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gst/mpegaudioparse/gstmpegaudioparse.c: Fix header parsing - stolen from ffmpeg (thank you! :) ).
Original commit message from CVS: 2004-01-30 Ronald Bultje <rbultje@ronald.bitfreak.net> * gst/mpegaudioparse/gstmpegaudioparse.c: (mp3_type_frame_length_from_header): Fix header parsing - stolen from ffmpeg (thank you! :) ).
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2 changed files with 38 additions and 50 deletions
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@ -1,3 +1,9 @@
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2004-01-30 Ronald Bultje <rbultje@ronald.bitfreak.net>
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* gst/mpegaudioparse/gstmpegaudioparse.c:
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(mp3_type_frame_length_from_header):
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Fix header parsing - stolen from ffmpeg (thank you! :) ).
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2004-01-30 Ronald Bultje <rbultje@ronald.bitfreak.net>
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* ext/esd/esdsink.c: (gst_esdsink_init):
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@ -127,61 +127,43 @@ mp3_type_frame_length_from_header (guint32 header, guint *put_layer,
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guint *put_samplerate)
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{
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guint length;
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gulong mode, samplerate, bitrate, layer, version, channels;
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gulong mode, samplerate, bitrate, layer, channels, padding;
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gint lsf, mpg25;
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/* we don't need extension, copyright, original or
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* emphasis for the frame length */
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header >>= 6;
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/* mode */
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mode = header & 0x3;
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header >>= 3;
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/* padding */
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length = header & 0x1;
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header >>= 1;
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/* sampling frequency */
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samplerate = header & 0x3;
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if (samplerate == 3)
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return 0;
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header >>= 2;
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/* bitrate index */
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bitrate = header & 0xF;
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if (bitrate == 15 || bitrate == 0)
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return 0;
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/* ignore error correction, too */
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header >>= 5;
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/* layer */
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layer = 4 - (header & 0x3);
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if (layer == 4)
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return 0;
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header >>= 2;
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/* version */
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version = header & 0x3;
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if (version == 1)
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return 0;
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/* lookup */
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channels = (mode == 3) ? 1 : 2;
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bitrate = mp3types_bitrates[version == 3 ? 0 : 1][layer - 1][bitrate];
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samplerate = mp3types_freqs[version > 0 ? version - 1 : 0][samplerate];
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/* calculating */
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if (layer == 1) {
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length = ((12000 * bitrate / samplerate) + length) * 4;
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if (header & (1 << 20)) {
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lsf = (header & (1 << 19)) ? 0 : 1;
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mpg25 = 0;
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} else {
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length += ((layer == 3 && version == 0) ? 144000 : 72000) * bitrate / samplerate;
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lsf = 1;
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mpg25 = 1;
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}
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mode = (header >> 6) & 0x3;
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channels = (mode == 3) ? 1 : 2;
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samplerate = (header >> 10) & 0x3;
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samplerate = mp3types_freqs[lsf + mpg25][samplerate];
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layer = 4 - ((header >> 17) & 0x3);
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bitrate = (header >> 12) & 0xF;
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bitrate = mp3types_bitrates[lsf][layer - 1][bitrate] * 1000;
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if (bitrate == 0)
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return 0;
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padding = (header >> 9) & 0x1;
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switch (layer) {
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case 1:
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length = (bitrate * 12) / samplerate + 4 * padding;
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break;
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case 2:
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length = (bitrate * 144) / samplerate + padding;
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break;
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default:
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case 3:
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length = (bitrate * 144) / (samplerate << lsf) + padding;
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break;
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}
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GST_DEBUG ("Calculated mp3 frame length of %u bytes", length);
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GST_DEBUG ("samplerate = %lu - bitrate = %lu - layer = %lu - version = %lu"
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" - channels = %lu",
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samplerate, bitrate, layer, version, channels);
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GST_DEBUG ("samplerate = %lu, bitrate = %lu, layer = %lu, channels = %lu",
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samplerate, bitrate, layer, channels);
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if (put_layer)
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*put_layer = layer;
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