The AVCodecContext width, height, coded_width, coded_height and format are used mainly as decoding hints and they get internally overwritten during the data parsing stage.
Do not assume they match the last AVFrame provided by avcodec_decode_video2 and assimilated functions since multi-threading and other frame reordering might make those values to refer to frames that will be outputted in the future. CC: [email protected] --- libavcodec/avcodec.h | 22 +++++++++++++++++++--- 1 file changed, 19 insertions(+), 3 deletions(-) diff --git a/libavcodec/avcodec.h b/libavcodec/avcodec.h index 3440126..59179dd 100644 --- a/libavcodec/avcodec.h +++ b/libavcodec/avcodec.h @@ -1217,21 +1217,31 @@ typedef struct AVCodecContext { /* video only */ /** * picture width / height. + * + * @note Those fields may not match the values of the last + * AVFrame outputted by avcodec_decode_video2 due frame + * reorderning. + * * - encoding: MUST be set by user. * - decoding: May be set by the user before opening the decoder if known e.g. * from the container. Some decoders will require the dimensions * to be set by the caller. During decoding, the decoder may - * overwrite those values as required. + * overwrite those values as required while parsing the data. */ int width, height; /** * Bitstream width / height, may be different from width/height e.g. when * the decoded frame is cropped before being output. + * + * @note Those field may not match the value of the last + * AVFrame outputted by avcodec_decode_video2 due frame + * reorderning. + * * - encoding: unused * - decoding: May be set by the user before opening the decoder if known * e.g. from the container. During decoding, the decoder may - * overwrite those values as required. + * overwrite those values as required while parsing the data. */ int coded_width, coded_height; @@ -1250,8 +1260,14 @@ typedef struct AVCodecContext { * Pixel format, see AV_PIX_FMT_xxx. * May be set by the demuxer if known from headers. * May be overriden by the decoder if it knows better. + * + * @note This field may not match the value of the last + * AVFrame outputted by avcodec_decode_video2 due frame + * reorderning. + * * - encoding: Set by user. - * - decoding: Set by user if known, overridden by libavcodec if known + * - decoding: Set by user if known, overridden by libavcodec while + * parsing the data. */ enum AVPixelFormat pix_fmt; -- 1.9.0 _______________________________________________ libav-devel mailing list [email protected] https://lists.libav.org/mailman/listinfo/libav-devel
