> On May 29, 2023, at 23:54, myp...@gmail.com wrote: > > On Fri, May 19, 2023 at 4:41 PM Zhao Zhili <quinkbl...@foxmail.com> wrote: >> >> From: Zhao Zhili <zhiliz...@tencent.com> >> >> start_code_size depends on whether PS comes from out-of-band or >> in-band. Make the code more readable. >> --- >> libavcodec/h264_mp4toannexb_bsf.c | 34 ++++++++++++++++++++++++------- >> 1 file changed, 27 insertions(+), 7 deletions(-) >> >> diff --git a/libavcodec/h264_mp4toannexb_bsf.c >> b/libavcodec/h264_mp4toannexb_bsf.c >> index d11be455c2..7dce1ae9b6 100644 >> --- a/libavcodec/h264_mp4toannexb_bsf.c >> +++ b/libavcodec/h264_mp4toannexb_bsf.c >> @@ -43,10 +43,26 @@ typedef struct H264BSFContext { >> int extradata_parsed; >> } H264BSFContext; >> >> +enum PsSource { >> + PS_OUT_OF_BAND = -1, >> + PS_NONE = 0, >> + PS_IN_BAND = 1, >> +}; >> + >> static void count_or_copy(uint8_t **out, uint64_t *out_size, >> - const uint8_t *in, int in_size, int ps, int copy) >> + const uint8_t *in, int in_size, enum PsSource ps, >> int copy) >> { >> - uint8_t start_code_size = ps < 0 ? 0 : *out_size == 0 || ps ? 4 : 3; >> + uint8_t start_code_size; >> + >> + if (ps == PS_OUT_OF_BAND) >> + /* start code already present in out-of-band ps data, so don't need >> to >> + * add it manually again >> + */ >> + start_code_size = 0; >> + else if (ps == PS_IN_BAND || *out_size == 0) >> + start_code_size = 4; >> + else >> + start_code_size = 3; > I prefer the original style, they are shorter and more concise
It takes a little time to figure out what two ternary do in a single statement, it takes more time to figure out why, and multiple ternaries is hard to write comments properly. Multiple ternaries in a single statement works in simple cases. For current situation, I prefer ‘if-else’. >> >> if (copy) { >> memcpy(*out + start_code_size, in, in_size); >> @@ -202,6 +218,7 @@ static int h264_mp4toannexb_filter(AVBSFContext *ctx, >> AVPacket *opkt) >> >> do { >> uint32_t nal_size = 0; >> + enum PsSource ps; >> >> /* possible overread ok due to padding */ >> for (int i = 0; i < s->length_size; i++) >> @@ -230,7 +247,7 @@ static int h264_mp4toannexb_filter(AVBSFContext *ctx, >> AVPacket *opkt) >> if (!s->sps_size) { >> LOG_ONCE(ctx, AV_LOG_WARNING, "SPS not present in >> the stream, nor in AVCC, stream may be unreadable\n"); >> } else { >> - count_or_copy(&out, &out_size, s->sps, s->sps_size, >> -1, j); >> + count_or_copy(&out, &out_size, s->sps, s->sps_size, >> PS_OUT_OF_BAND, j); >> sps_seen = 1; >> } >> } >> @@ -246,19 +263,22 @@ static int h264_mp4toannexb_filter(AVBSFContext *ctx, >> AVPacket *opkt) >> if (new_idr && unit_type == H264_NAL_IDR_SLICE && !sps_seen && >> !pps_seen) { >> if (ctx->par_out->extradata) >> count_or_copy(&out, &out_size, ctx->par_out->extradata, >> - ctx->par_out->extradata_size, -1, j); >> + ctx->par_out->extradata_size, >> PS_OUT_OF_BAND, j); >> new_idr = 0; >> /* if only SPS has been seen, also insert PPS */ >> } else if (new_idr && unit_type == H264_NAL_IDR_SLICE && >> sps_seen && !pps_seen) { >> if (!s->pps_size) { >> LOG_ONCE(ctx, AV_LOG_WARNING, "PPS not present in the >> stream, nor in AVCC, stream may be unreadable\n"); >> } else { >> - count_or_copy(&out, &out_size, s->pps, s->pps_size, -1, >> j); >> + count_or_copy(&out, &out_size, s->pps, s->pps_size, >> PS_OUT_OF_BAND, j); >> } >> } >> >> - count_or_copy(&out, &out_size, buf, nal_size, >> - unit_type == H264_NAL_SPS || unit_type == >> H264_NAL_PPS, j); >> + if (unit_type == H264_NAL_SPS || unit_type == H264_NAL_PPS) >> + ps = PS_IN_BAND; >> + else >> + ps = PS_NONE; >> + count_or_copy(&out, &out_size, buf, nal_size, ps, j); >> if (!new_idr && unit_type == H264_NAL_SLICE) { >> new_idr = 1; >> sps_seen = 0; >> -- >> 2.25.1 >> >> _______________________________________________ >> ffmpeg-devel mailing list >> ffmpeg-devel@ffmpeg.org >> https://ffmpeg.org/mailman/listinfo/ffmpeg-devel >> >> To unsubscribe, visit link above, or email >> ffmpeg-devel-requ...@ffmpeg.org with subject "unsubscribe". > > > > -- > ======================================= > Jun zhao/赵军 > +++++++++++++++++++++++++++++++++++++++ > _______________________________________________ > ffmpeg-devel mailing list > ffmpeg-devel@ffmpeg.org > https://ffmpeg.org/mailman/listinfo/ffmpeg-devel > > To unsubscribe, visit link above, or email > ffmpeg-devel-requ...@ffmpeg.org with subject "unsubscribe". _______________________________________________ ffmpeg-devel mailing list ffmpeg-devel@ffmpeg.org https://ffmpeg.org/mailman/listinfo/ffmpeg-devel To unsubscribe, visit link above, or email ffmpeg-devel-requ...@ffmpeg.org with subject "unsubscribe".