gstreamer/mediainfo/TODO

= Inspiration =
Simillar apps to take inspiration from:
http://www.fourcc.org/identifier/gspot_example.png
http://img.brothersoft.com/screenshots/softimage/g/gspot-190045-1.jpeg
http://www.headbands.com/gspot/v26x/index.htm

= browsing =
- if one has grillo installed we could use grillo sources in addition to local files
- there should be a "open url" menu entry in addition
- if initial directory contains a glob as a last entry, we could set a filter on
  the file-choser
- when a stream plays we hide the file-browser pane or show a text entry
- we could also take playlists and use totem-pl-parser
  - needs a list-view to show the playlist instead of the file-browser
- if the input arg starts with '@' we could read the file and show uris listed
  line by lien in the tree view. 

= compare =
- dup detail pane and allow to pick a new file
  - create new Info() pane and reuse the DiscovererInfo
- show differing entries in red
- add a narrow vertical bar between the two details panes and mark blocks with a
  delta red
- diffing one (broken) file against several known working files would be nice
  - it would build ranges for the group of files (e.g. for the video width)
  - it would highlight fields that the are different to any of the working files

= structural view/hex view =
- make parsing elements post structural messages (if enabled via property)
  - message would contain:
    - stream offset in bytes
    - block identifier (e.g. fourcc)
    - human readable description (if available)
    - flags (e.g. if the block is used or skipped)
    - indentation depth
  - we would need a way to indicate that e.g. h264parse would be indented below
    the containing container block
- a structured hex view would be nice
  (somehow align the parse tree with the hexdump)

= playback =
- have a menu command to turn auto-play off
- show level meters for audio next or below video drawable
- show a seek bar under the drawable / or seek by scrubbing on the drawable

= unsorted =
- show named audio channel configurations instead only numbers
  e.g. "mono", "stereo", "5.1"
- tag lists
  - if there is a "language-code" in the tags (or subtitles?) use flag icons
    - deluge installs some under: /usr/share/pyshared/deluge/data/mediainfo/pixmaps/flags/
    - famfamfam-flag-png: locale/usr/share/flags/countries/
  - geo-tags: map-widget?, link to google-maps?, rev-geocoding
  - artist: links to {last.fm,wikipedia}
  - format dates nicely (current locale, xx days ago?)
- more codec details
  - caps have profile/level strings, can we also turn them into wikilinks?
- bitrate and encode_size are related, calculate one from the other if missing
  - encoded_size = duration * bitrate;
  - bitrate = encoded_size / duration;
  - needed in: quicktime, ogg/theora

== deep scan mode ==
- play the file by using fakesinks and gather statistics:
- update fields when playing
  - listen for duration messages on the bus
- get bit-rate over time
  - specify window size, get min,max,avg bitrate for each window
  - gst-mi can draw them as a graph
- get key-frame statistics (using gst-index)
  - number of keyframes
  - min,max,avg keyframe interval
- disconts
- read-pos on source (show if there is excessive seeking)
- raw data statistics
  - audio: level, ...
  - video: histogram, contrast, ...

= TODO for gstreamer =
- file/stream layout
  - from every element we'd like to know what data is processed, what is pushed
    further and some metadata about it:
    layout {
      gsize offset;         // in bytes
      gsize length;         // in bytes
      gboolean known;       // or an enum: handled, skipped, unknown
      gchar *name;          // e.g. atom/chunk name
      gchar *description;   // long description or NULL
      enum block_type type; // meta, audio, video, text, ...
    };
    - offset is not neccesarily easy to determine for later elements, not sure
      if we can make it relative
  - elements could emit messages with this info
    - need a common way to enable it ("post-stream-layout" property)
  - we would need a cairo custom widget to draw a table
    - one row per element
    - each row contains colored segments

= TODO for gstreamer-plugins =
- wav: no bitrate for uncompressed files
- mp4: no bitrate for many formats

= TODO for discoverer =
- add deep-scan mode (see above)
  - add a mode property: quick-scan, deep-scan
   (or just a boolean for deep-scan that is false by default)
  - gst-discoverer will use "-d" for deep-scan/details
    (-a for analyze or -s for scan are used otherwise already)
  - in deep-scan, don't stop on handle_message::GST_MESSAGE_ASYNC_DONE
    - in deep-scan we need pad-probes for encoded data pads (to get bitrates)
      - uridecodebin_pad_added_cb() has raw pads :/
      - look at uridecodebin_element_added_cb()
    - the pads on uri-decodebin are sufficient to get keyframes and disconts
    - qtdemux could return stsz table to get bitrate profile
      http://wiki.multimedia.cx/index.php?title=QuickTime_container#stsz
- get duration per stream
  - this would need individual queries on the demuxer src pads
  - or duration as part of per stream tags
   - we need byte-durations for calculating compression ratio
- errors/warnings about files/stream processing
  - we'd like to know about fixable, unfixable issues in the file/stream
  - many elements do this already (178 uses in 89 files)
  - the pipeline and thus the bus is internal to discoverer, so it would be nice
    if it could gather the messages and offer them
  - having them globaly should be enough
- CBR/VBR type for each stream
  - can we derive that from the bitrate tags (no min/max bitrate set)?
  find . -name "*.c" -exec egrep -Hn "GST_TAG[A-Z_]*_BITRATE" {} \;
  - formats
    - all raw files are cbr
    - some codecs are cbr only (some speech codecs)
    - audio
      - in an MP3 file, if there is no VBRI or Xing,
        it probably is not a vbr stream
      -
- lossy/lossless compression/encoding
  - show compression type:
    - all raw formats are lossless
    - some audio formats are lossless (flac, wavpack, ...)
    - some video formats can be lossless (dirac, ...)
  - show compression raitio (in/out)
    - depends on the target raw format
    - need binary size for each stream, can we do byte queries on each pad?
  - if we have stream sizes we could also show container overhead

= discoverer workflow =
== sync quick-scan ==
app                   disco
---                   -----
 |    discover_uri()    |
 |--------------------->|
 |         done         |
 |<---------------------|
 |

== async quick-scan ==
app                   disco
---                   -----
 | discover_uri_async() |
 |--------------------->|
 |         ...          |
 | discover_uri_async() |
 |--------------------->|
 |       start()        |
 |--------------------->|
 |     ::discovered     |
 |<---------------------|
 |         ...          |
 |     ::discovered     |
 |<---------------------|
 |     ::finisheded     |
 |<---------------------|
 |

== sync deep-scan ==
- same as "sync quick-scan", no intermediate result

== async deep-scan ==
- same as "async quick-scan", but each discovered signal is followed by an
  "analyzed" signal with detailed information
  - we could also just emit discovered twice.

app                   disco
---                   -----
 | discover_uri_async() |
 |--------------------->|
 |         ...          |
 | discover_uri_async() |
 |--------------------->|
 |       start()        |
 |--------------------->|
 |     ::discovered     |
 |<---------------------|
 |     ::analyzed       |
 |<---------------------|
 |         ...          |
 |     ::discovered     |
 |<---------------------|
 |     ::analyzed       |
 |<---------------------|
 |     ::finisheded     |
 |<---------------------|
 |