[FFmpeg-devel] [PATCH v5] avcodec/libx264: fix extradata when config annexb=0
Zhao Zhili
quinkblack at foxmail.com
Sun Mar 17 05:46:47 EET 2024
> On Mar 14, 2024, at 21:14, Andreas Rheinhardt <andreas.rheinhardt at outlook.com> wrote:
>
> Zhao Zhili:
>> From: Zhao Zhili <zhilizhao at tencent.com>
>>
>> ---
>> v5: Decode chroma_format_idc directly instead of ff_h264_decode_seq_parameter_set
>> v4: Fix missing SEI in set_avcc_extradata
>> v3: Remove unnecessary inclusion
>>
>> libavcodec/libx264.c | 162 ++++++++++++++++++++++++++++++++++++-------
>> 1 file changed, 138 insertions(+), 24 deletions(-)
>>
>> diff --git a/libavcodec/libx264.c b/libavcodec/libx264.c
>> index 10d646bd76..64cefb5fb0 100644
>> --- a/libavcodec/libx264.c
>> +++ b/libavcodec/libx264.c
>> @@ -38,6 +38,7 @@
>> #include "packet_internal.h"
>> #include "atsc_a53.h"
>> #include "sei.h"
>> +#include "golomb.h"
>>
>> #include <x264.h>
>> #include <float.h>
>> @@ -865,6 +866,140 @@ static int convert_pix_fmt(enum AVPixelFormat pix_fmt)
>> return 0;
>> }
>>
>> +static int save_sei(AVCodecContext *avctx, x264_nal_t *nal)
>> +{
>> + X264Context *x4 = avctx->priv_data;
>> +
>> + av_log(avctx, AV_LOG_INFO, "%s\n", nal->p_payload + 25);
>> + x4->sei_size = nal->i_payload;
>> + x4->sei = av_malloc(x4->sei_size);
>> + if (!x4->sei)
>> + return AVERROR(ENOMEM);
>> +
>> + memcpy(x4->sei, nal->p_payload, nal->i_payload);
>> +
>> + return 0;
>> +}
>> +
>> +static int set_avcc_extradata(AVCodecContext *avctx, x264_nal_t *nal, int nnal)
>> +{
>> + X264Context *x4 = avctx->priv_data;
>> + x264_nal_t *sps_nal = NULL;
>> + x264_nal_t *pps_nal = NULL;
>> + uint8_t *p, *sps;
>> + int ret;
>> +
>> + /* We know it's in the order of SPS/PPS/SEI, but it's not documented in x264 API.
>> + * The x264 param i_sps_id implies there is a single pair of SPS/PPS.
>> + */
>> + for (int i = 0; i < nnal; i++) {
>> + switch (nal[i].i_type) {
>> + case NAL_SPS:
>> + sps_nal = &nal[i];
>> + break;
>> + case NAL_PPS:
>> + pps_nal = &nal[i];
>> + break;
>> + case NAL_SEI:
>> + ret = save_sei(avctx, &nal[i]);
>> + if (ret < 0)
>> + return ret;
>> + break;
>> + }
>> + }
>> + if (!sps_nal || !pps_nal)
>> + return AVERROR_EXTERNAL;
>> +
>> + avctx->extradata_size = sps_nal->i_payload + pps_nal->i_payload + 7;
>> + avctx->extradata = av_mallocz(avctx->extradata_size + AV_INPUT_BUFFER_PADDING_SIZE);
>> + if (!avctx->extradata)
>> + return AVERROR(ENOMEM);
>> +
>> + // Now create AVCDecoderConfigurationRecord
>> + p = avctx->extradata;
>> + // Skip size part
>> + sps = sps_nal->p_payload + 4;
>> + *p++ = 1; // version
>> + *p++ = sps[1]; // AVCProfileIndication
>> + *p++ = sps[2]; // profile_compatibility
>> + *p++ = sps[3]; // AVCLevelIndication
>> + *p++ = 0xFF;
>> + *p++ = 0xE0 | 0x01; // 3 bits reserved (111) + 5 bits number of sps
>> + memcpy(p, sps_nal->p_payload + 2, sps_nal->i_payload - 2);
>> + // Make sps has AV_INPUT_BUFFER_PADDING_SIZE padding, so it can be used
>> + // with GetBitContext
>> + sps = p + 2;
>> + p += sps_nal->i_payload - 2;
>> + *p++ = 1;
>> + memcpy(p, pps_nal->p_payload + 2, pps_nal->i_payload - 2);
>> + p += pps_nal->i_payload - 2;
>> +
>> + if (sps[3] != 66 && sps[3] != 77 && sps[3] != 88) {
>> + GetBitContext gbc;
>> + int chroma_format_idc;
>> + int bit_depth_luma_minus8, bit_depth_chroma_minus8;
>> +
>> + /* It's not possible to have emulation prevention byte before
>> + * bit_depth_chroma_minus8 due to the range of sps id, chroma_format_idc
>> + * and so on. So we can read directly without need to escape emulation
>> + * prevention byte.
>
> There is a slight problem here: You ignore the possibility of
> profile_idc being zero. After all, all values not being used are merely
> reserved and can be used at any time (although I doubt that they will
> ever use this). Shall we ignore this?
> The above check (and presumably the ISOBMFF spec for this) uses an
> opt-out check for profile, whereas the H.264 spec actually uses an
> opt-in check. I just wanted to mention it, feel free to ignore it.
>
>> + *
>> + * +4 to skip until sps id.
>> + */
>> + init_get_bits8(&gbc, sps + 4, sps_nal->i_payload - 4 - 4);
>> + // Skip sps id
>> + get_ue_golomb_31(&gbc);
>> + chroma_format_idc = get_ue_golomb_31(&gbc);
>> + if (chroma_format_idc == 3)
>> + skip_bits1(&gbc);
>> + bit_depth_luma_minus8 = get_ue_golomb_31(&gbc);
>> + bit_depth_chroma_minus8 = get_ue_golomb_31(&gbc);
>> +
>> + *p++ = 0xFC | chroma_format_idc;
>> + *p++ = 0xF8 | bit_depth_luma_minus8;
>> + *p++ = 0xF8 | bit_depth_chroma_minus8;
>> + *p++ = 0;
>> + }
>> + av_assert0(avctx->extradata + avctx->extradata_size >= p);
>
> Does this have to be an av_assert0?
Switched to assert2 in v6.
>
>> + avctx->extradata_size = p - avctx->extradata;
>> +
>> + return 0;
>> +}
>> +
>> +static int set_extradata(AVCodecContext *avctx)
>> +{
>> + X264Context *x4 = avctx->priv_data;
>> + x264_nal_t *nal;
>> + uint8_t *p;
>> + int nnal, s;
>> +
>> + s = x264_encoder_headers(x4->enc, &nal, &nnal);
>> + if (s < 0)
>> + return AVERROR_EXTERNAL;
>> +
>> + if (!x4->params.b_annexb)
>> + return set_avcc_extradata(avctx, nal, nnal);
>> +
>> + avctx->extradata = p = av_mallocz(s + AV_INPUT_BUFFER_PADDING_SIZE);
>> + if (!p)
>> + return AVERROR(ENOMEM);
>> +
>> + for (int i = 0; i < nnal; i++) {
>> + /* Don't put the SEI in extradata. */
>> + if (nal[i].i_type == NAL_SEI) {
>> + s = save_sei(avctx, &nal[i]);
>> + if (s < 0)
>> + return s;
>> + continue;
>> + }
>> + memcpy(p, nal[i].p_payload, nal[i].i_payload);
>> + p += nal[i].i_payload;
>> + }
>> + avctx->extradata_size = p - avctx->extradata;
>> +
>> + return 0;
>> +}
>> +
>> #define PARSE_X264_OPT(name, var)\
>> if (x4->var && x264_param_parse(&x4->params, name, x4->var) < 0) {\
>> av_log(avctx, AV_LOG_ERROR, "Error parsing option '%s' with value '%s'.\n", name, x4->var);\
>> @@ -1233,30 +1368,9 @@ FF_ENABLE_DEPRECATION_WARNINGS
>> return AVERROR_EXTERNAL;
>>
>> if (avctx->flags & AV_CODEC_FLAG_GLOBAL_HEADER) {
>> - x264_nal_t *nal;
>> - uint8_t *p;
>> - int nnal, s, i;
>> -
>> - s = x264_encoder_headers(x4->enc, &nal, &nnal);
>> - avctx->extradata = p = av_mallocz(s + AV_INPUT_BUFFER_PADDING_SIZE);
>> - if (!p)
>> - return AVERROR(ENOMEM);
>> -
>> - for (i = 0; i < nnal; i++) {
>> - /* Don't put the SEI in extradata. */
>> - if (nal[i].i_type == NAL_SEI) {
>> - av_log(avctx, AV_LOG_INFO, "%s\n", nal[i].p_payload+25);
>> - x4->sei_size = nal[i].i_payload;
>> - x4->sei = av_malloc(x4->sei_size);
>> - if (!x4->sei)
>> - return AVERROR(ENOMEM);
>> - memcpy(x4->sei, nal[i].p_payload, nal[i].i_payload);
>> - continue;
>> - }
>> - memcpy(p, nal[i].p_payload, nal[i].i_payload);
>> - p += nal[i].i_payload;
>> - }
>> - avctx->extradata_size = p - avctx->extradata;
>> + ret = set_extradata(avctx);
>> + if (ret < 0)
>> + return ret;
>> }
>>
>> cpb_props = ff_encode_add_cpb_side_data(avctx);
>
> You need a golomb configure dependency for get_ue_golomb_31().
Select golomb in configure and use conditional compile in case of only
x262 is enabled. I think atsc_a53 has the same problem but it’s unrelated
to current patch.
>
> - Andreas
>
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