), encodeFilename(filename))
+
+        return True, info