On 06/05/2011 06:31 PM, Stefano Sabatini wrote: > /** > * Bits per sample/pixel of internal libavcodec pixel/sample format. > * This field is applicable only when sample_fmt is AV_SAMPLE_FMT_S32. > * - encoding: set by user. > * - decoding: set by libavcodec. > */ > int bits_per_raw_sample;
This just describes the accuracy of the data inside the internal libavcodec sample *after decoding* or *before encoding*. For example, 24-bit audio data in AV_SAMPLE_FMT_S32 is still scaled to 32 bit range as required by the sample format, but this field is set to 24 to indicate that there is only 24 bits of information. So say you want to convert 24-bit audio from 1 lossless codec to another lossless codec, the encoder will know that it can discard the low 8 bits and encode in 24-bit mode if it has one because bits_per_raw_sample is 24. bits_per_coded_sample refers to the size of the samples *before decoding* or *after encoding*. The 2 values may be the same, and probably are in most cases, but they're used for different purposes. bits_per_raw_sample depends on the decoder implementation and sample format, where-as bits_per_coded_sample depends only on the CODEC_ID and thus is the one used by libavformat. -Justin _______________________________________________ libav-devel mailing list [email protected] https://lists.libav.org/mailman/listinfo/libav-devel
